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Sample records for unmodified gold nanoparticle

  1. Colorimetric detection of Cucumber green mottle mosaic virus using unmodified gold nanoparticles as colorimetric probes.

    Science.gov (United States)

    Wang, Lin; Liu, Zhanmin; Xia, Xueying; Yang, Cuiyun; Huang, Junyi; Wan, Sibao

    2017-05-01

    Cucumber green mottle mosaic virus (CGMMV)causes a severe mosaic symptom of watermelon and cucumber, and can be transmitted via infected cucumber seeds, leaves and soil. It remains a challenge to detect this virus to prevent its introduction and infection and spread in fields. For this purpose, a simple and sensitive label-free colorimetric detection method for CGMMV has been developed with unmodified gold nanoparticles (AuNPs) as colorimetric probes. The method is based on the finding that the presence of RT-PCR target products of CGMMV and species-specific probes results in color change of AuNPs from red to blue after NaCl induction. Normally, species-specific probes attach to the surface of AuNPs and thereby increasing their resistance to NaCl-induced aggregation. The concentration of sodium, probes in the reaction system and evaluation of specificity and sensitivity of a novel assay, visual detection of Cucumber green mottle mosaic virus using unmodified AuNPs has been carried out with simple preparation of samples in our study. Through this assay, as low as 30pg/μL of CGMMV RNA was thus detected visually, by the naked eye, without the need for any sophisticated, expensive instrumentation and biochemical reagents. The specificity was 100% and exhibited good reproducibility in our assays. The results note that this assay is highly species-specific, simple, low-cost, and visual for easy detection of CGMMV in plant tissues. Therefore, visual assay is a potentially useful tool for middle or small-scales corporations and entry-exit inspection and quarantine bureau to detect CGMMV in cucumber seeds or plant tissues. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. [Sensing of Cu²⁺ Based on Fenton Reaction and Unmodified Gold Nanoparticles].

    Science.gov (United States)

    Xing, Yun-peng; Liu, Chun; Zhou, Xiao-hong; Zhang, Li-pei; Shi, Han-chang

    2015-11-01

    Heavy metal pollution has received great attentions in recent years. The traditional methods for heavy metal detection rely on the expensive laboratory instruments and need time-consuming preparation steps; therefore, it is urgent to develop quick and highly sensitive new technologies for heavy metal detection. The colorimetric method based on the gold nanoparticles (AuNPs) features with simple operation, high sensitivity and low cost, therefore, enabling it widely concerned and used in the environmental monitoring, food safety and chemical and biological sensing fields. This work developed a simple, rapid and highly sensitive strategy based on the Fenton reaction and unmodified AuNPs for the detection of Cu²⁺ in water samples. The hydroxyl radical ( · OH) generated by the Fenton reaction between the Cu²⁺ and sodium ascorbate (SA) oxidized the single stranded DNA (ssDNA) attached on the AuNPs surface into variable sequence fragments. The cleavage of ssDNA induced the aggregation of AuNPs in a certain salt solution, therefore, resulting in the changes on the absorbance of solution. The assay conditions were optimized to be pH value of 7.9, 11 mg · L⁻¹ ssDNA, 8 mmol · L⁻¹ SA and 70 mmol · L⁻¹ NaCl. Results showed that the absorbance ratio values at the wavelengths of 700 and 525 nm (A₇₀₀/A₅₂₅) were linearly correlated with the Cu²⁺ concentrations. The linear detection range was 0.1-10.0 µmol · L⁻¹ with a detection limit of 24 nmol · L⁻¹ (3σ). Spiked recoveries ranged from 87%-120% in three sorts of water, including drinking water, tap water and lake water, which confirmed that the potentials of the proposed assay for Cu²⁺ detection in reality.

  3. Simple colorimetric detection of doxycycline and oxytetracycline using unmodified gold nanoparticles

    Science.gov (United States)

    Li, Jie; Fan, Shumin; Li, Zhigang; Xie, Yuanzhe; Wang, Rui; Ge, Baoyu; Wu, Jing; Wang, Ruiyong

    2014-08-01

    The interaction between tetracycline antibiotics and gold nanoparticles was studied. With citrate-coated gold nanoparticles as colorimetric probe, a simple and rapid detection method for doxycycline and oxytetracycline has been developed. This method relies on the distance-dependent optical properties of gold nanoparticles. In weakly acidic buffer medium, doxycycline and oxytetracycline could rapidly induce the aggregation of gold nanoparticles, resulting in red-to-blue (or purple) colour change. The experimental parameters were optimized with regard to pH, the concentration of the gold nanoparticles and the reaction time. Under optimal experimental conditions, the linear range of the colorimetric sensor for doxycycline/oxytetracycline was 0.06-0.66 and 0.59-8.85 μg mL-1, respectively. The corresponding limit of detection for doxycycline and oxytetracycline was 0.0086 and 0.0838 μg mL-1, respectively. This assay was sensitive, selective, simple and readily used to detect tetracycline antibiotics in food products.

  4. Label-free aptamer-based colorimetric detection of mercury ions in aqueous media using unmodified gold nanoparticles as colorimetric probe

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li; Li, Baoxin; Qi, Yingying; Jin, Yan [Shaanxi Normal University, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Materials Science, Xi' an (China)

    2009-04-15

    We report a simple and sensitive aptamer-based colorimetric detection of mercury ions (Hg{sup 2+}) using unmodified gold nanoparticles as colorimetric probe. It is based on the fact that bare gold nanoparticles interact differently with short single-strand DNA and double-stranded DNA. The anti-Hg{sup 2+} aptamer is rich in thymine (T) and readily forms T-Hg{sup 2+}-T configuration in the presence of Hg{sup 2+}. By measuring color change or adsorption ratio, the bare gold nanoparticles can effectively differentiate the Hg{sup 2+}-induced conformational change of the aptamer in the presence of a given salt with high concentration. The assay shows a linear response toward Hg{sup 2+} concentration through a five-decade range of 1 x 10{sup -4} mol L{sup -1} to 1 x 10{sup -9} mol L{sup -1}. Even with the naked eye, we could identify micromolar Hg{sup 2+} concentrations within minutes. By using the spectrometric method, the detection limit was improved to the nanomolar range (0.6 nM). The assay shows excellent selectivity for Hg{sup 2+} over other metal cations including K{sup +}, Ba{sup 2+}, Ni{sup 2+}, Pb{sup 2+}, Cu{sup 2+}, Cd{sup 2+}, Mg{sup 2+}, Ca{sup 2+}, Zn{sup 2+}, Al{sup 3+}, and Fe{sup 3+}. The major advantages of this Hg{sup 2+} assay are its water-solubility, simplicity, low cost, visual colorimetry, and high sensitivity. This method provides a potentially useful tool for the Hg{sup 2+} detection. (orig.)

  5. Self-catalytic growth of unmodified gold nanoparticles as conductive bridges mediated gap-electrical signal transduction for DNA hybridization detection.

    Science.gov (United States)

    Zhang, Jing; Nie, Huagui; Wu, Zhan; Yang, Zhi; Zhang, Lijie; Xu, Xiangju; Huang, Shaoming

    2014-01-21

    A simple and sensitive gap-electrical biosensor based on self-catalytic growth of unmodified gold nanoparticles (AuNPs) as conductive bridges has been developed for amplifying DNA hybridization events. In this strategy, the signal amplification degree of such conductive bridges is closely related to the variation of the glucose oxidase (GOx)-like catalytic activity of AuNPs upon interaction with single- and double-stranded DNA (ssDNA and dsDNA), respectively. In the presence of target DNA, the obtained dsDNA product cannot adsorb onto the surface of AuNPs due to electrostatic interaction, which makes the unmodified AuNPs exhibit excellent GOx-like catalytic activity. Such catalytic activity can enlarge the diameters of AuNPs in the glucose and HAuCl4 solution and result in a connection between most of the AuNPs and a conductive gold film formation with a dramatically increased conductance. For the control sample, the catalytic activity sites of AuNPs are fully blocked by ssDNA due to the noncovalent interaction between nucleotide bases and AuNPs. Thus, the growth of the assembled AuNPs will not happen and the conductance between microelectrodes will be not changed. Under the optimal experimental conditions, the developed strategy exhibited a sensitive response to target DNA with a high signal-to-noise ratio. Moreover, this strategy was also demonstrated to provide excellent differentiation ability for single-nucleotide polymorphism. Such performances indicated the great potential of this label-free electrical strategy for clinical diagnostics and genetic analysis under real biological sample separation.

  6. Colorimetric and bare eye determination of urinary methylamphetamine based on the use of aptamers and the salt-induced aggregation of unmodified gold nanoparticles

    International Nuclear Information System (INIS)

    Shi, Qiunan; Shi, Yupeng; Pan, Yi; Yi, Changqing; Yue, Zhenfeng; Zhang, Heng

    2015-01-01

    Methamphetamine (METH) is second only to marijuana as a widely used illicit drug. We are presenting a simple colorimetric assay for sensitive and visual detection of METH in human urine using a METH-specific aptamer as the recognition element and unmodified gold nanoparticles as indicators. The method is based on the finding that the presence of METH results in AuNPs solution’s color change from red to blue. Normally, aptamers attach to the surface of AuNPs and thereby increasing their resistance to NaCl-induced aggregation. If, however, the aptamer bind to METH via G-quartets, rapid salt induced aggregation occurs associated with the formation of a blue colored solution. Urinary METH can be quantified via this effect either visually or by measurement of the absorbance ratios at 660 and 525 nm, respectively. It works in the 2 μM to 10 μM concentration range with a detection limit at 0.82 μM. The method is fast and also works well in human urine. It is believed to represent a widely applicable aptamer-based detection scheme. (author)

  7. Simple, Fast and Selective Detection of Adenosine Triphosphate at Physiological pH Using Unmodified Gold Nanoparticles as Colorimetric Probes and Metal Ions as Cross-Linkers

    Directory of Open Access Journals (Sweden)

    Huan Pang

    2012-11-01

    Full Text Available We report a simple, fast and selective colorimetric assay of adenosine triphosphate (ATP using unmodified gold nanoparticles (AuNPs as probes and metal ions as cross-linkers. ATP can be assembled onto the surface of AuNPs through interaction between the electron-rich nitrogen atoms and the electron-deficient surface of AuNPs. Accordingly, Cu2+ ions induce a change in the color and UV/Vis absorbance of AuNPs by coordinating to the triphosphate groups and a ring nitrogen of ATP. A detection limit of 50 nM was achieved, which is comparable to or lower than that achievable by the currently used electrochemical, spectroscopic or chromatographic methods. The theoretical simplicity and high selectivity reported herein demonstrated that AuNPs-based colorimetric assay could be applied in a wide variety of fields by rationally designing the surface chemistry of AuNPs. In addition, our results indicate that ATP-modified AuNPs are less stable in Cu2+, Cd2+ or Zn2+-containing solutions due to the formation of the corresponding dimeric metal-ATP complexes.

  8. A colorimetric platform for sensitively differentiating telomere DNA with different lengths, monitoring G-quadruplex and dsDNA based on silver nanoclusters and unmodified gold nanoparticles

    Science.gov (United States)

    Qu, Fei; Chen, Zeqiu; You, Jinmao; Song, Cuihua

    2018-05-01

    Human telomere DNA plays a vital role in genome integrity control and carcinogenesis as an indication for extensive cell proliferation. Herein, silver nanoclusters (Ag NCs) templated by polymer and unmodified gold nanoparticles (Au NPs) are designed as a new colorimetric platform for sensitively differentiating telomere DNA with different lengths, monitoring G-quadruplex and dsDNA. Ag NCs can produce the aggregation of Au NPs, so the color of Au NPs changes to blue and the absorption peak moves to 700 nm. While the telomere DNA can protect Au NPs from aggregation, the color turns to red again and the absorption band blue shift. Benefiting from the obvious color change, we can differentiate the length of telomere DNA by naked eyes. As the length of telomere DNA is longer, the variation of color becomes more noticeable. The detection limits of telomere DNA containing 10, 22, 40, 64 bases are estimated to be 1.41, 1.21, 0.23 and 0.22 nM, respectively. On the other hand, when telomere DNA forms G-quadruplex in the presence of K+, or dsDNA with complementary sequence, both G-quadruplex and dsDNA can protect Au NPs better than the unfolded telomere DNA. Hence, a new colorimetric platform for monitoring structure conversion of DNA is established by Ag NCs-Au NPs system, and to prove this type of application, a selective K+ sensor is developed.

  9. Hybridization chain reaction-based colorimetric aptasensor of adenosine 5'-triphosphate on unmodified gold nanoparticles and two label-free hairpin probes.

    Science.gov (United States)

    Gao, Zhuangqiang; Qiu, Zhenli; Lu, Minghua; Shu, Jian; Tang, Dianping

    2017-03-15

    This work designs a new label-free aptasensor for the colorimetric determination of small molecules (adenosine 5'-triphosphate, ATP) by using visible gold nanoparticles as the signal-generation tags, based on target-triggered hybridization chain reaction (HCR) between two hairpin DNA probes. The assay is carried out referring to the change in the color/absorbance by salt-induced aggregation of gold nanoparticles after the interaction with hairpins, gold nanoparticles and ATP. To construct such an assay system, two hairpin DNA probes with a short single-stranded DNA at the sticky end are utilized for interaction with gold nanoparticles. In the absence of target ATP, the hairpin DNA probes can prevent gold nanoparticles from the salt-induced aggregation through the interaction of the single-stranded DNA at the sticky end with gold nanoparticles. Upon target ATP introduction, the aptamer-based hairpin probe is opened to expose a new sticky end for the strand-displacement reaction with another complementary hairpin, thus resulting in the decreasing single-stranded DNA because of the consumption of hairpins. In this case, gold nanoparticles are uncovered owing to the formation of double-stranded DNA, which causes their aggregation upon addition of the salt, thereby leading to the change in the red-to-blue color. Under the optimal conditions, the HCR-based colorimetric assay presents good visible color or absorbance responses for the determination of target ATP at a concentration as low as 1.0nM. Importantly, the methodology can be further extended to quantitatively or qualitatively monitor other small molecules or biotoxins by changing the sequence of the corresponding aptamer. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Disulfide-induced self-assembled targets : A novel strategy for the label free colorimetric detection of DNAs/RNAs via unmodified gold nanoparticles

    NARCIS (Netherlands)

    Shokri, Ehsan; Hosseini, Morteza; Davari, Mehdi D.; Ganjali, Mohammad R.; Peppelenbosch, Maikel P.; Rezaee, Farhad

    2017-01-01

    A modified non-cross-linking gold-nanoparticles (Au-NPs) aggregation strategy has been developed for the label free colorimetric detection of DNAs/RNAs based on self-assembling target species in the presence of thiolated probes. Two complementary thiol-modified probes, each of which specifically

  11. Disulfide-induced self-assembled targets: A novel strategy for the label free colorimetric detection of DNAs/RNAs via unmodified gold nanoparticles

    NARCIS (Netherlands)

    Shokri, E. (Ehsan); M. Hosseini (Morteza); Davari, M.D. (Mehdi D.); Ganjali, M.R. (Mohammad R.); M.P. Peppelenbosch (Maikel); F. Rezaee (Farhad)

    2017-01-01

    textabstractA modified non-cross-linking gold-nanoparticles (Au-NPs) aggregation strategy has been developed for the label free colorimetric detection of DNAs/RNAs based on self-assembling target species in the presence of thiolated probes. Two complementary thiol- modified probes, each of which

  12. Disulfide-induced self-assembled targets: A novel strategy for the label free colorimetric detection of DNAs/RNAs via unmodified gold nanoparticles

    Science.gov (United States)

    Shokri, Ehsan; Hosseini, Morteza; Davari, Mehdi D.; Ganjali, Mohammad R.; Peppelenbosch, Maikel P.; Rezaee, Farhad

    2017-04-01

    A modified non-cross-linking gold-nanoparticles (Au-NPs) aggregation strategy has been developed for the label free colorimetric detection of DNAs/RNAs based on self-assembling target species in the presence of thiolated probes. Two complementary thiol- modified probes, each of which specifically binds at one half of the target introduced SH groups at both ends of dsDNA. Continuous disulfide bond formation at 3‧ and 5‧ terminals of targets leads to the self-assembly of dsDNAs into the sulfur- rich and flexible products with different lengths. These products have a high affinity for the surface of Au-NPs and efficiently protect the surface from salt induced aggregation. To evaluate the assay efficacy, a small part of the citrus tristeza virus (CTV) genome was targeted, leading to a detection limit of about 5 × 10-9 mol.L-1 over a linear ranged from 20 × 10-9 to 10 × 10-7 mol.L-1. This approach also exhibits good reproducibility and recovery levels in the presence of plant total RNA or human plasma total circulating RNA extracts. Self-assembled targets can be then sensitively distinguished from non-assembled or mismatched targets after gel electrophoresis. The disulfide reaction method and integrating self-assembled DNAs/RNAs targets with bare AuNPs as a sensitive indicator provide us a powerful and simple visual detection tool for a wide range of applications.

  13. Enzymes immobilization on Fe 3O 4-gold nanoparticles

    Science.gov (United States)

    Kalska-Szostko, B.; Rogowska, M.; Dubis, A.; Szymański, K.

    2012-01-01

    In the present study Fe3O4 magnetic nanoparticles were synthesized by coprecipitation of Fe2+ and Fe3+ from chlorides. In the next step magnetite-gold core-shell nanoparticles were synthesized from HAuCl4 using an ethanol as a reducing agent. Finally, magnetic nanoparticles were functionalized by hexadecanethiol. The immobilization of biological molecules (trypsin and glucose oxidase) to the thiol-modified and unmodified magnetite-gold nanoparticles surface was tested. The resulting nanoparticles were characterized by infrared spectroscopy, differential scanning calorimetry, Mössbauer spectroscopy and transmission electron microscopy.

  14. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  15. Gold Nanoparticle Microwave Synthesis

    International Nuclear Information System (INIS)

    Krantz, Kelsie E.; Christian, Jonathan H.; Coopersmith, Kaitlin; Washington II, Aaron L.; Murph, Simona H.

    2016-01-01

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  16. Immunological properties of gold nanoparticles.

    Science.gov (United States)

    Dykman, Lev A; Khlebtsov, Nikolai G

    2017-03-01

    In the past decade, gold nanoparticles have attracted strong interest from the nanobiotechnological community owing to the significant progress made in robust and easy-to-make synthesis technologies, in surface functionalization, and in promising biomedical applications. These include bioimaging, gene diagnostics, analytical sensing, photothermal treatment of tumors, and targeted delivery of various biomolecular and chemical cargos. For the last-named application, gold nanoparticles should be properly fabricated to deliver the cargo into the targeted cells through effective endocytosis. In this review, we discuss recent progress in understanding the selective penetration of gold nanoparticles into immune cells. The interaction of gold nanoparticles with immune cell receptors is discussed. As distinct from other published reviews, we present a summary of the immunological properties of gold nanoparticles. This review also summarizes what is known about the application of gold nanoparticles as an antigen carrier and adjuvant in immunization for the preparation of antibodies in vivo . For each of the above topics, the basic principles, recent advances, and current challenges are discussed. Thus, this review presents a detailed analysis of data on interaction of gold nanoparticles with immune cells. Emphasis is placed on the systematization of data over production of antibodies by using gold nanoparticles and adjuvant properties of gold nanoparticles. Specifically, we start our discussion with current data on interaction of various gold nanoparticles with immune cells. The next section describes existing technologies to improve production of antibodies in vivo by using gold nanoparticles conjugated with specific ligands. Finally, we describe what is known about adjuvant properties of bare gold or functionalized nanoparticles. In the Conclusion section, we present a short summary of reported data and some challenges and perspectives.

  17. Chemically functionalized gold nanoparticles: Synthesis, characterization, and applications

    Science.gov (United States)

    Daniel, Weston Lewis

    This thesis focuses on the development and application of gold nanoparticle based detection systems and biomimetic structures. Each class of modified nanoparticle has properties that are defined by its chemical moieties that interface with solution and the gold nanoparticle core. In Chapter 2, a comparison of the biomolecular composition and binding properties of various preparations of antibody oligonucleotide gold nanoparticle conjugates is presented. These constructs differed significantly in terms of their structure and binding properties. Chapter 3 reports the use of electroless gold deposition as a light scattering signal enhancer in a multiplexed, microarray-based scanometric immunoassay using the gold nanoparticle probes evaluated in Chapter 2. The use of gold development results in greater signal enhancement than the typical silver development, and multiple rounds of metal development were found to increase the resulting signal compared to one development. Chapter 4 describes an amplified scanometric detection method for human telomerase activity. Gold nanoparticles functionalized with specific oligonucleotide sequences can efficiently capture telomerase enzymes and subsequently be elongated. Both the elongated and unmodified oligonucleotide sequences are simultaneously measured. At low telomerase concentrations, elongated strands cannot be detected, but the unmodified sequences, which come from the same probe particles, can be detected because their concentration is higher, providing a novel form of amplification. Chapter 5 reports the development of a novel colorimetric nitrite and nitrate ion assay based upon gold nanoparticle probes functionalized with Griess reaction reagents. This assay takes advantage of the distance-dependent plasmonic properties of the gold nanoparticles and the ability of nitrite ion to facilitate the cross coupling of novel nanoparticle probes. The assay works on the concept of a kinetic end point and can be triggered at the EPA

  18. Directed Assembly of Gold Nanoparticles

    DEFF Research Database (Denmark)

    Westerlund, Axel Rune Fredrik; Bjørnholm, Thomas

    2009-01-01

    As a complement to common "top-down" lithography techniques, "bottom-up" assembly techniques are emerging as promising tools to build nanoscale structures in a predictable way. Gold nanoparticles that are stable and relatively easy to synthesize are important building blocks in many such structures...... due to their useful optical and electronic properties. Programmed assembly of gold nanoparticles in one, two, and three dimensions is therefore of large interest. This review focuses on the progress from the last three years in the field of directed gold nanoparticle and nanorod assembly using...

  19. Immunological properties of gold nanoparticles

    OpenAIRE

    Dykman, Lev A.; Khlebtsov, Nikolai G.

    2016-01-01

    In the past decade, gold nanoparticles have attracted strong interest from the nanobiotechnological community owing to the significant progress made in robust and easy-to-make synthesis technologies, in surface functionalization, and in promising biomedical applications. These include bioimaging, gene diagnostics, analytical sensing, photothermal treatment of tumors, and targeted delivery of various biomolecular and chemical cargos. For the last-named application, gold nanoparticles should be...

  20. Enzymes immobilization on Fe{sub 3}O{sub 4}-gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kalska-Szostko, B., E-mail: kalska@uwb.edu.pl [Institute of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Bialystok (Poland); Rogowska, M.; Dubis, A. [Institute of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Bialystok (Poland); Szymanski, K. [Department of Physics, University of Bialystok, Lipowa 41, 15-424 Bialystok (Poland)

    2012-01-15

    In the present study Fe{sub 3}O{sub 4} magnetic nanoparticles were synthesized by coprecipitation of Fe{sup 2+} and Fe{sup 3+} from chlorides. In the next step magnetite-gold core-shell nanoparticles were synthesized from HAuCl{sub 4} using an ethanol as a reducing agent. Finally, magnetic nanoparticles were functionalized by hexadecanethiol. The immobilization of biological molecules (trypsin and glucose oxidase) to the thiol-modified and unmodified magnetite-gold nanoparticles surface was tested. The resulting nanoparticles were characterized by infrared spectroscopy, differential scanning calorimetry, Moessbauer spectroscopy and transmission electron microscopy.

  1. Gold nanoparticles stabilized by chitosan

    International Nuclear Information System (INIS)

    Geraldes, Adriana N.; Oliveira, Maria Jose A.; Silva, Andressa A. da; Leal, Jessica; Batista, Jorge G.S.; Lugao, Ademar B.

    2015-01-01

    In our laboratory has been growing the interest in studying gold nanoparticles and for this reason, the aim of this work is report the first results of the effect of chitosan as stabilizer in gold nanoparticle formulation. AuNPs were synthesized by reducing hydrogen tetrachloroaurate (HAuCl 4 ) using NaBH 4 or gamma irradiation (25kGy) as reduction agent. The chitosan (3 mol L -1 ) was added at 0.5; 1.0 and 1.5 mL. The gold nanoparticles were characterized by UV-Vis absorption spectroscopy, X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Their physical stability was determined using a UV-Vis spectrophotometer over one week during storage at room temperature. Absorption measurements indicated that the plasmon resonance wavelength appears at a wavelength around 530 nm. Has been observed that Chitosan in such quantities were not effective in stabilizing the AuNPs. (author)

  2. Surface vertical deposition for gold nanoparticle film

    International Nuclear Information System (INIS)

    Diao, J J; Qiu, F S; Chen, G D; Reeves, M E

    2003-01-01

    In this rapid communication, we present the surface vertical deposition (SVD) method to synthesize the gold nanoparticle films. Under conditions where the surface of the gold nanoparticle suspension descends slowly by evaporation, the gold nanoparticles in the solid-liquid-gas junction of the suspension aggregate together on the substrate by the force of solid and liquid interface. When the surface properties of the substrate and colloidal nanoparticle suspension define for the SVD, the density of gold nanoparticles in the thin film made by SVD only depends on the descending velocity of the suspension surface and on the concentration of the gold nanoparticle suspension. (rapid communication)

  3. Gold Nanoparticle Mediated Phototherapy for Cancer

    International Nuclear Information System (INIS)

    Yao, C.; Zhang, L.; Wang, J.; He, Y.; Xin, J.; Wang, S.; Xu, H.; Zhang, Z.

    2016-01-01

    Gold nanoparticles exhibit very unique physiochemical and optical properties, which now are extensively studied in range of medical diagnostic and therapeutic applications. In particular, gold nanoparticles show promise in the advancement of cancer treatments. This review will provide insights into the four different cancer treatments such as photothermal therapy, gold nanoparticle-aided photodynamic therapy, gold nanoparticle-aided radiation therapy, and their use as drug carrier. We also discuss the mechanism of every method and the adverse effects and its limitations

  4. Flower-shaped gold nanoparticles: Preparation, characterization, and electro

    Directory of Open Access Journals (Sweden)

    Islam M. Al-Akraa

    2017-09-01

    Full Text Available The modification of a glassy carbon electrode with gold nanoparticles was pursued, characterized, and examined for electrocatalytic applications. The fabrication process of this electrode involved assembling the gold nanoparticles atop of amino group grafted glassy carbon electrode. The scanning electron microscopy indicated the deposition of gold nanoparticles in flower-shaped nanostructures with an average particle size of ca. 150 nm. Interestingly, the electrode exhibited outstanding enhancement in the electrocatalytic activity toward the oxygen evolution reaction, which reflected from the large negative shift (ca. 0.8 V in its onset potential, in comparison with that observed at the bulk unmodified glassy carbon and gold electrodes. Alternatively, the Tafel plot of the modified electrode revealed a significant increase (∼one order of magnitude in the apparent exchange current density of the oxygen evolution reaction upon the modification, which infers a faster charge transfer. Kinetically, gold nanoparticles are believed to facilitate a favorable adsorption of OH− (fundamental step in oxygen evolution reaction, which allows the charge transfer at reasonably lower anodic polarizations.

  5. A Novel Strategy for Synthesis of Gold Nanoparticle Self Assemblies

    NARCIS (Netherlands)

    Verma, Jyoti; Lal, Sumit; van Veen, Henk A.; van Noorden, Cornelis J. F.

    2014-01-01

    Gold nanoparticle self assemblies are one-dimensional structures of gold nanoparticles. Gold nanoparticle self assemblies exhibit unique physical properties and find applications in the development of biosensors. Methodologies currently available for lab-scale and commercial synthesis of gold

  6. Glyco-gold nanoparticles: synthesis and applications

    Directory of Open Access Journals (Sweden)

    Federica Compostella

    2017-05-01

    Full Text Available Glyco-gold nanoparticles combine in a single entity the peculiar properties of gold nanoparticles with the biological activity of carbohydrates. The result is an exciting nanosystem, able to mimic the natural multivalent presentation of saccharide moieties and to exploit the peculiar optical properties of the metallic core. In this review, we present recent advances on glyco-gold nanoparticle applications in different biological fields, highlighting the key parameters which inspire the glyco nanoparticle design.

  7. Paper-based tuberculosis diagnostic devices with colorimetric gold nanoparticles

    International Nuclear Information System (INIS)

    Tsai, Tsung-Ting; Shen, Shu-Wei; Chen, Chien-Fu; Cheng, Chao-Min

    2013-01-01

    A colorimetric sensing strategy employing gold nanoparticles and a paper assay platform has been developed for tuberculosis diagnosis. Unmodified gold nanoparticles and single-stranded detection oligonucleotides are used to achieve rapid diagnosis without complicated and time-consuming thiolated or other surface-modified probe preparation processes. To eliminate the use of sophisticated equipment for data analysis, the color variance for multiple detection results was simultaneously collected and concentrated on cellulose paper with the data readout transmitted for cloud computing via a smartphone. The results show that the 2.6 nM tuberculosis mycobacterium target sequences extracted from patients can easily be detected, and the turnaround time after the human DNA is extracted from clinical samples was approximately 1 h. (paper)

  8. Encapsulation of gold nanoparticles into self-assembling protein nanoparticles

    Directory of Open Access Journals (Sweden)

    Yang Yongkun

    2012-10-01

    Full Text Available Abstract Background Gold nanoparticles are useful tools for biological applications due to their attractive physical and chemical properties. Their applications can be further expanded when they are functionalized with biological molecules. The biological molecules not only provide the interfaces for interactions between nanoparticles and biological environment, but also contribute their biological functions to the nanoparticles. Therefore, we used self-assembling protein nanoparticles (SAPNs to encapsulate gold nanoparticles. The protein nanoparticles are formed upon self-assembly of a protein chain that is composed of a pentameric coiled-coil domain at the N-terminus and trimeric coiled-coil domain at the C-terminus. The self-assembling protein nanoparticles form a central cavity of about 10 nm in size, which is ideal for the encapsulation of gold nanoparticles with similar sizes. Results We have used SAPNs to encapsulate several commercially available gold nanoparticles. The hydrodynamic size and the surface coating of gold nanoparticles are two important factors influencing successful encapsulation by the SAPNs. Gold nanoparticles with a hydrodynamic size of less than 15 nm can successfully be encapsulated. Gold nanoparticles with citrate coating appear to have stronger interactions with the proteins, which can interfere with the formation of regular protein nanoparticles. Upon encapsulation gold nanoparticles with polymer coating interfere less strongly with the ability of the SAPNs to assemble into nanoparticles. Although the central cavity of the SAPNs carries an overall charge, the electrostatic interaction appears to be less critical for the efficient encapsulation of gold nanoparticles into the protein nanoparticles. Conclusions The SAPNs can be used to encapsulate gold nanoparticles. The SAPNs can be further functionalized by engineering functional peptides or proteins to either their N- or C-termini. Therefore encapsulation of gold

  9. Biosynthesis of gold nanoparticles using diatoms-silica-gold and EPS-gold bionanocomposite formation

    OpenAIRE

    Schröfel, Adam; Kratošová, Gabriela; Bohunická, Markéta; Dobročka, Edmund; Vávra, Ivo

    2011-01-01

    Novel synthesis of gold nanoparticles, EPS-gold, and silica-gold bionanocomposites by biologically driven processes employing two diatom strains (Navicula atomus, Diadesmis gallica) is described. Transmission electron microscopy (TEM) and electron diffraction analysis (SAED) revealed a presence of gold nanoparticles in the experimental solutions of the diatom culture mixed with tetrachloroaureate. Nature of the gold nanoparticles was confirmed by X-ray diffraction studies. Scanning electron m...

  10. Glyco-gold nanoparticles: synthesis and applications

    OpenAIRE

    Compostella, Federica; Pitirollo, Olimpia; Silvestri, Alessandro; Polito, Laura

    2017-01-01

    Glyco-gold nanoparticles combine in a single entity the peculiar properties of gold nanoparticles with the biological activity of carbohydrates. The result is an exciting nanosystem, able to mimic the natural multivalent presentation of saccharide moieties and to exploit the peculiar optical properties of the metallic core. In this review, we present recent advances on glyco-gold nanoparticle applications in different biological fields, highlighting the key parameters which inspire the glyco ...

  11. Gold nanoparticles: generation and characterization

    International Nuclear Information System (INIS)

    Dey, G.R.

    2013-07-01

    In this presentation we report the reduction of Au 3+ through chemical and free radical (e solv - ) reactions both in non-aqueous and aqueous media. In chemical reduction, the spectral nature in ascorbic acid (AA) and citric acid (CA) systems was different. The band intensity of gold nanoparticles was lower in AA system. While in free radical reaction, the yield of nanoparticles was pure i.e. free from excess reactants. Under the study 60-200 nm size nanoparticles were generated, which are inert to oxygen. Using pulse radiolysis technique, the initial rate for e solv - reaction with Au 3+ was determined to be 7.6 x 10 9 M -1 s -1 . (author)

  12. Reverse Transfection Using Gold Nanoparticles

    Science.gov (United States)

    Yamada, Shigeru; Fujita, Satoshi; Uchimura, Eiichiro; Miyake, Masato; Miyake, Jun

    Reverse transfection from a solid surface has the potential to deliver genes into various types of cell and tissue more effectively than conventional methods of transfection. We present a method for reverse transfection using a gold colloid (GC) as a nanoscaffold by generating nanoclusters of the DNA/reagentcomplex on a glass surface, which could then be used for the regulation of the particle size of the complex and delivery of DNA into nuclei. With this method, we have found that the conjugation of gold nanoparticles (20 nm in particle size) to the pEGFP-N1/Jet-PEI complex resulted in an increase in the intensity of fluorescence of enhanced green fluorescent protein (EGFP) (based on the efficiency of transfection) from human mesenchymal stem cells (hMSCs), as compared with the control without GC. In this manner, we constructed a method for reverse transfection using GC to deliver genes into the cells effectively.

  13. [Biosynthesis of gold nanoparticles by Azospirillum brasilense].

    Science.gov (United States)

    Kupriashina, M A; Vetchinkina, E P; Burov, A M; Ponomareva, E G; Nikitina, V E

    2014-01-01

    Plant-associated nitrogen-fixing soil bacteria Azospirillum brasilense were shown to reduce the gold of chloroauric acid to elemental gold, resulting in formation of gold nanoparicles. Extracellular phenoloxidizing enzymes (laccases and Mn peroxidases) were shown to participate in reduction of Au+3 (HAuCl4) to Au(0). Transmission electron microscopy revealed accumulation of colloidal gold nanoparticles of diverse shape in the culture liquid of A. brasilense strains Sp245 and Sp7. The size of the electron-dense nanospheres was 5 to 50 nm, and the size of nanoprisms varied from 5 to 300 nm. The tentative mechanism responsible for formation of gold nanoparticles is discussed.

  14. Encapsulation of gold nanoparticles into self-assembling protein nanoparticles

    OpenAIRE

    Yang Yongkun; Burkhard Peter

    2012-01-01

    Abstract Background Gold nanoparticles are useful tools for biological applications due to their attractive physical and chemical properties. Their applications can be further expanded when they are functionalized with biological molecules. The biological molecules not only provide the interfaces for interactions between nanoparticles and biological environment, but also contribute their biological functions to the nanoparticles. Therefore, we used self-assembling protein nanoparticles (SAPNs...

  15. Spherical aggregates composed of gold nanoparticles

    International Nuclear Information System (INIS)

    Chen, C-C; Kuo, P-L; Cheng, Y-C

    2009-01-01

    Alkylated triethylenetetramine (C12E3) was synthesized and used as both a reductant in the preparation of gold nanoparticles by the reduction of HAuCl 4 and a stabilizer in the subsequent self-assembly of the gold nanoparticles. In acidic aqueous solution, spherical aggregates (with a diameter of about 202 ± 22 nm) of gold nanoparticles (with the mean diameter of ∼18.7 nm) were formed. The anion-induced ammonium adsorption of the alkylated amines on the gold nanoparticles was considered to provide the electrostatic repulsion and steric hindrance between the gold nanoparticles, which constituted the barrier that prevented the individual particles from coagulating. However, as the amino groups became deprotonated with increasing pH, the ammonium adsorption was weakened, and the amino groups were desorbed from the gold surface, resulting in discrete gold particles. The results indicate that the morphology of the reduced gold nanoparticles is controllable through pH-'tunable' aggregation under the mediation of the amino groups of alkylated amine to create spherical microstructures.

  16. Gold nanoparticles produced in a microalga

    International Nuclear Information System (INIS)

    Luangpipat, Tiyaporn; Beattie, Isabel R.; Chisti, Yusuf; Haverkamp, Richard G.

    2011-01-01

    An efficient biological route to production of gold nanoparticles which allows the nanoparticles to be easily recovered remains elusive. Live cells of the green microalga Chlorella vulgaris were incubated with a solution of gold chloride and harvested by centrifugation. Nanoparticles inside intact cells were identified by transmission electron microscopy and confirmed to be metallic gold by synchrotron based X-ray powder diffraction and X-ray absorption spectroscopy. These intracellular gold nanoparticles were 40–60 nm in diameter. At a concentration of 1.4% Au in the alga, a better than 97% recovery of the gold from solution was achieved. A maximum of 4.2% Au in the alga was obtained. Exposure of C. vulgaris to solutions containing dissolved salts of palladium, ruthenium, and rhodium also resulted in the production of the corresponding nanoparticles within the cells. These were surmised to be also metallic, but were produced at a much lower intracellular concentration than achieved with gold. Iridium was apparently toxic to the alga. No nanoparticles were observed using platinum solutions. C. vulgaris provides a possible route to large scale production of gold nanoparticles.

  17. CO oxidation on gold nanoparticles: Theoretical studies

    DEFF Research Database (Denmark)

    Remediakis, Ioannis; Lopez, Nuria; Nørskov, Jens Kehlet

    2005-01-01

    We present a summary of our theoretical results regarding CO oxidation on both oxide-supported and isolated gold nanoparticles. Using Density Functional Theory we have studied the adsorption of molecules and the oxidation reaction of CO on gold clusters. Low-coordinated sites on the gold...... nanoparticles can adsorb small inorganic molecules such as O2 and CO, and the presence of these sites is the key factor for the catalytic properties of supported gold nanoclusters. Other contributions, induced by the presence of the support, can provide parallel channels for the reaction and modulate the final...

  18. Nanotoxicity of gold and iron nanoparticles.

    Science.gov (United States)

    Maiti, Souvik

    2011-02-01

    The extensive use of potentially hazardous nanoparticles in industrial applications suggest that their biological effects need to be evaluated following clinical testing practices as applicable for any new pharmaceutical. It was rationalized that a non hypothesis-driven approach is best suited for discovering the biological effects of nanoparticles. Gold nanoparticles (approximately 18 nm), showed no drastic effect on gene expression in cells but iron nanoparticles showed perturbations in the expression of a set of functional genes.

  19. Emission analysis on the effect of nanoparticles on neat biodiesel in unmodified diesel engine.

    Science.gov (United States)

    Pandian, Amith Kishore; Ramakrishnan, Ramesh Bapu Bathey; Devarajan, Yuvarajan

    2017-10-01

    Biodiesels derived from the mahua seeds are established as a promising alternative for the diesel fuel owing to its non-edible nature and improved properties. TiO 2 nanoparticle in powder form is added to neat mahua oil biodiesel (BD100) to examine its effect on emission characteristics. TiO 2 nanoparticle is chosen as an additive owing to its catalytic effect, higher surface energy, and larger surface to volume ratio. TiO 2 nanoparticle with an average size of 60 nm was synthesized by sol-gel route. TiO 2 nanoparticles are added with mahua biodiesel (BD100) at 100 and 200 ppm. Mahua oil biodiesel doped with 100 and 200 ppm of TiO 2 nanoparticles are referred as BD100T100 and BD100T200. A constant speed diesel engine is employed for the experimental trail. Engine is fueled with diesel, BD100, BD100T100, and BD100T200, respectively. Experimental result confirmed that the modified fuels (BD100T200 and BD100T100) showed a significant reduction in all the emissions. Further, the addition of TiO 2 nanoparticle (200 ppm) to mahua biodiesel gave respective reduction of 9.3, 5.8, 6.6, and 2.7% in carbon monoxide, hydrocarbon, nitrogen oxide, and smoke emissions when compared to neat mahua biodiesel.

  20. Gold Nanoparticle Labels Amplify Ellipsometric Signals

    Science.gov (United States)

    Venkatasubbarao, Srivatsa

    2008-01-01

    The ellipsometric method reported in the immediately preceding article was developed in conjunction with a method of using gold nanoparticles as labels on biomolecules that one seeks to detect. The purpose of the labeling is to exploit the optical properties of the gold nanoparticles in order to amplify the measurable ellipsometric effects and thereby to enable ultrasensitive detection of the labeled biomolecules without need to develop more-complex ellipsometric instrumentation. The colorimetric, polarization, light-scattering, and other optical properties of nanoparticles depend on their sizes and shapes. In the present method, these size-and-shape-dependent properties are used to magnify the polarization of scattered light and the diattenuation and retardance of signals derived from ellipsometry. The size-and-shape-dependent optical properties of the nanoparticles make it possible to interrogate the nanoparticles by use of light of various wavelengths, as appropriate, to optimally detect particles of a specific type at high sensitivity. Hence, by incorporating gold nanoparticles bound to biomolecules as primary or secondary labels, the performance of ellipsometry as a means of detecting the biomolecules can be improved. The use of gold nanoparticles as labels in ellipsometry has been found to afford sensitivity that equals or exceeds the sensitivity achieved by use of fluorescence-based methods. Potential applications for ellipsometric detection of gold nanoparticle-labeled biomolecules include monitoring molecules of interest in biological samples, in-vitro diagnostics, process monitoring, general environmental monitoring, and detection of biohazards.

  1. Lamellar multilayer hexadecylaniline-modified gold nanoparticle ...

    Indian Academy of Sciences (India)

    standard Wilhelmy plate was used for surface pressure sensing. Multilayer ... carried out on a JEOL model 1200EX instrument operated at an accelerating voltage of ... the gold nanoparticles within domains (and reorganization of the domains ...

  2. Nonlinear optical studies of single gold nanoparticles

    NARCIS (Netherlands)

    Dijk, Meindert Alexander van

    2007-01-01

    Gold nanoparticles are spherical clusters of gold atoms, with diameters typically between 1 and 100 nanometers. The applications of these particles are rather diverse, from optical labels for biological experiments to data carrier for optical data storage. The goal of my project was to develop new

  3. Radiofrequency Heating Pathways for Gold Nanoparticles

    Science.gov (United States)

    Collins, C. B.; McCoy, R. S.; Ackerson, B. J.; Collins, G. J.

    2015-01-01

    This feature article reviews the thermal dissipation of nanoscopic gold under radiofrequency (RF) irradiation. It also presents previously unpublished data addressing obscure aspects of this phenomenon. While applications in biology motivated initial investigation of RF heating of gold nanoparticles, recent controversy concerning whether thermal effects can be attributed to nanoscopic gold highlight the need to understand the involved mechanism or mechanisms of heating. Both the nature of the particle and the nature of the RF field influence heating. Aspects of nanoparticle chemistry and physics, including the hydrodynamic diameter of the particle, the oxidation state and related magnetism of the core, and the chemical nature of the ligand shell may all strongly influence to what extent a nanoparticle heats in an RF field. Aspects of RF include: power, frequency and antenna designs that emphasize relative strength of magnetic or electric fields, and also influence the extent to which a gold nanoparticle heats in RF. These nanoparticle and RF properties are analysed in the context of three heating mechanisms proposed to explain gold nanoparticle heating in an RF field. This article also makes a critical analysis of the existing literature in the context of the nanoparticle preparations, RF structure, and suggested mechanisms in previously reported experiments. PMID:24962620

  4. Synthesis of radioactive gold nanoparticle in surfactant medium

    International Nuclear Information System (INIS)

    Swadesh Mandal

    2014-01-01

    The present study describes the synthesis of radioactive gold nanoparticle in surfactant medium. Proton irradiated stable 197 Au and radioactive 198 Au were simultaneously used for production of radioactive gold nanoparticle. Face centered cubic gold nanoparticles with size of 4-50 nm were found in proton irradiated gold foil. However, the size of nanoparticle varies with pH using both stable and radioactive gold. (author)

  5. Biosynthesis of Gold Nanoparticles Using Pseudomonas Aeruginosa

    International Nuclear Information System (INIS)

    Abd El-Aziz, M.; Badr, Y.; Mahmoud, M. A.

    2007-01-01

    Pseudomonas aeruginosa were used for extracellular biosynthesis of gold nanoparticles (Au NPs). Consequently, Au NPs were formed due to reduction of gold ion by bacterial cell supernatant of P. aeruginos ATCC 90271, P. aeruginos (2) and P. aeruginos (1). The UV-Vis. and fluorescence spectra of the bacterial as well as chemical prepared Au NPs were recorded. Transmission electron microscopy (TEM) micrograph showed the formation of well-dispersed gold nanoparticles in the range of 15-30 nm. The process of reduction being extracellular and may lead to the development of an easy bioprocess for synthesis of Au NPs

  6. Gold nanoparticles extraction from dielectric scattering background

    Science.gov (United States)

    Hong, Xin; Wang, Jingxin

    2014-11-01

    The unique advantages such as brightness, non-photobleaching, good bio-compatibility make gold nanoparticles desirable labels and play important roles in biotech and related research and applications. Distinguishing gold nanoparticles from other dielectric scattering particles is of more importance, especially in bio-tracing and imaging. The enhancement image results from the localized surface plasmon resonance associated with gold nanopartilces makes themselves distinguishable from other dielectric particles, based on which, we propose a dual-wavelength detection method by employing a high sensitive cross-polarization microscopy.

  7. Subchronic inhalation toxicity of gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Chung Yong

    2011-05-01

    Full Text Available Abstract Background Gold nanoparticles are widely used in consumer products, including cosmetics, food packaging, beverages, toothpaste, automobiles, and lubricants. With this increase in consumer products containing gold nanoparticles, the potential for worker exposure to gold nanoparticles will also increase. Only a few studies have produced data on the in vivo toxicology of gold nanoparticles, meaning that the absorption, distribution, metabolism, and excretion (ADME of gold nanoparticles remain unclear. Results The toxicity of gold nanoparticles was studied in Sprague Dawley rats by inhalation. Seven-week-old rats, weighing approximately 200 g (males and 145 g (females, were divided into 4 groups (10 rats in each group: fresh-air control, low-dose (2.36 × 104 particle/cm3, 0.04 μg/m3, middle-dose (2.36 × 105 particle/cm3, 0.38 μg/m3, and high-dose (1.85 × 106 particle/cm3, 20.02 μg/m3. The animals were exposed to gold nanoparticles (average diameter 4-5 nm for 6 hours/day, 5 days/week, for 90-days in a whole-body inhalation chamber. In addition to mortality and clinical observations, body weight, food consumption, and lung function were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry tests, and organ weights were measured. Cellular differential counts and cytotoxicity measurements, such as albumin, lactate dehydrogenase (LDH, and total protein were also monitored in a cellular bronchoalveolar lavage (BAL fluid. Among lung function test measurements, tidal volume and minute volume showed a tendency to decrease comparing control and dose groups during the 90-days of exposure. Although no statistically significant differences were found in cellular differential counts, histopathologic examination showed minimal alveoli, an inflammatory infiltrate with a mixed cell type, and increased macrophages in the high-dose rats. Tissue

  8. Gold nano-particles fixed on glass

    International Nuclear Information System (INIS)

    Worsch, Christian; Wisniewski, Wolfgang; Kracker, Michael; Rüssel, Christian

    2012-01-01

    Highlights: ► We produced wear resistant gold–ruby coatings on amorphous substrates. ► Thin sputtered gold layers were covered by or embedded in silica coatings. ► Annealing above T g of the substrate glass led to the formation of gold nano particles. ► A 1 1 1-texture of the gold particles is observed via XRD and EBSD. ► EBSD-patterns can be acquired from crystals covered by a thin layer of glass. - Abstract: A simple process for producing wear resistant gold nano-particle coatings on transparent substrates is proposed. Soda-lime-silica glasses were sputtered with gold and subsequently coated with SiO 2 using a combustion chemical vapor deposition technique. Some samples were first coated with silica, sputtered with gold and then coated with a second layer of silica. The samples were annealed for 20 min at either 550 or 600 °C. This resulted in the formation of round, well separated gold nano-particles with sizes from 15 to 200 nm. The color of the coated glass was equivalent to that of gold–ruby glasses. Silica/gold/silica coatings annealed at 600 °C for 20 min were strongly adherent and scratch resistant. X-ray diffraction and electron backscatter diffraction (EBSD) were used to describe the crystal orientations of the embedded particles. The gold particles are preferably oriented with their (1 1 1) planes perpendicular to the surface.

  9. Gold nanoparticle-based electrochemical biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Pingarron, Jose M.; Yanez-Sedeno, Paloma; Gonzalez-Cortes, Araceli [Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid (Spain)

    2008-08-01

    The unique properties of gold nanoparticles to provide a suitable microenvironment for biomolecules immobilization retaining their biological activity, and to facilitate electron transfer between the immobilized proteins and electrode surfaces, have led to an intensive use of this nanomaterial for the construction of electrochemical biosensors with enhanced analytical performance with respect to other biosensor designs. Recent advances in this field are reviewed in this article. The advantageous operational characteristics of the biosensing devices designed making use of gold nanoparticles are highlighted with respect to non-nanostructured biosensors and some illustrative examples are commented. Electrochemical enzyme biosensors including those using hybrid materials with carbon nanotubes and polymers, sol-gel matrices, and layer-by-layer architectures are considered. Moreover, electrochemical immunosensors in which gold nanoparticles play a crucial role in the electrode transduction enhancement of the affinity reaction as well as in the efficiency of immunoreagents immobilization in a stable mode are reviewed. Similarly, recent advances in the development of DNA biosensors using gold nanoparticles to improve DNA immobilization on electrode surfaces and as suitable labels to improve detection of hybridization events are considered. Finally, other biosensors designed with gold nanoparticles oriented to electrically contact redox enzymes to electrodes by a reconstitution process and to the study of direct electron transfer between redox proteins and electrode surfaces have also been treated. (author)

  10. Gold nanoparticle-based electrochemical biosensors

    International Nuclear Information System (INIS)

    Pingarron, Jose M.; Yanez-Sedeno, Paloma; Gonzalez-Cortes, Araceli

    2008-01-01

    The unique properties of gold nanoparticles to provide a suitable microenvironment for biomolecules immobilization retaining their biological activity, and to facilitate electron transfer between the immobilized proteins and electrode surfaces, have led to an intensive use of this nanomaterial for the construction of electrochemical biosensors with enhanced analytical performance with respect to other biosensor designs. Recent advances in this field are reviewed in this article. The advantageous operational characteristics of the biosensing devices designed making use of gold nanoparticles are highlighted with respect to non-nanostructured biosensors and some illustrative examples are commented. Electrochemical enzyme biosensors including those using hybrid materials with carbon nanotubes and polymers, sol-gel matrices, and layer-by-layer architectures are considered. Moreover, electrochemical immunosensors in which gold nanoparticles play a crucial role in the electrode transduction enhancement of the affinity reaction as well as in the efficiency of immunoreagents immobilization in a stable mode are reviewed. Similarly, recent advances in the development of DNA biosensors using gold nanoparticles to improve DNA immobilization on electrode surfaces and as suitable labels to improve detection of hybridization events are considered. Finally, other biosensors designed with gold nanoparticles oriented to electrically contact redox enzymes to electrodes by a reconstitution process and to the study of direct electron transfer between redox proteins and electrode surfaces have also been treated

  11. Phonon assisted thermophoretic motion of gold nanoparticles inside carbon nanotubes

    DEFF Research Database (Denmark)

    Schoen, Philipp A.E.; Walther, Jens Honore; Poulikakos, Dimos

    2007-01-01

    The authors investigate the thermally driven mass transport of gold nanoparticles confined inside carbon nanotubes using molecular dynamics simulations. The observed thermophoretic motion of the gold nanoparticles correlates with the phonon dispersion exhibited by a standard carbon nanotube and...

  12. Increased cellular uptake of peptide-modified PEGylated gold nanoparticles.

    Science.gov (United States)

    He, Bo; Yang, Dan; Qin, Mengmeng; Zhang, Yuan; He, Bing; Dai, Wenbing; Wang, Xueqing; Zhang, Qiang; Zhang, Hua; Yin, Changcheng

    2017-12-09

    Gold nanoparticles are promising drug delivery vehicles for nucleic acids, small molecules, and proteins, allowing various modifications on the particle surface. However, the instability and low bioavailability of gold nanoparticles compromise their clinical application. Here, we functionalized gold nanoparticles with CPP fragments (CALNNPFVYLI, CALRRRRRRRR) through sulfhydryl PEG to increase their stability and bioavailability. The resulting gold nanoparticles were characterized with transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-visible spectrometry and X-ray photoelectron spectroscopy (XPS), and the stability in biological solutions was evaluated. Comparing to PEGylated gold nanoparticles, CPP (CALNNPFVYLI, CALRRRRRRRR)-modified gold nanoparticles showed 46 folds increase in cellular uptake in A549 and B16 cell lines, as evidenced by the inductively coupled plasma atomic emission spectroscopy (ICP-AES). The interactions between gold nanoparticles and liposomes indicated CPP-modified gold nanoparticles bind to cell membrane more effectively than PEGylated gold nanoparticles. Surface plasmon resonance (SPR) was used to measure interactions between nanoparticles and the membrane. TEM and uptake inhibitor experiments indicated that the cellular entry of gold nanoparticles was mediated by clathrin and macropinocytosis. Other energy independent endocytosis pathways were also identified. Our work revealed a new strategy to modify gold nanoparticles with CPP and illustrated the cellular uptake pathway of CPP-modified gold nanoparticles. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Microbially Induced Precipitation of Gold(0) Nanoparticles.

    Science.gov (United States)

    Roh, Yu; Kang, Serku; Park, Bitna; Kim, Yumi

    2015-01-01

    The objectives of this study were to synthesize gold nanoparticles by biomineralization using metal-reducing bacteria and to characterize their mineralogical properties. The metal-reducing bacteria were able to reduce Au(III) to Au(0) with organic fatty acids as electron donors, as indicated by the color change of the culture solution from colorless gold ions to black precipitates at 25 degrees C. XRD, SEM- and TEM-EDS analyses of the precipitates showed that Au(0) was precipitated and formed at either the cell membrane or extracellularly. The Au(0) nanoparticles were about 200 nm in size and ball-shaped. Biomineralization for elemental Au(0) nanoparticle synthesis may be useful for the recovery of natural gold in natural environments.

  14. Formation of gold nanoparticles by glycolipids of Lactobacillus casei

    OpenAIRE

    Kikuchi, Fumiya; Kato, Yugo; Furihata, Kazuo; Kogure, Toshihiro; Imura, Yuki; Yoshimura, Etsuro; Suzuki, Michio

    2016-01-01

    Gold nanoparticles have particular properties distinct from those of bulk gold crystals, and such nanoparticles are used in various applications in optics, catalysis, and drug delivery. Many reports on microbial synthesis of gold nanoparticles have appeared. However, the molecular details (reduction and dispersion) of such synthesis remain unclear. In the present study, we studied gold nanoparticle synthesis by Lactobacillus casei. A comparison of L. casei components before and after addition...

  15. Preparation of gold nanoparticles for plasmonic applications

    Energy Technology Data Exchange (ETDEWEB)

    Benkovicova, Monika, E-mail: monika.benkovicova@savba.sk [Institute of Physics SAS, Dubravska cesta 9, 845 11 Bratislava (Slovakia); Polymer Institute SAS, Dubravska cesta 9, 845 41 Bratislava (Slovakia); Vegso, Karol; Siffalovic, Peter; Jergel, Matej; Luby, Stefan; Majkova, Eva [Institute of Physics SAS, Dubravska cesta 9, 845 11 Bratislava (Slovakia)

    2013-09-30

    We present a simple hot injection method for the preparation of colloidal solutions of hydrophobic spherical gold nanoparticles with the diameter around 20 nm and size dispersion below 20%. Various surfactants with different lengths of hydrocarbon chains, such as oleylamine, 1-octadecanethiol, poly (N-vinylpyrrolidone), and AgNO{sub 3} in 1,5-pentanediol, were used for sterical stabilization in the colloidal solution. The hydrodynamic nanoparticle size and size dispersion were determined by the dynamic light scattering (DLS) while the small-angle X-ray scattering (SAXS) from the colloidal solution provided information on the size of the metallic nanoparticle core (without surfactant). Plasmon enhanced resonant absorption peaks between 500 nm and 600 nm were detected by the UV–VIS spectrophotometry. The nanoparticle arrays on silicon prepared by solvent evaporation or Langmuir-Schaefer method were inspected by high-resolution scanning electron microscopy and grazing-incidence SAXS (GISAXS). The presence of side maxima in the GISAXS pattern gives evidence of the nanoparticle ordering by self-assembly while very close values of the interparticle distance derived from GISAXS and the nanoparticle size derived from DLS indicate a close-packed order. - Highlights: ► Preparation of gold nanoparticles by use a various of surfactants ► Preparation of monodisperse nanoparticles ► Characterization of nanoparticles on a solid substrate.

  16. Optical Epitaxial Growth of Gold Nanoparticle Arrays.

    Science.gov (United States)

    Huang, Ningfeng; Martínez, Luis Javier; Jaquay, Eric; Nakano, Aiichiro; Povinelli, Michelle L

    2015-09-09

    We use an optical analogue of epitaxial growth to assemble gold nanoparticles into 2D arrays. Particles are attracted to a growth template via optical forces and interact through optical binding. Competition between effects determines the final particle arrangements. We use a Monte Carlo model to design a template that favors growth of hexagonal particle arrays. We experimentally demonstrate growth of a highly stable array of 50 gold particles with 200 nm diameter, spaced by 1.1 μm.

  17. Gold-coated nanoparticles for use in biotechnology applications

    Science.gov (United States)

    Berning, Douglas E [Los Alamos, NM; Kraus, Jr., Robert H.; Atcher, Robert W [Los Alamos, NM; Schmidt, Jurgen G [Los Alamos, NM

    2009-07-07

    A process of preparing gold-coated magnetic nanoparticles is disclosed and includes forming a suspension of magnetic nanoparticles within a suitable liquid, adding an amount of a reducible gold compound and a reducing agent to the suspension, and, maintaining the suspension for time sufficient to form gold-coated magnetic nanoparticles.

  18. Quinone-Enriched Gold Nanoparticles in Bioelectrochemistry and Charge Storage

    DEFF Research Database (Denmark)

    Wagner, Michal; Qvortrup, Katrine; Tanner, David Ackland

    for merging gold nanoparticles with resultant anthraquinones include one-pot microwave assisted synthesis or after-mixing of separately prepared gold nanoparticles with selected compounds. The quinone-enriched gold nanoparticles can be transferred onto different electrode surfaces, thus enabling facile...

  19. Gold nanoparticle-pentacene memory-transistors

    OpenAIRE

    Novembre , Christophe; Guerin , David; Lmimouni , Kamal; Gamrat , Christian; Vuillaume , Dominique

    2008-01-01

    We demonstrate an organic memory-transistor device based on a pentacene-gold nanoparticles active layer. Gold (Au) nanoparticles are immobilized on the gate dielectric (silicon dioxide) of a pentacene transistor by an amino-terminated self-assembled monolayer. Under the application of writing and erasing pulses on the gate, large threshold voltage shift (22 V) and on/off drain current ratio of ~3E4 are obtained. The hole field-effect mobility of the transistor is similar in the on and off sta...

  20. Ordered arrays of nanoporous gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Dong Wang

    2012-09-01

    Full Text Available A combination of a “top-down” approach (substrate-conformal imprint lithography and two “bottom-up” approaches (dewetting and dealloying enables fabrication of perfectly ordered 2-dimensional arrays of nanoporous gold nanoparticles. The dewetting of Au/Ag bilayers on the periodically prepatterned substrates leads to the interdiffusion of Au and Ag and the formation of an array of Au–Ag alloy nanoparticles. The array of alloy nanoparticles is transformed into an array of nanoporous gold nanoparticles by a following dealloying step. Large areas of this new type of material arrangement can be realized with this technique. In addition, this technique allows for the control of particle size, particle spacing, and ligament size (or pore size by varying the period of the structure, total metal layer thickness, and the thickness ratio of the as-deposited bilayers.

  1. Synthesis of gold nanoparticles with graphene oxide.

    Science.gov (United States)

    Wang, Wenshuo; He, Dawei; Zhang, Xiqing; Duan, Jiahua; Wu, Hongpeng; Xu, Haiteng; Wang, Yongsheng

    2014-05-01

    Single sheets of functionalized graphene oxide are derived through chemical exfoliation of natural flake graphite. We present an effective synthetic method of graphene-gold nanoparticles hybrid nanocomposites. AFM (Atomic Force Microscope) was used to measure the thickness of the individual GO nanosheet. FTIR (Fourier transform infrared) spectroscopy was used to verify the attachment of oxygen functionalities on the surface of graphene oxide. TEM (Transmission Electron Microscope) data revealed the average diameters of the gold colloids and characterized the composite particles situation. Absorption spectroscopy showed that before and after synthesis the gold particle size did not change. Our studies indicate that the hybrid is potential substrates for catalysts and biosensors.

  2. Surface interactions between gold nanoparticles and biochar

    Science.gov (United States)

    Engineered nanomaterials are directly applied to agricultural soils as a part of pesticide/fertilize formulations and sludge/manure amendments. Yet, no prior reports are available on the extent and reversibility of gold nanoparticles (nAu) retention by soil components including charcoal black carbo...

  3. Gold nanoparticles as nanosources of heat

    Science.gov (United States)

    Baffou, Guillaume

    2018-04-01

    Under illumination at their plasmonic resonance wavelength, gold nanoparticles can absorb incident light and turn into efficient nanosources of heat remotely controllable by light. This fundamental scheme is at the basis of an active field of research coined thermoplasmonics and encompasses numerous applications in physics, chemistry and biology at the micro and nano scales. Warning, no authors found for 2018Phot........48.

  4. Antifungal activity of gold nanoparticles prepared by solvothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Tokeer, E-mail: tahmad3@jmi.ac.in [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Wani, Irshad A.; Lone, Irfan H.; Ganguly, Aparna [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Manzoor, Nikhat; Ahmad, Aijaz [Department of Biosciences, Jamia Millia Islamia, New Delhi 110025 (India); Ahmed, Jahangeer [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Al-Shihri, Ayed S. [Department of Chemistry, Faculty of Science, King Khalid University, Abha 61413, P.O. Box 9004 (Saudi Arabia)

    2013-01-15

    Graphical abstract: Gold nanoparticles (7 and 15 nm) of very high surface area (329 and 269 m{sup 2}/g) have been successfully synthesized through solvothermal method by using tin chloride and sodium borohydride as reducing agents. As-prepared gold nanoparticles shows very excellent antifungal activity against Candida isolates and activity increases with decrease in the particle size. Display Omitted Highlights: ► Effect of reducing agents on the morphology of gold nanoparticles. ► Highly uniform and monodisperse gold nanoparticles (7 nm). ► Highest surface area of gold nanoparticles (329 m{sup 2/}g). ► Excellent antifungal activity of gold nanoparticles against Candida strains. -- Abstract: Gold nanoparticles have been successfully synthesized by solvothermal method using SnCl{sub 2} and NaBH{sub 4} as reducing agents. X-ray diffraction studies show highly crystalline and monophasic nature of the gold nanoparticles with face centred cubic structure. The transmission electron microscopic studies show the formation of nearly spherical gold nanoparticles of average size of 15 nm using SnCl{sub 2}, however, NaBH{sub 4} produced highly uniform, monodispersed and spherical gold nanoparticles of average grain size of 7 nm. A high surface area of 329 m{sup 2}/g for 7 nm and 269 m{sup 2}/g for 15 nm gold nanoparticles was observed. UV–vis studies assert the excitations over the visible region due to transverse and longitudinal surface plasmon modes. The gold nanoparticles exhibit excellent size dependant antifungal activity and greater biocidal action against Candida isolates for 7 nm sized gold nanoparticles restricting the transmembrane H{sup +} efflux of the Candida species than 15 nm sized gold nanoparticles.

  5. Antifungal activity of gold nanoparticles prepared by solvothermal method

    International Nuclear Information System (INIS)

    Ahmad, Tokeer; Wani, Irshad A.; Lone, Irfan H.; Ganguly, Aparna; Manzoor, Nikhat; Ahmad, Aijaz; Ahmed, Jahangeer; Al-Shihri, Ayed S.

    2013-01-01

    Graphical abstract: Gold nanoparticles (7 and 15 nm) of very high surface area (329 and 269 m 2 /g) have been successfully synthesized through solvothermal method by using tin chloride and sodium borohydride as reducing agents. As-prepared gold nanoparticles shows very excellent antifungal activity against Candida isolates and activity increases with decrease in the particle size. Display Omitted Highlights: ► Effect of reducing agents on the morphology of gold nanoparticles. ► Highly uniform and monodisperse gold nanoparticles (7 nm). ► Highest surface area of gold nanoparticles (329 m 2/ g). ► Excellent antifungal activity of gold nanoparticles against Candida strains. -- Abstract: Gold nanoparticles have been successfully synthesized by solvothermal method using SnCl 2 and NaBH 4 as reducing agents. X-ray diffraction studies show highly crystalline and monophasic nature of the gold nanoparticles with face centred cubic structure. The transmission electron microscopic studies show the formation of nearly spherical gold nanoparticles of average size of 15 nm using SnCl 2 , however, NaBH 4 produced highly uniform, monodispersed and spherical gold nanoparticles of average grain size of 7 nm. A high surface area of 329 m 2 /g for 7 nm and 269 m 2 /g for 15 nm gold nanoparticles was observed. UV–vis studies assert the excitations over the visible region due to transverse and longitudinal surface plasmon modes. The gold nanoparticles exhibit excellent size dependant antifungal activity and greater biocidal action against Candida isolates for 7 nm sized gold nanoparticles restricting the transmembrane H + efflux of the Candida species than 15 nm sized gold nanoparticles.

  6. Synthesis and characterization of cobalt/gold bimetallic nanoparticles

    International Nuclear Information System (INIS)

    Cheng, Guangjun; Hight Walker, Angela R.

    2007-01-01

    Cobalt/gold (Co/Au) bimetallic nanoparticles are prepared by chemically reducing gold (III) chloride to gold in the presence of pre-synthesized Co nanoparticles. Transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption spectrometry, and a superconducting quantum interference device (SQUID) magnetometer have been used to characterize as-prepared bimetallic nanoparticles. Our findings demonstrate Au not only grows onto Co nanoparticles, forming a surface coating, but also diffuses into Co nanoparticles. The introduction of Au alters the crystalline structure of Co nanoparticles and changes their magnetic properties. Dodecanethiols induce a reorganization of as-prepared Co/Au bimetallic nanoparticles

  7. Absorption Spectra of Gold Nanoparticle Suspensions

    Science.gov (United States)

    Anan'eva, M. V.; Nurmukhametov, D. R.; Zverev, A. S.; Nelyubina, N. V.; Zvekov, A. A.; Russakov, D. M.; Kalenskii, A. V.; Eremenko, A. N.

    2018-02-01

    Three gold nanoparticle suspensions are obtained, and mean radii in distributions - (6.1 ± 0.2), (11.9 ± 0.3), and (17.3 ± 0.7) nm - are determined by the transmission electron microscopy method. The optical absorption spectra of suspensions are obtained and studied. Calculation of spectral dependences of the absorption index of suspensions at values of the gold complex refractive index taken from the literature showed a significant deviation of experimental and calculated data in the region of 450-800 nm. Spectral dependences of the absorption of suspensions are simulated within the framework of the Mie-Drude theory taking into account the interband absorption in the form of an additional term in the imaginary part of the dielectric permittivity of the Gaussian type. It is shown that to quantify the spectral dependences in the region of the plasmon absorption band of nanoparticles, correction of the parameters of the interband absorption is necessary in addition to the increase of the relaxation parameter of the Drude theory. Spectral dependences of the dielectric permittivity of gold in nanodimensional state are refined from the solution of the inverse problem. The results of the present work are important for predicting the special features of operation of photonic devices and optical detonators based on gold nanoparticles.

  8. The golden age: gold nanoparticles for biomedicine†

    Science.gov (United States)

    Dreaden, Erik C.; Alkilany, Alaaldin M.; Huang, Xiaohua; Murphy, Catherine J.; El-Sayed, Mostafa A.

    2018-01-01

    Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic properties have also attracted tremendous attention due to their historical applications in art and ancient medicine and current applications in enhanced optoelectronics and photovoltaics. In spite of their modest alchemical beginnings, gold nanoparticles exhibit physical properties that are truly different from both small molecules and bulk materials, as well as from other nanoscale particles. Their unique combination of properties is just beginning to be fully realized in range of medical diagnostic and therapeutic applications. This critical review will provide insights into the design, synthesis, functionalization, and applications of these artificial molecules in biomedicine and discuss their tailored interactions with biological systems to achieve improved patient health. Further, we provide a survey of the rapidly expanding body of literature on this topic and argue that gold nanotechnology-enabled biomedicine is not simply an act of ‘gilding the (nanomedicinal) lily’, but that a new ‘Golden Age’ of biomedical nanotechnology is truly upon us. Moving forward, the most challenging nanoscience ahead of us will be to find new chemical and physical methods of functionalizing gold nanoparticles with compounds that can promote efficient binding, clearance, and biocompatibility and to assess their safety to other biological systems and their long-term term effects on human health and reproduction (472 references). PMID:22109657

  9. Monofunctional gold nanoparticles: synthesis and applications

    International Nuclear Information System (INIS)

    Huo Qun; Worden, James G.

    2007-01-01

    The ability to control the assembly of nanoparticle building blocks is critically important for the development of new materials and devices. The properties and functions of nanomaterials are not only dependent on the size and properties of individual particles, but also the interparticle distance and interactions. In order to control the structures of nanoassemblies, it is important to first achieve a precise control on the chemical functionality of nanoparticle building blocks. This review discusses three methods that have been reported recently for the preparation of monofunctional gold nanoparticles, i.e., nanoparticles with a single chemical functional group attached to each particle. The advantages and disadvantages of the three methods are discussed and compared. With a single functional group attached to the surface, one can treat such nanoparticles as molecular building blocks to react with other molecules or nanoparticles. In other words, by using appropriate chemical reactions, nanoparticles can be linked together into nanoassemblies and materials by covalent bonds, similar to the total chemical synthesis of complicated organic compounds from smaller molecular units. An example of using this approach for the synthesis of nanoparticle/polymer hybrid materials with optical limiting properties is presented. Other potential applications and advantages of covalent bond-based nanoarchitectures vs. non-covalent interaction-based supramolecular self-assemblies are also discussed briefly in this review

  10. Protracted elimination of gold nanoparticles from mouse liver

    DEFF Research Database (Denmark)

    Sadauskas, Evaldas; Wallin, Håkan; Stoltenberg, Meredin

    2009-01-01

    The present study aims at revealing the fate of 40-nm gold nanoparticles after intravenous injections. The gold nanoparticles were traced histochemically with light and transmission electron microscopy using autometallographic (AMG) staining, and the gold content in the liver was determined with ...

  11. Gold nanoparticles: preparation, functionalisation and applications in biochemistry and immunochemistry

    International Nuclear Information System (INIS)

    Dykman, Lev A; Bogatyrev, Vladimir A

    2007-01-01

    The review summarises data on the synthesis and functionalisation of gold nanoparticles and their applications in biological investigations. Particular attention is given to applications of colloidal gold in solid-phase assays, immunoassay and studies of biologically active compounds by vibrational spectroscopy. A special section deals with the use of gold nanoparticles as antigen carriers in immunisation.

  12. Terminalia chebula mediated green and rapid synthesis of gold nanoparticles

    Science.gov (United States)

    Mohan Kumar, Kesarla; Mandal, Badal Kumar; Sinha, Madhulika; Krishnakumar, Varadhan

    2012-02-01

    Biologically inspired experimental process in synthesising nanoparticles is of great interest in present scenario. Biosynthesis of nanoparticles is considered to be one of the best green techniques in synthesising metal nanoparticles. Here, an in situ green biogenic synthesis of gold nanoparticles using aqueous extracts of Terminalia chebula as reducing and stabilizing agent is reported. Gold nanoparticles were confirmed by surface plasmon resonance in the range of 535 nm using UV-visible spectrometry. TEM analysis revealed that the morphology of the particles thus formed contains anisotropic gold nanoparticles with size ranging from 6 to 60 nm. Hydrolysable tannins present in the extract of T. chebula are responsible for reductions and stabilization of gold nanoparticles. Antimicrobial activity of gold nanoparticles showed better activity towards gram positive S. aureus compared to gram negative E. coli using standard well diffusion method.

  13. Immobilization of gold nanoparticles on cell culture surfaces for safe and enhanced gold nanoparticle-mediated laser transfection

    Science.gov (United States)

    Kalies, Stefan; Heinemann, Dag; Schomaker, Markus; Gentemann, Lara; Meyer, Heiko; Ripken, Tammo

    2014-01-01

    Abstract. In comparison to standard transfection methods, gold nanoparticle-mediated laser transfection has proven to be a versatile alternative. This is based on its minor influence on cell viability and its high efficiency, especially for the delivery of small molecules like small interfering RNA. However, in order to transfer it to routine usage, a safety aspect is of major concern: The avoidance of nanoparticle uptake by the cells is desired. The immobilization of the gold nanoparticles on cell culture surfaces can address this issue. In this study, we achieved this by silanization of the appropriate surfaces and the binding of gold nanoparticles to them. Comparable perforation efficiencies to the previous approaches of gold nanoparticle-mediated laser transfection with free gold nanoparticles are demonstrated. The uptake of the immobilized particles by the cells is unlikely. Consequently, these investigations offer the possibility of bringing gold nanoparticle-mediated laser transfection closer to routine usage. PMID:25069006

  14. Application of gold nanoparticles in separation sciences

    Czech Academy of Sciences Publication Activity Database

    Sýkora, D.; Kašička, Václav; Mikšík, Ivan; Řezanka, P.; Záruba, K.; Matějka, P.; Král, V.

    2010-01-01

    Roč. 33, č. 3 (2010), s. 372-387 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GA203/09/0675; GA ČR(CZ) GA203/08/1428; GA MŠk(CZ) 1M0510 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50110509 Keywords : gold nanoparticles * electrophoresis * chromatography Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.631, year: 2010

  15. Preparation of gold nanoparticles by arc discharge in water

    International Nuclear Information System (INIS)

    Lung, Jen-Kuang; Huang, Jen-Chuen; Tien, Der-Chi; Liao, Chih-Yu; Tseng, Kuo-Hsiung; Tsung, Tsing-Tshin; Kao, Wen-Shiow; Tsai, Teh-Hua; Jwo, Ching-Song; Lin, Hong-Ming; Stobinski, Leszek

    2007-01-01

    Gold nanoparticles have been attracting attention due to their extensive application in chemistry, physics, material science, electronics, catalysis and bionanotechnology. Synthesis of gold nanoparticles often involves toxic and expensive physical-chemistry methods. Preparation of gold nanoparticles by arc discharge in water is proposed for the first time. Fabrication of gold nanostructures in deionized water has been successfully established. The evidence of gold particles' light absorbance reveals a unique surface plasmon resonance for Au nanoparticles suspended in deionized water. Gold nanostructures uniformly dispersed in water, their UV-Vis absorption and crystalline size are shown. Our experimental results demonstrate that fabrication of gold nanoparticles by arc discharge in water is an alternative, cheap, effective and environmentally friendly method

  16. Photochemical Synthesis of the Bioconjugate Folic Acid-Gold Nanoparticles

    DEFF Research Database (Denmark)

    León, John Jairo Castillo; Bertel, Linda; Páez-Mozo, Edgar

    2013-01-01

    In this paper we present a rapid and simple onepot method to obtain gold nanoparticles functionalized with folic acid using a photochemistry method. The bioconjugate folic acid-gold nanoparticle was generated in one step using a photo-reduction method, mixing hydrogen tetrachloroaurate with folic...... at 4°C prolongs the stability of folic acid-gold nanoparticle suspensions to up to 26 days. Ultraviolet visible and Fourier transform infrared spectroscopy showed a surface plasmon band of around 534nm and fluorescence spectroscopy exhibited a quenching effect on gold nanoparticles in the fluorescence...... emission of folic acid and thus confirmed the conjugation of folic acid to the surface of gold nanoparticles. In this study we demonstrate the use of a photochemistry method to obtain folic acid-gold nanoparticles in a simple and rapid way without the use of surfactants and long reaction times...

  17. Functionalized Carbon Nanotubes with Gold Nanoparticles to Fabricate a Sensor for Hydrogen Peroxide Determination

    Directory of Open Access Journals (Sweden)

    Halimeh Rajabzade

    2012-01-01

    Full Text Available A highly sensitive electrode was prepared based on gold nanoparticles/nanotubes/ionic liquid for measurement of Hydrogen peroxide. Gold nanoparticles of 20–25 nm were synthesized on a nanotube carbon paste electrode by cyclic voltammetry technique while the coverage was controlled by applied potential and time. The gold nanoparticles were modified to form a monolayer on CNT, followed by decoration with ionic liquid for determination of hydrogen peroxide. The experimental conditions, applied potential and pH, for hydrogen peroxide monitoring were optimized, and hydrogen peroxide was determined amperometrically at 0.3 V vs. SCE at pH 7.0. Electrocatalytic effects of gold deposited CNT were observed with respect to unmodified one. The sensitivity obtained was 5 times higher for modified one. The presence of Au particles in the matrix of CNTs provides an environment for the enhanced electrocatalytic activities. The sensor has a high sensitivity, quickly response to H2O2 and good stability. The synergistic influence of MWNT, Au particles and IL contributes to the excellent performance for the sensor. The sensor responds to H2O2 in the linear range from 0.02 µM to 0.3 mM. The detection limit was down to 0.4 µM when the signal to noise ratio is 3.

  18. The effect of cysteine on electrodeposition of gold nanoparticle

    International Nuclear Information System (INIS)

    Dolati, A.; Imanieh, I.; Salehi, F.; Farahani, M.

    2011-01-01

    Highlights: → Cysteine was found as an appropriate additive for electrodeposition of gold nanoparticles. → The deposition mechanism of gold nanoparticle was determined as instantaneous nucleation. → Oxygen reduction on the gold nanoparticle surface was eight times greater than that on the conventional gold deposits. - Abstract: The most applications of gold nanoparticles are in the photo-electronical accessories and bio-chemical sensors. Chloride solution with cysteine additive was used as electrolyte in gold nanoparticles electrodeposition. The nucleation and growing mechanism were studied by electrochemical techniques such as cyclic voltammetry and chronoamperometry, in order to obtain a suitable nano structure. The deposition mechanism was determined as instantaneous nucleation and the dimension of particles was controlled in nanometric particle size range. Atomic Force Microscope was used to evaluate the effect of cysteine on the morphology and topography of gold nanoparticles. Finally the catalytic property of gold nanoparticle electrodeposited was studied in KOH solution, where oxygen reduction on the gold nanoparticle surface was eight times greater than that on the conventional gold deposits.

  19. X-Ray Spectroscopy of Gold Nanoparticles

    Science.gov (United States)

    Nahar, Sultana N.; Montenegro, M.; Pradhan, A. K.; Pitzer, R.

    2009-06-01

    Inner shell transitions, such as 1s-2p, in heavy elements can absorb or produce hard X-rays, and hence are widely used in nanoparticles. Bio-medical research for cancer treatment has been using heavy element nanoparticles, embeded in malignant tumor, for efficient absorption of irradiated X-rays and leading emission of hard X-rays and energetic electrons to kill the surrounding cells. Ejection of a 1s electron during ionization of the element by absorption of a X-ray photon initiates the Auger cascades of emission of photons and electrons. We have investigated gold nanoparticles for the optimal energy range, below the K-edge (1s) ionization threshold, that corresponds to resonant absorption of X-rays with large attenuation coefficients, orders of magnitude higher over the background as well as to that at K-edge threshold. We applied these attenuation coefficients in Monte Carlo simulation to study the intensities of emission of photons and electrons by Auger cascades. The numerical experiments were carried out in a phantom of water cube with a thin layer, 0.1mm/g, of gold nanoparticles 10 cm inside from the surface using the well-known code Geant4. We will present results on photon and electron emission spectra from passing monochromatic X-ray beams at 67 keV, which is the resonant energy for resonant K_{α} lines, at 82 keV, the K-shell ionization threshold, and at 2 MeV where the resonant effect is non-existent. Our findings show a high peak in the gold nanoparticle absorption curve indicating complete absorption of radiation within the gold layer. The photon and electron emission spectra show resonant features. Acknowledgement: Partially supported by a Large Interdisciplinary Grant award of the Ohio State University and NASA APRA program (SNN). The computational work was carried out on the Cray X1 and Itanium 4 cluster at the Ohio Supercomputer Center, Columbus Ohio. "Resonant X-ray Irradiation of High-Z Nanoparticles For Cancer Theranostics" (refereed

  20. Facially amphiphilic thiol capped gold and silver nanoparticles

    Indian Academy of Sciences (India)

    Abstract. A series of bile acid-derived facially amphiphilic thiols have been used to cap sliver and gold nanoparticles. The self-assembling properties of these steroid-capped nanoparticles have been investigated and reported in this article.

  1. Comparative study of synthesized silver and gold nanoparticles ...

    Indian Academy of Sciences (India)

    The present investigation aimed at comparing the synthesis, characterization and in vitro anticancer ... Bauhinia tomentosa Linn; silver nanoparticles; gold nanoparticles; A-549; HEp-2; MCF-7. 1. Introduction ..... Methods 65 55. [33] Singh A K ...

  2. Microbial biosynthesis of nontoxic gold nanoparticles

    International Nuclear Information System (INIS)

    Roy, Swarup; Das, Tapan Kumar; Maiti, Guru Prasad; Basu, Utpal

    2016-01-01

    Graphical abstract: The manuscript deals with the fungus mediated optimized biologically synthesized GNPs using Aspergillus foetidus and characterization of biosynthesized GNPs using various physico-chemical methods. The fairly stable synthesized nanoparticles have size in the range of 10–40 nm. Cytotoxicity study of biosynthesized GNPs on Human lung cancer cell line A549 showed no significant toxicity of GNPs. - Highlights: • A novel biosynthesis process of GNPs using Aspergillus foetidus. • Biosynthesized GNPs are in the range of 10–40 nm as observed from TEM. • This process of synthesis is an optimized biosynthesis process of GNPs. • Biosynthesized GNPs are noncytotoxic against A549 cell line. - Abstract: We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergillus foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30–50 nm. The spherical and polydispersed GNPs in the range of 10–40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 °C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion.

  3. Microbial biosynthesis of nontoxic gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Swarup, E-mail: swaruproy@klyuniv.ac.in [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Das, Tapan Kumar [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Maiti, Guru Prasad [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India); Department of Anesthesiology, Texas Tech University Health science Center, 3601 4th Street, Lubbock, TX 79430 (United States); Basu, Utpal [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India)

    2016-01-15

    Graphical abstract: The manuscript deals with the fungus mediated optimized biologically synthesized GNPs using Aspergillus foetidus and characterization of biosynthesized GNPs using various physico-chemical methods. The fairly stable synthesized nanoparticles have size in the range of 10–40 nm. Cytotoxicity study of biosynthesized GNPs on Human lung cancer cell line A549 showed no significant toxicity of GNPs. - Highlights: • A novel biosynthesis process of GNPs using Aspergillus foetidus. • Biosynthesized GNPs are in the range of 10–40 nm as observed from TEM. • This process of synthesis is an optimized biosynthesis process of GNPs. • Biosynthesized GNPs are noncytotoxic against A549 cell line. - Abstract: We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergillus foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30–50 nm. The spherical and polydispersed GNPs in the range of 10–40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 °C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion.

  4. Amoxicillin functionalized gold nanoparticles reverts MRSA resistance

    International Nuclear Information System (INIS)

    Kalita, Sanjeeb; Kandimalla, Raghuram; Sharma, Kaustav Kalyan; Kataki, Amal Chandra; Deka, Manab; Kotoky, Jibon

    2016-01-01

    In this study, we have described the biosynthesis of biocompatible gold nanoparticles (GNPs) from aqueous extract of the aerial parts of a pteridophyte, “Adiantum philippense” by microwave irradiation and its surface functionalization with broad spectrum beta lactam antibiotic, amoxicillin (Amox). The functionalization of amoxicillin on GNPs (GNP-Amox) was carried out via electrostatic interaction of protonated amino group and thioether moiety mediated attractive forces. The synthesized GNPs and GNP-Amox were physicochemically characterized. UV–Vis spectroscopy, Zeta potential, XRD, FTIR and SERS (surface enhanced raman spectra) results confirmed the loading of Amox into GNPs. Loading of Amox to GNPs reduce amoxicillin cytotoxicity, whereas GNPs were found to be nontoxic to mouse fibroblast cell line (L929) as evident from MTT and acridine orange/ethidium bromide (AO/EtBr) live/dead cell assays. The GNP-Amox conjugates demonstrated enhanced broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria. Furthermore, in-vitro and in-vivo assays of GNP-Amox revealed potent anti-MRSA activity and improved the survival rate. This indicates the subversion of antibiotic resistance mechanism by overcoming the effect of high levels of β-lactamase produced by methicillin resistant Staphylococcus aureus (MRSA). Taken together, this study demonstrates the positive attributes from GNP-Amox conjugates as a promising antibacterial therapeutic agent against MRSA as well as other pathogens. - Highlights: • Aqueous extract of A. phillippens was used as a reducing and capping agent for synthesis of microwave irradiated gold nanoparticles. • GNPs were loaded with amoxicillin for restoration in antibacterial activity of amoxicillin against MRSA strains. • Gold nanoparticles and GNP-Amox were found biocompitable as tested on L929 cell line. • The nanoparticle antibiotic conjugates exhibited restoration of amoxicillin activity against MRSA in

  5. Amoxicillin functionalized gold nanoparticles reverts MRSA resistance

    Energy Technology Data Exchange (ETDEWEB)

    Kalita, Sanjeeb; Kandimalla, Raghuram; Sharma, Kaustav Kalyan [Drug Discovery Lab, Life Science Division, Institute of Advanced Study in Science and Technology (IASST), Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India); Kataki, Amal Chandra [Dr. B. Borooah Cancer Institute, Guwahati, Assam (India); Department of Applied Sciences, Gopinath Bordoloi Nagar, Jalukbari, Gauhati University, Guwahati 781014, Assam (India); Deka, Manab [Department of Applied Sciences, Gopinath Bordoloi Nagar, Jalukbari, Gauhati University, Guwahati 781014, Assam (India); Kotoky, Jibon, E-mail: jkotoky@gmail.com [Drug Discovery Lab, Life Science Division, Institute of Advanced Study in Science and Technology (IASST), Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India)

    2016-04-01

    In this study, we have described the biosynthesis of biocompatible gold nanoparticles (GNPs) from aqueous extract of the aerial parts of a pteridophyte, “Adiantum philippense” by microwave irradiation and its surface functionalization with broad spectrum beta lactam antibiotic, amoxicillin (Amox). The functionalization of amoxicillin on GNPs (GNP-Amox) was carried out via electrostatic interaction of protonated amino group and thioether moiety mediated attractive forces. The synthesized GNPs and GNP-Amox were physicochemically characterized. UV–Vis spectroscopy, Zeta potential, XRD, FTIR and SERS (surface enhanced raman spectra) results confirmed the loading of Amox into GNPs. Loading of Amox to GNPs reduce amoxicillin cytotoxicity, whereas GNPs were found to be nontoxic to mouse fibroblast cell line (L929) as evident from MTT and acridine orange/ethidium bromide (AO/EtBr) live/dead cell assays. The GNP-Amox conjugates demonstrated enhanced broad-spectrum bactericidal activity against both Gram-positive and Gram-negative bacteria. Furthermore, in-vitro and in-vivo assays of GNP-Amox revealed potent anti-MRSA activity and improved the survival rate. This indicates the subversion of antibiotic resistance mechanism by overcoming the effect of high levels of β-lactamase produced by methicillin resistant Staphylococcus aureus (MRSA). Taken together, this study demonstrates the positive attributes from GNP-Amox conjugates as a promising antibacterial therapeutic agent against MRSA as well as other pathogens. - Highlights: • Aqueous extract of A. phillippens was used as a reducing and capping agent for synthesis of microwave irradiated gold nanoparticles. • GNPs were loaded with amoxicillin for restoration in antibacterial activity of amoxicillin against MRSA strains. • Gold nanoparticles and GNP-Amox were found biocompitable as tested on L929 cell line. • The nanoparticle antibiotic conjugates exhibited restoration of amoxicillin activity against MRSA in

  6. Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

    Energy Technology Data Exchange (ETDEWEB)

    Mahl, Dirk; Diendorf, Joerg; Ristig, Simon [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Greulich, Christina [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Li Zian; Farle, Michael [University of Duisburg-Essen, Faculty of Physics, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Koeller, Manfred [Ruhr-University of Bochum, Bergmannsheil University Hospital/Surgical Research (Germany); Epple, Matthias, E-mail: matthias.epple@uni-due.de [University of Duisburg-Essen, Department of Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)

    2012-10-15

    Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly(N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 {mu}g mL{sup -1} induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  7. Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

    Science.gov (United States)

    Mahl, Dirk; Diendorf, Jörg; Ristig, Simon; Greulich, Christina; Li, Zi-An; Farle, Michael; Köller, Manfred; Epple, Matthias

    2012-10-01

    Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly( N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 μg mL-1 induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  8. Silver, gold, and alloyed silver–gold nanoparticles: characterization and comparative cell-biologic action

    International Nuclear Information System (INIS)

    Mahl, Dirk; Diendorf, Jörg; Ristig, Simon; Greulich, Christina; Li Zian; Farle, Michael; Köller, Manfred; Epple, Matthias

    2012-01-01

    Silver, gold, and silver–gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly(N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15–25 nm), gold (5–6 nm), and silver–gold (50:50; 10–12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver–gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver–gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver–gold nanoparticles in the concentration range of 5–20 μg mL −1 induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  9. Biosynthesis and Application of Silver and Gold Nanoparticles

    OpenAIRE

    Sadowski, Zygmunt

    2010-01-01

    A green chemistry synthetic route has been used for both silver and gold nanoparticles synthesis. The reaction occurred at ambient temperature. Among the nanoparticles biological organism, some microorganisms such as bacteria, fungi, and yeast have been exploited for nanoparticles synthesis. Several plant biomass or plant extracts have been successfully used for extracellular biosynthesis of silver and gold nanoparticles. Analytical techniques, such as ultraviolet-visible spectroscopy (UV-vis...

  10. Gold and gold-copper nanoparticles in 2-propanol: A radiation chemical study

    International Nuclear Information System (INIS)

    Dey, G.R.

    2011-01-01

    The studies on the reduction of Au 3+ to gold nanoparticles in presence and absence of Cu 2+ under deoxygenated conditions in 2-propanol by radiolytic method have been carried out. On γ-radiolysis, preliminary yellow colored solution of Au 3+ changed to purple color owing to gold nanoparticles formation, which exhibits an absorption peak at around 540 nm. In the presence of Cu 2+ , absorption of gold-copper nanoparticles, which was also produced during γ-radiolysis, was red shifted in contrast to the system containing no Cu 2+ . Under DLS studies the sizes of gold nanoparticles in the absence and the presence of Cu 2+ were found to be larger (>400 nm). However, in presence of polyethylene glycol, a stabilizer the nanoparticle sizes became smaller, sizes measured for gold and gold-copper nanoparticles are 40 and 140 nm, respectively. Moreover, the change in UV-vis spectra in the Cu 2+ and Au 3+ mixed system highlights the formation of gold-copper nanoparticles in core-shell type arrangement. - Highlights: → Present radiation chemical study highlights high reactivity of Au ·2+ with Cu 2+ . → Absorption of gold-copper nanoparticles is blue shifted as compared to copper nanoparticles. → Change in UV-vis spectra with dose emphasizes core-shell type arrangement of Au-Cu nanoparticles.

  11. Naked Gold Nanoparticles and hot Electrons in Water.

    Science.gov (United States)

    Ghandi, Khashayar; Wang, Furong; Landry, Cody; Mostafavi, Mehran

    2018-05-08

    The ionizing radiation in aqueous solutions of gold nanoparticles, stabilized by electrostatic non-covalent intermolecular forces and steric interactions, with antimicrobial compounds, are investigated with picosecond pulse radiolysis techniques. Upon pulse radiolysis of an aqueous solution containing very low concentrations of gold nanoparticles with naked surfaces available in water (not obstructed by chemical bonds), a change to Cerenkov spectrum over a large range of wavelengths are observed and pre-solvated electrons are captured by gold nanoparticles exclusively (not by ionic liquid surfactants used to stabilize the nanoparticles). The solvated electrons are also found to decay rapidly compared with the decay kinetics in water. These very fast reactions with electrons in water could provide an enhanced oxidizing zone around gold nanoparticles and this could be the reason for radio sensitizing behavior of gold nanoparticles in radiation therapy.

  12. Different Effects of the Immunomodulatory Drug GMDP Immobilized onto Aminopropyl Modified and Unmodified Mesoporous Silica Nanoparticles upon Peritoneal Macrophages of Women with Endometriosis

    Directory of Open Access Journals (Sweden)

    Yuliya Antsiferova

    2013-01-01

    Full Text Available The aim of the present work was to compare in vitro the possibility of application of unmodified silica nanoparticles (UMNPs and modified by aminopropyl groups silica nanoparticles (AMNPs for topical delivery of immunomodulatory drug GMDP to the peritoneal macrophages of women with endometriosis. The absence of cytotoxic effect and high cellular uptake was demonstrated for both types of silica nanoparticles. The immobilization of GMDP on the UMNPs led to the suppression of the stimulatory effect of GMDP on the membrane expression of scavenger receptors SR-AI and SR-B, mRNAs expression of NOD2 and RAGE, and synthesis of proteolytic enzyme MMP-9 and its inhibitor TIMP-1. GMDP, immobilized onto AMNPs, enhanced the initially reduced membrane expression of SRs and increased NOD2, RAGE, and MMP-9 mRNAs expression by macrophages. Simultaneously high level of mRNAs expression of factors, preventing undesirable hyperactivation of peritoneal macrophages (SOCS1 and TIMP-1, was observed in macrophages incubated in the presence of GMDP, immobilized onto AMNPs. The effect of AMNPs immobilized GMDP in some cases exceeded the effect of free GMDP. Thus, among the studied types of silica nanoparticles, AMNPs are the most suitable nanoparticles for topical delivery of GMDP to the peritoneal macrophages.

  13. Different effects of the immunomodulatory drug GMDP immobilized onto aminopropyl modified and unmodified mesoporous silica nanoparticles upon peritoneal macrophages of women with endometriosis.

    Science.gov (United States)

    Antsiferova, Yuliya; Sotnikova, Nataliya; Parfenyuk, Elena

    2013-01-01

    The aim of the present work was to compare in vitro the possibility of application of unmodified silica nanoparticles (UMNPs) and modified by aminopropyl groups silica nanoparticles (AMNPs) for topical delivery of immunomodulatory drug GMDP to the peritoneal macrophages of women with endometriosis. The absence of cytotoxic effect and high cellular uptake was demonstrated for both types of silica nanoparticles. The immobilization of GMDP on the UMNPs led to the suppression of the stimulatory effect of GMDP on the membrane expression of scavenger receptors SR-AI and SR-B, mRNAs expression of NOD2 and RAGE, and synthesis of proteolytic enzyme MMP-9 and its inhibitor TIMP-1. GMDP, immobilized onto AMNPs, enhanced the initially reduced membrane expression of SRs and increased NOD2, RAGE, and MMP-9 mRNAs expression by macrophages. Simultaneously high level of mRNAs expression of factors, preventing undesirable hyperactivation of peritoneal macrophages (SOCS1 and TIMP-1), was observed in macrophages incubated in the presence of GMDP, immobilized onto AMNPs. The effect of AMNPs immobilized GMDP in some cases exceeded the effect of free GMDP. Thus, among the studied types of silica nanoparticles, AMNPs are the most suitable nanoparticles for topical delivery of GMDP to the peritoneal macrophages.

  14. Surface modification of silica particles with gold nanoparticles as an augmentation of gold nanoparticle mediated laser perforation

    Science.gov (United States)

    Kalies, Stefan; Gentemann, Lara; Schomaker, Markus; Heinemann, Dag; Ripken, Tammo; Meyer, Heiko

    2014-01-01

    Gold nanoparticle mediated (GNOME) laser transfection/perforation fulfills the demands of a reliable transfection technique. It provides efficient delivery and has a negligible impact on cell viability. Furthermore, it reaches high-throughput applicability. However, currently only large gold particles (> 80 nm) allow successful GNOME laser perforation, probably due to insufficient sedimentation of smaller gold nanoparticles. The objective of this study is to determine whether this aspect can be addressed by a modification of silica particles with gold nanoparticles. Throughout the analysis, we show that after the attachment of gold nanoparticles to silica particles, comparable or better efficiencies to GNOME laser perforation are reached. In combination with 1 µm silica particles, we report laser perforation with gold nanoparticles with sizes down to 4 nm. Therefore, our investigations have great importance for the future research in and the fields of laser transfection combined with plasmonics. PMID:25136494

  15. Interaction of gold nanoparticles with nanosecond laser pulses: Nanoparticle heating

    International Nuclear Information System (INIS)

    Nedyalkov, N.N.; Imamova, S.E.; Atanasov, P.A.; Toshkova, R.A.; Gardeva, E.G.; Yossifova, L.S.; Alexandrov, M.T.; Obara, M.

    2011-01-01

    Theoretical and experimental results on the heating process of gold nanoparticles irradiated by nanosecond laser pulses are presented. The efficiency of particle heating is demonstrated by in-vitro photothermal therapy of human tumor cells. Gold nanoparticles with diameters of 40 and 100 nm are added as colloid in the cell culture and the samples are irradiated by nanosecond pulses at wavelength of 532 nm delivered by Nd:YAG laser system. The results indicate clear cytotoxic effect of application of nanoparticle as more efficient is the case of using particles with diameter of 100 nm. The theoretical analysis of the heating process of nanoparticle interacting with laser radiation is based on the Mie scattering theory, which is used for calculation of the particle absorption coefficient, and two-dimensional heat diffusion model, which describes the particle and the surrounding medium temperature evolution. Using this model the dependence of the achieved maximal temperature in the particles on the applied laser fluence and time evolution of the particle temperature is obtained.

  16. Interaction of gold nanoparticles with nanosecond laser pulses: Nanoparticle heating

    Science.gov (United States)

    Nedyalkov, N. N.; Imamova, S. E.; Atanasov, P. A.; Toshkova, R. A.; Gardeva, E. G.; Yossifova, L. S.; Alexandrov, M. T.; Obara, M.

    2011-04-01

    Theoretical and experimental results on the heating process of gold nanoparticles irradiated by nanosecond laser pulses are presented. The efficiency of particle heating is demonstrated by in-vitro photothermal therapy of human tumor cells. Gold nanoparticles with diameters of 40 and 100 nm are added as colloid in the cell culture and the samples are irradiated by nanosecond pulses at wavelength of 532 nm delivered by Nd:YAG laser system. The results indicate clear cytotoxic effect of application of nanoparticle as more efficient is the case of using particles with diameter of 100 nm. The theoretical analysis of the heating process of nanoparticle interacting with laser radiation is based on the Mie scattering theory, which is used for calculation of the particle absorption coefficient, and two-dimensional heat diffusion model, which describes the particle and the surrounding medium temperature evolution. Using this model the dependence of the achieved maximal temperature in the particles on the applied laser fluence and time evolution of the particle temperature is obtained.

  17. Functional gold nanoparticles for optical affinity biosensing

    Czech Academy of Sciences Publication Activity Database

    Špringer, Tomáš; Chadtová Song, Xue; Ermini, Maria Laura; Lamačová, Josefína; Homola, Jiří

    2017-01-01

    Roč. 409, č. 16 (2017), s. 4087-4097 ISSN 1618-2642 R&D Projects: GA ČR(CZ) GBP205/12/G118 Grant - others:AV ČR(CZ) AP1101 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985882 Keywords : Gold nanoparticles * Cancer marker carcinoembryonic antigen * Surface plasmon resonance Subject RIV: FS - Medical Facilities ; Equipment OBOR OECD: Medical laboratory technology (including laboratory samples analysis Impact factor: 3.431, year: 2016

  18. Multifunctional gold nanoparticles for diagnosis and therapy of disease

    NARCIS (Netherlands)

    Mieszawska, Aneta J.; Mulder, Willem J. M.; Fayad, Zahi A.; Cormode, David P.

    2013-01-01

    Gold nanoparticles (AuNPs) have a number of physical properties that make them appealing for medical applications. For example, the attenuation of X-rays by gold nanoparticles has led to their use in computed tomography imaging and as adjuvants for radiotherapy. AuNPs have numerous other

  19. Green Chemistry Techniques for Gold Nanoparticles Synthesis

    Science.gov (United States)

    Cannavino, Sarah A.; King, Christy A.; Ferrara, Davon W.

    Gold nanoparticles (AuNPs) are often utilized in many technological and research applications ranging from the detection of tumors, molecular and biological sensors, and as nanoantennas to probe physical processes. As these applications move from the research laboratory to industrial settings, there is a need to develop efficient and sustainable synthesis techniques. Recent research has shown that several food products and beverages containing polyphenols, a common antioxidant, can be used as reducing agents in the synthesis of AuNPs in solution. In this study, we explore a variety of products to determine which allow for the most reproducible solution of nanoparticles based on the size and shapes of particles present. We analyzed the AuNPs solutions using extinction spectroscopy and atomic force microscopy. We also develop a laboratory activity to introduce introductory chemistry and physics students to AuNP synthesis techniques and analysis.

  20. Colorimetric gold nanoparticles-based aptasensors

    Directory of Open Access Journals (Sweden)

    Rezavn Yazdian-Robati

    2018-01-01

    Full Text Available Recognition of different agents including chemical and biological plays important role in forensic, biomedical and environmentalfield.In recent decades, nanotechnology and nano materials had a high impact on development of sensors. Using  nanomaterials in construction of biosensors can effectively improve the Sensitivity and other features of biosensors. Different type of nanostructures including nanotubes, nanodiamonds, thin films ,nanorods, nanoparticles(NP, nanofibers andvarious clusters have been explored and applied in construction of biosensors. Among nanomaterials mentioned above, gold nanoparticle (GNPas a new class of unique fluorescence quenchers, is receiving significant attention in developing of optical biosensors because of their unique physical, chemical and biological properties. In this mini review, we discussed the use of GNPs in construction of colorimetric aptasensorsas a class of optical sensors for detection of antibiotics, toxins and infection diseases.

  1. Electrocatalytic glucose oxidation at gold and gold-carbon nanoparticulate film prepared from oppositely charged nanoparticles

    International Nuclear Information System (INIS)

    Karczmarczyk, Aleksandra; Celebanska, Anna; Nogala, Wojciech; Sashuk, Volodymyr; Chernyaeva, Olga; Opallo, Marcin

    2014-01-01

    Graphical abstract: - Highlights: • Gold nanoparticulate film electrodes were prepared by layer-by-layer method from oppositely charged nanoparticles. • Positively charged nanoparticles play dominant role in glucose oxidation in alkaline solution. • Gold and gold-carbon nanoparticulate film electrodes exhibit similar glucose oxidation current and onset potential. - Abstract: Electrocatalytic oxidation of glucose was studied at nanoparticulate gold and gold-carbon film electrodes. These electrodes were prepared by a layer-by-layer method without application of any linker molecules. Gold nanoparticles were stabilized by undecane thiols functionalized by trimethyl ammonium or carboxylate groups, whereas the carbon nanoparticles were covered by phenylsulfonate functionalities. The gold nanoparticulate electrodes were characterized by UV-vis and XPS spectroscopy, atomic force microscopy and voltammetry, before and after heat-treatment. Heat-treatment facilitates the aggregation of the nanoparticles and affects the structure of the film. The comparison of the results obtained with film electrodes prepared from gold nanoparticles with the same charge and with gold-carbon nanoparticulate electrodes, proved that positively charged nanoparticles are responsible for the high electrocatalytic activity, whereas negatively charged ones act rather as a linker of the film

  2. Ultrasensitive interdigitated capacitance immunosensor using gold nanoparticles

    Science.gov (United States)

    Alizadeh Zeinabad, Hojjat; Ghourchian, Hedayatollah; Falahati, Mojtaba; Fathipour, Morteza; Azizi, Marzieh; Boutorabi, Seyed Mehdi

    2018-06-01

    Immunosensors based on interdigitated electrodes (IDEs), have recently demonstrated significant improvements in the sensitivity of capacitance detection. Herein, a novel type of highly sensitive, compact and portable immunosensor based on a gold interdigital capacitor has been designed and developed for the rapid detection of hepatitis B surface antigen (HBsAg). To improve the efficiency of antibody immobilization and time-saving, a self-assembled monolayer (SAM) of 2-mercaptoethylamine film was coated on IDEs. Afterwards, carboxyl groups on primary antibodies were activated through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and were immobilized on amino-terminated SAM for better control of the oriented immobilization of antibodies on gold IDEs. In addition, gold nanoparticles conjugated with a secondary antibody were used to enhance the sensitivity. Under optimal conditions, the immunosensor exhibited the sensitivity of 0.22 nF.pg ml–1, the linear range from 5 pg ml‑1 to 1 ng ml–1 and the detection limit of 1.34 pg ml‑1, at a signal-to-noise ratio of 3.

  3. Temperature driven transport of gold nanoparticles physisorbed inside carbon nanotubes

    DEFF Research Database (Denmark)

    Schoen, P.A.E.; Poulikakos, D.; Walther, Jens Honore

    2006-01-01

    We use molecular dynamics simulations to demonstrate the temperature driven mass transport of solid gold nanoparticles, physisorbed inside carbon nanotubes (CNTs). Our results indicate that the nanoparticle experiences a guided motion, in the direction opposite to the direction of the temperature...... affects the nanoparticle motion along the carbon lattice....

  4. Phytofabricated gold nanoparticles and their biomedical applications.

    Science.gov (United States)

    Ahmad, Bashir; Hafeez, Nabia; Bashir, Shumaila; Rauf, Abdur; Mujeeb-Ur-Rehman

    2017-05-01

    In a couple of decades, nanotechnology has become a trending technology owing to its integrated science collection that incorporates variety of fields such as chemistry, physics, medicine, catalytic processes, food processing industries, electronics and energy sectors. One of the emerging fields of nanotechnology that has gained momentous admiration is nano-biotechnology. Nano-biotechnology is an integrated combination of biology with nanotechnology that encompasses the tailoring, and synthesis of small particles that are less than 100nm in size and subsequent exploitation of these particles for their biological applications. Though the variety of physical techniques and chemical procedures are known for the nanoparticles synthesis, biological approach is considered to be the preferred one. Environmental hazards and concerns associated with the physical and chemical approaches of nanoparticles synthesis has added impetus and zenith to the biological approach involving the use of plants and microorganisms. The current review article is focused on the synthesis of plant-derived (phytochemical) gold nanoparticles alongside their scope in biomedical applications. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  5. Pseudo-template synthesis of gold nanoparticles based on polyhydrosilanes

    International Nuclear Information System (INIS)

    Sacarescu, Liviu; Simionescu, Mihaela; Sacarescu, Gabriela

    2011-01-01

    Highly stable colloidal gold nanoparticles are obtained in a pseudo-template system using a specific polyhydrosilane copolymeric structure. This process takes place in situ by microwaves activation of the polymer solution in a non-polar solvent followed by stirring with solid HAuCl 4 in natural light. The experimental procedure is very simple and the resulted colloidal gold solution is indefinitely stable. The specific surface plasmon resonance absorption band of the gold nanoparticles is strongly red shifted and is strictly related to their size. AFM correlated with DLS analysis showed flattened round shaped colloidal polymer-gold nanoparticles with large diameters. SEM-EDX combined analysis reveals that the polysilane-gold nanoparticles show a natural tendency to auto-assemble in close packed structures which form large areas over the polymer film surface.

  6. Phospholipid-assisted synthesis of size-controlled gold nanoparticles

    International Nuclear Information System (INIS)

    He Peng; Zhu Xinyuan

    2007-01-01

    Morphology and size control of gold nanoparticles (AuNPs) by phospholipids (PLs) has been reported. It was found that gold entities could form nanostructures with different sizes controlled by PLs in an aqueous solution. During the preparation of 1.5 nm gold seeds, AuNPs were obtained from the reduction of gold complex by sodium borohydride and capped by citrate for stabilization. With the different ratios between seed solution and growth solution, which was composed by gold complex and PLs, gold seeds grew into larger nanoparticles step by step until enough large size up to 30 nm. The main discovery of this work is that common biomolecules, such as PLs can be used to control nanoparticle size. This conclusion has been confirmed by transmission electron micrographs, particle size analysis, and UV-vis spectra

  7. GOLD NANOPARTICLES: A REVIVAL IN PRECIOUS METAL ADMINISTRATION TO PATIENTS

    Science.gov (United States)

    Thakor, AS; Jokerst, J; Zaveleta, C; Massoud, TF; Gambhir, SS

    2011-01-01

    Gold has been used as a therapeutic agent to treat a wide variety of rheumatic diseases including psoriatic arthritis, juvenile arthritis and discoid lupus erythematosus. Although the use of gold has been largely superseded by newer drugs, gold nanoparticles are being used effectively in laboratory based clinical diagnostic methods whilst concurrently showing great promise in vivo either as a diagnostic imaging agent or a therapeutic agent. For these reasons, gold nanoparticles are therefore well placed to enter mainstream clinical practice in the near future. Hence, the present review summarizes the chemistry, pharmacokinetics, bio-distribution, metabolism and toxicity of bulk gold in humans based on decades of clinical observation and experiments in which gold was used to treat patients with rheumatoid arthritis. The beneficial attributes of gold nanoparticles, such as their ease of synthesis, functionalization and shape control are also highlighted demonstrating why gold nanoparticles are an attractive target for further development and optimization. The importance of controlling the size and shape of gold nanoparticles to minimize any potential toxic side effects is also discussed. PMID:21846107

  8. Multifunctional gold nanoparticles for diagnosis and therapy of disease

    Science.gov (United States)

    Mieszawska, Aneta J.; Mulder, Willem J. M.; Fayad, Zahi A.

    2013-01-01

    Gold nanoparticles (AuNPs) have a number of physical properties that make them appealing for medical applications. For example, the attenuation of X-rays by gold nanoparticles has led to their use in computed tomography imaging and as adjuvants for radiotherapy. AuNPs have numerous other applications in imaging, therapy and diagnostic systems. The advanced state of synthetic chemistry of gold nanoparticles offers precise control over physicochemical and optical properties. Furthermore gold cores are inert and are considered to be biocompatible and non-toxic. The surface of gold nanoparticles can easily be modified for a specific application and ligands for targeting, drugs or biocompatible coatings can be introduced. AuNPs can be incorporated into larger structures such as polymeric nanoparticles or liposomes that deliver large payloads for enhanced diagnostic applications, efficiently encapsulate drugs for concurrent therapy or add additional imaging labels. This array of features has led to the afore-mentioned applications in biomedical fields, but more recently in approaches where multifunctional gold nanoparticles are used for multiple methods, such as concurrent diagnosis and therapy, so called theranostics. The following review covers basic principles and recent findings in gold nanoparticle applications for imaging, therapy and diagnostics, with a focus on reports of multifunctional AuNPs. PMID:23360440

  9. Polyethylenimine-mediated synthetic insertion of gold nanoparticles into mesoporous silica nanoparticles for drug loading and biocatalysis.

    Science.gov (United States)

    Pandey, Prem C; Pandey, Govind; Narayan, Roger J

    2017-03-27

    Mesoporous silica nanoparticles (MSNPs) have been used as an efficient and safe carrier for drug delivery and biocatalysis. The surface modification of MSNPs using suitable reagents may provide a robust framework in which two or more components can be incorporated to give multifunctional capabilities (e.g., synthesis of noble metal nanoparticles within mesoporous architecture along with loading of a bioactive molecule). In this study, the authors reported on a new synthetic route for the synthesis of gold nanoparticles (AuNPs) within (1) unmodified MSNPs and (2) 3-trihydroxysilylpropyl methylphosphonate-modified MSNPs. A cationic polymer, polyethylenimine (PEI), and formaldehyde were used to mediate synthetic incorporation of AuNPs within MSNPs. The AuNPs incorporated within the mesoporous matrix were characterized by transmission electron microscopy, energy dispersive x-ray analysis, and high-resolution scanning electron microscopy. PEI in the presence of formaldehyde enabled synthetic incorporation of AuNPs in both unmodified and modified MSNPs. The use of unmodified MSNPs was associated with an increase in the polycrystalline structure of the AuNPs within the MSNPs. The AuNPs within modified MSNPs showed better catalytic activity than those within unmodified MSNPs. MSNPs with an average size of 200 nm and with a pore size of 4-6 nm were used for synthetic insertion of AuNPs. It was found that the PEI coating enabled AuNPs synthesis within the mesopores in the presence of formaldehyde or tetrahydrofuran hydroperoxide at a temperature between 10 and 25 °C or at 60 °C in the absence of organic reducing agents. The as-made AuNP-inserted MSNPs exhibited enhanced catalytic activity. For example, these materials enabled rapid catalytic oxidation of the o-dianisidine substrate to produce a colored solution in proportion to the amount of H 2 O 2 generated as a function of glucose oxidase-catalyzed oxidation of glucose; a linear concentration range from 80 to

  10. Biodistribution of gold nanoparticles following intratracheal instillation in mouse lung

    DEFF Research Database (Denmark)

    Sadauskas, Evaldas; Jacobsen, Nicklas R.; Danscher, Gorm

    2009-01-01

    plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA). The liver is the major site of deposition of circulating gold nanoparticles. Therefore the degree of translocation was determined by the hepatic deposition of gold. Mice were instilled with 5 intratracheal doses of gold...... repeatedly during 3 weeks, the load was substantial. Ultrastructurally, AMG silver enhanced gold nanoparticles were found in lysosome-/endosome-like organelles of the macrophages and analysis with AMG, ICP-MS and NAA of the liver revealed an almost total lack of translocation of nanoparticles. In mice given...... repeated instillations of 2 nm gold nanoparticles, 1.4‰ (by ICP-MS) to 1.9‰ (by NAA) of the instilled gold was detected in the liver. With the 40 nm gold, no gold was detected in the liver (detection level 2 ng, 0.1‰) except for one mouse in which 3‰ of the instilled gold was found in the liver. No gold...

  11. Multifunctional gold nanoparticles for photodynamic therapy of cancer

    Science.gov (United States)

    Khaing Oo, Maung Kyaw

    As an important and growing branch of photomedicine, photodynamic therapy (PDT) is being increasingly employed in clinical applications particularly for the treatment of skin cancer. This dissertation focuses on the synthesis, characterization and deployment of gold nanoparticles for enhanced PDT of fibrosarcoma cancer cells. We have developed robust strategies and methods in fabrication of gold nanoparticles with positively- and negatively-tethered surface charges by photo-reduction of gold chloride salt using branched polyethyleneimine and sodium citrate respectively. An optimal concentration window of gold salt has been established to yield the most stable and monodispersed gold nanoparticles. 5-aminolevulinic acid (5-ALA), a photosensitizing precursor, has been successfully conjugated on to positively charged gold nanoparticles through electrostatic interactions. The 5-ALA/gold nanoparticle conjugates are biocompatible and have shown to be preferably taken up by cancer cells. Subsequent light irradiation results in the generation of reactive oxygen species (ROS) in cancer cells, leading to their destruction without adverse effects on normal fibroblasts. We have demonstrated for the first time that gold nanoparticles can enhance PDT efficacy by 50% compared to the treatment with 5-ALA alone. Collected evidence has strongly suggested that this enhancement stems from the elevated formation of ROS via the strongly localized electric field of gold nanoparticles. Through single cell imaging using surface-enhanced Raman scattering enabled by the very same gold nanoparticles, we have shown that multifunctionality of gold nanoparticles can be harvested concurrently for biomedical applications in general and for PDT in specific. In other words, gold nanoparticles can be used not only for targeted drug delivery and field-enhanced ROS formation, but also for monitoring cell destructions during PDT. Finally, our COMSOL Multiphysics simulation of the size-dependent electric

  12. Synthesis of gold nanoparticles with different atomistic structural characteristics

    International Nuclear Information System (INIS)

    Esparza, R.; Rosas, G.; Lopez Fuentes, M.; Sanchez Ramirez, J.F.; Pal, U.; Ascencio, J.A.; Perez, R.

    2007-01-01

    A chemical reduction method was used to produce nanometric gold particles. Depending on the concentration of the main reactant compound different nanometric sizes and consequently different atomic structural configurations of the particles are obtained. Insights on the structural nature of the gold nanoparticles are obtained through a comparison between digitally-processed experimental high-resolution electron microscopy images and theoretically-simulated images obtained with a multislice approach of the dynamical theory of electron diffraction. Quantum molecular mechanical calculations, based on density functional theory, are carried out to explain the relationships between the stability of the gold nanoparticles, the atomic structural configurations and the size of nanoparticles

  13. The use of gold nanoparticles to enhance radiotherapy in mice

    International Nuclear Information System (INIS)

    Hainfeld, James F; Slatkin, Daniel N; Smilowitz, Henry M

    2004-01-01

    Mice bearing subcutaneous EMT-6 mammary carcinomas received a single intravenous injection of 1.9 nm diameter gold particles (up to 2.7 g Au/kg body weight), which elevated concentrations of gold to 7 mg Au/g in tumours. Tumour-to-normal-tissue gold concentration ratios remained ∼8:1 during several minutes of 250 kVp x-ray therapy. One-year survival was 86% versus 20% with x-rays alone and 0% with gold alone. The increase in tumours safely ablated was dependent on the amount of gold injected. The gold nanoparticles were apparently non-toxic to mice and were largely cleared from the body through the kidneys. This novel use of small gold nanoparticles permitted achievement of the high metal content in tumours necessary for significant high-Z radioenhancement. (note)

  14. Gold Nanoparticle Conjugation Enhances the Antiacanthamoebic Effects of Chlorhexidine

    Science.gov (United States)

    Aqeel, Yousuf; Siddiqui, Ruqaiyyah; Anwar, Ayaz; Shah, Muhammad Raza

    2015-01-01

    Acanthamoeba keratitis is a serious infection with blinding consequences and often associated with contact lens wear. Early diagnosis, followed by aggressive topical application of drugs, is a prerequisite in successful treatment, but even then prognosis remains poor. Several drugs have shown promise, including chlorhexidine gluconate; however, host cell toxicity at physiologically relevant concentrations remains a challenge. Nanoparticles, subcolloidal structures ranging in size from 10 to 100 nm, are effective drug carriers for enhancing drug potency. The overall aim of the present study was to determine whether conjugation with gold nanoparticles enhances the antiacanthamoebic potential of chlorhexidine. Gold-conjugated chlorhexidine nanoparticles were synthesized. Briefly, gold solution was mixed with chlorhexidine and reduced by adding sodium borohydride, resulting in an intense deep red color, indicative of colloidal gold-conjugated chlorhexidine nanoparticles. The synthesis was confirmed using UV-visible spectrophotometry that shows a plasmon resonance peak of 500 to 550 nm, indicative of gold nanoparticles. Further characterization using matrix-assisted laser desorption ionization-mass spectrometry showed a gold-conjugated chlorhexidine complex at m/z 699 ranging in size from 20 to 100 nm, as determined using atomic force microscopy. To determine the amoebicidal and amoebistatic effects, amoebae were incubated with gold-conjugated chlorhexidine nanoparticles. For controls, amoebae also were incubated with gold and silver nanoparticles alone, chlorhexidine alone, neomycin-conjugated nanoparticles, and neomycin alone. The findings showed that gold-conjugated chlorhexidine nanoparticles exhibited significant amoebicidal and amoebistatic effects at 5 μM. Amoebicidal effects were observed by parasite viability testing using a Trypan blue exclusion assay and flow-cytometric analysis using propidium iodide, while amoebistatic effects were observed using growth

  15. Circular magnetoplasmonic modes in gold nanoparticles.

    Science.gov (United States)

    Pineider, Francesco; Campo, Giulio; Bonanni, Valentina; Fernández, César de Julián; Mattei, Giovanni; Caneschi, Andrea; Gatteschi, Dante; Sangregorio, Claudio

    2013-10-09

    The quest for efficient ways of modulating localized surface plasmon resonance is one of the frontiers in current research in plasmonics; the use of a magnetic field as a source of modulation is among the most promising candidates for active plasmonics. Here we report the observation of magnetoplasmonic modes on colloidal gold nanoparticles detected by means of magnetic circular dichroism (MCD) spectroscopy and provide a model that is able to rationalize and reproduce the experiment with unprecedented qualitative and quantitative accuracy. We believe that the steep slope observed at the plasmon resonance in the MCD spectrum can be very efficient in detecting changes in the refractive index of the surrounding medium, and we give a simple proof of principle of its possible implementation for magnetoplasmonic refractometric sensing.

  16. A gold-nanoparticle stoppered [2]rotaxane

    DEFF Research Database (Denmark)

    Ulfkjær, Anne; Nielsen, Frederik W; Al-Kerdi, Hana

    2018-01-01

    into real devices are still eminent. Nano-sized molecular machines operate the complex biological machinery of life, and the idea of mimicking the amazing functions using artificial nano-structures is intriguing. Both in small-molecule molecular machine components and in many naturally occurring molecular......The construction of molecular machines has captured the imagination of scientists for decades. Despite significant progress in the synthesis and studies of the properties of small-molecule components (smaller than 2-5 kilo Dalton), challenges regarding the incorporation of molecular components...... machines, mechanically interlocked molecules and structures are key functional components. In this work, we describe our initial efforts to interface mechanically-interlocked molecules and gold-nanoparticles (AuNPs); the molecular wire connecting the AuNPs is covered in an insulating rotaxane-layer, thus...

  17. Optical Properties of Linoleic Acid Protected Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Ratan Das

    2011-01-01

    Full Text Available Linoleic acid-protected gold nanoparticles have been synthesized through the chemical reduction of tetrachloroaurate ions by ethanol in presence of sodium linoleate. The structure of these nanoparticles is investigated using transmission electron microscopy, which shows that the Au nanoparticles are spherical in shape with a narrow size distribution which ranges from 8 to 15 nm. Colloidal dispersion of gold nanoparticles in cyclohexane exhibits absorption bands in the ultraviolet-visible range due to surface plasmon resonance, with absorption maximum at 530 nm. Fluorescence spectra of gold nanoparticles also show an emission peak at 610 nm when illuminated at 450 nm. UV-Vis spectroscopy reveals that these nanoparticles remain stable for 10 days.

  18. Quantitative detection of gold nanoparticles on individual, unstained cancer cells by Scanning Electron Microscopy

    NARCIS (Netherlands)

    Hartsuiker, Liesbeth; van Es, Peter; Petersen, Wilhelmina; van Leeuwen, Ton; Terstappen, Leonardus Wendelinus Mathias Marie; Otto, Cornelis

    2011-01-01

    Gold nanoparticles are rapidly emerging for use in biomedical applications. Characterization of the interaction and delivery of nanoparticles to cells through microscopy is important. Scanning electron microscopes have the intrinsic resolution to visualize gold nanoparticles on cells. A novel sample

  19. Quantitative detection of gold nanoparticles on individual, unstained cancer cells by scanning electron microscopy

    NARCIS (Netherlands)

    Hartsuiker, L.; van Es, P.; Petersen, W.; van Leeuwen, T. G.; Terstappen, L. W. M. M.; Otto, C.

    2011-01-01

    Gold nanoparticles are rapidly emerging for use in biomedical applications. Characterization of the interaction and delivery of nanoparticles to cells through microscopy is important. Scanning electron microscopes have the intrinsic resolution to visualize gold nanoparticles on cells. A novel sample

  20. Fabrication of gold nanoparticle arrays by block copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiao Ling

    2011-02-15

    Gold nanoparticle is one of the widely research objects in various fields including catalysis and biotechnology. Precise control of gold nanoparticles placement and their integration is essential to take full advantage of these unique properties for applications. An approach to self-assembling of gold nanoparticles (AuNPs) from reconstructed block copolymer was introduced. Highly ordered polystyrene-block-poly(2-vinylpyridine)(PS-b-P2VP) micellar arrays were obtained by solvent annealing. Subsequent immersion of the films in a preferential solvent for P2VP caused a reorganization of the film to generate a porous structure upon drying. PEG-coated AuNPs were spin-coated onto this reconstruction PS-b-P2VP template. When such films were exposed to toluene vapor-which is non-selective solvent for PEO and P2VP, AuNPs were drawn into those porous to form ordered arrays. Gold nanospheres with size 12±1.8 nm were synthesized by reducing HAuCl{sub 4} via sodium citrate. Gold nanorods (aspect ratio about 6) were prepared from seed-mediated surfactant capping wet chemical method and the aspect ratio is tunable by changing surfactant amount. PEG ligand is used to modify gold nanoparticle surface by removing the original surfactant (sodium citrate -gold nanospheres: CTAB-gold nanorods), which have affinity with certain block copolymer component. Once gold nanoparticle is modified with PEG thiol, they were spin coated onto PS-b-P2VP template, which was prepared by solvent annealing and surface reconstruction process. So gold nanoparticle array was fabricated by this self-assembling process. The same idea can be applied on other nanoparticles.

  1. Fabrication of gold nanoparticle arrays by block copolymer

    International Nuclear Information System (INIS)

    Chen, Xiao Ling

    2011-02-01

    Gold nanoparticle is one of the widely research objects in various fields including catalysis and biotechnology. Precise control of gold nanoparticles placement and their integration is essential to take full advantage of these unique properties for applications. An approach to self-assembling of gold nanoparticles (AuNPs) from reconstructed block copolymer was introduced. Highly ordered polystyrene-block-poly(2-vinylpyridine)(PS-b-P2VP) micellar arrays were obtained by solvent annealing. Subsequent immersion of the films in a preferential solvent for P2VP caused a reorganization of the film to generate a porous structure upon drying. PEG-coated AuNPs were spin-coated onto this reconstruction PS-b-P2VP template. When such films were exposed to toluene vapor-which is non-selective solvent for PEO and P2VP, AuNPs were drawn into those porous to form ordered arrays. Gold nanospheres with size 12±1.8 nm were synthesized by reducing HAuCl 4 via sodium citrate. Gold nanorods (aspect ratio about 6) were prepared from seed-mediated surfactant capping wet chemical method and the aspect ratio is tunable by changing surfactant amount. PEG ligand is used to modify gold nanoparticle surface by removing the original surfactant (sodium citrate -gold nanospheres: CTAB-gold nanorods), which have affinity with certain block copolymer component. Once gold nanoparticle is modified with PEG thiol, they were spin coated onto PS-b-P2VP template, which was prepared by solvent annealing and surface reconstruction process. So gold nanoparticle array was fabricated by this self-assembling process. The same idea can be applied on other nanoparticles

  2. Extracellular mycosynthesis of gold nanoparticles using Fusarium solani

    Science.gov (United States)

    Gopinath, K.; Arumugam, A.

    2014-08-01

    The development of eco-friendly methods for the synthesis of nanomaterial shape and size is an important area of research in the field of nanotechnology. The present investigation deals with the extracellular rapid biosynthesis of gold nanoparticles using Fusarium solani culture filtrate. The UV-vis spectra of the fungal culture filtrate medium containing gold ion showed peak at 527 nm corresponding to the plasmon absorbance of gold nanoparticles. FTIR spectra provide an evidence for the presence of heterocyclic compound in the culture filtrate, which increases the stability of the synthesized gold nanoparticles. The X-ray analysis respects the Bragg's law and confirmed the crystalline nature of the gold nanoparticles. AFM analysis showed the results of particle sizes (41 nm). Transmission electron microscopy (TEM) showed that the gold nanoparticles are spherical in shape with the size range from 20 to 50 nm. The use of F. solani will offer several advantages since it is considered as a non-human pathogenic organism. The fungus F. solani has a fast growth rate, rapid capacity of metallic ions reduction, NPs stabilization and facile and economical biomass handling. Extracellular biosynthesis of gold nanoparticles could be highly advantageous from the point of view of synthesis in large quantities, time consumption, eco-friendly, non-toxic and easy downstream processing.

  3. Preparation and bactericide activity of gallic acid stabilized gold nanoparticles

    International Nuclear Information System (INIS)

    Moreno-Alvarez, S. A.; Martinez-Castanon, G. A.; Nino-Martinez, N.; Reyes-Macias, J. F.; Patino-Marin, N.; Loyola-Rodriguez, J. P.; Ruiz, Facundo

    2010-01-01

    In this work, gold nanoparticles with three different sizes (13.7, 39.4, and 76.7 nm) were prepared using a simple aqueous method with gallic acid as the reducing and stabilizing agent, the different sizes were obtained varying some experimental parameters as the pH of the reaction and the amount of the gallic acid. The prepared nanoparticles were characterized using X-ray diffraction, transmission electron microscopy, dynamic light scattering, and UV-Vis spectroscopy. Samples were identified as elemental gold and present spherical morphology, a narrow size distribution and good stabilization according to TEM and DLS results. The antibacterial activity of this gallic acid stabilized gold nanoparticles against S. mutans (the etiologic agent of dental caries) was assessed using a microdilution method obtaining a minimum inhibitory concentration of 12.31, 12.31, and 49.25 μg/mL for 13.7, 39.4, and 76.7 nm gold nanoparticles, respectively. The antibacterial assay showed that gold nanoparticles prepared in this work present a bactericide activity by a synergistic action with gallic acid. The MIC found for this nanoparticles are much lower than those reported for mixtures of gold nanoparticles and antibiotics.

  4. Preparation and bactericide activity of gallic acid stabilized gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Alvarez, S. A. [UASLP, Doctorado Institucional en Ingenieria y Ciencia de Materiales (Mexico); Martinez-Castanon, G. A., E-mail: mtzcastanon@fciencias.uaslp.m [UASLP, Maestria en Ciencias Odontologicas, Facultad de Estomatologia (Mexico); Nino-Martinez, N. [UASLP, Facultad de Ciencias (Mexico); Reyes-Macias, J. F.; Patino-Marin, N.; Loyola-Rodriguez, J. P. [UASLP, Maestria en Ciencias Odontologicas, Facultad de Estomatologia (Mexico); Ruiz, Facundo [UASLP, Facultad de Ciencias (Mexico)

    2010-10-15

    In this work, gold nanoparticles with three different sizes (13.7, 39.4, and 76.7 nm) were prepared using a simple aqueous method with gallic acid as the reducing and stabilizing agent, the different sizes were obtained varying some experimental parameters as the pH of the reaction and the amount of the gallic acid. The prepared nanoparticles were characterized using X-ray diffraction, transmission electron microscopy, dynamic light scattering, and UV-Vis spectroscopy. Samples were identified as elemental gold and present spherical morphology, a narrow size distribution and good stabilization according to TEM and DLS results. The antibacterial activity of this gallic acid stabilized gold nanoparticles against S. mutans (the etiologic agent of dental caries) was assessed using a microdilution method obtaining a minimum inhibitory concentration of 12.31, 12.31, and 49.25 {mu}g/mL for 13.7, 39.4, and 76.7 nm gold nanoparticles, respectively. The antibacterial assay showed that gold nanoparticles prepared in this work present a bactericide activity by a synergistic action with gallic acid. The MIC found for this nanoparticles are much lower than those reported for mixtures of gold nanoparticles and antibiotics.

  5. Bayesian object classification of gold nanoparticles

    KAUST Repository

    Konomi, Bledar A.; Dhavala, Soma S.; Huang, Jianhua Z.; Kundu, Subrata; Huitink, David; Liang, Hong; Ding, Yu; Mallick, Bani K.

    2013-01-01

    The properties of materials synthesized with nanoparticles (NPs) are highly correlated to the sizes and shapes of the nanoparticles. The transmission electron microscopy (TEM) imaging technique can be used to measure the morphological characteristics of NPs, which can be simple circles or more complex irregular polygons with varying degrees of scales and sizes. A major difficulty in analyzing the TEM images is the overlapping of objects, having different morphological properties with no specific information about the number of objects present. Furthermore, the objects lying along the boundary render automated image analysis much more difficult. To overcome these challenges, we propose a Bayesian method based on the marked-point process representation of the objects. We derive models, both for the marks which parameterize the morphological aspects and the points which determine the location of the objects. The proposed model is an automatic image segmentation and classification procedure, which simultaneously detects the boundaries and classifies the NPs into one of the predetermined shape families. We execute the inference by sampling the posterior distribution using Markov chainMonte Carlo (MCMC) since the posterior is doubly intractable. We apply our novel method to several TEM imaging samples of gold NPs, producing the needed statistical characterization of their morphology. © Institute of Mathematical Statistics, 2013.

  6. Bayesian object classification of gold nanoparticles

    KAUST Repository

    Konomi, Bledar A.

    2013-06-01

    The properties of materials synthesized with nanoparticles (NPs) are highly correlated to the sizes and shapes of the nanoparticles. The transmission electron microscopy (TEM) imaging technique can be used to measure the morphological characteristics of NPs, which can be simple circles or more complex irregular polygons with varying degrees of scales and sizes. A major difficulty in analyzing the TEM images is the overlapping of objects, having different morphological properties with no specific information about the number of objects present. Furthermore, the objects lying along the boundary render automated image analysis much more difficult. To overcome these challenges, we propose a Bayesian method based on the marked-point process representation of the objects. We derive models, both for the marks which parameterize the morphological aspects and the points which determine the location of the objects. The proposed model is an automatic image segmentation and classification procedure, which simultaneously detects the boundaries and classifies the NPs into one of the predetermined shape families. We execute the inference by sampling the posterior distribution using Markov chainMonte Carlo (MCMC) since the posterior is doubly intractable. We apply our novel method to several TEM imaging samples of gold NPs, producing the needed statistical characterization of their morphology. © Institute of Mathematical Statistics, 2013.

  7. Selective colorimetric sensors based on the monitoring of an unmodified silver nanoparticles (AgNPs) reduction for a simple and rapid determination of mercury

    Science.gov (United States)

    Jarujamrus, Purim; Amatatongchai, Maliwan; Thima, Araya; Khongrangdee, Thatsanee; Mongkontong, Chakrit

    2015-05-01

    In this work, selective colorimetric sensors for simple and rapid detection of Hg(II) ions based on the monitoring of an unmodified silver nanoparticles (AgNPs) reduction were developed. The average diameter of synthesized AgNPs was 8.3 ± 1.4 nm which was characterized by transmission electron microscopy (TEM). The abrupt change in absorbance of the unmodified AgNPs was observed which progressively decreased and slightly shifted to the blue wavelength as the concentration of Hg(II) increased, indicating the oxidation of Ag(0) to Ag(I) occurred. It appears that the AgNPs were oxidized by Hg(II), resulting in disintegration of the AgNPs into smaller particles as well as mediating the reduction of Hg(II) to Hg(0) adsorbed onto the surface of AgNPs. The adsorption of Hg(0) resulted in the lack of sufficient charges on AgNPs surfaces due to the decrease in the surface coverage of negatively charged citrate molecules, which then leaded to enlargement of AgNPs. The calibration curve of this technique was demonstrated from 0.5 to 7 ppm (r2 = 0.995), the limit of detection (LOD) was 0.06 ppm (SDblank/slope of calibration curve) with the precision (RSD, n = 4) of 3.24-4.53. Interestingly, the results show a significant enhance in the Hg(II) analytical sensitivity when Cu(II) is doped onto the unmodified AgNPs, which improves the quantitative detection limit to 0.008 ppm. In addition, greater selectivity toward Hg(II) compared with the other metal ions tested was observed. Furthermore, the percentage recoveries of spiked drinking water, tap water and SRM1641d (mercury in water) were in acceptable range with a good precision (RSD) which were in agreement with the values obtained from graphite furnace atomic absorption spectrometer (GFAAS). The technique proposed in this study provides a rapid, simple, sensitive and selective detection method for Hg(II) in water samples.

  8. Preparation of Gold Nanoparticles for Biomedical Applications Using ...

    African Journals Online (AJOL)

    HP

    Tropical Journal of Pharmaceutical Research June 2013; 12 (3): 295-298 ... Applications Using Chemometric Technique. Soheila Honary. 1* ... approach for optimizing and testing the robustness of gold nanoparticle preparation method.

  9. Size control synthesis of starch capped-gold nanoparticles

    International Nuclear Information System (INIS)

    Tajammul Hussain, S.; Iqbal, M.; Mazhar, M.

    2009-01-01

    Metallic gold nanoparticles have been synthesized by the reduction of chloroaurate anions [AuCl 4 ] - solution with hydrazine in the aqueous starch and ethylene glycol solution at room temperature and at atmospheric pressure. The characterization of synthesized gold nanoparticles by UV-vis spectroscopy, high resolution transmission electron microscopy (HRTEM), electron diffraction analysis, X-ray diffraction (XRD), and X-rays photoelectron spectroscopy (XPS) indicate that average size of pure gold nanoparticles is 3.5 nm, they are spherical in shape and are pure metallic gold. The concentration effects of [AuCl 4 ] - anions, starch, ethylene glycol, and hydrazine, on particle size, were investigated, and the stabilization mechanism of Au nanoparticles by starch polymer molecules was also studied by FT-IR and thermogravimetric analysis (TGA). FT-IR and TGA analysis shows that hydroxyl groups of starch are responsible of capping and stabilizing gold nanoparticles. The UV-vis spectrum of these samples shows that there is blue shift in surface plasmon resonance peak with decrease in particle size due to the quantum confinement effect, a supporting evidence of formation of gold nanoparticles and this shift remains stable even after 3 months.

  10. Synthesis of hexagonal gold nanoparticles using a microfluidic reaction system

    International Nuclear Information System (INIS)

    Weng, Chen-Hsun; Lee, Gwo-Bin; Huang, Chih-Chia; Yeh, Chen-Sheng; Lei, Huan-Yao

    2008-01-01

    A new microfluidic reaction system capable of mixing, transporting and reacting is developed for the synthesis of gold nanoparticles. It allows for a rapid and a cost-effective approach to accelerate the synthesis of gold nanoparticles. The microfluidic reaction chip is made from micro-electro-mechanical-system technologies which integrate a micro-mixer, micro-pumps, a micro-valve, micro-heaters and a micro temperature sensor on a single chip. Successful synthesis of dispersed gold nanoparticles has been demonstrated within a shorter period of time, as compared to traditional methods. It is experimentally found that precise control of the mixing/heating time for gold salts and reducing agents plays an essential role in the synthesis of gold nanoparticles. The growth process of hexagonal gold nanoparticles by a thermal aqueous approach is also systematically studied by using the same microfluidic reaction system. The development of the microfluidic reaction system could be promising for the synthesis of functional nanoparticles for future biomedical applications

  11. Grafting of gold nanoparticles on polyethyleneterephthalate using dithiol interlayer

    International Nuclear Information System (INIS)

    Reznickova, A.; Kolska, Z.; Zaruba, K.; Svorcik, V.

    2014-01-01

    Two different procedures of grafting of polyethyleneterephthalate (PET), modified by plasma treatment, with gold nanoparticles (nanospheres) are studied. In the first procedure the PET foil was grafted with biphenyl-4,4′-dithiol and subsequently with gold nanoparticles. In the second one the PET foil was grafted with gold nanoparticles previously coated by the same dithiol. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and electrokinetic analysis were used for characterization of the polymer surface at different modification steps. Gold nanoparticles were characterized by ultraviolet–visible spectroscopy. The first procedure was found to be more effective. It was proved that the dithiol was chemically bonded to the surface of the plasma activated PET and it mediates subsequent grafting of the gold nanoparticles. - Highlights: • Two different techniques were used for coating of PET with gold nanoparticles. • Grafted GNPs were characterized by XPS, FTIR, UV–vis, zeta potential, AFM. • More effective coating is achieved by deposition of GNPs earlier grafted with thiol. • The studied structures may have potential application in electronics or biomedicine

  12. Presenting Precision Glycomacromolecules on Gold Nanoparticles for Increased Lectin Binding

    Directory of Open Access Journals (Sweden)

    Sophia Boden

    2017-12-01

    Full Text Available Glyco-functionalized gold nanoparticles have great potential as biosensors and as inhibitors due to their increased binding to carbohydrate-recognizing receptors such as the lectins. Here we apply previously developed solid phase polymer synthesis to obtain a series of precision glycomacromolecules that allows for straightforward variation of their chemical structure as well as functionalization of gold nanoparticles by ligand exchange. A novel building block is introduced allowing for the change of spacer building blocks within the macromolecular scaffold going from an ethylene glycol unit to an aliphatic spacer. Furthermore, the valency and overall length of the glycomacromolecule is varied. All glyco-functionalized gold nanoparticles show high degree of functionalization along with high stability in buffer solution. Therefore, a series of measurements applying UV-Vis spectroscopy, dynamic light scattering (DLS and surface plasmon resonance (SPR were performed studying the aggregation behavior of the glyco-functionalized gold nanoparticles in presence of model lectin Concanavalin A. While the multivalent presentation of glycomacromolecules on gold nanoparticles (AuNPs showed a strong increase in binding compared to the free ligands, we also observed an influence of the chemical structure of the ligand such as its valency or hydrophobicity on the resulting lectin interactions. The straightforward variation of the chemical structure of the precision glycomacromolecule thus gives access to tailor-made glyco-gold nanoparticles (glyco-AuNPs and fine-tuning of their lectin binding properties.

  13. Synthesis, characterization and self-assembly with gold nanoparticles

    Indian Academy of Sciences (India)

    Administrator

    characterization and self-assembly with gold nanoparticles. JUN-BO LI. 1, ... gold surface lead to the enhancement of device prop- erties. 36,37 ... Reactions were monitored by thin-layer ..... plasmon (SP) absorption band (figure 5) of TOAB-.

  14. Toward efficient modification of large gold nanoparticles with DNA

    NARCIS (Netherlands)

    Gill, R.; Göeken, Kristian L; Subramaniam, V.

    2014-01-01

    DNA-coated gold nanoparticles are one of the most researched nano-bio hybrid systems. Traditionally their synthesis has been a long and tedious process, involving slow salt addition and long incubation steps. This stems from the fact that both DNA and gold particles are negatively charged, therefore

  15. Applications of Gold Nanoparticles in Nanomedicine: Recent Advances in Vaccines.

    Science.gov (United States)

    Carabineiro, Sónia Alexandra Correia

    2017-05-22

    Nowadays, gold is used in (nano-)medicine, usually in the form of nanoparticles, due to the solid proofs given of its therapeutic effects on several diseases. Gold also plays an important role in the vaccine field as an adjuvant and a carrier, reducing toxicity, enhancing immunogenic activity, and providing stability in storage. An even brighter golden future is expected for gold applications in this area.

  16. Generation of polypeptide-templated gold nanoparticles using ionizing radiation.

    Science.gov (United States)

    Walker, Candace Rae; Pushpavanam, Karthik; Nair, Divya Geetha; Potta, Thrimoorthy; Sutiyoso, Caesario; Kodibagkar, Vikram D; Sapareto, Stephen; Chang, John; Rege, Kaushal

    2013-08-13

    Ionizing radiation, including γ rays and X-rays, are high-energy electromagnetic radiation with diverse applications in nuclear energy, astrophysics, and medicine. In this work, we describe the use of ionizing radiation and cysteine-containing elastin-like polypeptides (C(n)ELPs, where n = 2 or 12 cysteines in the polypeptide sequence) for the generation of gold nanoparticles. In the presence of C(n)ELPs, ionizing radiation doses higher than 175 Gy resulted in the formation of maroon-colored gold nanoparticle dispersions, with maximal absorbance at 520 nm, from colorless metal salts. Visible color changes were not observed in any of the control systems, indicating that ionizing radiation, gold salt solution, and C(n)ELPs were all required for nanoparticle formation. The hydrodynamic diameters of nanoparticles, determined using dynamic light scattering, were in the range of 80-150 nm, while TEM imaging indicated the formation of gold cores 10-20 nm in diameter. Interestingly, C2ELPs formed 1-2 nm diameter gold nanoparticles in the absence of radiation. Our results describe a facile method of nanoparticle formation in which nanoparticle size can be tailored based on radiation dose and C(n)ELP type. Further improvements in these polypeptide-based systems can lead to colorimetric detection of ionizing radiation in a variety of applications.

  17. Gold Nanoparticles Obtained by Bio-precipitation from Gold(III) Solutions

    International Nuclear Information System (INIS)

    Gardea-Torresdey, J.L.; Tiemann, K.J.; Gamez, G.; Dokken, K.; Tehuacanero, S.; Jose-Yacaman, M.

    1999-01-01

    The use of metal nanoparticles has shown to be very important in recent industrial applications. Currently gold nanoparticles are being produced by physical methods such as evaporation. Biological processes may be an alternative to physical methods for the production of gold nanoparticles. Alfalfa biomass has shown to be effective at passively binding and reducing gold from solutions containing gold(III) ions and resulting in the formation of gold(0) nanoparticles. High resolution microscopy has shown that five different types of gold particles are present after reaction with gold(III) ions with alfalfa biomass. These particles include: fcc tetrahedral, hexagonal platelet, icosahedral multiple twinned, decahedral multiple twinned, and irregular shaped particles. Further analysis on the frequency of distribution has shown that icosahedral and irregular particles are more frequently formed. In addition, the larger particles observed may be formed through the coalescence of smaller particles. Through modification of the chemical parameters, more uniform particle size distribution may be obtained by the alfalfa bio-reduction of gold(III) from solution

  18. Reversible, reagentless solubility changes in phosphatidylcholine-stabilized gold nanoparticles

    International Nuclear Information System (INIS)

    Mackiewicz, Marilyn R; Ayres, Benjamin R; Reed, Scott M

    2008-01-01

    Phosphatidylcholine (PC) is a versatile ligand for synthesizing gold nanoparticles that are soluble in either organic or aqueous media. Here we report a novel route to organic-soluble, PC-stabilized gold nanoparticles that can be re-suspended in water after removal of the organic solvent. Similarly, we show that PC-stabilized gold nanoparticles synthesized in water can be re-suspended in organic solvents after complete removal of water. Without complete removal of the solvent, the nanoparticles retain their original solubility and do not phase transfer. This change in solvent preference from organic to aqueous and vice versa without the use of an additional phase transfer reagent is novel, visually striking, and of utility for synthetic modification of nanoparticles. This approach allows chemical reactions to be performed on nanoparticles in organic solvents followed by conversion of the products to water-soluble materials. A narrow distribution of PC-stabilized gold nanoparticles was obtained after phase transfer to water as characterized by UV-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM), demonstrating that the narrow distribution obtained from the organic synthesis is retained after transfer to water. This method produces water-soluble nanoparticles with a narrower dispersity than is possible with direct aqueous synthesis

  19. Uptake and depuration of gold nanoparticles in Daphnia magna

    DEFF Research Database (Denmark)

    Skjolding, Lars Michael; Kern, Kristina; Hjorth, Rune

    2014-01-01

    This study presents a series of short-term studies (total duration 48 h) of uptake and depuration of engineered nanoparticles (ENP) in neonate Daphnia magna. Gold nanoparticles (Au NP) were used to study the influence of size, stabilizing agent and feeding on uptake and depuration kinetics...

  20. A halogen-free synthesis of gold nanoparticles using gold(III) oxide

    International Nuclear Information System (INIS)

    Sashuk, Volodymyr; Rogaczewski, Konrad

    2016-01-01

    Gold nanoparticles are one of the most used nanomaterials. They are usually synthesized by the reduction of gold(III) chloride. However, the presence of halide ions in the reaction mixture is not always welcome. In some cases, these ions have detrimental influence on the morphology and structure of resulting nanoparticles. Here, we present a simple and halogen-free procedure to prepare gold nanoparticles by reduction of gold(III) oxide in neat oleylamine. The method provides the particles with an average size below 10 nm and dispersity of tens of percent. The process of nanoparticle formation was monitored using UV–Vis spectroscopy. The structure and chemical composition of the nanoparticles was determined by SEM, XPS and EDX. We also proposed the mechanism of reduction of gold(III) oxide based on MS, IR and NMR data. Importantly, the synthetic protocol is general and applicable for the preparation of other coinage metal nanoparticles from the corresponding metal oxides. For instance, we demonstrated that the absence of halogen enables efficient alloying of metals when preparing gold–silver bimetallic nanoparticles.

  1. Vibrational properties of gold nanoparticles obtained by green synthesis

    Science.gov (United States)

    Alvarez, Ramón A. B.; Cortez-Valadez, M.; Bueno, L. Oscar Neira; Britto Hurtado, R.; Rocha-Rocha, O.; Delgado-Beleño, Y.; Martinez-Nuñez, C. E.; Serrano-Corrales, Luis Ivan; Arizpe-Chávez, H.; Flores-Acosta, M.

    2016-10-01

    This study reports the synthesis and characterization of gold nanoparticles through an ecological method to obtain nanostructures from the extract of the plant Opuntia ficus-indica. Colloidal nanoparticles show sizes that vary between 10-20 nm, and present various geometric morphologies. The samples were characterized through optical absorption, Raman Spectroscopy and Transmission Electron Microscopy (TEM). Additionally, low energy metallic clusters of Aun (n=2-20 atoms) were modeled by computational quantum chemistry. The theoretical results were obtained with Density Functional Theory (DFT). The predicted results of Au clusters show a tendency and are correlated with the experimental results concerning the optical absorption bands and Raman spectroscopy in gold nanoparticles.

  2. Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng

    2014-01-01

    With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite-1 is reported and their high...... zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2-3nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50% conversion of ethanol with 98...

  3. Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng

    2014-01-01

    With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite‐1 is reported and their high...... zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2–3 nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50 % conversion of ethanol with 98...

  4. Minute synthesis of extremely stable gold nanoparticles.

    Science.gov (United States)

    Zhou, Min; Wang, Baoxiang; Rozynek, Zbigniew; Xie, Zhaohui; Fossum, Jon Otto; Yu, Xiaofeng; Raaen, Steinar

    2009-12-16

    We describe a rapid environmentally friendly wet-chemical approach to synthesize extremely stable non-toxic, biocompatible, water-soluble monodispersed gold nanoparticles (AuNPs) in one step at room temperature. The particles have been successfully achieved in just a few minutes by merely adding sodium hydroxide (NaOH) acting as an initiator for the reduction of HAuCl(4) in aqueous solution in the presence of polyvinylpyrrolidone (PVP) without the use of any reducing agent. It is also proved to be highly efficient for the preparation of AuNPs with controllable sizes. The AuNPs show remarkable stability in water media with high concentrations of salt, various buffer solutions and physiological conditions in biotechnology and biomedicine. Moreover, the AuNPs are also non-toxic at high concentration (100 microM). Therefore, it provides great opportunities to use these AuNPs for biotechnology and biomedicine. This new approach also involved several green chemistry concepts, such as the selection of environmentally benign reagents and solvents, without energy consumption, and less reaction time.

  5. Minute synthesis of extremely stable gold nanoparticles

    International Nuclear Information System (INIS)

    Zhou Min; Wang Baoxiang; Rozynek, Zbigniew; Xie Zhaohui; Fossum, Jon Otto; Yu Xiaofeng; Raaen, Steinar

    2009-01-01

    We describe a rapid environmentally friendly wet-chemical approach to synthesize extremely stable non-toxic, biocompatible, water-soluble monodispersed gold nanoparticles (AuNPs) in one step at room temperature. The particles have been successfully achieved in just a few minutes by merely adding sodium hydroxide (NaOH) acting as an initiator for the reduction of HAuCl 4 in aqueous solution in the presence of polyvinylpyrrolidone (PVP) without the use of any reducing agent. It is also proved to be highly efficient for the preparation of AuNPs with controllable sizes. The AuNPs show remarkable stability in water media with high concentrations of salt, various buffer solutions and physiological conditions in biotechnology and biomedicine. Moreover, the AuNPs are also non-toxic at high concentration (100 μM). Therefore, it provides great opportunities to use these AuNPs for biotechnology and biomedicine. This new approach also involved several green chemistry concepts, such as the selection of environmentally benign reagents and solvents, without energy consumption, and less reaction time.

  6. Cancer nanomedicine: gold nanoparticle mediated combined cancer therapy

    Science.gov (United States)

    Yang, C.; Bromma, Kyle; Chithrani, B. D.

    2018-02-01

    Recent developments in nanotechnology has provided new tools for cancer therapy and diagnosis. Among other nanomaterial systems, gold nanoparticles are being used as radiation dose enhancers and anticancer drug carriers in cancer therapy. Fate of gold nanoparticles within biological tissues can be probed using techniques such as TEM (transmission electron microscopy) and SEM (Scanning Electron Microscopy) due to their high electron density. We have shown for the first time that cancer drug loaded gold nanoparticles can reach the nucleus (or the brain) of cancer cells enhancing the therapeutic effect dramatically. Nucleus of the cancer cells are the most desirable target in cancer therapy. In chemotherapy, smart delivery of highly toxic anticancer drugs through packaging using nanoparticles will reduce the side effects and improve the quality and care of cancer patients. In radiation therapy, use of gold nanoparticles as radiation dose enhancer is very promising due to enhanced localized dose within the cancer tissue. Recent advancement in nanomaterial characterization techniques will facilitate mapping of nanomaterial distribution within biological specimens to correlate the radiobiological effects due to treatment. Hence, gold nanoparticle mediated combined chemoradiation would provide promising tools to achieve personalized and tailored cancer treatments in the near future.

  7. Detection of mercury(II) ions using colorimetric gold nanoparticles on paper-based analytical devices.

    Science.gov (United States)

    Chen, Guan-Hua; Chen, Wei-Yu; Yen, Yu-Chun; Wang, Chia-Wei; Chang, Huan-Tsung; Chen, Chien-Fu

    2014-07-15

    An on-field colorimetric sensing strategy employing gold nanoparticles (AuNPs) and a paper-based analytical platform was investigated for mercury ion (Hg(2+)) detection at water sources. By utilizing thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry, label-free detection oligonucleotide sequences were attached to unmodified gold nanoparticles to provide rapid mercury ion sensing without complicated and time-consuming thiolated or other costly labeled probe preparation processes. Not only is this strategy's sensing mechanism specific toward Hg(2+), rather than other metal ions, but also the conformational change in the detection oligonucleotide sequences introduces different degrees of AuNP aggregation that causes the color of AuNPs to exhibit a mixture variance. To eliminate the use of sophisticated equipment and minimize the power requirement for data analysis and transmission, the color variance of multiple detection results were transferred and concentrated on cellulose-based paper analytical devices, and the data were subsequently transmitted for the readout and storage of results using cloud computing via a smartphone. As a result, a detection limit of 50 nM for Hg(2+) spiked pond and river water could be achieved. Furthermore, multiple tests could be performed simultaneously with a 40 min turnaround time. These results suggest that the proposed platform possesses the capability for sensitive and high-throughput on-site mercury pollution monitoring in resource-constrained settings.

  8. Comparison of amino acids interaction with gold nanoparticle.

    Science.gov (United States)

    Ramezani, Fatemeh; Amanlou, Massoud; Rafii-Tabar, Hashem

    2014-04-01

    The study of nanomaterial/biomolecule interface is an important emerging field in bionanoscience, and additionally in many biological processes such as hard-tissue growth and cell-surface adhesion. To have a deeper understanding of the amino acids/gold nanoparticle assemblies, the adsorption of these amino acids on the gold nanoparticles (GNPs) has been investigated via molecular dynamics simulation. In these simulations, all the constituent atoms of the nanoparticles were considered to be dynamic. The geometries of amino acids, when adsorbed on the nanoparticle, were studied and their flexibilities were compared with one another. The interaction of each of 20 amino acids was considered with 3 and 8 nm gold GNPs.

  9. Microwave absorption properties of gold nanoparticle doped polymers

    DEFF Research Database (Denmark)

    Jiang, Chenhui; Ouattara, Lassana; Ingrosso, Chiara

    2011-01-01

    This paper presents a method for characterizing microwave absorption properties of gold nanoparticle doped polymers. The method is based on on-wafer measurements at the frequencies from 0.5GHz to 20GHz. The on-wafer measurement method makes it possible to characterize electromagnetic (EM) property...... of small volume samples. The epoxy based SU8 polymer and SU8 doped with gold nanoparticles are chosen as the samples under test. Two types of microwave test devices are designed for exciting the samples through electrical coupling and magnetic coupling, respectively. Measurement results demonstrate...... that the nanocomposites absorb a certain amount of microwave energy due to gold nanoparticles. Higher nanoparticle concentration results in more significant absorption effect....

  10. Functionalization of lamellar molybdenum disulphide nanocomposite with gold nanoparticles

    International Nuclear Information System (INIS)

    Lavayen, V.; O'Dwyer, C.; Ana, M.A. Santa; Mirabal, N.; Benavente, E.; Cardenas, G.; Gonzalez, G.; Torres, C.M. Sotomayor

    2007-01-01

    This work explores the functionalization of an organic-inorganic MoS 2 lamellar compound, prepared by a chemical liquid deposition method (CLD), that has an interlamellar distance of ∼5.2 nm, using clusters of gold nanoparticles. The gold nanoparticles have a mean diameter of 1.2 nm, a stability of ∼85 days, and a zeta potential measured to be ζ -6.8 mV (solid). The nanoparticles are localized in the hydrophilic zones, defined by the presence of amine groups of the surfactant between the lamella of MoS 2 . SEM, TEM, EDAX and electron diffraction provide conclusive evidence of the interlamellar insertion of the gold nanoparticles in the MoS 2

  11. Functionalization of lamellar molybdenum disulphide nanocomposite with gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lavayen, V. [Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland) and Department of Chemistry, Faculty of Sciences, Universidad de Chile, P.O. Box 653, Santiago (Chile)]. E-mail: vlavayen@tyndall.ie; O' Dwyer, C. [Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland); Ana, M.A. Santa [Department of Chemistry, Faculty of Sciences, Universidad de Chile, P.O. Box 653, Santiago (Chile); Mirabal, N. [Department of Chemistry, Faculty of Sciences, Universidad de Chile, P.O. Box 653, Santiago (Chile); Benavente, E. [Department of Chemistry, Universidad Tecnologica Metropolitana, P.O. Box 9845, Santiago (Chile); Cardenas, G. [Department of Polymers, Faculty of Chemistry Science, Universidad de Concepcion, P.O. Box 160-C, Concepcion (Chile); Gonzalez, G. [Department of Chemistry, Faculty of Sciences, Universidad de Chile, P.O. Box 653, Santiago (Chile); Torres, C.M. Sotomayor [Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland)

    2007-01-30

    This work explores the functionalization of an organic-inorganic MoS{sub 2} lamellar compound, prepared by a chemical liquid deposition method (CLD), that has an interlamellar distance of {approx}5.2 nm, using clusters of gold nanoparticles. The gold nanoparticles have a mean diameter of 1.2 nm, a stability of {approx}85 days, and a zeta potential measured to be {zeta} -6.8 mV (solid). The nanoparticles are localized in the hydrophilic zones, defined by the presence of amine groups of the surfactant between the lamella of MoS{sub 2}. SEM, TEM, EDAX and electron diffraction provide conclusive evidence of the interlamellar insertion of the gold nanoparticles in the MoS{sub 2}.

  12. Microwave absorption properties of gold nanoparticle doped polymers

    Science.gov (United States)

    Jiang, C.; Ouattara, L.; Ingrosso, C.; Curri, M. L.; Krozer, V.; Boisen, A.; Jakobsen, M. H.; Johansen, T. K.

    2011-03-01

    This paper presents a method for characterizing microwave absorption properties of gold nanoparticle doped polymers. The method is based on on-wafer measurements at the frequencies from 0.5 GHz to 20 GHz. The on-wafer measurement method makes it possible to characterize electromagnetic (EM) property of small volume samples. The epoxy based SU8 polymer and SU8 doped with gold nanoparticles are chosen as the samples under test. Two types of microwave test devices are designed for exciting the samples through electrical coupling and magnetic coupling, respectively. Measurement results demonstrate that the nanocomposites absorb a certain amount of microwave energy due to gold nanoparticles. Higher nanoparticle concentration results in more significant absorption effect.

  13. Responsive Block Copolymer and Gold Nanoparticle Hybrid Nanotubes.

    Science.gov (United States)

    Chang, Sehoon; Singamaneni, Srikanth; Young, Seth; Tsukruk, Vladimir

    2009-03-01

    We demonstrate the facile fabrication of responsive polymer and metal nanoparticle composite nanotube structures. The nanotubes are comprised of responsive block copolymer, polystyrene-block-poly (2-vinylpyridine) (PS-b-P2VP), and gold nanoparticles. PS-b-P2VP nanotubes were fabricated using porous alumina template and in situ reduction of the gold nanoparticles in P2VP domains. Owing to the pH sensitive nature of P2VP (anionic polymer with a pKa of 3.8), the nanotubes exhibit a dramatic change in topology in response to the changes in the external pH. Furthermore, the gold nanoparticles in the responsive block exhibit a reversible aggregation, causing a reversible change in optical properties such as absorption.

  14. Protein coated gold nanoparticles as template for the directed synthesis of highly fluorescent gold nanoclusters

    Science.gov (United States)

    Zhang, Lingyan; Han, Fei

    2018-04-01

    Bovine serum albumin (BSA) modified gold nanoparticles (AuNPs) was selected as template for the synthesis of AuNPs@gold nanoclusters (AuNCs) core/shell nanoparticles, in which BSA not only acted as dual functions agent for both anchoring and reducing Au3+ ions, but also was employed as a bridge between the AuNPs and AuNCs. Optical properties of AuNPs@AuNCs core/shell nanoparticles were studied using UV-visible and fluorescence spectroscopy. The prepared AuNPs@AuNCs core/shell nanoparticles exhibited sphere size uniformity with improved monodispersity, excellent fluorescence and fluorescent stability. Compared with AuNCs, AuNPs@AuNCs core/shell nanoparticles possessed large size and strong fluorescence intensity due to the effect of AuNPs as core. Moreover, the mechanism of the AuNPs induced fluorescence changes of the core/shell nanoparticles was first explored.

  15. Dendritic functionalization of monolayer-protected gold nanoparticles

    International Nuclear Information System (INIS)

    Cutler, Erin C.; Lundin, Erik; Garabato, B. Davis; Choi, Daeock; Shon, Young-Seok

    2007-01-01

    This paper describes the facile synthesis of nanoparticle-cored dendrimers (NCDs) and nanoparticle megamers from monolayer-protected gold clusters using either single or multi-step reactions. First, 11-mercaptoundecanoic acid/hexanethiolate-protected gold clusters were synthesized using the Schiffrin reaction followed by the ligand place-exchange reaction. A convergent approach for the synthesis of nanoparticle-cored dendrimers uses a single step reaction that is an ester coupling reaction of hydroxy-functionalized dendrons with carboxylic acid-functionalized gold clusters. A divergent approach, which is based on multi-step reactions, employs the repetition of an amide coupling reaction and a Michael addition reaction to build polyamidoamine dendritic architectures around a nanoparticle core. Nanoparticle megamers, which are large dendrimer-induced nanoparticle aggregates with an average diameter of more than 300 nm, were prepared by the amide coupling reaction between polyamiodoamine [G-2] dendrimers and carboxylic acid-functionalized gold clusters. 1 H NMR spectroscopy, FT-IR spectroscopy, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) were used for the characterization of these hybrid nanoparticles

  16. One-Step Synthesis of PEGylated Gold Nanoparticles with Tunable Surface Charge

    Directory of Open Access Journals (Sweden)

    Rares Stiufiuc

    2013-01-01

    Full Text Available The present work reports a rapid, simple and efficient one-step synthesis and detailed characterisation of stable aqueous colloids of gold nanoparticles (AuNPs coated with unmodified poly(ethyleneglycol (PEG molecules of different molecular weights and surface charges. By mixing and heating aqueous solutions of PEG with variable molecular chain and gold(III chloride hydrate (HAuCl4 in the presence of NaOH, we have successfully produced uniform colloidal 5 nm PEG coated AuNPs of spherical shape with tunable surface charge and an average diameter of 30 nm within a few minutes. It has been found out that PEGylated AuNPs provide optical enhancement of the characteristic vibrational bands of PEG molecules attached to the gold surface when they are excited with both visible (532 nm and NIR (785 nm laser lines. The surface enhanced Raman scattering (SERS signal does not depend on the length of the PEG molecular chain enveloping the AuNPs, and the stability of the colloid is not affected by the addition of concentrated salt solution (0.1 M NaCl, thus suggesting their potential use for in vitro and in vivo applications. Moreover, by gradually changing the chain length of the biopolymer, we were able to control nanoparticles’ surface charge from −28 to −2 mV, without any modification of the Raman enhancement properties and of the colloidal stability.

  17. Gold nanoparticle trapping and delivery for therapeutic applications

    Directory of Open Access Journals (Sweden)

    Aziz MS

    2011-12-01

    Full Text Available MS Aziz1, Nathaporn Suwanpayak3,4, Muhammad Arif Jalil2, R Jomtarak4, T Saktioto2, Jalil Ali1, PP Yupapin41Institute of Advanced Photonics Science, 2Ibnu Sina Institute of Fundamental Science Studies, Nanotechnology Research Alliance, Universiti Teknologi Malaysia, Johor Bahru, Malaysia; 3King Mongkut's Institute of Technology Ladkrabang, Chump on Campus, Chumphon, 4Nanoscale Science and Engineering Research Alliance (N'SERA, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok, ThailandAbstract: A new optical trapping design to transport gold nanoparticles using a PANDA ring resonator system is proposed. Intense optical fields in the form of dark solitons controlled by Gaussian pulses are used to trap and transport nanoscopic volumes of matter to the desired destination via an optical waveguide. Theoretically, the gradient and scattering forces are responsible for this trapping phenomenon, where in practice such systems can be fabricated and a thin-film device formed on the specific artificial medical materials, for instance, an artificial bone. The dynamic behavior of the tweezers can be tuned by controlling the optical pulse input power and parameters of the ring resonator system. Different trap sizes can be generated to trap different gold nanoparticles sizes, which is useful for gold nanoparticle therapy. In this paper, we have shown the utility of gold nanoparticle trapping and delivery for therapy, which may be useful for cosmetic therapy and related applications.Keywords: gold nanoparticle trapping, particle trapping, therapy, transport

  18. Synthesis and characterization of pHLIP® coated gold nanoparticles.

    Science.gov (United States)

    Daniels, Jennifer L; Crawford, Troy M; Andreev, Oleg A; Reshetnyak, Yana K

    2017-07-01

    Novel approaches in synthesis of spherical and multispiked gold nanoparticles coated with polyethylene glycol (PEG) and pH Low Insertion Peptide (pHLIP ® ) were introduced. The presence of a tumor-targeting pHLIP ® peptide in the nanoparticle coating enhances the stability of particles in solution and promotes a pH-dependent cellular uptake. The spherical particles were prepared with sodium citrate as a gold reducing agent to form particles of 7.0±2.5 nm in mean metallic core diameter and ∼43 nm in mean hydrodynamic diameter. The particles that were injected into tumors in mice (21 µg of gold) were homogeneously distributed within a tumor mass with no staining of the muscle tissue adjacent to the tumor. Up to 30% of the injected gold dose remained within the tumor one hour post-injection. The multispiked gold nanoparticles with a mean metallic core diameter of 146.0±50.4 nm and a mean hydrodynamic size of ~161 nm were prepared using ascorbic acid as a reducing agent and disk-like bicelles as a template. Only the presence of a soft template, like bicelles, ensured the appearance of spiked nanoparticles with resonance in the near infrared region. The irradiation of spiked gold nanoparticles by an 805 nm laser led to the time- and concentration-dependent increase of temperature. Both pHLIP ® and PEG coated gold spherical and multispiked nanoparticles might find application in radiation and thermal therapies of tumors.

  19. Synthesis and characterization of pHLIP® coated gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Jennifer L. Daniels

    2017-07-01

    Full Text Available Novel approaches in synthesis of spherical and multispiked gold nanoparticles coated with polyethylene glycol (PEG and pH Low Insertion Peptide (pHLIP® were introduced. The presence of a tumor-targeting pHLIP® peptide in the nanoparticle coating enhances the stability of particles in solution and promotes a pH-dependent cellular uptake. The spherical particles were prepared with sodium citrate as a gold reducing agent to form particles of 7.0±2.5 nm in mean metallic core diameter and ∼43 nm in mean hydrodynamic diameter. The particles that were injected into tumors in mice (21 µg of gold were homogeneously distributed within a tumor mass with no staining of the muscle tissue adjacent to the tumor. Up to 30% of the injected gold dose remained within the tumor one hour post-injection. The multispiked gold nanoparticles with a mean metallic core diameter of 146.0±50.4 nm and a mean hydrodynamic size of ~161 nm were prepared using ascorbic acid as a reducing agent and disk-like bicelles as a template. Only the presence of a soft template, like bicelles, ensured the appearance of spiked nanoparticles with resonance in the near infrared region. The irradiation of spiked gold nanoparticles by an 805 nm laser led to the time- and concentration-dependent increase of temperature. Both pHLIP® and PEG coated gold spherical and multispiked nanoparticles might find application in radiation and thermal therapies of tumors.

  20. Collagen-Gold Nanoparticle Conjugates for Versatile Biosensing

    Directory of Open Access Journals (Sweden)

    Sarah Unser

    2017-02-01

    Full Text Available Integration of noble metal nanoparticles with proteins offers promising potential to create a wide variety of biosensors that possess both improved selectivity and versatility. The multitude of functionalities that proteins offer coupled with the unique optical properties of noble metal nanoparticles can allow for the realization of simple, colorimetric sensors for a significantly larger range of targets. Herein, we integrate the structural protein collagen with 10 nm gold nanoparticles to develop a protein-nanoparticle conjugate which possess the functionality of the protein with the desired colorimetric properties of the nanoparticles. Applying the many interactions that collagen undergoes in the extracellular matrix, we are able to selectively detect both glucose and heparin with the same collagen-nanoparticle conjugate. Glucose is directly detected through the cross-linking of the collagen fibrils, which brings the attached nanoparticles into closer proximity, leading to a red-shift in the LSPR frequency. Conversely, heparin is detected through a competition assay in which heparin-gold nanoparticles are added to solution and compete with heparin in the solution for the binding sites on the collagen fibrils. The collagen-nanoparticle conjugates are shown to detect both glucose and heparin in the physiological range. Lastly, glucose is selectively detected in 50% mouse serum with the collagen-nanoparticle devices possessing a linear range of 3–25 mM, which is also within the physiologically relevant range.

  1. Hydrophobically modified chitosan/gold nanoparticles for DNA delivery

    International Nuclear Information System (INIS)

    Bhattarai, Shanta Raj; Remant Bahadur, K.C.; Aryal, Santosh; Bhattarai, Narayan; Kim, Sun Young; Yi, Ho Keun; Hwang, Pyoung Han; Kim, Hak Yong

    2008-01-01

    Present study dealt an application of modified chitosan gold nanoparticles (Nac-6-Au) for the immobilization of necked plasmid DNA. Gold nanoparticles stabilized with N-acylated chitosan were prepared by graft-onto approach. The stabilized gold nanoparticles were characterized by different physico-chemical techniques such as UV-vis, TEM, ELS and DLS. MTT assay was used for in vitro cytotoxicity of the nanoparticles into three different cell lines (NIH 3T3, CT-26 and MCF-7). The formulation of plasmid DNA with the nanoparticles corresponds to the complex forming capacity and in-vitro/in-vivo transfection efficiency was studied via gel electrophoresis and transfection methods, respectively. Results showed the modified chitosan gold nanoparticles were well-dispersed and spherical in shape with average size around 10∼12 nm in triple distilled water at pH 7.4, and showed relatively no cytotoxicity at low concentration. Addition of plasmid DNA on the aqueous solution of the nanoparticles markedly reduced surface potential (50.0∼66.6%) as well as resulted in a 13.33% increase in hydrodynamic diameters of the formulated nanoparticles. Transfection efficiency of Nac-6-Au/DNA was dependent on cell type, and higher β-galactosidase activity was observed on MCF-7 breast cancer cell. Typically, this activity was 5 times higher in 4.5 mg/ml nanoparticles concentration than that achieved by the nanoparticles of other concentrations (and/or control). However, this activity was lower in in-vitro and dramatically higher in in-vivo than that of commercially available transfection kit (Lipofectin (registered) ) and DNA. From these results, it can be expected to develop alternative new vectors for gene delivery

  2. Microbial mediated preparation, characterization and optimization of gold nanoparticles.

    Science.gov (United States)

    Barabadi, Hamed; Honary, Soheila; Ebrahimi, Pouneh; Mohammadi, Milad Ali; Alizadeh, Ahad; Naghibi, Farzaneh

    2014-01-01

    The need for eco-friendly and cost effective methods for nanoparticles synthesis is developing interest in biological approaches which are free from the use of toxic chemicals as byproducts. This study aimed to biosynthesize and optimize the size of gold nanoparticles which produced by biotechnological method using Penicillium crustosum isolated from soil. Initially, Penicillium crustosum was grown in fluid czapek dox broth on shaker at 28 °C and 200 rpm for ten days and then the supernatant was separated from the mycelia to convert AuCl₄ solution into gold nanoparticles. The synthesized nanoparticles in the optimum conditions were formed with fairly well-defined dimensions and good monodispersity. The characterizations were done by using different methods (UV-Visible Spectroscopy, Fluorescence, FT-IR, AFM (Atomic Force Microscopy) and DLS (Dynamic Light Scattering). The bioconversion was optimized by Box-Behnken experimental design. The results show that the effective factors in this process were concentration of AuCl₄, pH of medium and temperature of shaker incubator. The R(2) value was calculated to be 0.9999 indicating the accuracy and ability of the polynomial model. It can be concluded that the use of multivariate analysis facilitated to find out the optimum conditions for the biosynthesis of gold nanoparticles induced by Penicillium crustosum in a time and cost effective process. The current approach suggested that rapid synthesis of gold nanoparticles would be suitable for developing a biological process for mass scale production of formulations.

  3. Interaction of gold nanoparticles with Pfu DNA polymerase and effect on polymerase chain reaction.

    Science.gov (United States)

    Sun, L-P; Wang, S; Zhang, Z-W; Ma, Y-Y; Lai, Y-Q; Weng, J; Zhang, Q-Q

    2011-03-01

    The interaction of gold nanoparticles with Pfu DNA polymerase has been investigated by a number of biological, optical and electronic spectroscopic techniques. Polymerase chain reaction was performed to show gold nanoparticles' biological effect. Ultraviolet-visible and circular dichroism spectra analysis were applied to character the structure of Pfu DNA polymerase after conjugation with gold nanoparticles. X-ray photoelectron spectroscopy was used to investigate the bond properties of the polymerase-gold nanoparticles complex. The authors demonstrate that gold nanoparticles do not affect the amplification efficiency of polymerase chain reaction using Pfu DNA polymerase, and Pfu DNA polymerase displays no significant changes of the secondary structure upon interaction with gold nanoparticles. The adsorption of Pfu DNA polymerase to gold nanoparticles is mainly through Au-NH(2) bond and electrostatic interaction. These findings may have important implications regarding the safety issue as gold nanoparticles are widely used in biomedical applications.

  4. Template assisted synthesis and optical properties of gold nanoparticles.

    Science.gov (United States)

    Fodor, Petru; Lasalvia, Vincenzo

    2009-03-01

    A hybrid nanofabrication method (interference lithography + self assembly) was explored for the fabrication of arrays of gold nanoparticles. To ensure the uniformity of the nanoparticles, a template assisted synthesis was used in which the gold is electrodeposited in the pores of anodized aluminum membranes. The spacing between the pores and their ordering is controlled in the first fabrication step of the template in which laser lithography and metal deposition are used to produce aluminum films with controlled strain profiles. The diameter of the pores produced after anodizing the aluminum film in acidic solution determines the diameter of the gold particles, while their aspect ratio is controlled through the deposition time. Optical absorbance spectroscopy is used to evaluate the ability to tune the nanoparticles plasmon resonance spectra through control over their size and aspect ratio.

  5. Ligands Exchange Process on Gold Nanoparticles in Acetone Solution

    Science.gov (United States)

    Hu, C. L.; Mu, Y. Y.; Bian, Z. C.; Luo, Z. H.; Luo, K.; Huang, A. Z.

    2018-05-01

    The ligands exchange process on gold nanoparticles (GNPs) was proceeded by using hydrophobic group (PPh3) and hydrophilic group (THPO) in acetone solution. The FTIR and XPS results demonstrated that part of THPO was replaced by PPh3 which was dissolved in polar solution (acetone); the results were in accordance with the electrochemical analysis where the differential capacity decreased with increasing exchange time. After 12 h, the exchange process terminated and the final ratio of PPh3 and THPO was about 1.4: 1. This ratio remained unchanged although the PPh3 and THPO modified GNPs re-dispersed in the PPh3 acetone solution demonstrating the stable adsorption of both ligands after exchanging for 12 h. The TEM images showed that the gold nanoparticles were self-assembled from scattered to arranged morphology due to the existence of hydrophilic and hydrophobic ligands and led to Janus gold nanoparticles.

  6. Femtosecond laser generated gold nanoparticles and their plasmonic properties

    International Nuclear Information System (INIS)

    Das, Rupali; Navas, M. P.; Soni, R. K.

    2016-01-01

    The pulsed laser ablation in liquid medium is now commonly used to generate stable colloidal nanoparticles (NPs) in absence of any chemical additives or stabilizer with diverse applications. In this paper, we report generation of gold NPs (Au NPs) by ultra-short laser pulses. Femtosecond (fs) laser radiation (λ = 800 nm) has been used to ablate a gold target in pure de-ionized water to produce gold colloids with smallsize distribution. The average size of the particles can be further controlled by subjecting to laser-induced post-irradiation providing a versatile physical method of size-selected gold nanoparticles. The optical extinction and morphological dimensions were investigated with UV-Vis spectroscopy and Transmission Electron Microscopy measurements, respectively. Finite difference time domain (FDTD) method is employed to calculate localized surface plasmon (LSPR) wavelength and the near-field generated by Au NPs and their hybrids.

  7. Radiation-induced synthesis of gold, iron-oxide composite nanoparticles

    International Nuclear Information System (INIS)

    Seino, Satoshi; Yamamoto, Takao; Nakagawa, Takashi; Kinoshita, Takuya; Kojima, Takao; Taniguchi, Ryoichi; Okuda, Shuichi

    2007-01-01

    Composite nanoparticles consisting of magnetic iron oxide nanoparticles and gold nanoparticles were synthesized using gamma-rays or electron beam. Ionizing irradiation induces the generation of reducing species inside the aqueous solution, and gold ions are reduced to form metallic Au nanoparticles. The size of Au nanoparticles depended on the dose rate and the concentration of support iron oxide. The gold nanoparticles on iron oxide nanoparticles selectively adsorb biomolecules via Au-S bonding. By using magnetic property of the support iron oxide nanoparticles, the composite nanoparticles are expected as a new type of magnetic nanocarrier for biomedical applications. (author)

  8. Gold nanoparticles for tumour detection and treatment

    NARCIS (Netherlands)

    Hartsuiker, Liesbeth; Petersen, W.; Petersen, Wilhelmina; Jose, J.; Jose, J.; van Es, P.; van Es, Peter; Lenferink, Aufrid T.M.; Poot, Andreas A.; Terstappen, Leonardus Wendelinus Mathias Marie; van Leeuwen, Ton; Manohar, Srirang; Otto, Cornelis

    2011-01-01

    The use of nanoparticles in biomedical applications is emerging rapidly. Recent developments have led to numerous studies of noble metal nanoparticles, down to the level of single molecule detection in living cells. The application of noble metal nanoparticles in diagnostics and treatment of early

  9. Preparation of 2 nm gold nanoparticles for in vitro and in vivo applications

    OpenAIRE

    Moyano, Daniel F.; Duncan, Bradley; Rotello, Vincent M.

    2013-01-01

    Gold nanoparticles have been a versatile tool in recent years for the exploration of biological systems. However, challenges with purification and adequate surface coverage limit the biocompatibility of gold nanoparticles. Here, we describe a detailed procedure for the synthesis, purification, and functionalization of biologically compatible gold nanoparticles for in vitro and in vivo studies.

  10. Preparation of DNA/Gold Nanoparticle Encapsulated in Calcium Phosphate

    Directory of Open Access Journals (Sweden)

    Tomoko Ito

    2011-01-01

    Full Text Available Biocompatible DNA/gold nanoparticle complex with a protective calcium phosphate (CaP coating was prepared by incubating DNA/gold nanoparticle complex coated by hyaluronic acid in SBF (simulated body fluid with a Ca concentration above 2 mM. The CaP-coated DNA complex was revealed to have high compatibility with cells and resistance against enzymatic degradation. By immersion in acetate buffer (pH 4.5, the CaP capsule released the contained DNA complex. This CaP capsule including a DNA complex is promising as a sustained-release system of DNA complexes for gene therapy.

  11. Authentication of gold nanoparticle encoded pharmaceutical tablets using polarimetric signatures.

    Science.gov (United States)

    Carnicer, Artur; Arteaga, Oriol; Suñé-Negre, Josep M; Javidi, Bahram

    2016-10-01

    The counterfeiting of pharmaceutical products represents concerns for both industry and the safety of the general public. Falsification produces losses to companies and poses health risks for patients. In order to detect fake pharmaceutical tablets, we propose producing film-coated tablets with gold nanoparticle encoding. These coated tablets contain unique polarimetric signatures. We present experiments to show that ellipsometric optical techniques, in combination with machine learning algorithms, can be used to distinguish genuine and fake samples. To the best of our knowledge, this is the first report using gold nanoparticles encoded with optical polarimetric classifiers to prevent the counterfeiting of pharmaceutical products.

  12. Gold nanoparticles in breast cancer treatment: Promise and potential pitfalls

    Science.gov (United States)

    Lee, Jihyoun; Chatterjee, Dev Kumar; Lee, Min Hyuk; Krishnan, Sunil

    2014-01-01

    Despite remarkable achievements in the treatment of breast cancer, some obstacles still remain. Gold nanoparticles may prove valuable in addressing these problems owing to their unique characteristics, including their enhanced permeability and retention in tumor tissue, their light absorbance and surface plasmon resonance in near-infrared light, their interaction with radiation to generate secondary electrons, and their ability to be conjugated with drugs or other agents. Herein, we discuss some basic concepts of gold nanoparticles, and early results from studies regarding their use in breast cancer, including toxicity and side effects. We also discuss these particles’ potential clinical applications. PMID:24556077

  13. Recent progress in theranostic applications of hybrid gold nanoparticles.

    Science.gov (United States)

    Gharatape, Alireza; Salehi, Roya

    2017-09-29

    A significant area of research is theranostic applications of nanoparticles, which involves efforts to improve delivery and reduce side effects. Accordingly, the introduction of a safe, effective, and, most importantly, renewable strategy to target, deliver and image disease cells is important. This state-of-the-art review focuses on studies done from 2013 to 2016 regarding the development of hybrid gold nanoparticles as theranostic agents in the diagnosis and treatment of cancer and infectious disease. Several syntheses (chemical and green) methods of gold nanoparticles and their applications in imaging, targeting, and delivery are reviewed; their photothermal efficiency is discussed as is the toxicity of gold nanoparticles. Owing to the unique characterizations of hybrid gold nanoparticles and their potential to be developed as multifunctional, we predict they will present an undeniable role in clinical studies and provide treatment platforms for various diseases. Thus, their clearance and interactions with extra- and intra-cellular molecules need to be considered in future projects. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. GOLD NANOPARTICLES ENCAPSULATED IN A POLYMERIC MATRIX OF SODIUM ALGINATE

    Directory of Open Access Journals (Sweden)

    Oana Lelia POP

    2016-11-01

    Full Text Available Plasmonic nanoparticles can be used as building blocks for the design of multifunctional systems based on polymeric capsules. The use of functionalised particles in therapeutics and imaging and understanding their effect on the cell functions are among the current challenges in nanobiotechnology and nanomedicine. The aim of the study was to manufacture and characterize polymeric microstructures by encapsulating plasmonic gold nanoparticles in biocompatible matrix of sodium alginate. The gold nanoparticles were obtained by reduction of tetracluoroauric acid with sodium citrate. To characterize the microcapsules, UV-Vis and FTIR spectroscopy, optical and confocal microscopy experiments were performed. In vitro cytotoxicity tests on HFL-1 cells were also performed. The capsules have spherical shape and 120 μm diameter. The presence of encapsulated gold nanoparticles is also shown by confocal microscopy. In vitro tests show that the microcapsules are not cytotoxic upon 24 h of cells exposure to microcapsules concentrations ranging from 2.5 to 25 capsules per cell. The obtained microcapsules of sodium alginate loaded with plasmonic gold nanoparticles could potentially be considered as release systems for biologically relevant molecules.

  15. Photoluminescence enhancement of dye-doped nanoparticles by surface plasmon resonance effects of gold colloidal nanoparticles

    International Nuclear Information System (INIS)

    Chu, Viet Ha; Nghiem, Thi Ha Lien; Tran, Hong Nhung; Fort, Emmanuel

    2011-01-01

    Due to the energy transfer from surface plasmons, the fluorescence of fluorophores near metallic nanostructures can be enhanced. This effect has been intensively studied recently for biosensor applications. This work reports on the luminescence enhancement of 100 nm Cy3 dye-doped polystyrene nanoparticles by energy transfer from surface plasmons of gold colloidal nanoparticles with sizes of 20 and 100 nm. Optimal luminescence enhancement of the fluorophores has been observed in the mixture with 20 nm gold nanoparticles. This can be attributed to the resonance energy transfer from gold nanoparticles to the fluorophore beads. The interaction between the fluorophores and gold particles is attributed to far-field interaction

  16. Gold Nanoparticles Assembly on Silicon and Gold Surfaces: Mechanism, Stability and Efficiency in Diclofenac Biosensing

    OpenAIRE

    Ben Haddada , Maroua; Hübner , Maria; Casale , Sandra; Knopp , Dietmar; Niessner , Reinhard; Salmain , Michele; Boujday , Souhir

    2016-01-01

    International audience; We investigated the assembly of Gold nanoparticles (AuNPs) on Gold and Silicon sensors with two final objectives: (i) understanding the factors governing the interaction and (ii) building up a nanostructured piezoelectric immunosensor for diclofenac, a small-sized pharmaceutical pollutant. Different surface chemistries were devised to achieve AuNPs assembly on planar substrates. These surface chemistries included amines to immobilize AuNPs via electrostatic interaction...

  17. Diazonium-derived aryl films on gold nanoparticles: evidence for a carbon-gold covalent bond.

    Science.gov (United States)

    Laurentius, Lars; Stoyanov, Stanislav R; Gusarov, Sergey; Kovalenko, Andriy; Du, Rongbing; Lopinski, Gregory P; McDermott, Mark T

    2011-05-24

    Tailoring the surface chemistry of metallic nanoparticles is generally a key step for their use in a wide range of applications. There are few examples of organic films covalently bound to metal nanoparticles. We demonstrate here that aryl films are formed on gold nanoparticles from the spontaneous reduction of diazonium salts. The structure and the bonding of the film is probed with surface-enhanced Raman scattering (SERS). Extinction spectroscopy and SERS show that a nitrobenzene film forms on gold nanoparticles from the corresponding diazonium salt. Comparison of the SERS spectrum with spectra computed from density functional theory models reveals a band characteristic of a Au-C stretch. The observation of this stretch is direct evidence of a covalent bond. A similar band is observed in high-resolution electron energy loss spectra of nitrobenzene layers on planar gold. The bonding of these types of films through a covalent interaction on gold is consistent with their enhanced stability observed in other studies. These findings provide motivation for the use of diazonium-derived films on gold and other metals in applications where high stability and/or strong adsorbate-substrate coupling are required.

  18. Peptide-functionalized iron oxide magnetic nanoparticle for gold mining

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Wei-Zheng; Cetinel, Sibel; Sharma, Kumakshi; Borujeny, Elham Rafie; Montemagno, Carlo, E-mail: montemag@ualberta.ca [Ingenuity Lab, 1-070C (Canada)

    2017-02-15

    Here, we present our work on preparing a novel nanomaterial composed of inorganic binding peptides and magnetic nanoparticles for inorganic mining. Two previously selected and well-characterized gold-binding peptides from cell surface display, AuBP1 and AuBP2, were exploited. This nanomaterial (AuBP-MNP) was designed to fulfill the following two significant functions: the surface conjugated gold-binding peptide will recognize and selectively bind to gold, while the magnetic nano-sized core will respond and migrate according to the applied external magnetic field. This will allow the smart nanomaterial to mine an individual material (gold) from a pool of mixture, without excessive solvent extraction, filtration, and concentration steps. The working efficiency of AuBP-MNP was determined by showing a dramatic reduction of gold nanoparticle colloid concentration, monitored by spectroscopy. The binding kinetics of AuBP-MNP onto the gold surface was determined using surface plasmon resonance (SPR) spectroscopy, which exhibits around 100 times higher binding kinetics than peptides alone. The binding capacity of AuBP-MNP was demonstrated by a bench-top mining test with gold microparticles.

  19. Banana peel extract mediated synthesis of gold nanoparticles.

    Science.gov (United States)

    Bankar, Ashok; Joshi, Bhagyashree; Kumar, Ameeta Ravi; Zinjarde, Smita

    2010-10-01

    Gold nanoparticles were synthesized by using banana peel extract (BPE) as a simple, non-toxic, eco-friendly 'green material'. The boiled, crushed, acetone precipitated, air-dried peel powder was used to reduce chloroauric acid. A variety of nanoparticles were formed when the reaction conditions were altered with respect to pH, BPE content, chloroauric acid concentration and temperature of incubation. The reaction mixtures displayed vivid colors and UV-vis spectra characteristic of gold nanoparticles. Dynamic light scattering (DLS) studies revealed that the average size of the nanoparticles under standard synthetic conditions was around 300nm. Scanning electron microscopy and energy dispersive spectrometry (EDS) confirmed these results. A coffee ring phenomenon, led to the aggregation of the nanoparticles into microcubes and microwire networks towards the periphery of the air-dried samples. X-ray diffraction studies of the samples revealed spectra that were characteristic for gold. Fourier transform infra red (FTIR) spectroscopy indicated the involvement of carboxyl, amine and hydroxyl groups in the synthetic process. The BPE mediated nanoparticles displayed efficient antimicrobial activity towards most of the tested fungal and bacterial cultures.

  20. A Nanostructured Sensor Based on Gold Nanoparticles and Nafion for Determination of Uric Acid

    Directory of Open Access Journals (Sweden)

    Natalia Stozhko

    2018-03-01

    Full Text Available The paper discusses the mechanism of uric acid (UA electrooxidation occurring on the surface of gold nanoparticles. It has been shown that the electrode process is purely electrochemical, uncomplicated with catalytic stages. The nanoeffects observed as the reduction of overvoltage and increased current of UA oxidation have been described. These nanoeffects are determined by the size of particles and do not depend on the method of particle preparation (citrate and “green” synthesis. The findings of these studies have been used to select a modifier for carbon screen-printed electrode (CSPE. It has been stated that CSPE modified with gold nanoparticles (5 nm and 2.5% Nafion (Nf may serve as non-enzymatic sensor for UA determination. The combination of the properties of nanoparticles and Nafion as a molecular sieve at the selected pH 5 phosphate buffer solution has significantly improved the resolution of the sensor compared to unmodified CSPE. A nanostructured sensor has demonstrated good selectivity in determining UA in the presence of ascorbic acid. The detection limit of UA is 0.25 μM. A linear calibration curve has been obtained over a range of 0.5–600 μM. The 2.5%Nf/Au(5nm/CSPE has been successfully applied to determining UA in blood serum and milk samples. The accuracy and reliability of the obtained results have been confirmed by a good correlation with the enzymatic spectrophotometric analysis (R2 = 0.9938 and the “added−found” technique (recovery close to 100%.

  1. DNA-directed self-assembly of gold nanoparticles into binary and ternary nanostructures

    International Nuclear Information System (INIS)

    Yao Hui; Yi Changqing; Tzang Chihung; Zhu Junjie; Yang Mengsu

    2007-01-01

    The assembly and characterization of gold nanoparticle-based binary and ternary structures are reported. Two strategies were used to assemble gold nanoparticles into ordered nanoscale architectures: in strategy 1, gold nanoparticles were functionalized with single-strand DNA (ssDNA) first, and then hybridized with complementary ssDNA-labelled nanoparticles to assemble designed architectures. In strategy 2, the designed architectures were constructed through hybridization between complementary ssDNA first, then by assembling gold nanoparticles to the scaffolding through gold-sulfur bonds. Both TEM measurements and agarose gel electrophoresis confirmed that the latter strategy is more efficient in generating the designed nanostructures

  2. Aquatic Fern (Azolla Sp.) Assisted Synthesis of Gold Nanoparticles

    Science.gov (United States)

    Jha, Anal K.; Prasad, K.

    2016-02-01

    Aquatic pteridophyte (Azolla sp.) was taken to assess its potential to synthesize the metal (Au) nanoparticles. The synthesized particles were characterized using X-ray, UV-visible, scanning and transmission electron microscopy analyses. Nanoparticles almost spherical in shape having the sizes of 5-17nm are found. UV-visible study revealed the surface plasmon resonance at 538nm. Responsible phytochemicals for the transformation were principally phenolics, tannins, anthraquinone glycosides and sugars present abundantly in the plant thereby bestowing it adaptive prodigality. Also, the use of Azolla sp. for the synthesis of gold nanoparticles offers the benefit of eco-friendliness.

  3. Nonlinear optical properties of interconnected gold nanoparticles on silicon

    Science.gov (United States)

    Lesuffleur, Antoine; Gogol, Philippe; Beauvillain, Pierre; Guizal, B.; Van Labeke, D.; Georges, P.

    2008-12-01

    We report second harmonic generation (SHG) measurements in reflectivity from chains of gold nanoparticles interconnected with metallic bridges. We measured more than 30 times a SHG enhancement when a surface plasmon resonance was excited in the chains of nanoparticles, which was influenced by coupling due to the electrical connectivity of the bridges. This enhancement was confirmed by rigorous coupled wave method calculations and came from high localization of the electric field at the bridge. The introduction of 10% random defects into the chains of nanoparticles dropped the SHG by a factor of 2 and was shown to be very sensitive to the fundamental wavelength.

  4. Synthesis of multifunctional gold nanoparticles for image guided therapy

    International Nuclear Information System (INIS)

    Laurent, Gautier

    2014-01-01

    The original properties of nanoparticles make them extremely attractive in the field of oncology. In fast, gold nanoparticles coated by macrocyclic ligands allow imaging and therapy with only one object. Therefore, multifunctional platforms are very promising for image-guided therapy, winch constitutes an important step towards personalization of treatment. This consists of stimulating the therapeutic activity of the nanoparticles when their accumulation is high within the tumor zone and low in healthy tissues. A higher selectivity of the treatment is therefore expected. Biodistribution study by SPECT/CT has shown free circulation, renal elimination and a moderate retention by the liver of the nanoparticles. However, this retention is not due to the opsonisation processes. The MRI study of rats' brain carrying a gliosarcoma has shown an accumulation of nanoparticles Au-at-FADOTAGA-Gd in the tumor. Moreover, the co-labeling of these nanoparticles by Ge and 64Cts2+ was successfully performed. As a result, PET/MRI images, a much researched combination but rarely achieved, were acquired on the same animal alter intravenous injection of the co-labeled nanoparticles. The radiosensitizing character of nanoparticles Au-at-TADOTAGA was confirmed by the follow up of tumor growth alter a treatment by MRT (microbeam irradiation) 15 minutes after intratumoral injection of nanoparticles. The therapeutic gain of this treatment has been validated by MRT 24 hours after intravenous injection of nanoparticles to rats carrying gliosarcoma (radioresistant tumor in radiosensitive organ). (author)

  5. Thermally stable silica-coated hydrophobic gold nanoparticles.

    Science.gov (United States)

    Kanehara, Masayuki; Watanabe, Yuka; Teranishi, Toshiharu

    2009-01-01

    We have successfully developed a method for silica coating on hydrophobic dodecanethiol-protected Au nanoparticles with coating thickness ranging from 10 to 40 nm. The formation of silica-coated Au nanoparticles could be accomplished via the preparation of hydrophilic Au nanoparticle micelles by cationic surfactant encapsulation in aqueous phase, followed by hydrolysis of tetraethylorthosilicate on the hydrophilic surface of gold nanoparticle micelles. Silica-coated Au nanoparticles exhibited quite high thermal stability, that is, no agglomeration of the Au cores could be observed after annealing at 600 degrees C for 30 min. Silica-coated Au nanoparticles could serve as a template to derive hollow nanoparticles. An addition of NaCN solution to silica-coated Au nanoparticles led the formation of hollow silica nanoparticles, which were redispersible in deionized water. The formation of the hollow silica nanoparticles results from the mesoporous structures of the silica shell and such a mesoporous structure is applicable to both catalyst support and drug delivery.

  6. Monomer adsorption of indocyanine green to gold nanoparticles

    NARCIS (Netherlands)

    Guerrini, Luca; Hartsuiker, Liesbeth; Manohar, Srirang; Otto, Cornelis

    2011-01-01

    NIR-dye encoded gold nanoparticles (GNP) are rapidly emerging as contrast agents in many bio-imaging/sensing applications. The coding process is usually carried out without control or a clear understanding of the metal–liquid interface properties which, in contrast, are critical in determining the

  7. Reaction parameters for controlled sonosynthesis of gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez M, A. L. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Colon esq. Paseo Tollocan s/n, 50120 Toluca, Estado de Mexico (Mexico); Cabrera L, L. I. [UNAM-UAEM, Centro Conjunto de Investigacion en Quimica Sustentable, Km 14.5 Carretera Toluca-Atlacomulco, 50200 San Cayetano-Toluca, Estado de Mexico (Mexico)

    2015-07-01

    The synthesis of gold nanoparticles by sonochemical technique has been previously performed with excellent results. The synthesis has been carried out in the presence of citric acid, a strong reducing agent, which allows the nucleation and growth of gold nanoparticles, at the same time that controls particle size. In this work we report the use of sodium tartrate as a mild reducing agent that allows a better understanding of the effect of the reaction parameters during gold nanoparticle synthesis. A conventional sonication bath (37 k Hz) was used for the sonochemical synthesis. This work focuses on the reaction temperature effect and the effect of sodium tartrate concentration. It was confirmed that particle size, and particle morphology is dependent of these two reaction parameters. Equally, colloidal stabilization was related to reaction temperature and sodium tartrate concentration. It was also determined that Ostwald ripening takes place during sonochemical reaction under our conditions, allowing to understand the mechanism that takes place during synthesis. Gold nanoparticles with main particle size of 17 nm were achieved by this method. Characterization techniques used: Fourier transform infrared spectra (Ftir), X-ray diffraction and Atomic Force Microscope was used in order to determine particle size of the synthetic product of reaction M10c by tapping mode. (Author)

  8. Facially amphiphilic thiol capped gold and silver nanoparticles

    Indian Academy of Sciences (India)

    Wintec

    *For correspondence. Also at the Chemical Biology Unit,. Jawaharlal Nehru Centre for Advanced Scientific Research,. Bangalore 560 064. Facially amphiphilic thiol capped gold and silver nanoparticles. †. SHREEDHAR BHAT a and UDAY MAITRA*. Department of Organic Chemistry, Indian Institute of Science, Bangalore ...

  9. Oligothia dendrimers for the formation of gold nanoparticles

    NARCIS (Netherlands)

    d'Aleo, A.; Williams, R.M.; Osswald, F.; Edamana, P.; Hahn, U.; van Heyst, J.; Tichelaar, F.D.; Voegtle, F.; De Cola, L.

    2004-01-01

    The synthesis and characterization of oligothia dendrimers and their use for the formation of gold nanoparticles is described. The role played by these dendrimers in controlling the stability and size of the particles is discussed. It is shown that the generation of the dendrimers, as well as the

  10. Reaction parameters for controlled sonosynthesis of gold nanoparticles

    International Nuclear Information System (INIS)

    Gonzalez M, A. L.; Cabrera L, L. I.

    2015-01-01

    The synthesis of gold nanoparticles by sonochemical technique has been previously performed with excellent results. The synthesis has been carried out in the presence of citric acid, a strong reducing agent, which allows the nucleation and growth of gold nanoparticles, at the same time that controls particle size. In this work we report the use of sodium tartrate as a mild reducing agent that allows a better understanding of the effect of the reaction parameters during gold nanoparticle synthesis. A conventional sonication bath (37 k Hz) was used for the sonochemical synthesis. This work focuses on the reaction temperature effect and the effect of sodium tartrate concentration. It was confirmed that particle size, and particle morphology is dependent of these two reaction parameters. Equally, colloidal stabilization was related to reaction temperature and sodium tartrate concentration. It was also determined that Ostwald ripening takes place during sonochemical reaction under our conditions, allowing to understand the mechanism that takes place during synthesis. Gold nanoparticles with main particle size of 17 nm were achieved by this method. Characterization techniques used: Fourier transform infrared spectra (Ftir), X-ray diffraction and Atomic Force Microscope was used in order to determine particle size of the synthetic product of reaction M10c by tapping mode. (Author)

  11. Gold nanoparticle-based microfluidic sensor for mercury detection

    DEFF Research Database (Denmark)

    Lafleur, Josiane P.; Jensen, Thomas Glasdam; Kutter, Jörg Peter

    2011-01-01

    The contamination of natural resources by human activity can have severe socio-economical impacts. Conventional methods of environmental analysis can be significantly improved by the development of portable microscale technologies for remote/field sensing. A gold nanoparticle-based lab...

  12. Interaction between manufactured gold nanoparticles and naturally occurring organic macromolecules

    International Nuclear Information System (INIS)

    Diegoli, Sara; Manciulea, Adriana L.; Begum, Shakiela; Jones, Ian P.; Lead, Jamie R.; Preece, Jon A.

    2008-01-01

    The increasing exploitation of nanomaterials into many consumer and other products is raising concerns as these nanomaterials are likely to be released into the environment. Due to our lack of knowledge about the environmental chemistry, transport and ecotoxicology of nanomaterials, it is of paramount importance to study how natural aquatic colloids can interact with manufactured gold nanoparticles as these interactions will determine their environmental fate and behaviour. In this context, our work aims to quantify the effect of naturally occurring riverine macromolecules - International Humic Substances Society (IHSS) Suwannee River Humic Acid Standard (SRHA) - on citrate- and acrylate-stabilized gold nanoparticles. The influence of SRHA on the stability of the gold colloids was studied as a function of pH by UV-visible absorption spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). At high ionic strengths (0.1 M), extensive and rapid aggregation occurred, while more subtle effects were observed at lower ionic strength values. Evidence was found that SRHA enhances particle stability at extreme pH values (ionic strength < 0.01 M) by substituting and/or over-coating the original stabilizer on the gold nanoparticle surface, thus affecting surface charge and chemistry. These findings have important implications for the fate and behaviour of nanoparticles in the environment and their ecotoxicity

  13. Design and Fabrication of Microfiber Containing Gold Nanoparticles

    DEFF Research Database (Denmark)

    Jørgensen, Mette Marie; Wang, Guanghui; Hu, Dora Juan Juan

    2010-01-01

    We present a simple fabrication method for embedding gold nanoparticles (GNPs) in a microfiber with two main advantages. The GNPs are positioned within the microfiber securing maximum enhancement of the electrical field and protection of the GNPs from the surroundings; moreover incoupling losses...

  14. The effects of gold nanoparticles size and concentration on viscosity ...

    African Journals Online (AJOL)

    This study was carried out to investigate viscosity in relation with the temperature, flow activation energy and dielectric properties for 10, 20 and 50 nm gold nanoparticles size (GNPs) in addition to absorption and fluorescence spectra at different concentrations (0.2 × 10-3 to 1 × 10-2%) in an attempt to cover and understand ...

  15. The bioaccumulation and toxicity induced by gold nanoparticles in ...

    African Journals Online (AJOL)

    It is essential to characterize the bioaccumulation and toxicity of gold nanoparticles (GNPs) in blood prior to using them in drug delivery, diagnostics, and treatment. The aim of the present study was to evaluate the blood absorbance spectra after intraperitoneal administration of 50 μl of 10, 20, and 50 nm GNPs in rat for ...

  16. Ligand adsorption and exchange on pegylated gold nanoparticles

    Science.gov (United States)

    Previous researchers proposed that thiolated poly(ethylene glycol) (PEG-SH) adopts a “mushroom-like” conformation on gold nanoparticles (AuNPs) in water. However, information regarding the size and permeability of the PEG-SH mushroom caps and surface area passivated by the PEG-SH mushroom stems are ...

  17. Toxicological risk assessment of elemental gold following oral exposure to sheets and nanoparticles – A review

    DEFF Research Database (Denmark)

    Hadrup, Niels; Sharma, Anoop Kumar; Poulsen, Morten

    2015-01-01

    Elemental gold is used as a food coloring agent and in dental fillings. In addition, gold nanoparticles are gaining increasing attention due to their potential use as inert carriers for medical purposes. Although elemental gold is considered to be inert, there is evidence to suggest the release....... In addition, gold released from dental restorations has been reported to increase the risk of developing gold hypersensitivity. Regarding genotoxicity, in vitro studies indicate that gold nanoparticles induce DNA damage in mammalian cells. In vivo, gold nanoparticles induce genotoxic effects in Drosophila...

  18. Hybrid gold nanoparticles in molecular imaging and radiotherapy

    International Nuclear Information System (INIS)

    Katti, K.V.; Kannan, R.; Katti, K.; Kattumuri, V.; Pandrapragada, R.; Rahing, V.; Cutler, C.; Boote, E.; Casteel, S.W.; Smith, C.J.; Robertson, J.D.; Jurrison, S.

    2006-01-01

    Metallic nanoparticles, because of their size, chemical and physical properties, are particularly attractive as therapeutic probes in treating cancer. Central to any clinical advances in nanoparticulate based therapy will be to produce hybrid nanoparticles that can be targeted to vascular, extracellular or cell surface receptors. Development of hybrid nanoparticles that specifically target cancer vasculature has received considerable attention. Most cancers have leaky vasculature and the defective vascular architecture, created due to the rapid vascularisation necessary to serve fast growing cancers, in combination with poor lymphatic drainage allows increased permeation and retention effects. The leaky vasculature, because of higher porosity and permeability, serve as natural high affinity targets to metallic nanoparticles. Another attractive approach toward the application of nanotechnology to nanomedicine is the utility of nanoparticles that display inherent therapeutic properties. For example radioactive gold nanoparticles present attractive prospects in therapy of cancer. The radioactive properties of Au-198 (β(max) = 0.96 MeV; t(1/2) = 2.7 d) and Au-199 (β(max) 0.46 MeV; t(1/2) = 3.14 d) make them ideal candidates for use in radiotherapeutic applications. In addition, they both have imageable gamma emissions for dosimetry and pharmacokinetic studies and Au-199 can be made carrier-free by indirect methods. Gold nanoparticles are of interest for treatment of disease as they can deliver agents directly into cells and cellular components with a higher concentration of radioactivity, e.g. higher dose of radioactivity, to cancerous tumor cells

  19. Mercury adsorption to gold nanoparticle and thin film surfaces

    Science.gov (United States)

    Morris, Todd Ashley

    Mercury adsorption to gold nanoparticle and thin film surfaces was monitored by spectroscopic techniques. Adsorption of elemental mercury to colloidal gold nanoparticles causes a color change from wine-red to orange that was quantified by UV-Vis absorption spectroscopy. The wavelength of the surface plasmon mode of 5, 12, and 31 nm gold particles blue-shifts 17, 14, and 7.5 nm, respectively, after a saturation exposure of mercury vapor. Colorimetric detection of inorganic mercury was demonstrated by employing 2.5 nm gold nanoparticles. The addition of low microgram quantities of Hg 2+ to these nanoparticles induces a color change from yellow to peach or blue. It is postulated that Hg2+ is reduced to elemental mercury by SCN- before and/or during adsorption to the nanoparticle surface. It has been demonstrated that surface plasmon resonance spectroscopy (SPRS) is sensitive to mercury adsorption to gold and silver surfaces. By monitoring the maximum change in reflectivity as a function of amount of mercury adsorbed to the surface, 50 nm Ag films were shown to be 2--3 times more sensitive than 50 nm Au films and bimetallic 15 nm Au/35 nm Ag films. In addition, a surface coverage of ˜40 ng Hg/cm2 on the gold surface results in a 0.03° decrease in the SPR angle of minimum reflectivity. SPRS was employed to follow Hg exposure to self-assembled monolayers (SAMs) on Au. The data indicate that the hydrophilic or hydrophobic character of the SAM has a significant effect on the efficiency of Hg penetration. Water adsorbed to carboxylic acid end group of the hydrophilic SAMs is believed to slow the penetration of Hg compared to methyl terminated SAMs. Finally, two protocols were followed to remove mercury from gold films: immersion in concentrated nitric acid and thermal annealing up to 200°C. The latter protocol is preferred because it removes all of the adsorbed mercury from the gold surface and does not affect the morphology of the gold surface.

  20. Obtaining and characterization of thin films polyelectrolyte with gold nanoparticles

    International Nuclear Information System (INIS)

    Popiolski, Tatiane M.; Crespo, Janaina S.; Silva, Renato B.

    2011-01-01

    Thin films of polyelectrolytes are manufactured via sequential adsorption of weak polyelectrolytes from aqueous solutions based on electrostatic interaction of oppositely charged polymers. Metal containing polymeric compounds are of particular interest to the production of materials with electrical interface and optical properties. In this sense, the objective of this study was to obtain thin films of weak polyelectrolytes and analyze the distribution of gold nanoparticles stabilized by sodium citrate and by poly (vinylpyrrolidone). The characterization was performed using UV-visible, X-ray diffraction and atomic force microscopy. The techniques of UV-visible and X-ray diffraction was confirmed the presence of gold in the films, the atomic force microscopy images were used to analyze the morphology of the films and check the behavior of the diffusion of gold nanoparticles. (author)

  1. A simple gel electrophoresis method for separating polyhedral gold nanoparticles

    Science.gov (United States)

    Kim, Suhee; Lee, Hye Jin

    2015-07-01

    In this paper, a simple approach to separate differently shaped and sized polyhedral gold nanoparticles (NPs) within colloidal solutions via gel electrophoresis is described. Gel running parameters for separating efficiently gold NPs including gel composition, added surfactant types and applied voltage were investigated. The plasmonic properties and physical structure of the separated NPs extracted from the gel matrix were then investigated using transmission electron microscopy (TEM) and UV-vis spectrophotometry respectively. Data analysis revealed that gel electrophoresis conditions of a 1.5 % agarose gel with 0.1 % sodium dodecyl sulfate (SDS) surfactant under an applied voltage of 100 V resulted in the selective isolation of ~ 50 nm polyhedral shaped gold nanoparticles. Further efforts are underway to apply the method to purify biomolecule-conjugated polyhedral Au NPs that can be readily used for NP-enhanced biosensing platforms.

  2. Synthesis, Structure, Stability and Redispersion of Gold-based Nanoparticles

    Science.gov (United States)

    Tiruvalam, Ram Chandra

    Nanoscale gold has been shown to possess an intriguing combination of unexpected optical, photochemical and catalytic properties. The ability to control the size, shape, morphology, composition and dispersion of gold-based nanostructures is key to optimizing their performance for nanotechnology applications. The advanced electron microscopy studies described in this thesis analyze three important aspects of gold and gold-palladium alloy nanoparticles: namely, (i) the ability to synthesize gold nanoparticles of controlled size and shape in an aqueous medium; (ii) the colloidal preparation of designer gold-palladium alloys for selective oxidation catalysis; and (iii) the ability to disperse gold as finely and homogeneously as possible on a metal oxide or carbon support. The ability to exploit the nanoscale properties of gold for various engineering applications often depends on our ability to control size and shape of the nanoscale entity by careful manipulation of the synthesis parameters. We have explored an aqueous based synthesis route, using oleylamine as both a reductant and surfactant, for preparing gold nanostructures. By systematically varying synthesis parameters such as oleylamine concentration, reaction temperature, and aging time it is possible to identify processing regimens that generate Au nanostructures having either pseudo-spherical, faceted polyhedral, nanostar or wire shaped morphologies. Furthermore, by quenching the reaction partway through it is possible to create a class of metastable Au-containing structures such as nanocubes, nanoboxes and nanowires. Possible formation mechanisms for these gold based nano-objects are discussed. There is a growing interest in using supported bimetallic AuPd alloy nanoparticles for selective oxidation reactions. In this study, a systematic series of size controlled AuPd bimetallic particles have been prepared by colloidal synthesis methods. Particles having random alloy structures, as well as `designer

  3. Structure and nanotribology of thermally deposited gold nanoparticles on graphite

    Energy Technology Data Exchange (ETDEWEB)

    Cihan, Ebru [UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Özoğul, Alper [Department of Mechanical Engineering, Bilkent University, Ankara 06800 (Turkey); Baykara, Mehmet Z., E-mail: mehmet.baykara@bilkent.edu.tr [UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Department of Mechanical Engineering, Bilkent University, Ankara 06800 (Turkey)

    2015-11-01

    Graphical abstract: - Highlights: • Structure and tribology of thermally deposited AuNPs on HOPG have been studied. • Well-faceted, hexagonal AuNPs are formed on HOPG upon post-deposition annealing. • The crystalline character of the AuNPs is confirmed via TEM measurements. • AFM measurements reveal a “2/3” power law dependence of friction on load on AuNPs. • Friction forces at AuNP edges evolve linearly with increasing height and load. - Abstract: We present experiments involving the structural and frictional characterization of gold nanoparticles (AuNP) thermally deposited on highly oriented pyrolytic graphite (HOPG). The effect of thermal deposition amount, as well as post-deposition annealing on the morphology and distribution of gold on HOPG is studied via scanning electron microscopy (SEM) measurements, while transmission electron microscopy (TEM) is utilized to confirm the crystalline character of the nanoparticles. Lateral force measurements conducted via atomic force microscopy (AFM) under ambient conditions are employed to investigate the nanotribological properties of the gold nanoparticles as a function of normal load. Finally, the increase in lateral force experienced at the edges of the nanoparticles is studied as a function of normal load, as well as nanoparticle height. As a whole, our results constitute a comprehensive structural and frictional characterization of the AuNP/HOPG material system, forming the basis for nanotribology experiments involving the lateral manipulation of thermally deposited AuNPs on HOPG via AFM under ambient conditions.

  4. Structure and nanotribology of thermally deposited gold nanoparticles on graphite

    International Nuclear Information System (INIS)

    Cihan, Ebru; Özoğul, Alper; Baykara, Mehmet Z.

    2015-01-01

    Graphical abstract: - Highlights: • Structure and tribology of thermally deposited AuNPs on HOPG have been studied. • Well-faceted, hexagonal AuNPs are formed on HOPG upon post-deposition annealing. • The crystalline character of the AuNPs is confirmed via TEM measurements. • AFM measurements reveal a “2/3” power law dependence of friction on load on AuNPs. • Friction forces at AuNP edges evolve linearly with increasing height and load. - Abstract: We present experiments involving the structural and frictional characterization of gold nanoparticles (AuNP) thermally deposited on highly oriented pyrolytic graphite (HOPG). The effect of thermal deposition amount, as well as post-deposition annealing on the morphology and distribution of gold on HOPG is studied via scanning electron microscopy (SEM) measurements, while transmission electron microscopy (TEM) is utilized to confirm the crystalline character of the nanoparticles. Lateral force measurements conducted via atomic force microscopy (AFM) under ambient conditions are employed to investigate the nanotribological properties of the gold nanoparticles as a function of normal load. Finally, the increase in lateral force experienced at the edges of the nanoparticles is studied as a function of normal load, as well as nanoparticle height. As a whole, our results constitute a comprehensive structural and frictional characterization of the AuNP/HOPG material system, forming the basis for nanotribology experiments involving the lateral manipulation of thermally deposited AuNPs on HOPG via AFM under ambient conditions.

  5. Optical absorption of carbon-gold core-shell nanoparticles

    Science.gov (United States)

    Wang, Zhaolong; Quan, Xiaojun; Zhang, Zhuomin; Cheng, Ping

    2018-01-01

    In order to enhance the solar thermal energy conversion efficiency, we propose to use carbon-gold core-shell nanoparticles dispersed in liquid water. This work demonstrates theoretically that an absorbing carbon (C) core enclosed in a plasmonic gold (Au) nanoshell can enhance the absorption peak while broadening the absorption band; giving rise to a much higher solar absorption than most previously studied core-shell combinations. The exact Mie solution is used to evaluate the absorption efficiency factor of spherical nanoparticles in the wavelength region from 300 nm to 1100 nm as well as the electric field and power dissipation profiles inside the nanoparticles at specified wavelengths (mostly at the localized surface plasmon resonance wavelength). The field enhancement by the localized plasmons at the gold surfaces boosts the absorption of the carbon particle, resulting in a redshift of the absorption peak with increased peak height and bandwidth. In addition to spherical nanoparticles, we use the finite-difference time-domain method to calculate the absorption of cubic core-shell nanoparticles. Even stronger enhancement can be achieved with cubic C-Au core-shell structures due to the localized plasmonic resonances at the sharp edges of the Au shell. The solar absorption efficiency factor can exceed 1.5 in the spherical case and reach 2.3 in the cubic case with a shell thickness of 10 nm. Such broadband absorption enhancement is in great demand for solar thermal applications including steam generation.

  6. Variable temperature investigation of the atomic structure of gold nanoparticles

    International Nuclear Information System (INIS)

    Young, N P; Kirkland, A I; Huis, M A van; Zandbergen, H W; Xu, H

    2010-01-01

    The characterisation of nanoparticle structures is the first step towards understanding and optimising their utility in important technological applications such as catalysis. Using newly developed in-situ transmission electron microscopy (TEM) specimen holders, the temperature dependent atomic structure of gold nanoparticles in the size range 5-12 nm has been investigated. In this size interval, the decahedral morphology has been identified as the most favourable structure at or above room temperature, while particle surface roughening becomes evident above 600 0 C. An icosahedral transition has also been identified at low temperature in particles under 9 nm in diameter. These experimental results are consistent with recently published temperature dependent equilibrium phase maps for gold nanoparticles.

  7. Variable temperature investigation of the atomic structure of gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Young, N P; Kirkland, A I [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Huis, M A van; Zandbergen, H W [Kavli Insitute of Nanoscience, Delft University of Technolgy, Lorentzweg 1, NL-2628CJ, Delft (Netherlands); Xu, H, E-mail: neil.young@materials.ox.ac.u [Department of Geology and Geophysics, and Materials Science Program, University of Wisconsin-Madison, Madison, Wisconsin (United States)

    2010-07-01

    The characterisation of nanoparticle structures is the first step towards understanding and optimising their utility in important technological applications such as catalysis. Using newly developed in-situ transmission electron microscopy (TEM) specimen holders, the temperature dependent atomic structure of gold nanoparticles in the size range 5-12 nm has been investigated. In this size interval, the decahedral morphology has been identified as the most favourable structure at or above room temperature, while particle surface roughening becomes evident above 600{sup 0}C. An icosahedral transition has also been identified at low temperature in particles under 9 nm in diameter. These experimental results are consistent with recently published temperature dependent equilibrium phase maps for gold nanoparticles.

  8. The gold standard: gold nanoparticle libraries to understand the nano-bio interface.

    Science.gov (United States)

    Alkilany, Alaaldin M; Lohse, Samuel E; Murphy, Catherine J

    2013-03-19

    Since the late 1980s, researchers have prepared inorganic nanoparticles of many types--including elemental metals, metal oxides, metal sulfides, metal selenides, and metal tellurides--with excellent control over size and shape. Originally many researchers were primarily interested in exploring the quantum size effects predicted for such materials. Applications of inorganic nanomaterials initially centered on physics, optics, and engineering but have expanded to include biology. Many current nanomaterials can serve as biochemical sensors, contrast agents in cellular or tissue imaging, drug delivery vehicles, or even as therapeutics. In this Account we emphasize that the understanding of how nanomaterials will function in a biological system relies on the knowledge of the interface between biological systems and nanomaterials, the nano-bio interface. Gold nanoparticles can serve as excellent standards to understand more general features of the nano-bio interface because of its many advantages over other inorganic materials. The bulk material is chemically inert, and well-established synthetic methods allow researchers to control its size, shape, and surface chemistry. Gold's background concentration in biological systems is low, which makes it relatively easy to measure it at the part-per-billion level or lower in water. In addition, the large electron density of gold enables relatively simple electron microscopic experiments to localize it within thin sections of cells or tissue. Finally, gold's brilliant optical properties at the nanoscale are tunable with size, shape, and aggregation state and enable many of the promising chemical sensing, imaging, and therapeutic applications. Basic experiments with gold nanoparticles and cells include measuring the toxicity of the particles to cells in in vitro experiments. The species other than gold in the nanoparticle solution can be responsible for the apparent toxicity at a particular dose. Once the identity of the toxic

  9. Modified gold electrodes based on thiocytosine/guanine-gold nanoparticles for uric and ascorbic acid determination

    International Nuclear Information System (INIS)

    Vulcu, Adriana; Grosan, Camelia; Muresan, Liana Maria; Pruneanu, Stela; Olenic, Liliana

    2013-01-01

    The present paper describes the preparation of new modified surfaces for electrodes based on guanine/thiocytosine and gold nanoparticles. The gold nanoparticles were analyzed by UV–vis spectroscopy and transmission electron microscopy (TEM) and it was found that they have diameters between 30 and 40 nm. The layers were characterized by specular reflectance infrared spectroscopy (FTIR-RAS) and by atomic force microscopy (AFM). The thickness of layers was found to be approximately 30 nm for TC layers and 300 nm for GU layers. Every layer was characterized as electrochemical sensor (by cyclic voltammetry) both for uric acid and ascorbic acid determinations, separately and in their mixture. The modified sensors have good calibration functions with good sensitivity (between 1.145 and 1.406 mA cm −2 /decade), reproducibility ( t hiocytosine (Au T C) and gold g uanine (Au G U) layers

  10. Functionalization of biosynthesized gold nanoparticle from aqueous ...

    African Journals Online (AJOL)

    The biosynthesized nanoparticles and formulated nanodrug were characterized using UV-Vis spectrophotometry, Zetasizer, Scanning and transmission Electron Microscopy (SEM; TEM), Energy Dispersive spectrophotometry (EDAX) and Fourier Transform Infra-red Spectroscopy. Polyethylene glycol and Lincomycin were ...

  11. Human serum albumin mediated self-assembly of gold nanoparticles into hollow spheres

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, Nimai C [Singapore-MIT Alliance, Manufacturing Systems and Technology Programme, Nanyang Technological University, 65 Nanyang Drive, 637460 (Singapore); Shin, Kwanwoo [Interdisciplinary Program of Integrated Biotechnology, Sogang University, Shinsoo-dong, Mapo-gu, Seoul 121-742 (Korea, Republic of)], E-mail: ncnayak@gmail.com

    2008-07-02

    The assembly of nanoparticles in topologically predefined superstructures is an important area in nanoscale architecture. In this paper, we report an unusual aggregation phenomenon involving L-lysine capped gold nanoparticles and human serum albumin into hollow nanospheres. The electrostatic interaction between positively charged L-lysine capped gold nanoparticles and negatively charged human serum albumin at physiological pH led to the assembly of the gold nanoparticles into hollow spheres. The phenomenon can be explained by the dry hole opening mechanism.

  12. Human serum albumin mediated self-assembly of gold nanoparticles into hollow spheres

    International Nuclear Information System (INIS)

    Nayak, Nimai C; Shin, Kwanwoo

    2008-01-01

    The assembly of nanoparticles in topologically predefined superstructures is an important area in nanoscale architecture. In this paper, we report an unusual aggregation phenomenon involving L-lysine capped gold nanoparticles and human serum albumin into hollow nanospheres. The electrostatic interaction between positively charged L-lysine capped gold nanoparticles and negatively charged human serum albumin at physiological pH led to the assembly of the gold nanoparticles into hollow spheres. The phenomenon can be explained by the dry hole opening mechanism

  13. Aggregation and adhesion of gold nanoparticles in phosphate buffered saline

    Energy Technology Data Exchange (ETDEWEB)

    Du Shangfeng, E-mail: s.du@bham.ac.uk; Kendall, Kevin; Toloueinia, Panteha; Mehrabadi, Yasamin; Gupta, Gaurav; Newton, Jill [University of Birmingham, School of Chemical Engineering (United Kingdom)

    2012-03-15

    In applications in medicine and more specifically drug delivery, the dispersion stability of nanoparticles plays a significant role on their final performances. In this study, with the use of two laser technologies, dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA), we report a simple method to estimate the stability of nanoparticles dispersed in phosphate buffered saline (PBS). Stability has two features: (1) self-aggregation as the particles tend to stick to each other; (2) disappearance of particles as they adhere to surrounding substrate surfaces such as glass, metal, or polymer. By investigating the effects of sonication treatment and surface modification by five types of surfactants, including nonylphenol ethoxylate (NP9), polyvinyl pyrrolidone (PVP), human serum albumin (HSA), sodium dodecyl sulfate (SDS) and citrate ions on the dispersion stability, the varying self-aggregation and adhesion of gold nanoparticles dispersed in PBS are demonstrated. The results showed that PVP effectively prevented aggregation, while HSA exhibited the best performance in avoiding the adhesion of gold nanoparticle in PBS onto glass and metal. The simple principle of this method makes it a high potential to be applied to other nanoparticles, including virus particles, used in dispersing and processing.

  14. Thermally Stable Gold Nanoparticles with a Crosslinked Diblock Copolymer Shell

    Science.gov (United States)

    Jang, Se Gyu; Khan, Anzar; Hawker, Craig J.; Kramer, Edward J.

    2010-03-01

    The use of polymer-coated Au nanoparticles prepared using oligomeric- or polymeric-ligands tethered by Au-S bonds for incorporation into block copolymer templates under thermal processing has been limited due to dissociation of the Au-S bond at T > 100^oC where compromises their colloidal stability. We report a simple route to prepare sub-5nm gold nanoparticles with a thermally stable polymeric shell. An end-functional thiol ligand consisting of poly(styrene-b-1,2&3,4-isoprene-SH) is synthesized by anionic polymerization. After a standard thiol ligand synthesis of Au nanoparticles, the inner PI block is cross-linked through reaction with 1,1,3,3-tetramethyldisiloxane. Gold nanoparticles with the cross-linked shell are stable in organic solvents at 160^oC as well as in block copolymer films of PS-b-P2VP annealed in vacuum at 170^oC for several days. These nanoparticles can be designed to strongly segregate to the PS-P2VP interface resulting in very large Au nanoparticle volume fractions φp without macrophase separation as well as transitions between lamellar and bicontinuous morphologies as φp increases.

  15. Pair distribution function analysis applied to decahedral gold nanoparticles

    International Nuclear Information System (INIS)

    Nakotte, H; Silkwood, C; Kiefer, B; Karpov, D; Fohtung, E; Page, K; Wang, H-W; Olds, D; Manna, S; Fullerton, E E

    2017-01-01

    The five-fold symmetry of face-centered cubic (fcc) derived nanoparticles is inconsistent with the translational symmetry of a Bravais lattice and generally explained by multiple twinning of a tetrahedral subunit about a (joint) symmetry axis, with or without structural modification to the fcc motif. Unlike in bulk materials, five-fold twinning in cubic nanoparticles is common and strongly affects their structural, chemical, and electronic properties. To test and verify theoretical approaches, it is therefore pertinent that the local structural features of such materials can be fully characterized. The small size of nanoparticles severely limits the application of traditional analysis techniques, such as Bragg diffraction. A complete description of the atomic arrangement in nanoparticles therefore requires a departure from the concept of translational symmetry, and prevents fully evaluating all the structural features experimentally. We describe how recent advances in instrumentation, together with the increasing power of computing, are shaping the development of alternative analysis methods of scattering data for nanostructures. We present the application of Debye scattering and pair distribution function (PDF) analysis towards modeling of the total scattering data for the example of decahedral gold nanoparticles. PDF measurements provide a statistical description of the pair correlations of atoms within a material, allowing one to evaluate the probability of finding two atoms within a given distance. We explored the sensitivity of existing synchrotron x-ray PDF instruments for distinguishing four different simple models for our gold nanoparticles: a multiply twinned fcc decahedron with either a single gap or multiple distributed gaps, a relaxed body-centered orthorhombic (bco) decahedron, and a hybrid decahedron. The data simulations of the models were then compared with experimental data from synchrotron x-ray total scattering. We present our experimentally

  16. Hybridization thermodynamics of DNA bound to gold nanoparticles

    International Nuclear Information System (INIS)

    Lang, Brian

    2010-01-01

    Isothermal Titration Calorimetry (ITC) was used to study the thermodynamics of hybridization on DNA-functionalized colloidal gold nanoparticles. When compared to the thermodynamics of hybridization of DNA that is free in solution, the differences in the values of the Gibbs free energy of reaction, Δ r G o , the enthalpy, Δ r H o , and entropy, Δ r S o , were small. The change in Δ r G o between the free and bound states was always positive but with statistical significance outside the 95% confidence interval, implying the free DNA is slightly more stable than when in the bound state. Additionally, ITC was also able to reveal information about the binding stoichiometry of the hybridization reactions on the DNA-functionalized gold nanoparticles, and indicates that there is a significant fraction of the DNA on gold nanoparticle surface that is unavailable for DNA hybridization. Furthermore, the fraction of available DNA is dependent on the spacer group on the DNA that is used to span the gold surface from that to the probe DNA.

  17. Electron transport in gold colloidal nanoparticle-based strain gauges

    Science.gov (United States)

    Moreira, Helena; Grisolia, Jérémie; Sangeetha, Neralagatta M.; Decorde, Nicolas; Farcau, Cosmin; Viallet, Benoit; Chen, Ke; Viau, Guillaume; Ressier, Laurence

    2013-03-01

    A systematic approach for understanding the electron transport mechanisms in resistive strain gauges based on assemblies of gold colloidal nanoparticles (NPs) protected by organic ligands is described. The strain gauges were fabricated from parallel micrometer wide wires made of 14 nm gold (Au) colloidal NPs on polyethylene terephthalate substrates, elaborated by convective self-assembly. Electron transport in such devices occurs by inter-particle electron tunneling through the tunnel barrier imposed by the organic ligands protecting the NPs. This tunnel barrier was varied by changing the nature of organic ligands coating the nanoparticles: citrate (CIT), phosphines (BSPP, TDSP) and thiols (MPA, MUDA). Electro-mechanical tests indicate that only the gold NPs protected by phosphine and thiol ligands yield high gauge sensitivity. Temperature-dependent resistance measurements are explained using the ‘regular island array model’ that extracts transport parameters, i.e., the tunneling decay constant β and the Coulomb charging energy EC. This reveals that the Au@CIT nanoparticle assemblies exhibit a behavior characteristic of a strong-coupling regime, whereas those of Au@BSPP, Au@TDSP, Au@MPA and Au@MUDA nanoparticles manifest a weak-coupling regime. A comparison of the parameters extracted from the two methods indicates that the most sensitive gauges in the weak-coupling regime feature the highest β. Moreover, the EC values of these 14 nm NPs cannot be neglected in determining the β values.

  18. Living fungal hyphae-templated porous gold microwires using nanoparticles as building blocks

    International Nuclear Information System (INIS)

    Rehman, Asma; Majeed, Muhammad Irfan; Ihsan, Ayesha; Hussain, Syed Zajif; Saif-ur-Rehman; Ghauri, Muhammad Afzal; Khalid, Zafar M.; Hussain, Irshad

    2011-01-01

    A simple and environmentally benign green method is reported to decorate growing fungal hyphae with high loading of gold nanoparticles, which were initially produced using aqueous tea extract as a sole reducing/stabilizing agent. Inoculation of fungal spores in aqueous suspension of nanoparticles led to the growth of intensely red-coloured fungal hyphae due to the accumulation of gold nanoparticles. Heat treatment of these hybrid materials led to the formation of porous gold microwires. This report is thus an interesting example of using green and sustainable approach to produce nanostructured materials which have potential applications in catalysis, sensing and electronics.Graphical AbstractPorous gold microwires are formed by the heat treatment of fungal hyphae–gold nanoparticle composites. These nanoparticle-loaded composites were formed by growing Aspergillus niger in gold nanoparticles suspension produced using tea extract as the sole chemical source in addition to the gold salt.

  19. Simple Recovery of Intracellular Gold Nanoparticles from Peanut Seedling Roots.

    Science.gov (United States)

    Raju, D; Mehta, Urmil J; Ahmad, Absar

    2015-02-01

    Fabrication of inorganic nanomaterials via a biological route witnesses the formation either extracellularly, intracellulary or both. Whereas extracellular formation of these nanomaterials is cherished owing to their easy and economical extraction and purification processes; the intracellular formation of nanomaterials, due to the lack of a proper recovery protocol has always been dreaded, as the extraction processes used so far were tedious, costly, time consuming and often resulting in very low recovery. The aim of the present study was to overcome the problems related with the extraction and recovery of intracellularly synthesized inorganic nanoparticles, and to devise a method to increasing the output, the shape, size, composition and dispersal of nanoparticles is not altered. Water proved to be much better system as it provided well dispersed, stable gold nanoparticles and higher recovery. This is the first report, where intracellular nanoparticles have been recovered using a very cost-effective and eco-friendly approach.

  20. Quantitative electrical detection of immobilized protein using gold nanoparticles and gold enhancement on a biochip

    International Nuclear Information System (INIS)

    Lei, Kin Fong

    2011-01-01

    Electrical detection of the concentration of protein immobilized on a biochip is demonstrated. The concentration of the direct immobilized protein can be determined by the resistance values measured by an ohm-meter directly. Indium tin oxide interdigitated electrodes were utilized as the detection sites on the biochip. Protein, i.e. antibody, of certain concentration was first immobilized on the detection site. Gold nanoparticles were then applied to indicate the immobilized protein. Since the gold nanoparticles were tiny, a detectable electrical signal could not be generated. Hence, a gold enhancement process was performed for signal amplification. Gold nanoparticles were enlarged physically, such that a conductive metal layer was formed on the detection site. The presence and concentration of protein can be determined by the resistance value across the electrode measured by an ohm-meter. An immobilized protein concentration ranging from 50 to 1000 ng ml −1 can be detected quantitatively by the resistance values from 4300 to 1700 Ω. The proposed technique is potentially extended for the detection of immunoassay on the biochip. Since the protocol of the electrical detection does not involve sophisticated equipment, it can therefore be used for the development of a portable immunoassay device

  1. Synthesis of netlike gold nanoparticles using ampicillin as a stabilizing reagent and its application

    International Nuclear Information System (INIS)

    Song, Y.Z.; Zhou, J.F.; Song, Y.; Cheng, Z.P.; Xu, J.

    2012-01-01

    Graphical abstract: Electrochemical deposition of netlike gold nanoparticles (GNPs) on the surface of glassy carbon electrode and preparation of netlike GNPs in aqueous solution using ampicillin as a stabilizing reagent were proposed. The catalytic properties of netlike gold nanoparticles on the glassy carbon electrode for dopamine were demonstrated. The results indicate that the netlike gold nanoparticle modified electrode has an excellent repeatability and reproducibility. Display Omitted Highlights: ► Synthesis of netlike gold nanoparticles using ampicillin as a stabilizing reagent. ► Excellent repeatability and reproducibility of netlike gold nanoparticle modified glassy carbon electrode. ► The catalytic properties of netlike gold nanoparticle for dopamine. -- Abstract: Electrochemical deposition of netlike gold nanoparticles on the surface of glassy carbon electrode and preparation of netlike GNPs in aqueous solution using ampicillin as a stabilizing reagent were proposed. The netlike gold nanoparticles were characterized by scanning electron microscope, transmission electron microscope, infrared spectrometer, UV spectrophotometer, powder X-ray diffractometer and electrochemical analyzer. The catalysis of the netlike gold nanoparticles on the glassy carbon electrode for dopamine was demonstrated. The results indicate that the gold nanoparticle modified electrode has an excellent repeatability and reproducibility.

  2. Catalase coupled gold nanoparticles: Comparison between carbodiimide and biotin-streptavidin methods

    Science.gov (United States)

    Chirra, Hariharasudhan D.; Sexton, Travis; Biswal, Dipti; Hersh, Louis B.; Hilt, J. Zach

    2011-01-01

    The use of proteins for therapeutic applications requires the protein to maintain sufficient activity for the period of in vivo treatment. Many proteins exhibit a short half-life in vivo and, thus, require delivery systems for them to be applied as therapeutics. The relative biocompatibility and the ability to form functionalized bioconjugates via simple chemistry make gold nanoparticles excellent candidates as protein delivery systems. Herein, two protocols for coupling proteins to gold nanoparticles were compared. In the first, the strong biomolecular binding between biotin and streptavidin was used to couple catalase to the surface of gold nanoparticles. In the second protocol, the formation of an amide bond between carboxylic acid coated gold nanoparticles and free surface amines of catalase using carbodiimide chemistry was performed. The stability and kinetics of the different steps involved in these protocols were studied using UV-Visible spectroscopy, dynamic light scattering, and transmission electron microscopy. The addition of mercaptoundecanoic acid in conjugation with (N-(6-(biotinamido)hexyl)-3′-(2′-pyridyldithio)-propionamide increased the stability of biotinylated gold nanoparticles. Although the carbodiimide chemistry based bioconjugation approach exhibited a decrease in catalase activity, the carbodiimide chemistry based bioconjugation approach resulted in more active catalase per gold nanoparticle compared to that of mercaptoundecanoic acid stabilized biotinylated gold nanoparticles. Both coupling protocols resulted in gold nanoparticles loaded with active catalase. Thus, these gold nanoparticle systems and coupling protocols represent promising methods for the application of gold nanoparticles for protein delivery. PMID:21232642

  3. Dielectrophoresis of gold nanoparticles conjugated to DNA origami structures

    Directory of Open Access Journals (Sweden)

    Anja Henning-Knechtel

    2016-07-01

    Full Text Available DNA nanostructures are promising construction materials to bridge the gap between self-assembly of functional molecules and conventional top-down fabrication methods in nanotechnology. Their positioning onto specific locations of a microstructured substrate is an important task towards this aim. Here we study manipulation and positioning of pristine and of gold nanoparticle-conjugated tubular DNA origami structures using ac dielectrophoresis. The dielectrophoretic behavior was investigated employing fluorescence microscopy. For the pristine origami, a significant dielectrophoretic response was found to take place in the megahertz range, whereas, due to the higher polarizability of the metallic nanoparticles, the nanoparticle/DNA hybrid structures required a lower electrical field strength and frequency for a comparable trapping at the edges of the electrode structure. The nanoparticle conjugation additionally resulted in a remarkable alteration of the DNA structure arrangement. The growth of linear, chain-like structures in between electrodes at applied frequencies in the megahertz range was observed. The long-range chain formation is caused by a local, gold nanoparticle-induced field concentration along the DNA nanostructures, which in turn, creates dielectrophoretic forces that enable the observed self-alignment of the hybrid structures.

  4. In vivo integrity of polymer-coated gold nanoparticles

    Science.gov (United States)

    Kreyling, Wolfgang G.; Abdelmonem, Abuelmagd M.; Ali, Zulqurnain; Alves, Frauke; Geiser, Marianne; Haberl, Nadine; Hartmann, Raimo; Hirn, Stephanie; de Aberasturi, Dorleta Jimenez; Kantner, Karsten; Khadem-Saba, Gülnaz; Montenegro, Jose-Maria; Rejman, Joanna; Rojo, Teofilo; de Larramendi, Idoia Ruiz; Ufartes, Roser; Wenk, Alexander; Parak, Wolfgang J.

    2015-07-01

    Inorganic nanoparticles are frequently engineered with an organic surface coating to improve their physicochemical properties, and it is well known that their colloidal properties may change upon internalization by cells. While the stability of such nanoparticles is typically assayed in simple in vitro tests, their stability in a mammalian organism remains unknown. Here, we show that firmly grafted polymer shells around gold nanoparticles may degrade when injected into rats. We synthesized monodisperse radioactively labelled gold nanoparticles (198Au) and engineered an 111In-labelled polymer shell around them. Upon intravenous injection into rats, quantitative biodistribution analyses performed independently for 198Au and 111In showed partial removal of the polymer shell in vivo. While 198Au accumulates mostly in the liver, part of the 111In shows a non-particulate biodistribution similar to intravenous injection of chelated 111In. Further in vitro studies suggest that degradation of the polymer shell is caused by proteolytic enzymes in the liver. Our results show that even nanoparticles with high colloidal stability can change their physicochemical properties in vivo.

  5. Antibacterial nanocarriers of resveratrol with gold and silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sohyun [College of Pharmacy, Inje University, 197 Inje-ro Gimhae, Gyeongnam 621-749 (Korea, Republic of); Cha, Song-Hyun [National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Cho, Inyoung [School of Civil, Environmental and Architecture Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Park, Soomin [National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Park, Yohan [College of Pharmacy, Inje University, 197 Inje-ro Gimhae, Gyeongnam 621-749 (Korea, Republic of); Cho, Seonho [National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Park, Youmie, E-mail: youmiep@inje.ac.kr [College of Pharmacy, Inje University, 197 Inje-ro Gimhae, Gyeongnam 621-749 (Korea, Republic of); National Creative Research Initiatives (NCRI) Center for Isogeometric Optimal Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

    2016-01-01

    This study focused on the preparation of resveratrol nanocarrier systems and the evaluation of their in vitro antibacterial activities. Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) for resveratrol nanocarrier systems were synthesized using green synthetic routes. During the synthesis steps, resveratrol was utilized as a reducing agent to chemically reduce gold and silver ions to AuNPs and AgNPs. This system provides green and eco-friendly synthesis routes that do not involve additional chemical reducing agents. Resveratrol nanocarriers with AuNPs (Res-AuNPs) and AgNPs (Res-AgNPs) were observed to be spherical and to exhibit characteristic surface plasmon resonance at 547 nm and at 412–417 nm, respectively. The mean size of the nanoparticles ranged from 8.32 to 21.84 nm, as determined by high-resolution transmission electron microscopy. The face-centered cubic structure of the Res-AuNPs was confirmed by high-resolution X-ray diffraction. Fourier-transform infrared spectra indicated that the hydroxyl groups and C=C in the aromatic ring of resveratrol were involved in the reduction reaction. Res-AuNPs retained excellent colloidal stability during ultracentrifugation and re-dispersion, suggesting that resveratrol also played a role as a capping agent. Zeta potentials of Res-AuNPs and Res-AgNPs were in the range of − 20.58 to − 48.54 mV. Generally, against Gram-positive and Gram-negative bacteria, the Res-AuNPs and Res-AgNPs exhibited greater antibacterial activity compared to that of resveratrol alone. Among the tested strains, the highest antibacterial activity of the Res-AuNPs was observed against Streptococcus pneumoniae. The addition of sodium dodecyl sulfate during the synthesis of Res-AgNPs slightly increased their antibacterial activity. These results suggest that the newly developed resveratrol nanocarrier systems with metallic nanoparticles show potential for application as nano-antibacterial agents with enhanced activities. - Highlights

  6. Gold nanoparticles modified with coordination compounds of metals: synthesis and application

    International Nuclear Information System (INIS)

    Beloglazkina, Elena K; Majouga, Alexander G; Romashkina, Renata B; Zyk, Nikolai V; Zefirov, Nikolai S

    2012-01-01

    The data on the preparation methods and applications of gold nanoparticles with coordinated metal ions on the surfaces are generalized. The currently available data on the interaction of metal ions with gold nanoparticles modified with organic (particularly, sulfur-containing) ligands comprising terminal chelating groups are considered in detail as well as the applications of such modified nanoparticles. The bibliography includes 141 references.

  7. Growth of hydroxyapatite on physiologically clotted fibrin capped gold nanoparticles

    International Nuclear Information System (INIS)

    Sastry, T P; Sundaraseelan, J; Swarnalatha, K; Sobhana, S S Liji; Makheswari, M Uma; Sekar, S; Mandal, A B

    2008-01-01

    The growth of hydroxyapatite (HAp) on physiologically clotted fibrin (PCF)-gold nanoparticles is presented for the first time by employing a wet precipitation method. Fourier transform infrared (FTIR) spectroscopy confirmed the characteristic functionalities of PCF and HAp in the PCF-Au-HAp nanocomposite. Scanning electron microscopy (SEM) images have shown cuboidal nanostructures having a size in the range of 70-300 nm of HAp, whereas 2-50 nm sized particles were visualized in high-resolution transmission electron microscopy (TEM). Energy-dispersive x-ray (EDX) and x-ray diffraction (XRD) studies have confirmed the presence of HAp. These results show that gold nanoparticles with PCF acted as a matrix for the growth of HAp, and that PCF-Au-HAp nanocomposite is expected to have better osteoinductive properties

  8. Friction fluctuations of gold nanoparticles in the superlubric regime

    Science.gov (United States)

    Dietzel, Dirk; de Wijn, Astrid S.; Vorholzer, Matthias; Schirmeisen, Andre

    2018-04-01

    Superlubricity, or alternatively termed structural (super)lubrictiy, is a concept where ultra-low friction is expected at the interface between sliding surfaces if these surfaces are incommensurate and thus unable to interlock. In this work, we now report on sudden, reversible, friction changes that have been observed during AFM-based nanomanipulation experiments of gold nanoparticles sliding on highly oriented pyrolythic graphite. These effects can be explained by rotations of the gold nanoparticles within the concept of structural superlubricity, where the occurrence of ultra-low friction can depend extremely sensitively on the relative orientation between the slider and the substrate. From our theoretical simulations it will become apparent how even miniscule magnitudes of rotation are compatible to the observed effects and how size and shape of the particles can influence the dependence between friction and relative orientation.

  9. Electron energy loss spectroscopy of gold nanoparticles on graphene

    International Nuclear Information System (INIS)

    DeJarnette, Drew; Roper, D. Keith

    2014-01-01

    Plasmon excitation decay by absorption, scattering, and hot electron transfer has been distinguished from effects induced by incident photons for gold nanoparticles on graphene monolayer using electron energy loss spectroscopy (EELS). Gold nano-ellipses were evaporated onto lithographed graphene, which was transferred onto a silicon nitride transmission electron microscopy grid. Plasmon decay from lithographed nanoparticles measured with EELS was compared in the absence and presence of the graphene monolayer. Measured decay values compared favorably with estimated radiative and non-radiative contributions to decay in the absence of graphene. Graphene significantly enhanced low-energy plasmon decay, increasing mode width 38%, but did not affect higher energy plasmon or dark mode decay. This decay beyond expected radiative and non-radiative mechanisms was attributed to hot electron transfer, and had quantum efficiency of 20%, consistent with previous reports

  10. Towards thiol functionalization of vanadium pentoxide nanotubes using gold nanoparticles

    International Nuclear Information System (INIS)

    Lavayen, V.; O'Dwyer, C.; Cardenas, G.; Gonzalez, G.; Sotomayor Torres, C.M.

    2007-01-01

    Template-directed synthesis is a promising route to realize vanadate-based 1-D nanostructures, an example of which is the formation of vanadium pentoxide nanotubes and associated nanostructures. In this work, we report the interchange of long-chained alkyl amines with alkyl thiols. This reaction was followed using gold nanoparticles prepared by the Chemical Liquid Deposition (CLD) method with an average diameter of ∼0.9nm and a stability of ∼85 days. V 2 O 5 nanotubes (VOx-NTs) with lengths of ∼2μm and internal hollow diameters of 20-100nm were synthesized and functionalized in a Au-acetone colloid with a nominal concentration of ∼4x10 -3 mol dm -3 . The interchange reaction with dodecylamine is found only to occur in polar solvents and incorporation of the gold nanoparticles is not observed in the presence of n-decane

  11. Apertureless SNOM study on gold nanoparticles: Experiments and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Weizhe; Kimel, Alexey; Kirilyuk, Andrei; Rasing, Theo [Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

    2010-08-15

    Gold nanoparticles (about 10 nm in diameter) are investigated by an apertureless (or scattering-type) scanning near-field optical microscope (aSNOM) at 633 nm and a negative optical amplitude signal contrast is observed. To understand the size effect and the interactions between light, tip, and sample, an analytical solution is obtained by adopting a model considering the tip as a point dipole. This model successfully shows the contrast reversal measured in experiments. Some important aspects, however, are neglected by the quasistatic dipole model. Thus, three-dimensional (3D) numerical calculations by a finite integration technique are applied to study the interactions between tip apex, gold nanoparticle, and the substrate surface. The simulated near-field and far-field results help us not only to understand the experimentally acquired aSNOM images but also to investigate the complicated tip-particle-surface interactions. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  12. Gold nanoparticles on MoS2 layered crystal flakes

    International Nuclear Information System (INIS)

    Cao, Wei; Pankratov, Vladimir; Huttula, Marko; Shi, Xinying; Saukko, Sami; Huang, Zhongjia; Zhang, Meng

    2015-01-01

    Inorganic layered crystal MoS 2 is considered as one of the most promising and efficient semiconductor materials for future transistors, photoelectronics, and electrocatalysis. To boost MoS 2 -based material applications, one direction is to grow physically and chemically reactive nanoparticles onto MoS 2 . Here we report on a simple route to synthesis crystalized MoS 2 –Au complexes. The gold nanoparticles were grown on MoS 2 flakes through a wet method in the oxygen free environment at room temperature. Nanoparticles with diameters varying from 9 nm to 429 nm were controlled by the molar ratios of MoS 2 and HAuCl 4 precursors. MoS 2 host flakes keep intrinsic honeycomb layered structures and the Au nanoparticles cubic-center crystal microstructures. From product chemical states analysis, the synthesis was found driven by redox reactions between the sulphide and the chloroauric acid. Photoluminescence measurement showed that introducing Au nanoparticles onto MoS 2 stacks substantially prompted excitonic transitions of stacks, as an analogy for doping Si wafers with dopants. Such composites may have potential applications in wide ranges similar as the doped Si. - Highlights: • The Au nanoparticles were decorated on MoS 2 in oxygen free ambiences via a wet method. • The Au nanoparticles are size-controllable and crystalized. • Chemical reaction scheme was clarified. • The MoS 2 –Au complexes have strong photoluminescent properties

  13. Iron oxide and gold nanoparticles in cancer therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gotman, Irena, E-mail: gotman@technion.ac.il; Gutmanas, Elazar Y., E-mail: gutmanas@technion.ac.il [Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa, 32000 Israel (Israel); Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Psakhie, Sergey G. [Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Lozhkomoev, Aleksandr S. [Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2016-08-02

    Continuous research activities in the field of nanomedicine in the past decade have, to a great extent, been focused on nanoparticle technologies for cancer therapy. Gold and iron oxide nanoparticles (NP) are two of the most studied inorganic nanomaterials due to their unique optical and magnetic properties. Both types of NPs are emerging as promising systems for anti-tumor drug delivery and for nanoparticle-mediated thermal therapy of cancer. In thermal therapy, localized heating inside tumors or in proximity of tumor cells can be induced, for example, with Au NPs by radiofrequency ablation heating or conversion of photon energy (photothermal therapy) and in iron oxide magnetic NPs by heat generation through relaxation in an alternating magnetic field (magnetic hyperthermia). Furthermore, the superparamagnetic properties of iron oxide nanoparticles have led to their use as potent MRI (magnetic resonance imaging) contrast agents. Surface modification/coating can produce NPs with tailored and desired properties, such as enhanced blood circulation time, stability, biocompatibility and water solubility. To target nanoparticles to specific tumor cells, NPs should be conjugated with targeting moieties on the surface which bind to receptors or other molecular structures on the cell surface. The article presents several approaches to enhancing the specificity of Au and iron oxide nanoparticles for tumor tissue by appropriate surface modification/functionalization, as well as the effect of these treatments on the saturation magnetization value of iron oxide NPs. The use of other nanoparticles and nanostructures in cancer treatment is also briefly reviewed.

  14. Poly-thiosemicarbazide Membrane for Gold Adsorption and In-situ Growth of Gold Nanoparticles

    KAUST Repository

    Parra, Luis F.

    2012-12-01

    In this work the synergy between a polymer containing chelate sites and gold ions was explored by the fabrication of a polymeric membrane with embedded gold nanoparticles inside its matrix and by developing a process to recover gold from acidic solutions. After realizing that the thiosemicarbazide groups present in the monomeric unit of poly-thiosemicarbazide (PTSC) formed strong complexes with Au ions, membrane technology was used to exploit this property to its maximum. The incorporation of metal nanoparticles into polymeric matrices with current technologies involves either expensive and complicated procedures or leads to poor results in terms of agglomeration, loading, dispersion, stability or efficient use of raw materials. The fabrication procedure described in this thesis solves these problems by fabricating a PTSC membrane containing 33.5 wt% in the form of 2.9 nm gold nanoparticles (AuNPs) by a three step simple and scalable procedure. It showed outstanding results in all of the areas mentioned above and demonstrated catalytic activity for the reduction of 4-Nitrophenol (4−NP) to 4-Aminophenol (4−AP). The current exponential demand of gold for electronics has encouraged the development of efficient processes to recycle it. Several adsorbents used to recover gold from acidic solutions can be found in the literature with outstanding maximum uptakes,yet, poor kinetics leading to an overall inefficient process. The method developed in this dissertation consisted in permeating the gold-containing solution through a PTSC membrane that will capture all the Au ions by forming a metal complex with them. Forcing the ions through the pores of the membrane eliminates the diffusion limitations and the adsorption will only depended on the fast complexation kinetics, resulting in a very efficient process. A flux as high as 1868 L/h m2 was enough to capture >90% of the precious metal present in a solution of 100 ppm Au. The maximum uptake achieved without sacrificing

  15. Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis.

    Science.gov (United States)

    Dias, Jorge T; Svedberg, Gustav; Nystrand, Mats; Andersson-Svahn, Helene; Gantelius, Jesper

    2018-03-07

    The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity and convenient colorimetric readout. However, high densities of nanoparticles are typically needed for detection. The available synthesis-based enhancement protocols are either limited to gold and silver nanoparticles or rely on precise enzymatic control and optimization. Here, we present a protocol to enhance the colorimetric readout of gold, silver, silica, and iron oxide nanoprobes. It was observed that the colorimetric signal can be improved by up to a 10000-fold factor. The basis for such signal enhancement strategies is the chemical reduction of Au 3+ to Au 0 . There are several chemical reactions that enable the reduction of Au 3+ to Au 0 . In the protocol, Good's buffers and H2O2 are used and it is possible to favor the deposition of Au 0 onto the surface of existing nanoprobes, in detriment of the formation of new gold nanoparticles. The protocol consists of the incubation of the microarray with a solution consisting of chloroauric acid and H2O2 in 2-(N-morpholino)ethanesulfonic acid pH 6 buffer following the nanoprobe-based detection assay. The enhancement solution can be applied to paper and glass-based sensors. Moreover, it can be used in commercially available immunoassays as demonstrated by the application of the method to a commercial allergen microarray. The signal development requires less than 5 min of incubation with the enhancement solution and the readout can be assessed by naked eye or low-end image acquisition devices such as a table-top scanner or a digital camera.

  16. One-step synthesis of gold bimetallic nanoparticles with various metal-compositions

    International Nuclear Information System (INIS)

    Bratescu, Maria Antoaneta; Takai, Osamu; Saito, Nagahiro

    2013-01-01

    Highlights: ► Synthesis of bimetallic nanoparticles in an aqueous solution discharge. ► Alloying gold with divalent sp metals, trivalent sp metals, 3d or 4d metals. ► Formation mechanism of bimetallic nanoparticles by metal reduction and gold erosion. ► Blue and red shift of surface plasmon resonance. -- Abstract: A rapid, one-step process for the synthesis of bimetallic nanoparticles by simultaneous metal reduction and gold erosion in an aqueous solution discharge was investigated. Gold bimetallic nanoparticles were obtained by alloying gold with various types of metals belonging to one of the following categories: divalent sp metals, trivalent sp metals, 3d or 4d metals. The composition of the various gold bimetallic nanoparticles obtained depends on electrochemical factors, charge transfer between gold and other metal, and initial concentration of metal in solution. Transmission electron microscopy and energy dispersive spectroscopy show that the gold bimetallic nanoparticles were of mixed pattern, with sizes of between 5 and 20 nm. A red-shift of the surface plasmon resonance band in the case of the bimetallic nanoparticles Au–Fe, Au–Ga, and Au–In, and a blue-shift of the plasmon band of the Au–Ag nanoparticles was observed. In addition, the interaction of gold bimetallic nanoparticles with unpaired electrons, provided by a stable free radical molecule, was highest for those NPs obtained by alloying gold with a 3d metal

  17. Gold-Pluronic core-shell nanoparticles: synthesis, characterization and biological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Timea; Boca, Sanda [Babes-Bolyai University, Nanobiophotonics and Laser Microspectroscopy Center, Interdisciplinary Research Institute on Bio-Nano-Sciences and Faculty of Physics (Romania); Biro, Dominic [Sapientia University, Department of Mechanical Engineering, Faculty of Technical and Human Sciences (Romania); Baldeck, Patrice [Universite Joseph Fourier and CNRS, Laboratoire Interdisciplinaire de Physique, UMR 5588, CNRS (France); Astilean, Simion, E-mail: simion.astilean@phys.ubbcluj.ro [Babes-Bolyai University, Nanobiophotonics and Laser Microspectroscopy Center, Interdisciplinary Research Institute on Bio-Nano-Sciences and Faculty of Physics (Romania)

    2013-04-15

    This study presents the synthesis of gold-Pluronic core-shell nanoparticles by a two-step method and investigates their biological impact on cancer cells, specifically nanoparticle internalization and cytotoxicity. Uniform, 9-10-nm-sized, hydrophobic gold nanoparticles were synthesized in organic phase by reducing gold salt with oleylamine, after which oleylamine-protected gold nanoparticles were phase-transferred into aqueous medium using Pluronic F127 block copolymer, resulting in gold-Pluronic core-shell nanoparticles with a mean hydrodynamic diameter of {approx}35 nm. The formation and phase-transfer of gold nanoparticles were analyzed by UV-Vis absorption spectroscopy, transmission electron microscopy, and dynamic light scattering. The obtained gold-Pluronic core-shell nanoparticles proved to be highly stable in salted solution. Cytotoxicity tests showed no modification of cellular viability in the presence of properly purified particles. Furthermore, dark-field cellular imaging demonstrated that gold-Pluronic nanoparticles were able to be efficiently uptaken by cells, being internalized through nonspecific endocytosis. The high stability, proven biocompatibility, and imaging properties of gold-Pluronic core-shell nanoparticles hold promise for relevant intracellular applications, with such a design providing the feasibility to combine all multiple functionalities in one nanoparticle for simultaneous detection and imaging.

  18. Synthesis of Nanometer-Sized Poly (methyl methacrylate) Polymer Network by Gold Nanoparticle Template

    Science.gov (United States)

    Liu, Fu-Ken; Hsieh, Shang-Yu; Ko, Fu-Hsiang; Chu, Tieh-Chi; Dai, Bau-Tong

    2003-06-01

    Gold nanoparticle/polymer composites have been produced using a one-system polymer synthesis. The linear polymer, poly (methyl methacrylate) (PMMA, MW = 15,000 g/mol) is applied for the stabilization of gold nanoparticles. The Fourier transfer infrared (FT-IR) analysis data and transition electron microscopy (TEM) image reveal that the core shell structure of gold/PMMA nanocomposite has been synthesized. The ratio of the concentration of the capping polymer material to the concentration of the gold precursor could control the sizes of gold nanoparticles. With specific concentration of the reductant, the core-shell nanostructure could be fluctuated in order. After heating treatment, the network structure of PMMA capped gold nanoparticles could be synthesized as confirmed by the TEM image. The result indicates that PMMA not only acts as the stabilizer, but also as the bridge of the neighboring gold nanoparticles.

  19. Colorimetric detection of cholesterol based on enzyme modified gold nanoparticles

    Science.gov (United States)

    Nirala, Narsingh R.; Saxena, Preeti S.; Srivastava, Anchal

    2018-02-01

    We develop a simple colorimetric method for determination of free cholesterol in aqueous solution based on functionalized gold nanoparticles with cholesterol oxidase. Functionalized gold nanoparticles interact with free cholesterol to produce H2O2 in proportion to the level of cholesterol visually is being detected. The quenching in optical properties and agglomeration of functionalized gold nanoparticles play a key role in cholesterol sensing due to the electron accepting property of H2O2. While the lower ranges of cholesterol (lower detection limit i.e. 0.2 mg/dL) can be effectively detected using fluorescence study, the absorption study attests evident visual color change which becomes effective for detection of higher ranges of cholesterol (lower detection limit i.e. 19 mg/dL). The shades of red gradually change to blue/purple as the level of cholesterol detected (as evident at 100 mg/dL) using unaided eye without the use of expensive instruments. The potential of the proposed method to be applied in the field is shown by the proposed cholesterol measuring color wheel.

  20. Gold nanoparticles supported on magnesium oxide for CO oxidation

    Science.gov (United States)

    Carabineiro, Sónia Ac; Bogdanchikova, Nina; Pestryakov, Alexey; Tavares, Pedro B.; Fernandes, Lisete Sg; Figueiredo, José L.

    2011-06-01

    Au was loaded (1 wt%) on a commercial MgO support by three different methods: double impregnation, liquid-phase reductive deposition and ultrasonication. Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Upon loading with Au, MgO changed into Mg(OH)2 (the hydroxide was most likely formed by reaction with water, in which the gold precursor was dissolved). The size range for gold nanoparticles was 2-12 nm for the DIM method and 3-15 nm for LPRD and US. The average size of gold particles was 5.4 nm for DIM and larger than 6.5 for the other methods. CO oxidation was used as a test reaction to compare the catalytic activity. The best results were obtained with the DIM method, followed by LPRD and US. This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts.

  1. Gold nanoparticles supported on magnesium oxide for CO oxidation

    Directory of Open Access Journals (Sweden)

    Bogdanchikova Nina

    2011-01-01

    Full Text Available Abstract Au was loaded (1 wt% on a commercial MgO support by three different methods: double impregnation, liquid-phase reductive deposition and ultrasonication. Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Upon loading with Au, MgO changed into Mg(OH2 (the hydroxide was most likely formed by reaction with water, in which the gold precursor was dissolved. The size range for gold nanoparticles was 2-12 nm for the DIM method and 3-15 nm for LPRD and US. The average size of gold particles was 5.4 nm for DIM and larger than 6.5 for the other methods. CO oxidation was used as a test reaction to compare the catalytic activity. The best results were obtained with the DIM method, followed by LPRD and US. This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts.

  2. Extracellular biosynthesis of monodispersed gold nanoparticles by a SAM capping route

    Science.gov (United States)

    Wen, Li; Lin, Zhonghua; Gu, Pingying; Zhou, Jianzhang; Yao, Bingxing; Chen, Guoliang; Fu, Jinkun

    2009-02-01

    Monodispersed gold nanoparticles capped with a self-assembled monolayer of dodecanethiol were biosynthesized extracellularly by an efficient, simple, and environmental friendly procedure, which involved the use of Bacillus megatherium D01 as the reducing agent and the use of dodecanethiol as the capping ligand at 26 °C. The kinetics of gold nanoparticle formation was followed by transmission electron microscope (TEM) and UV-vis spectroscopy. It was shown that reaction time was an important parameter in controlling the morphology of gold nanoparticles. The effect of thiol on the shape, size, and dispersity of gold nanoparticles was also studied. The results showed that the presence of thiol during the biosynthesis could induce the formation of small size gold nanoparticles (gold nanoparticles capped with thiol of 1.9 ± 0.8 nm size were formed by using Bacillus megatherium D01.

  3. T cells enhance gold nanoparticle delivery to tumors in vivo

    Science.gov (United States)

    Kennedy, Laura C.; Bear, Adham S.; Young, Joseph K.; Lewinski, Nastassja A.; Kim, Jean; Foster, Aaron E.; Drezek, Rebekah A.

    2011-12-01

    Gold nanoparticle-mediated photothermal therapy (PTT) has shown great potential for the treatment of cancer in mouse studies and is now being evaluated in clinical trials. For this therapy, gold nanoparticles (AuNPs) are injected intravenously and are allowed to accumulate within the tumor via the enhanced permeability and retention (EPR) effect. The tumor is then irradiated with a near infrared laser, whose energy is absorbed by the AuNPs and translated into heat. While reliance on the EPR effect for tumor targeting has proven adequate for vascularized tumors in small animal models, the efficiency and specificity of tumor delivery in vivo, particularly in tumors with poor blood supply, has proven challenging. In this study, we examine whether human T cells can be used as cellular delivery vehicles for AuNP transport into tumors. We first demonstrate that T cells can be efficiently loaded with 45 nm gold colloid nanoparticles without affecting viability or function (e.g. migration and cytokine production). Using a human tumor xenograft mouse model, we next demonstrate that AuNP-loaded T cells retain their capacity to migrate to tumor sites in vivo. In addition, the efficiency of AuNP delivery to tumors in vivo is increased by more than four-fold compared to injection of free PEGylated AuNPs and the use of the T cell delivery system also dramatically alters the overall nanoparticle biodistribution. Thus, the use of T cell chaperones for AuNP delivery could enhance the efficacy of nanoparticle-based therapies and imaging applications by increasing AuNP tumor accumulation.

  4. Not all that glitters is gold - Electron microscopy study on uptake of gold nanoparticles in Daphnia magna and related artefacts

    DEFF Research Database (Denmark)

    Jensen, Louise Helene Søgaard; Skjolding, Lars Michael; Thit, Amalie

    2017-01-01

    techniques are used to investigate internalization of 10 nm gold nanoparticles in Daphnia magna gut lumen and gut epithelial cells upon 24h exposure and outline potential artefacts, i.e. high contract precipitates from sample preparation related to these techniques. Light sheet microscopy confirmed...... accumulation of gold nanoparticles in the gut lumen. Scanning transmission electron microscopy and elemental analysis revealed gold nanoparticles attached to the microvilli of gut cells. Interestingly, the peritrophic membrane appeared to act as a semipermeable barrier between the lumen and the gut epithelium...

  5. Curcumin coated gold nanoparticles: synthesis, characterization, cytotoxicity, antioxidant activity and its comparison with citrate coated gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Elnaz Shaabani

    2017-04-01

    Full Text Available Objective(s: Biological applications of gold nanoparticles have limitations because of the toxic chemicals used in their synthesis. Curcumin can be used as reducing as well as capping agent in synthesis of GNPs to eliminate the cytotoxicity. Conjugation of curcumin to gold also helps in increasing its solubility and bioavailability. Materials and Methods: Here we report synthesis of gold nanoparticles coated with citrate and curcumin and of two different sizes via chemical routes. UV-Vis absorbance spectroscopy, Dynamic Light Scattering and Transmission Electron Microscopy were applied to study the average particle size, size stability of the samples and zeta potential. Fourier transform infrared, Raman Spectroscopy and Fluorescence Spectroscopy were applied for detection of curcumin on the surface of GNPs. The antioxidant activity was evaluated using DPPH assay and Cytotoxicity was evaluated by MTT assay.Results: Particles were synthesized of 6 and 16 nm size. The average particle size was found to be 21.7 ± 5.7 by TEM. The zeta potential on the surface of Cur-GNPs was negative and larger than 25 mV which is a sign of their high stability. The stability of these particles (with different coatings but with similar sizes at different time intervals (up to 3 months and also in different media like cell culture medium, different buffers, glucose and at different pH conditions have been investigated thoroughly. Appearance of functional groups assigned to curcumin in FTIR and SERS spectra are sign of presence of curcumin in the sample. The quenching of the fluorescence in the presence of GNPs reveals the clear indication of the capping and binding of curcumin with GNPs. Cur-GNP1 (16 nm were found to exhibit highest antioxidant activity than other gold nanoparticles. Cytotoxicity evaluation using MTT assay on L929 cell line proved curcumin coated gold nanoparticles were non-toxic up to 40 ppm.Conclusion: The results revealed that larger curcumin

  6. Gold and silver nanoparticles conjugated with heparin derivative possess anti-angiogenesis properties

    International Nuclear Information System (INIS)

    Kemp, Melissa M; Linhardt, Robert J; Kumar, Ashavani; Ajayan, Pulickel; Mousa, Shaymaa; Dyskin, Evgeny; Yalcin, Murat; Mousa, Shaker A

    2009-01-01

    Silver and gold nanoparticles display unique physical and biological properties that have been extensively studied for biological and medical applications. Typically, gold and silver nanoparticles are prepared by chemical reductants that utilize excess toxic reactants, which need to be removed for biological purposes. We utilized a clean method involving a single synthetic step to prepare metal nanoparticles for evaluating potential effects on angiogenesis modulation. These nanoparticles were prepared by reducing silver nitrate and gold chloride with diaminopyridinyl (DAP)-derivatized heparin (HP) polysaccharides. Both gold and silver nanoparticles reduced with DAPHP exhibited effective inhibition of basic fibroblast growth factor (FGF-2)-induced angiogenesis, with an enhanced anti-angiogenesis efficacy with the conjugation to DAPHP (P<0.01) as compared to glucose conjugation. These results suggest that DAPHP-reduced silver nanoparticles and gold nanoparticles have potential in pathological angiogenesis accelerated disorders such as cancer and inflammatory diseases.

  7. Gold and silver nanoparticles conjugated with heparin derivative possess anti-angiogenesis properties

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Melissa M; Linhardt, Robert J [Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Kumar, Ashavani; Ajayan, Pulickel [Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX 77005 (United States); Mousa, Shaymaa; Dyskin, Evgeny; Yalcin, Murat; Mousa, Shaker A, E-mail: Shaker.mousa@acphs.ed [Pharmaceutical Research Institute, Albany College of Pharmacy and Health Sciences, Albany, NY 12208 (United States)

    2009-11-11

    Silver and gold nanoparticles display unique physical and biological properties that have been extensively studied for biological and medical applications. Typically, gold and silver nanoparticles are prepared by chemical reductants that utilize excess toxic reactants, which need to be removed for biological purposes. We utilized a clean method involving a single synthetic step to prepare metal nanoparticles for evaluating potential effects on angiogenesis modulation. These nanoparticles were prepared by reducing silver nitrate and gold chloride with diaminopyridinyl (DAP)-derivatized heparin (HP) polysaccharides. Both gold and silver nanoparticles reduced with DAPHP exhibited effective inhibition of basic fibroblast growth factor (FGF-2)-induced angiogenesis, with an enhanced anti-angiogenesis efficacy with the conjugation to DAPHP (P<0.01) as compared to glucose conjugation. These results suggest that DAPHP-reduced silver nanoparticles and gold nanoparticles have potential in pathological angiogenesis accelerated disorders such as cancer and inflammatory diseases.

  8. Synthesis and characterization of gold nanoparticles using Ficus religiosa extract

    Directory of Open Access Journals (Sweden)

    Kirtee Wani

    2013-03-01

    Full Text Available We report a cost effective and eco-friendly biosynthesis of gold nanoparticles (F-AuNPs using aqueous extract of Ficus religiosa as the reducing and stabilizing agent. These nanoparticles were characterized by various techniques such as UV-Vis, XRD, TEM and FTIR. The characteristic surface plasmon peak was observed at 540 nm while XRD analysis suggested it to be a face-centered cubic (fcc structure with peaks at 38.06, 44.46, 64.75 and 77.56. FTIR studies indicated the capping of the nanoparticles with polyphenols, amines and carboxylates present in the extract of Ficus religiosa whereas TEM analysis showed spherical morphology with other shapes such as triangles and hexagons. The F-AuNPs were found to be non-toxic to HEK 293 cells, thereby suggesting their potential application in the field of nanobiotechnology.

  9. Poly(amino acid) functionalized maghemite and gold nanoparticles

    International Nuclear Information System (INIS)

    Perego, Davide; Manuel Domínguez-Vera, José; Gálvez, Natividad; Masciocchi, Norberto; Guagliardi, Antonietta

    2013-01-01

    Bimodal MRI/OI imaging probes are of great interest in nanomedicine. Although many organic polymers have been studied thoroughly for in vivo applications, reports on the use of poly(amino acid)s as coating polymers are scarce. In this paper, poly-(d-glutamic acid, d-lysine) (PGL) has been used for coating maghemite and gold nanoparticles. An advantage of this flexible and biocompatible polymer is that, once anchored to the nanoparticle surface, dangling lysine amino groups are available for the incorporation of new functionalities. As an example, Alexa Fluor derivatives have been attached to PGL-coated maghemite nanoparticles to obtain magnetic/fluorescent materials. These dual-property materials could be used as bimodal MRI/OI probes for in vivo imaging. (paper)

  10. Preparation of gold nanoparticle dimers via streptavidin-induced interlinking

    International Nuclear Information System (INIS)

    Zon, Vera B.; Sachsenhauser, Matthias; Rant, Ulrich

    2013-01-01

    There is great interest in establishing efficient means of organizing nanoparticles into complex structures, especially in fields like nano-optical devices. One of the demonstrated routes uses biomolecular scaffolds, like the streptavidin–biotin system, to deterministically separate and structure particle complexes. However, controlled formation of streptavidin-linked nanoparticle dimers or trimers is challenging, and large aggregates are often formed under conditions that are difficult to regulate. Here, we studied the aggregates and interlinking kinetics of biotin-functionalized 20 nm gold nanoparticles in the presence of the interlinking protein, streptavidin. We found two different protein-linker concentration regions where small stable particle aggregates are formed: when the protein and nanoparticle concentrations are similar and when the protein to nanoparticle concentration ratio exceeds intermediate concentrations (10:1–100:1) that promote precipitation of large aggregates. We attribute this behavior to the limited availability of free-linker molecules and the limited availability of free ligand (biotin) on the particle surface for low and high protein concentrations, respectively. Furthermore, we show that the product can be additionally enriched up to 25 % through either centrifugation in sucrose or size-exclusion chromatography. These results provide additional understanding into the assembly of ligand-functionalized nanoparticles with water-soluble linkers and provide a facile way to produce well-defined small aggregates for potential use in, for instance, surface-enhanced spectroscopy

  11. Electron and photon emissions from gold nanoparticles irradiated by X-ray photons

    Energy Technology Data Exchange (ETDEWEB)

    Casta, R., E-mail: castaromain@gmail.com, E-mail: romain.casta@irsamc.ups-tlse.fr; Champeaux, J.-P.; Moretto-Capelle, P.; Sence, M.; Cafarelli, P. [Université de Toulouse, UPS, Laboratoire Collisions Agrégats Réactivité, IRSAMC, CNRS, UMR 5589 (France)

    2015-01-15

    In this paper, we develop a totally new probabilistic model for the electron and photon emission of gold nanoparticles irradiated by X-ray photons. This model allows direct applications to recent researches about the radiotherapy enhancement by gold nanoparticles in the context of cancer treatment. Our model uses, in a complete original way, simulated Auger cascade and stopping power to compute electron emission spectra, photon emission spectra and released energy inside the material of gold nanoparticles. It allows us to present new results about the electron and photon emission of gold nanoparticle irradiated by hard X-rays.

  12. pH induced protein-scaffold biosynthesis of tunable shape gold nanoparticles

    International Nuclear Information System (INIS)

    Zhang Xiaorong; He Xiaoxiao; Wang Kemin; Ren Fang; Qin Zhihe

    2011-01-01

    In this paper, a pH-inductive protein-scaffold biosynthesis of shape-tunable crystalline gold nanoparticles at room temperature has been developed. By simple manipulation of the reaction solution's pH, anisotropic gold nanoparticles including spheres, triangles and cubes could be produced by incubating an aqueous solution of sodium tetrachloroaurate with Dolichomitriopsis diversiformis biomasses after immersion in ultrapure Millipore water overnight. A moss protein with molecular weight of about 71 kDa and pI of 4.9 was the primary biomolecule involved in the biosynthesis of gold nanoparticles. The secondary configuration of the proteins by CD spectrum implied that the moss protein could display different secondary configurations including random coil, α-helix and intermediate conformations between random coil and α-helix for the experimental pH solution. The growth process of gold nanoparticles further showed that the moss protein with different configurations provided the template scaffold for the shape-controlled biosynthesis of gold nanoparticles. The constrained shape of the gold nanoparticles, however, disappeared in boiled moss extract. The gold nanoparticles with designed morphology were successfully reconstructed using the moss protein purified from the gold nanoparticles. Structural characterizations by SEM, TEM and SAED showed that the triangular and cubic gold nanoparticles were single crystalline.

  13. The Applications of Gold Nanoparticle-Initialed Chemiluminescence in Biomedical Detection

    Science.gov (United States)

    Liu, Zezhong; Zhao, Furong; Gao, Shandian; Shao, Junjun; Chang, Huiyun

    2016-10-01

    Chemiluminescence technique as a novel detection method has gained much attention in recent years owning to the merits of high sensitivity, wider linear ranges, and low background signal. Similarly, nanotechnology especially for gold nanoparticles has emerged as detection tools due to their unique physical and chemical properties. Recently, it has become increasingly popular to couple gold nanoparticles with chemiluminescence technique in biological agents' detection. In this review, we describe the superiority of both chemiluminescence and gold nanoparticles and conclude the different applications of gold nanoparticle-initialed chemiluminescence in biomedical detection.

  14. Sub-10 ohm resistance gold films prepared by removal of ligands from thiol-stabilized 6 nm gold nanoparticles.

    Science.gov (United States)

    Sugden, Mark W; Richardson, Tim H; Leggett, Graham

    2010-03-16

    The optical and electrical properties of dodecanethiol-stabilized nanoparticles (6 nm diameter gold core) have been investigated over a range of film thicknesses and temperatures. The surface plasmon resonance absorbance is found to be dependent on temperature. Heating of the nanoparticle film causes desorption of the thiol from the surface of the gold nanoparticle, resulting in irreversible changes to the absorption spectra of the nanoparticle film. Atomic force microscopy images of the samples before and after heating for different film thicknesses reveal structural changes and increased domain connectivity for thicker films leading to sub-10 ohm resistances measured for the 15-layer film.

  15. Synthesis and bioconjugation of gold nanoparticles as potential molecular probes for light-based imaging techniques

    NARCIS (Netherlands)

    Rayavarapu, Raja Gopal; Petersen, Wilma; Ungureanu, Constantin; Post, Janine N.; van Leeuwen, Ton G.; Manohar, Srirang

    2007-01-01

    We have synthesized and characterized gold nanoparticles (spheres and rods) with optical extinction bands within the "optical imaging window." The intense plasmon resonant driven absorption and scattering peaks of these nanoparticles make them suitable as contrast agents for optical imaging

  16. Heat Profiling of Three-Dimensionally Optically Trapped Gold Nanoparticles using Vesicle Cargo Release

    DEFF Research Database (Denmark)

    Kyrsting, Anders; Bendix, Pól Martin; Stamou, Dimitrios

    2011-01-01

    Irradiated metallic nanoparticles hold great promise as heat transducers in photothermal applications such as drug delivery assays or photothermal therapy. We quantify the temperature increase of individual gold nanoparticles trapped in three dimensions near lipid vesicles exhibiting temperature...

  17. Synthesis of gold nanoparticles stabilised by metal-chelator and the ...

    Indian Academy of Sciences (India)

    Unknown

    Hence, there is significant current interest in preparing nano-materials of ... methods are available to synthesize nanoparticles that are remarkably stable for .... Gold nanoparticle synthesis was undertaken after complete characterization of the.

  18. Interferometric detection of single gold nanoparticles calibrated against TEM size distributions

    DEFF Research Database (Denmark)

    Zhang, Lixue; Christensen, Sune; Bendix, Pól Martin

    2015-01-01

    Single nanoparticle analysis: An interferometric optical approach calibrates sizes of gold nanoparticles (AuNPs) from the interference intensities by calibrating their interferometric signals against the corresponding transmission electron microscopy measurements. This method is used to investigate...

  19. Investigating the toxicity, uptake, nanoparticle formation and genetic response of plants to gold.

    Directory of Open Access Journals (Sweden)

    Andrew F Taylor

    Full Text Available We have studied the physiological and genetic responses of Arabidopsis thaliana L. (Arabidopsis to gold. The root lengths of Arabidopsis seedlings grown on nutrient agar plates containing 100 mg/L gold were reduced by 75%. Oxidized gold was subsequently found in roots and shoots of these plants, but gold nanoparticles (reduced gold were only observed in the root tissues. We used a microarray-based study to monitor the expression of candidate genes involved in metal uptake and transport in Arabidopsis upon gold exposure. There was up-regulation of genes involved in plant stress response such as glutathione transferases, cytochromes P450, glucosyl transferases and peroxidases. In parallel, our data show the significant down-regulation of a discreet number of genes encoding proteins involved in the transport of copper, cadmium, iron and nickel ions, along with aquaporins, which bind to gold. We used Medicago sativa L. (alfalfa to study nanoparticle uptake from hydroponic culture using ionic gold as a non-nanoparticle control and concluded that nanoparticles between 5 and 100 nm in diameter are not directly accumulated by plants. Gold nanoparticles were only observed in plants exposed to ionic gold in solution. Together, we believe our results imply that gold is taken up by the plant predominantly as an ionic form, and that plants respond to gold exposure by up-regulating genes for plant stress and down-regulating specific metal transporters to reduce gold uptake.

  20. Investigating the Toxicity, Uptake, Nanoparticle Formation and Genetic Response of Plants to Gold

    Science.gov (United States)

    Taylor, Andrew F.; Rylott, Elizabeth L.; Anderson, Christopher W. N.; Bruce, Neil C.

    2014-01-01

    We have studied the physiological and genetic responses of Arabidopsis thaliana L. (Arabidopsis) to gold. The root lengths of Arabidopsis seedlings grown on nutrient agar plates containing 100 mg/L gold were reduced by 75%. Oxidized gold was subsequently found in roots and shoots of these plants, but gold nanoparticles (reduced gold) were only observed in the root tissues. We used a microarray-based study to monitor the expression of candidate genes involved in metal uptake and transport in Arabidopsis upon gold exposure. There was up-regulation of genes involved in plant stress response such as glutathione transferases, cytochromes P450, glucosyl transferases and peroxidases. In parallel, our data show the significant down-regulation of a discreet number of genes encoding proteins involved in the transport of copper, cadmium, iron and nickel ions, along with aquaporins, which bind to gold. We used Medicago sativa L. (alfalfa) to study nanoparticle uptake from hydroponic culture using ionic gold as a non-nanoparticle control and concluded that nanoparticles between 5 and 100 nm in diameter are not directly accumulated by plants. Gold nanoparticles were only observed in plants exposed to ionic gold in solution. Together, we believe our results imply that gold is taken up by the plant predominantly as an ionic form, and that plants respond to gold exposure by up-regulating genes for plant stress and down-regulating specific metal transporters to reduce gold uptake. PMID:24736522

  1. A biomolecular recognition approach for the functionalization of cellulose with gold nanoparticles.

    Science.gov (United States)

    Almeida, A; Rosa, A M M; Azevedo, A M; Prazeres, D M F

    2017-09-01

    Materials with new and improved functionalities can be obtained by modifying cellulose with gold nanoparticles (AuNPs) via the in situ reduction of a gold precursor or the deposition or covalent immobilization of pre-synthesized AuNPs. Here, we present an alternative biomolecular recognition approach to functionalize cellulose with biotin-AuNPs that relies on a complex of 2 recognition elements: a ZZ-CBM3 fusion that combines a carbohydrate-binding module (CBM) with the ZZ fragment of the staphylococcal protein A and an anti-biotin antibody. Paper and cellulose microparticles with AuNPs immobilized via the ZZ-CBM3:anti-biotin IgG supramolecular complex displayed an intense red color, whereas essentially no color was detected when AuNPs were deposited over the unmodified materials. Scanning electron microscopy analysis revealed a homogeneous distribution of AuNPs when immobilized via ZZ-CBM3:anti-biotin IgG complexes and aggregation of AuNPs when deposited over paper, suggesting that color differences are due to interparticle plasmon coupling effects. The approach could be used to functionalize paper substrates and cellulose nanocrystals with AuNPs. More important, however, is the fact that the occurrence of a biomolecular recognition event between the CBM-immobilized antibody and its specific, AuNP-conjugated antigen is signaled by red color. This opens up the way for the development of simple and straightforward paper/cellulose-based tests where detection of a target analyte can be made by direct use of color signaling. Copyright © 2017 John Wiley & Sons, Ltd.

  2. Anticancer activity of eco-friendly gold nanoparticles against lung and liver cancer cells

    OpenAIRE

    S. Rajeshkumar

    2016-01-01

    Gold nanoparticles have many applications in biomedical field. Improving delivery of anticancer agents to tumors using nanoparticles is one of the most promising research arenas in the field of nanotechnology. Eco-friendly gold nanoparticles synthesis was studied using marine bacteria Enterococcus sp. The nanoparticle synthesis started at 2 h of incubation time was identified by the formation of ruby red in the reaction mixture and SPR band centered at 545 nm. XRD shows that the strong four i...

  3. Plasma-activated core-shell gold nanoparticle films with enhanced catalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Llorca, Jordi, E-mail: jordi.llorca@upc.edu; Casanovas, Albert; Dominguez, Montserrat; Casanova, Ignasi [Universitat Politecnica de Catalunya, Institut de Tecniques Energetiques (Spain); Angurell, Inmaculada; Seco, Miquel; Rossell, Oriol [Universitat de Barcelona, Departament de Quimica Inorganica (Spain)

    2008-03-15

    Catalytically active gold nanoparticle films have been prepared from core-shell nanoparticles by plasma-activation and characterized by high-resolution transmission electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Methane can be selectively oxidized into formic acid with an O{sub 2}-H{sub 2} mixture in a catalytic wall reactor functionalized with plasma-activated gold nanoparticle films containing well-defined Au particles of about 3.5 nm in diameter. No catalytic activity was recorded over gold nanoparticle films prepared by thermal decomposition of core-shell nanoparticles due to particle agglomeration.

  4. Plasma-activated core-shell gold nanoparticle films with enhanced catalytic properties

    International Nuclear Information System (INIS)

    Llorca, Jordi; Casanovas, Albert; Dominguez, Montserrat; Casanova, Ignasi; Angurell, Inmaculada; Seco, Miquel; Rossell, Oriol

    2008-01-01

    Catalytically active gold nanoparticle films have been prepared from core-shell nanoparticles by plasma-activation and characterized by high-resolution transmission electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Methane can be selectively oxidized into formic acid with an O 2 -H 2 mixture in a catalytic wall reactor functionalized with plasma-activated gold nanoparticle films containing well-defined Au particles of about 3.5 nm in diameter. No catalytic activity was recorded over gold nanoparticle films prepared by thermal decomposition of core-shell nanoparticles due to particle agglomeration

  5. An in-vitro studies on green synthesis of gold nanoparticles against pathogens and cancer cells

    Directory of Open Access Journals (Sweden)

    V. Ramesh

    2015-11-01

    Full Text Available Nanotechnology is a most promising field for generating new applications in medicine. It is imperative to integrate nanoscience and medicine. The present investigation is highly warranted to through more light upon the gold nanoparticles reduced from gold salt through the active principle of medicinal plant. The special emphasis of investigation is the active principle along with gold nanoparticles against for cancer cells. The 70 - 90 nm sized particles were synthesized by using Diospyros ferrea and this confirmed by SEM. These gold nanoparticles showed a characteristic absorption peak at 540 nm in UV spectra. The possibility of protein as a stabilizing material in gold nanoparticles is revealed by FTIR analysis. Remarkably, as a result of wide screening on the application of newly synthesized gold nanoparticles their anticancer potential has been discovered using MTT assay. The antimicrobial activity of AuNPs showed effective against bacteria than the fungal strains.

  6. Polypyrrole–gold nanoparticle composites for highly sensitive DNA detection

    International Nuclear Information System (INIS)

    Spain, Elaine; Keyes, Tia E.; Forster, Robert J.

    2013-01-01

    DNA capture surfaces represent a powerful approach to developing highly sensitive sensors for identifying the cause of infection. Electrochemically deposited polypyrrole, PPy, films have been functionalized with electrodeposited gold nanoparticles to give a nanocomposite material, PPy–AuNP. Thiolated capture strand DNA, that is complementary to the sequence from the pathogen Staphylococcus aureus that causes mammary gland inflammation, was then immobilized onto the gold nanoparticles and any of the underlying gold electrode that is exposed. A probe strand, labelled with horse radish peroxidase, HRP, was then hybridized to the target. The concentration of the target was determined by measuring the current generated by reducing benzoquinone produced by the HRP label. Semi-log plots of the pathogen DNA concentration vs. faradaic current are linear from 150 pM to 1 μM and pM concentrations can be detected without the need for molecular, e.g., PCR or NASBA, amplification. The nanocomposite also exhibits excellent selectivity and single base mismatches in a 30 mer sequence can be detected

  7. Biosynthesis and characterization of gold nanoparticles using extracts of tamarindus indica L leaves

    Science.gov (United States)

    Correa, S. N.; Naranjo, A. M.; Herrera, A. P.

    2016-02-01

    This study reports the biosynthesis of gold nanoparticles using an extract of Tamarindus indica L. leaves. Phenols, ketones and carboxyls were present in the leaves of T. indica. These organic compounds that allowed the synthesis of nanoparticles were identified by gas chromatography coupled to mass spectrometry (GC/MS) and High Pressure Liquid Chromatographic (HPLC). Synthesis of gold nanoparticles was performed with the extract of T. indica leaves and an Au+3 aqueous solutions (HAuCl4) at room temperature with one hour of reaction time. Characterization of gold nanoparticles was performed by UV visible spectroscopy, scanning electron microscopy (SEM) and EDX. The results indicated the formation of gold nanoparticles with a wavelength of 576nm and an average size of 52±5nm. The EDX technique confirmed the presence of gold nanoparticles with 12.88% in solution.

  8. Biosynthesis and characterization of gold nanoparticles using extracts of tamarindus indica L leaves

    International Nuclear Information System (INIS)

    Correa, S N; Naranjo, A M; Herrera, A P

    2016-01-01

    This study reports the biosynthesis of gold nanoparticles using an extract of Tamarindus indica L. leaves. Phenols, ketones and carboxyls were present in the leaves of T. indica. These organic compounds that allowed the synthesis of nanoparticles were identified by gas chromatography coupled to mass spectrometry (GC/MS) and High Pressure Liquid Chromatographic (HPLC). Synthesis of gold nanoparticles was performed with the extract of T. indica leaves and an Au +3 aqueous solutions (HAuCl 4 ) at room temperature with one hour of reaction time. Characterization of gold nanoparticles was performed by UV visible spectroscopy, scanning electron microscopy (SEM) and EDX. The results indicated the formation of gold nanoparticles with a wavelength of 576nm and an average size of 52±5nm. The EDX technique confirmed the presence of gold nanoparticles with 12.88% in solution. (paper)

  9. Microbial deposition of gold nanoparticles by the metal-reducing bacterium Shewanella algae

    International Nuclear Information System (INIS)

    Konishi, Y.; Tsukiyama, T.; Tachimi, T.; Saitoh, N.; Nomura, T.; Nagamine, S.

    2007-01-01

    Microbial reduction and deposition of gold nanoparticles was achieved at 25 deg. C over the pH range 2.0-7.0 using the mesophilic bacterium Shewanella algae in the presence of H 2 as the electron donor. The reductive deposition of gold by the resting cells of S. algae was a fast process: 1 mM AuCl 4 - ions were completely reduced to elemental gold within 30 min. At a solution pH of 7, gold nanoparticles 10-20 nm in size were deposited in the periplasmic space of S. algae cells. At pH 2.8, gold nanoparticles 15-200 nm in size were deposited on the bacterial cells, and the biogenic nanoparticles exhibited a variety of shapes that included nanotriangles: in particular, single crystalline gold nanotriangles 100-200 nm in size were microbially deposited. At a solution pH of 2.0, gold nanoparticles about 20 nm in size were deposited intracellularly, and larger gold particles approximately 350 nm in size were deposited extracellularly. The solution pH was an important factor in controlling the morphology of the biogenic gold particles and the location of gold deposition. Microbial deposition of gold nanoparticles is potentially attractive as an environmentally friendly alternative to conventional methods

  10. Oxidative stress and toxicity of gold nanoparticles in Mytilus edulis

    International Nuclear Information System (INIS)

    Tedesco, Sara; Doyle, Hugh; Blasco, Julian; Redmond, Gareth; Sheehan, David

    2010-01-01

    Gold nanoparticles (AuNP) have potential applications in drug delivery, cancer diagnosis and therapy, food industry and environment remediation. However, little is known about their potential toxicity or fate in the environment. Mytilus edulis was exposed in tanks to750 ppb AuNP (average diameter 5.3 ± 1 nm) for 24 h to study in vivo biological effects of nanoparticles. Traditional biomarkers and an affinity procedure selective for thiol-containing proteins followed by two-dimensional electrophoresis (2DE) separations were used to study toxicity and oxidative stress responses. Results were compared to those obtained for treatment with cadmium chloride, a well known pro-oxidant. M. edulis mainly accumulated AuNP in digestive gland which also showed higher lipid peroxidation. One-dimensional SDS/PAGE (1DE) and 2DE analysis of digestive gland samples revealed decreased thiol-containing proteins for AuNP. Lysosomal membrane stability measured in haemolymph gave lower values for neutral red retention time (NRRT) in both treatments but was greater in AuNP. Oxidative stress occurred within 24 h of AuNP exposure in M. edulis. Previously we showed that larger diameter AuNP caused modest effects, indicating that nanoparticle size is a key factor in biological responses to nanoparticles. This study suggests that M. edulis is a suitable model animal for environmental toxicology studies of nanoparticles.

  11. Enhancement of antibiotic effect via gold:silver-alloy nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Moreira dos Santos, Margarida, E-mail: margarida.santos@fct.unl.pt; Queiroz, Margarida Joao; Baptista, Pedro V. [Universidade Nova de Lisboa, CIGMH, Departamento Ciencias da Vida, Faculdade de Ciencias e Tecnologia (Portugal)

    2012-05-15

    A strategy for the development of novel antimicrobials is to combine the stability and pleiotropic effects of inorganic compounds with the specificity and efficiency of organic compounds, such as antibiotics. Here we report on the use of gold:silver-alloy (Au:Ag-alloy) nanoparticles, obtained via a single-step citrate co-reduction method, combined to conventional antibiotics to enhance their antimicrobial effect on bacteria. Addition of the alloy nanoparticles considerably decreased the dose of antibiotic necessary to show antimicrobial effect, both for bacterial cells growing in rich medium in suspension and for bacterial cells resting in a physiological buffer on a humid cellulose surface. The observed effect was more pronounced than the sum of the individual effects of the nanoparticles and antibiotic. We demonstrate the enhancement effect of Au:Ag-alloy nanoparticles with a size distribution of 32.5 {+-} 7.5 nm mean diameter on the antimicrobial effect of (i) kanamycin on Escherichia coli (Gram-negative bacterium), and (ii) a {beta}-lactam antibiotic on both a sensitive and resistant strain of Staphylococcus aureus (Gram-positive bacterium). Together, these results may pave the way for the combined use of nanoparticle-antibiotic conjugates towards decreasing antibiotic resistance currently observed for certain bacteria and conventional antibiotics.

  12. A Comparative XAFS Study of Gold-thiolate Nanoparticles and Nanoclusters

    International Nuclear Information System (INIS)

    Chevrier, D M; Chatt, A; Zhang, P; Sham, T K

    2013-01-01

    Tiopronin-capped gold nanoparticles and gold nanoclusters of sizes 3.0 and 1.5 nm, respectively, were investigated with XAFS at the gold L 3 -edge. The specific EXAFS fitting procedure is discussed for obtaining reliable fit parameters for each system. The difficulties and challenges faced when analysing EXAFS data for gold nanoparticles and nanoclusters are also mentioned. Fitting results for gold nanoparticles reveal a small amount of surface Au-thiolate interactions with a large Au-Au metal core. For gold nanoclusters, only a one-shell fit was obtainable. Instead of Au-Au metal core, long-range interactions are expected for gold nanoclusters. Tiopronin-capped gold nanoclusters are proposed to be polymeric in nature, which helps explain the observed red luminescence.

  13. Controlled growth of gold nanoparticles in zeolite L via ion-exchange reactions and thermal reduction processes

    KAUST Repository

    Zeng, Shangjing; Ding, Shuang; Li, Shangyu; Wang, Runwei; Zhang, Zongtao

    2014-01-01

    The growth of gold nanoparticles in zeolite can be controlled using ion-exchange reactions and thermal reduction processes. We produce a number of different sizes of the gold nanoparticles with the particle size increasing with increased temperature

  14. Gold Nanoparticles and Their Alternatives for Radiation Therapy Enhancement

    Directory of Open Access Journals (Sweden)

    Daniel R. Cooper

    2014-10-01

    Full Text Available Radiation therapy is one of the most commonly used treatments for cancer. The dose of delivered ionizing radiation can be amplified by the presence of high-Z materials via an enhancement of the photoelectric effect; the most widely studied material is gold (atomic number 79. However, a large amount is needed to obtain a significant dose enhancement, presenting a challenge for delivery. In order to make this technique of broader applicability, the gold must be targeted, or alternative formulations developed that do not rely solely on the photoelectric effect. One possible approach is to excite scintillating nanoparticles with ionizing radiation, and then exploit energy transfer between these particles and attached dyes in a manner analogous to photodynamic therapy. Doped rare-earth halides and semiconductor quantum dots have been investigated for this purpose. However, although the spectrum of emitted light after radiation excitation is usually similar to that seen with light excitation, the yield is not. Measurement of scintillation yields is challenging, and in many cases has been done only for bulk materials, with little understanding of how the principles translate to the nanoscale. Another alternative is to use local heating using gold or iron, followed by application of ionizing radiation. Hyperthermia pre-sensitizes the tumors, leading to an improved response. Another approach is to use chemotherapeutic drugs that can radiosensitize tumors. Drugs may be attached to high-Z nanoparticles or encapsulated. This article discusses each of these techniques, giving an overview of the current state of nanoparticle-assisted radiation therapy and future directions.

  15. Investigation of thiol derivatized gold nanoparticle sensors for gas analysis

    Science.gov (United States)

    Stephens, Jared S.

    Analysis of volatile organic compounds (VOCs) in air and exhaled breath by sensor array is a very useful testing technique. It can provide non-invasive, fast, inexpensive testing for many diseases. Breath analysis has been very successful in identifying cancer and other diseases by using a chemiresistor sensor or array with gold nanoparticles to detect biomarkers. Acetone is a biomarker for diabetes and having a portable testing device could help to monitor diabetic and therapeutic progress. An advantage to this testing method is it is conducted at room temperature instead of 200 degrees Celsius. 3. The objective of this research is to determine the effect of thiol derivatized gold nanoparticles based on sensor(s) detection of VOCs. The VOCs to be tested are acetone, ethanol, and a mixture of acetone and ethanol. Each chip is tested under all three VOCs and three concentration levels (0.1, 1, and 5.0 ppm). VOC samples are used to test the sensors' ability to detect and differentiate VOCs. Sensors (also referred to as a chip) are prepared using several types of thiol derivatized gold nanoparticles. The factors are: thiol compound and molar volume loading of the thiol in synthesis. The average resistance results are used to determine the VOC selectivity of the sensors tested. The results show a trend of increasing resistance as VOC concentration is increased relative to dry air; which is used as baseline for VOCs. Several sensors show a high selectivity to one or more VOCs. Overall the 57 micromoles of 4-methoxy-toluenethiol sensor shows the strongest selectivity for VOCs tested. 3. Gerfen, Kurt. 2012. Detection of Acetone in Air Using Silver Ion Exchanged ZSM-5 and Zinc Oxide Sensing Films. Master of Science thesis, University of Louisville.

  16. Multiscale simulations of ligand adsorption and exchange on gold nanoparticles.

    Science.gov (United States)

    Gao, Hui-Min; Liu, Hong; Qian, Hu-Jun; Jiao, Gui-Sheng; Lu, Zhong-Yuan

    2018-01-17

    We have developed a multiscale model that combines first-principles methods with atomistic and mesoscopic simulations to explore the molecular structures and packing density of the ligands present on the gold nanoparticle (AuNP) surface, as well as the adsorption/exchange reaction kinetics of cetyltrimethylammonium bromide (CTAB)/PEG-SH ligands on different facets of gold, namely, Au(111), Au(100), and Au(110). Our model predicts that on clean gold surfaces, CTAB adsorption is diffusion limited. Specifically, CTAB has the preferentially higher adsorption rate and coverage density on Au(100) and Au(110) surfaces, forming a more compact layer with respect to that on the Au(111) surface, which could result in greater growth of gold nanoparticles along the (111) direction. As opposed to CTAB adsorption, the exchange reaction between PEG-SH with CTAB shows no selectivity to different crystal faces, and the reaction process follows Langmuir diffusion kinetics. Kinetic analysis reveals that, in water, the exchange reaction is zeroth order with respect to the concentration of an incoming PEG-SH, indicative of a dissociative exchange mechanism. The observed rate constant decreases exponentially with the PEG-SH chain length, consistent with a diffusion process for the free PEG-SH in water. In particular, we show that the exchange efficiency increases as the chain rigidness and size of the incoming ligand and/or steric bulk of the initial protecting ligand shell are decreased. Our objectives are to provide a model to assess the kinetics and thermodynamics of the adsorption/exchange reaction process, and we expect that these findings will have important implications for routine surface characterization of AuNPs.

  17. Microwave-induced synthesis of highly dispersed gold nanoparticles within the pore channels of mesoporous silica

    International Nuclear Information System (INIS)

    Gu Jinlou; Fan Wei; Shimojima, Atsushi; Okubo, Tatsuya

    2008-01-01

    Highly dispersed gold nanoparticles have been incorporated into the pore channels of SBA-15 mesoporous silica through a newly developed strategy assisted by microwave radiation (MR). The sizes of gold are effectively controlled attributed to the rapid and homogeneous nucleation, simultaneous propagation and termination of gold precursor by MR. Diol moieties with high dielectric and dielectric loss constants, and hence a high microwave activation, were firstly introduced to the pore channels of SBA-15 by a simple addition reaction between amino group and glycidiol and subsequently served as the reduction centers for gold nanoparticles. Extraction of the entrapped gold from the nanocomposite resulted in milligram quantities of gold nanoparticles with low dispersity. The successful assembly process of diol groups and formation of gold nanoparticles were monitored and tracked by solid-state NMR and UV-vis measurements. Characterization by small angle X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the incorporation of gold nanoparticles would not breakup the structural integrity and long-range periodicity of SBA-15. The gold nanoparticles had a narrow size distribution with diameters in the size range of 5-10 nm through TEM observation. The average particles size is 7.9 nm via calculation by the Scherrer formula and TEM measurements. Nitrogen adsorption and desorption isotherms gave further evidence that the employed method was efficient and gold nanoparticles were successfully incorporated into the pore channels of SBA-15. - Graphical abstract: A facile and novel strategy has been developed to incorporate gold nanoparticles into the pore channels of mesoporous SBA-15 assisted by microwave radiation (MR) with mild reaction condition and rapid reaction speed. Due to the rapid and homogeneous nucleation, simultaneous propagation and termination by MR, the size of gold nanoparticles are effectively controlled

  18. Cancer-selective, single agent chemoradiosensitising gold nanoparticles

    OpenAIRE

    Grellet, Sophie; Tzelepi, Konstantina; Roskamp, Meike; Williams, Phil; Sharif, Aquila; Slade-Carter, Richard; Goldie, Peter; Whilde, Nicky; ?mia?ek, Ma?gorzata A.; Mason, Nigel J.; Golding, Jon P.

    2017-01-01

    Two nanometre gold nanoparticles (AuNPs), bearing sugar moieties and/or thiol-polyethylene glycol-amine (PEG-amine), were synthesised and evaluated for their in vitro toxicity and ability to radiosensitise cells with 220 kV and 6 MV X-rays, using four cell lines representing normal and cancerous skin and breast tissues. Acute 3 h exposure of cells to AuNPs, bearing PEG-amine only or a 50:50 ratio of alpha-galactose derivative and PEG-amine resulted in selective uptake and toxicity towards can...

  19. Photoacoustic emission from fluorescent nanodiamonds enhanced with gold nanoparticles

    Science.gov (United States)

    Zhang, Bailin; Fang, Chia-Yi; Chang, Cheng-Chun; Peterson, Ralph; Maswadi, Saher; Glickman, Randolph D.; Chang, Huan-Cheng; Ye, Jing Yong

    2012-01-01

    Fluorescent nanodiamonds (FNDs) have drawn much attention in recent years for biomedical imaging applications due to their desired physical properties including excellent photostability, high biocompatibility, extended far-red fluorescence emission, and ease of surface functionalization. Here we explore a new feature of FNDs, i.e. their photoacoustic emission capability, which may lead to potential applications of using FNDs as a dual imaging contrast agent for combined fluorescence and photoacoustic imaging modalities. We observed significant enhancement of photoacoustic emission from FNDs when they were conjugated with gold nanoparticles (GNPs). PMID:22808436

  20. Photoacoustic emission from fluorescent nanodiamonds enhanced with gold nanoparticles.

    Science.gov (United States)

    Zhang, Bailin; Fang, Chia-Yi; Chang, Cheng-Chun; Peterson, Ralph; Maswadi, Saher; Glickman, Randolph D; Chang, Huan-Cheng; Ye, Jing Yong

    2012-07-01

    Fluorescent nanodiamonds (FNDs) have drawn much attention in recent years for biomedical imaging applications due to their desired physical properties including excellent photostability, high biocompatibility, extended far-red fluorescence emission, and ease of surface functionalization. Here we explore a new feature of FNDs, i.e. their photoacoustic emission capability, which may lead to potential applications of using FNDs as a dual imaging contrast agent for combined fluorescence and photoacoustic imaging modalities. We observed significant enhancement of photoacoustic emission from FNDs when they were conjugated with gold nanoparticles (GNPs).

  1. Uptake of gold nanoparticles in primary human endothelial cells

    DEFF Research Database (Denmark)

    Klingberg, Henrik; Oddershede, Lene B.; Löschner, Katrin

    2015-01-01

    Gold nanoparticles (AuNPs) are relevant in nanomedicine for drug delivery in the vascular system, where endothelial cells are the first point of contact. We investigated the uptake of 80 nm AuNPs in primary human umbilical vein endothelial cells (HUVECs) by flow cytometry, 3D confocal microscopy......–3 or more particles. Pre-treatment with chlorpromazine inhibited the AuNP-uptake in HUVECs, indicating that internalisation occurred mainly by clathrin-mediated endocytosis. Cell activation by exposure to tumour necrosis factor or lipopolysaccharide had a slight or no effect on the uptake of Au...

  2. Particle size-dependent organ distribution of gold nanoparticles after intravenous administration

    NARCIS (Netherlands)

    De Jong, Wim H.; Hagens, Werner I.; Krystek, Petra; Burger, Marina C.; Sips, Adriënne J A M; Geertsma, Robert E.

    2008-01-01

    A kinetic study was performed to determine the influence of particle size on the in vivo tissue distribution of spherical-shaped gold nanoparticles in the rat. Gold nanoparticles were chosen as model substances as they are used in several medical applications. In addition, the detection of the

  3. Photoinduced charge and energy transfer in phthalocyanine-functionalized gold nanoparticles

    NARCIS (Netherlands)

    Kotiaho, Anne; Lahtinen, Riikka; Efimov, Alexander; Metsberg, Hanna Kaisa; Sariola, Essi; Lehtivuori, Heli; Tkachenko, Nikolai V.; Lemmetyinen, Helge

    2010-01-01

    Photoinduced processes in phthalocyanine-functionalized gold nanoparticles (Pc-AuNPs) have been investigated by spectroscopic measurements. The metal-free phthalocyanines used have two linkers with thioacetate groups for bonding to the gold nanoparticle surface, and the attachment was achieved using

  4. Gold-manganese nanoparticles for targeted diagnostic and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Murph, Simona Hunyadi [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-11-10

    Imagine the possibility of non-invasive, non-radiation based Magnetic resonance imaging (MRI) in combating cardiac disease. Researchers at the Savannah River National Laboratory (SRNL) are developing a process that would use nanotechnology in a novel, targeted approach that would allow MRIs to be more descriptive and brighter, and to target specific organs. Researchers at SRNL have discovered a way to use multifunctional metallic gold-manganese nanoparticles to create a unique, targeted positive contrast agent. SRNL Senior Scientist Dr. Simona Hunyadi Murph says she first thought of using the nanoparticles for cardiac disease applications after learning that people who survive an infarct exhibit up to 15 times higher rate of developing chronic heart failure, arrhythmias and/or sudden death compared to the general population. Without question, nanotechnology will revolutionize the future of technology. The development of functional nanomaterials with multi-detection modalities opens up new avenues for creating multi-purpose technologies for biomedical applications.

  5. Antibacterial gold nanoparticles-biomass assisted synthesis and characterization.

    Science.gov (United States)

    Badwaik, Vivek D; Willis, Chad B; Pender, Dillon S; Paripelly, Rammohan; Shah, Monic; Kherde, Yogesh A; Vangala, Lakshmisri M; Gonzalez, Matthew S; Dakshinamurthy, Rajalingam

    2013-10-01

    Xylose is a natural monosaccharide found in biomass such as straw, pecan shells, cottonseed hulls, and corncobs. Using this monosaccharide, we report the facile, green synthesis and characterization of stable xylose encapsulated gold nanoparticles (Xyl-GNPs) with potent antibacterial activity. Xyl-GNPs were synthesized using the reduction property of xylose in an aqueous solution containing choloraurate anions carried out at room temperature and atmospheric pressure. These nanoparticles were stable and near spherical in shape with an average diameter of 15 +/- 5 nm. Microbiological assay results showed the concentration dependent antibacterial activity of these particles against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus epidermidis) bacteria. Thus the facile, environmentally friendly Xyl-GNPs have many potential applications in chemical and biomedical industries, particularly in the development of antibacterial agents in the field of biomedicine.

  6. Gold Nanoparticles and Microwave Irradiation Inhibit Beta-Amyloid Amyloidogenesis

    Directory of Open Access Journals (Sweden)

    Bastus Neus

    2008-01-01

    Full Text Available Abstract Peptide-Gold nanoparticles selectively attached to β-amyloid protein (Aβ amyloidogenic aggregates were irradiated with microwave. This treatment produces dramatic effects on the Aβ aggregates, inhibiting both the amyloidogenesis and the restoration of the amyloidogenic potential. This novel approach offers a new strategy to inhibit, locally and remotely, the amyloidogenic process, which could have application in Alzheimer’s disease therapy. We have studied the irradiation effect on the amyloidogenic process in the presence of conjugates peptide-nanoparticle by transmission electronic microscopy observations and by Thioflavine T assays to quantify the amount of fibrils in suspension. The amyloidogenic aggregates rather than the amyloid fibrils seem to be better targets for the treatment of the disease. Our results could contribute to the development of a new therapeutic strategy to inhibit the amyloidogenic process in Alzheimer’s disease.

  7. Gold and silver nanoparticles based superquenching of fluorescence: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Debanjana; Chattopadhyay, Nitin, E-mail: nitin.chattopadhyay@yahoo.com

    2015-04-15

    The short review highlights the recent advances on the gold and silver nanoparticles induced efficient quenching of fluorescence from various fluorophores looking at their promising use as optical rulers and chemo-/bio- sensors. The fluorescence quenching often leads to the increase in the Stern–Volmer constant (K{sub SV}~10{sup 7}–10{sup 10} mol{sup −1} dm{sup 3}) several orders of magnitude higher than the values observed for the normal photochemical quenching processes (~10{sup 2} mol{sup −1} dm{sup 3}). This amplified quenching has been termed as “super-quenching” or “hyper-quenching”. Energy transfer (ET) is established from the donor to the metal nanoparticles rationalizing these fast quenching processes. Considering the distance dependence of the ET process, Förster resonance energy transfer (FRET) and nanometal surface energy transfer (NSET) are ascribed to take place. These sensitive distance dependent phenomena serve as the spectroscopic ruler to measure the intra- or intermolecular distances between the interacting partners. In this account focus has been laid on the size dependent energy transfer and super- and hyper- quenching of the fluorescence of the donor moieties by the nanometals and their probable applications in sensing. Rationalization has been made for the nanoparticle induced huge enhancement in the quenching efficiency. The impact of this review lies in the possible application of these amplified quenching processes in designing high sensitive chemical and biological sensors. - Highlights: • Super efficient quenching of fluorescence of probes by gold and silver nanoparticles is highlighted. • The amplified fluorescence quenching of dyes and polymers is rationalized. • Energy transfer is assigned to be responsible for the efficient quenching process. • Amplified quenching has its potential use in designing sensitive chemical/biological sensors.

  8. Assessment of the In Vivo Toxicity of Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Liau Ian

    2009-01-01

    Full Text Available Abstract The environmental impact of nanoparticles is evident; however, their toxicity due to their nanosize is rarely discussed. Gold nanoparticles (GNPs may serve as a promising model to address the size-dependent biological response to nanoparticles because they show good biocompatibility and their size can be controlled with great precision during their chemical synthesis. Naked GNPs ranging from 3 to 100 nm were injected intraperitoneally into BALB/C mice at a dose of 8 mg/kg/week. GNPs of 3, 5, 50, and 100 nm did not show harmful effects; however, GNPs ranging from 8 to 37 nm induced severe sickness in mice. Mice injected with GNPs in this range showed fatigue, loss of appetite, change of fur color, and weight loss. Starting from day 14, mice in this group exhibited a camel-like back and crooked spine. The majority of mice in these groups died within 21 days. Injection of 5 and 3 nm GNPs, however, did not induce sickness or lethality in mice. Pathological examination of the major organs of the mice in the diseased groups indicated an increase of Kupffer cells in the liver, loss of structural integrity in the lungs, and diffusion of white pulp in the spleen. The pathological abnormality was associated with the presence of gold particles at the diseased sites, which were verified by ex vivo Coherent anti-Stoke Raman scattering microscopy. Modifying the surface of the GNPs by incorporating immunogenic peptides ameliorated their toxicity. This reduction in the toxicity is associated with an increase in the ability to induce antibody response. The toxicity of GNPs may be a fundamental determinant of the environmental toxicity of nanoparticles.

  9. Gold and silver nanoparticles based superquenching of fluorescence: A review

    International Nuclear Information System (INIS)

    Ghosh, Debanjana; Chattopadhyay, Nitin

    2015-01-01

    The short review highlights the recent advances on the gold and silver nanoparticles induced efficient quenching of fluorescence from various fluorophores looking at their promising use as optical rulers and chemo-/bio- sensors. The fluorescence quenching often leads to the increase in the Stern–Volmer constant (K SV ~10 7 –10 10 mol −1 dm 3 ) several orders of magnitude higher than the values observed for the normal photochemical quenching processes (~10 2 mol −1 dm 3 ). This amplified quenching has been termed as “super-quenching” or “hyper-quenching”. Energy transfer (ET) is established from the donor to the metal nanoparticles rationalizing these fast quenching processes. Considering the distance dependence of the ET process, Förster resonance energy transfer (FRET) and nanometal surface energy transfer (NSET) are ascribed to take place. These sensitive distance dependent phenomena serve as the spectroscopic ruler to measure the intra- or intermolecular distances between the interacting partners. In this account focus has been laid on the size dependent energy transfer and super- and hyper- quenching of the fluorescence of the donor moieties by the nanometals and their probable applications in sensing. Rationalization has been made for the nanoparticle induced huge enhancement in the quenching efficiency. The impact of this review lies in the possible application of these amplified quenching processes in designing high sensitive chemical and biological sensors. - Highlights: • Super efficient quenching of fluorescence of probes by gold and silver nanoparticles is highlighted. • The amplified fluorescence quenching of dyes and polymers is rationalized. • Energy transfer is assigned to be responsible for the efficient quenching process. • Amplified quenching has its potential use in designing sensitive chemical/biological sensors

  10. Use of Soybean Lecithin in Shape Controlled Synthesis of Gold Nanoparticles

    Science.gov (United States)

    Ayres, Benjamin Robert

    The work presented in this dissertation is a composite of experiments in the growth of gold nanoparticles with specific optical properties of interest. The goal is to synthesize these gold nanoparticles using soybean extract for not only shape control, but for propensity as a biocompatible delivery system. The optical properties of these nanoparticles has found great application in coloring glass during the Roman empire and, over the centuries, has grown into its own research field in applications of nanoparticulate materials. Many of the current functions include use in biological systems as biosensors and therapeutic applications, thus making biocompatibility a necessity. Current use of cetyltrimethylammonium bromide leads to rod-shaped gold nanoparticles, however, the stability of these gold nanoparticles does not endure for extended periods of time in aqueous media. In my research, two important components were found to be necessary for stable, anisotropic growth of gold nanoparticles. In the first experiments, it was found that bromide played a key role in shape control. Bromide exchange on the gold atoms led to specific packing of the growing crystals, allowing for two-dimensional growth of gold nanoparticles. It was also discerned that soybean lecithin contained ligands that blocked specific gold facets leading to prismatic gold nanoparticle growth. These gold nanoprisms give a near infrared plasmon absorption similar to that of rod-shaped gold nanoparticles. These gold nanoprisms are discovered to be extremely stable in aqueous media and remain soluble for extended periods of time, far longer than that of gold nanoparticles grown using cetyltrimethylammonium bromide. Since soy lecithin has a plethora of compounds present, it became necessary to discover which compound was responsible for the shape control of the gold nanoprisms in order to optimize the synthesis and allow for a maximum yield of the gold nanoprisms. Many of these components were identified

  11. Enhancement of antibiotic effect via gold:silver-alloy nanoparticles

    International Nuclear Information System (INIS)

    Moreira dos Santos, Margarida; Queiroz, Margarida João; Baptista, Pedro V.

    2012-01-01

    A strategy for the development of novel antimicrobials is to combine the stability and pleiotropic effects of inorganic compounds with the specificity and efficiency of organic compounds, such as antibiotics. Here we report on the use of gold:silver-alloy (Au:Ag-alloy) nanoparticles, obtained via a single-step citrate co-reduction method, combined to conventional antibiotics to enhance their antimicrobial effect on bacteria. Addition of the alloy nanoparticles considerably decreased the dose of antibiotic necessary to show antimicrobial effect, both for bacterial cells growing in rich medium in suspension and for bacterial cells resting in a physiological buffer on a humid cellulose surface. The observed effect was more pronounced than the sum of the individual effects of the nanoparticles and antibiotic. We demonstrate the enhancement effect of Au:Ag-alloy nanoparticles with a size distribution of 32.5 ± 7.5 nm mean diameter on the antimicrobial effect of (i) kanamycin on Escherichia coli (Gram-negative bacterium), and (ii) a β-lactam antibiotic on both a sensitive and resistant strain of Staphylococcus aureus (Gram-positive bacterium). Together, these results may pave the way for the combined use of nanoparticle–antibiotic conjugates towards decreasing antibiotic resistance currently observed for certain bacteria and conventional antibiotics.

  12. Biogenic silver and gold nanoparticles synthesized using red ginseng root extract, and their applications.

    Science.gov (United States)

    Singh, Priyanka; Kim, Yeon Ju; Wang, Chao; Mathiyalagan, Ramya; El-Agamy Farh, Mohamed; Yang, Deok Chun

    2016-05-01

    In the present study, we report a green methodology for the synthesis of silver and gold nanoparticles, using the root extract of the herbal medicinal plant Korean red ginseng. The silver and gold nanoparticles were synthesized within 1 h and 10 min respectively. The nanoparticles generated were not aggregated, and remained stable for a long time, which suggests the nature of nanoparticles. The phytochemicals and ginsenosides present in the root extract assist in reducing and stabilizing the synthesized nanoparticles. The red ginseng root extract-generated silver nanoparticles exhibit antimicrobial activity against pathogenic microorganisms including Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus cereus, and Candida albicans. In addition, the silver nanoparticles exhibit biofilm degrading activity against S. aureus and Pseudomonas aeruginosa. Thus, the present study opens up a new possibility of synthesizing silver and gold nanoparticles in a green and rapid manner using Korean red ginseng root extract, and explores their biomedical applications.

  13. Polymer supported gold nanoparticles: Synthesis and characterization of functionalized polystyrene-supported gold nanoparticles and their application in catalytic oxidation of alcohols in water

    Science.gov (United States)

    Kaboudin, Babak; Khanmohammadi, Hamid; Kazemi, Foad

    2017-12-01

    Sulfonated polystyrene microsphere were functionalized using ethylene diamine to introduce amine groups to the polymer chains. The amine functionalized polymers were used as a support for gold nanoparticles. A thorough structural characterization has been carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) images, EDS, CHN and atomic absorption spectroscopy. The polymer supported gold nanoparticles was found to be an efficient catalyst for the oxidation of alcohols in water.

  14. Preparation of gold nanoparticles-agarose gel composite and its application in SERS detection

    Science.gov (United States)

    Ma, Xiaoyuan; Xia, Yu; Ni, Lili; Song, Liangjing; Wang, Zhouping

    2014-03-01

    Agarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Nanocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-Vis-NIR absorption spectroscopy. Based on the swelling-contraction characteristics of agarose gel and the adjustable localized surface plasmon resonance (LSPR) of the gold nanoparticles, the nanocomposites were used as surface enhanced Raman scattering (SERS) substrate to detect the Raman signal molecules (NBA, MBA, 1NAT). Results revealed that the porous structure of the agarose gel provided a good carrier for the enrichment of the gold nanoparticles. The gold nanoparticles dynamic hot-spot effect arising from the agarose gel contraction loss of water in the air greatly enhanced the Raman signal. Furthermore, the gel could be cleaned with washing solution and recycling could be achieved for Raman detection.

  15. Detection of Volatile Organic Compound Gas Using Localized Surface Plasmon Resonance of Gold Nanoparticles

    International Nuclear Information System (INIS)

    Sri Nengsih; Akrajas Ali Umar; Muhamad Mat Salleh; Muhammad Yahaya

    2011-01-01

    This paper reports on the detection of several organic vapors using the unique characteristic of localized surface plasmon resonance (LSPR) gold nanoparticles. Gold nanoparticles on quartz substrate were prepared using seed mediated growth method. In a typical process, gold nanoparticles with average size ca. 36 nm were obtained to densely grown on the substrate. Detection of gas was based on the change in the LSPR of the gold nanoparticles film upon the exposure to the gas sample. It was found that gold nanoparticles were sensitive to the presence of volatile organic compound (VOC) gas from the change in the surface plasmon resonance (SPR) intensity. The mechanism for the detection of VOCs gas will be discussed. (author)

  16. Simulation studies on structural and thermal properties of alkane thiol capped gold nanoparticles.

    Science.gov (United States)

    Devi, J Meena

    2017-06-01

    The structural and thermal properties of the passivated gold nanoparticles were explored employing molecular dynamics simulation for the different surface coverage densities of the self-assembled monolayer (SAM) of alkane thiol. The structural properties of the monolayer protected gold nanoparticles such us overall shape, organization and conformation of the capping alkane thiol chains were found to be influenced by the capping density. The structural order of the thiol capped gold nanoparticles enhances with the increase in the surface coverage density. The specific heat capacity of the alkane thiol capped gold nanoparticles was found to increase linearly with the thiol coverage density. This may be attributed to the enhancement in the lattice vibrational energy. The present simulation results suggest, that the structural and thermal properties of the alkane thiol capped gold nanoparticles may be modified by the suitable selection of the SAM coverage density. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Effect of Nanoparticle Core Size on Polymer-Coated Gold Nanoparticle Location in Block Copolymers

    Science.gov (United States)

    Petrie, J. D.; Fredrickson, G. H.; Kramer, E. J.

    2009-03-01

    Gold nanoparticles modified by short chain polymer thiols [Au-PS] can be designed to strongly localize either in the PS domains of a polystyrene-b-poly(2-vinylpyridine) [PS-PVP] block copolymer or at the interface. The P2VP block has a stronger attractive interaction with bare gold than the PS block. Thus, when the areal chain density σ of end-attached PS chains falls below a critical areal chain density σc the Au-PS nanoparticles adsorb to the PS-b-P2VP interface. The effect of the polymer ligand molecular weight on the σc has been shown to scale as σc˜ ((R + Rg)/(R*Rg))̂2, where R is the curvature of the Au nanoparticle core radius. To test this scaling relation for σc further we are synthesizing gold nanoparticles with different core radii and will present preliminary results on σc as a function of R.

  18. Hyperthermia effects in the presence of gold nanoparticles together with chemotherapy on Saos-2 cell line

    International Nuclear Information System (INIS)

    Sazgarnia, A.; Bahreyni Toosi, M. H.; Haji Ghahremani, F.; Rajabi, O.; Aledavood, A.; Esmaily, H.

    2011-01-01

    Hyperthermia created by microwave, infrared, ultrasound and other methods, is often utilized as an adjuvant to sensitize cancer cells to the effects of chemotherapy and radiation therapy. We investigated the efficacy of hyperthermia using microwave in synergy with chemotherapy in the presence and absence and gold nanoparticles. Material and Methods: After culturing and proliferation of the Saos-2 cell line derived from human osteogenic sarcoma, the cells were incubated at two concentrations of gold nanoparticles in two diameters of 20 and 40 nm and in the absence and presence of doxorubicin in different groups. Forty eight hours after irradiating the cells with microwave up to a temperature of 42 d egree C , cell survival rate was determined using the MTT method, in order to study the effectiveness of the therapeutic parameters. Results: Cell survival in the presence of gold nanoparticles was greater than 95%. After chemotherapy by doxorubicin with and without 40 nm gold nanoparticles, cell survival rates were determined as 62.8% and 37.1 %, declining down to 17% and 4.1% respectively following the combined treatment with microwave and chemotherapy in the presence of 20 and 40 nm gold nanoparticles. Discussion and Conclusions: Gold nanoparticles did not induce any cytotoxicity by themselves; their presence along with microwave provided a reduction in survival rate that was comparable in severity with the lethal effects of doxorubicin. microwave hyperthermia with gold nanoparticles produced a higher treatment efficiency in comparison to similar groups in which gold nanoparticles were absent. The synergism observed between hyperthermia and chemotherapy was dependent in gold nanoparticles' size and concentration. This finding could be caused by increased uptake of doxorubicin by the cells in the presence of gold nanoparticles.

  19. Surface Plasmons and Surface Enhanced Raman Spectra of Aggregated and Alloyed Gold-Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Y. Fleger

    2009-01-01

    Full Text Available Effects of size, morphology, and composition of gold and silver nanoparticles on surface plasmon resonance (SPR and surface enhanced Raman spectroscopy (SERS are studied with the purpose of optimizing SERS substrates. Various gold and silver films made by evaporation and subsequent annealing give different morphologies and compositions of nanoparticles and thus different position of the SPR peak. SERS measurements of 4-mercaptobenzoic acid obtained from these films reveal that the proximity of the SPR peak to the exciting laser wavelength is not the only factor leading to the highest Raman enhancement. Silver nanoparticles evaporated on top of larger gold nanoparticles show higher SERS than gold-silver alloyed nanoparticles, in spite of the fact that the SPR peak of alloyed nanoparticles is narrower and closer to the excitation wavelength. The highest Raman enhancement was obtained for substrates with a two-peak particle size distribution for excitation wavelengths close to the SPR.

  20. Extracellular biosynthesis of gold and silver nanoparticles using Krishna tulsi ( Ocimum sanctum) leaf

    Science.gov (United States)

    Philip, Daizy; Unni, C.

    2011-05-01

    Aqueous extract of Ocimum sanctum leaf is used as reducing agent for the environmentally friendly synthesis of gold and silver nanoparticles. The nanoparticles were characterized using UV-vis, transmission electron microscopy (TEM), X-ray diffraction (XRD) and FTIR analysis. These methods allow the synthesis of hexagonal gold nanoparticles having size ∼30 nm showing two surface plasmon resonance (SPR) bands by changing the relative concentration of HAuCl 4 and the extract. Broadening of SPR is observed at larger quantities of the extract possibly due to biosorption of gold ions. Silver nanoparticles with size in the range 10-20 nm having symmetric SPR band centered around 409 nm are obtained for the colloid synthesized at room temperature at a pH of 8. Crystallinity of the nanoparticles is confirmed from the XRD pattern. Biomolecules responsible for capping are different in gold and silver nanoparticles as evidenced by the FTIR spectra.

  1. Biosynthesis of size-controlled gold nanoparticles using fungus, Penicillium sp.

    Science.gov (United States)

    Zhang, Xiaorong; He, Xiaoxiao; Wang, Kemin; Wang, Yonghong; Li, Huimin; Tan, Weihong

    2009-10-01

    The unique optoelectronic and physicochemical properties of gold nanoparticles are significantly dependent on the particle size, shape and structure. In this paper, biosynthesis of size-controlled gold nanoparticles using fungus Penicillium sp. is reported. Fungus Penicillium sp. could successfully bioreduce and nucleate AuCl4(-) ions, and lead to the assembly and formation of intracellular Au nanoparticles with spherical morphology and good monodispersity after exposure to HAuCl4 solution. Reaction temperature, as an important physiological parameter for fungus Penicillium sp. growth, could significantly control the size of the biosynthesized Au nanoparticles. The biological compositions and FTIR spectra analysis of fungus Penicillium sp. exposed to HAuCl4 solution indicated the intracellular reducing sugar played an important role in the occurrence of intracellular reduction of AuCl4(-) ions and the growth of gold nanoparticles. Furthermore, the intracellular gold nanoparticles could be easily separated from the fungal cell lysate by ultrasonication and centrifugation.

  2. Piper betle-mediated green synthesis of biocompatible gold nanoparticles

    Science.gov (United States)

    Punuri, Jayasekhar Babu; Sharma, Pragya; Sibyala, Saranya; Tamuli, Ranjan; Bora, Utpal

    2012-08-01

    Here, we report the novel use of the ethonolic leaf extract of Piper betle for gold nanoparticle (AuNP) synthesis. The successful formation of AuNPs was confirmed by UV-visible spectroscopy, and different parameters such as leaf extract concentration (2%), gold salt concentration (0.5 mM), and time (18 s) were optimized. The synthesized AuNPs were characterized with different biophysical techniques such as transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX). TEM experiments showed that nanoparticles were of various shapes and sizes ranging from 10 to 35 nm. FT-IR spectroscopy revealed that AuNPs were functionalized with biomolecules that have primary amine group -NH2, carbonyl group, -OH groups, and other stabilizing functional groups. EDX showed the presence of the elements on the surface of the AuNPs. FT-IR and EDX together confirmed the presence of biomolecules bounded on the AuNPs. Cytotoxicity of the AuNPs was tested on HeLa and MCF-7 cancer cell lines, and they were found to be nontoxic, indicating their biocompatibility. Thus, synthesized AuNPs have potential for use in various biomedical applications.

  3. Stable graphene oxide-gold nanoparticle platforms for biosensing applications.

    Science.gov (United States)

    Hernández-Sánchez, Dania; Villabona-Leal, Giovanny; Saucedo-Orozco, Izcoatl; Bracamonte, Victoria; Pérez, Elías; Bittencourt, Carla; Quintana, Mildred

    2018-01-17

    Graphene oxide-gold nanoparticle (AuNPs@GO) hybrids were fabricated in water dispersions of graphene oxide (GO) and Au precursor completely free of stabilizing agents by UV-light irradiation. Gold nanoparticle (AuNP) nucleation, growth, and stabilization mechanisms at the surface of GO are discussed on the basis of UV-Vis, Raman, IR, and X-Ray photo-spectroscopy studies. The analyses of AuNPs@GO hybrids by transmission electron microscopy (TEM), thermogravimetric (TGA) and electrochemical tests show that they exhibit outstanding chemical, thermal and electrochemical stabilities. Thus, AuNPs@GO biosensing platforms were fabricated for surface enhanced Raman spectroscopy (SERS) detection of crystal violet (CV), a SERS standard molecule, and in a different set of experiments, for flavin adenine dinucleotide (FAD), a flavoprotein coenzyme that plays an important role in many oxidoreductase and reversible redox conversions in biochemical reactions. AuNPs@GO hybrids synthesized by using UV light irradiation show exceptional stability and high intensification of the Raman signals showing that they have high potential for use as biomedical probes for the detection, monitoring, and diagnosis of medical diseases.

  4. Gold nanoparticles in plastic columnar discotic liquid crystalline material

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Mukesh, E-mail: mukeshphysics927@gmail.com [Center of Material Sciences, Institute of Interdisciplinary Studies, University of Allahabad, Allahabad 211002 (India); Kumar, Sandeep [Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India); Dhar, Ravindra, E-mail: dr.ravindra.dhar@gmail.com [Center of Material Sciences, Institute of Interdisciplinary Studies, University of Allahabad, Allahabad 211002 (India)

    2016-05-10

    Highlights: • Dispersion of Gold nanoparticles in a discotic liquid crystal has been studied. • σ{sub i} increases by seven orders of magnitude in the case of 1.2 wt% GNPs composites. • X-ray scattering results revel that a decrement in the core–core separation. • Study suggests that dispersion at low concentrations is uniform. • Band gap has decreased due to dispersion of GNPs in HAT4. - Abstract: We have studied the effect of gold nanoparticles (GNPs) on the thermodynamical, optical and dielectrical parameters of a discotic liquid crystal (DLC) namely hexabutyloxytriphenylene (HAT4). It has been observed that with the increase of GNPs concentration in DLC, composites shows two different regions. In the first regions i.e. low concentrations (<1 wt%), columnar hexagonal-isotropic (Col{sub hp}-I{sub L}) transition temperature and enthalpy (ΔH) decrease rapidly while in the second region i.e. higher concentrations (>1 wt%) Col{sub hp}-I{sub L} transition temperature and ΔH are approximately constant. It has been observed that, in the case of composites having 0.2 and 0.6 wt% of GNPs, conductivity has enhanced but it is poor as compared to the composite having 1.2 wt% of GNPs. For 1.2 wt% of GNPs, conductivity has increased by seven orders of magnitude as compared to the DLC. Optical study suggests that band gap of nanocomposites has decreased due to dispersion of GNPs.

  5. Gold nanoparticles enlighten the future of cancer theranostics

    Directory of Open Access Journals (Sweden)

    Guo J

    2017-08-01

    Full Text Available Jianfeng Guo,1 Kamil Rahme,2–4 Yan He,1 Lin-Lin Li,5 Justin D Holmes,3,4 Caitriona M O’Driscoll6 1School of Pharmaceutical Sciences, Jilin University, Changchun, China; 2Department of Sciences, Faculty of Natural and Applied Science, Notre Dame University (Louaize, Zouk Mosbeh, Lebanon; 3Department of Chemistry, Tyndall National Institute, University College Cork, Cork, 4AMBER@CRANN, Trinity College Dublin, Dublin, Ireland; 5The First Hospital of Jilin University, Changchun, China; 6Pharmacodelivery Group, School of Pharmacy, University College Cork, Cork, Ireland Abstract: Development of multifunctional nanomaterials, one of the most interesting and advanced research areas in the field of nanotechnology, is anticipated to revolutionize cancer diagnosis and treatment. Gold nanoparticles (AuNPs are now being widely utilized in bioimaging and phototherapy due to their tunable and highly sensitive optical and electronic properties (the surface plasmon resonance. As a new concept, termed “theranostics,” multifunctional AuNPs may contain diagnostic and therapeutic functions that can be integrated into one system, thereby simultaneously facilitating diagnosis and therapy and monitoring therapeutic responses. In this review, the important properties of AuNPs relevant to diagnostic and phototherapeutic applications such as structure, shape, optics, and surface chemistry are described. Barriers for translational development of theranostic AuNPs and recent advances in the application of AuNPs for cancer diagnosis, photothermal, and photodynamic therapy are discussed. Keywords: multifunctional gold nanoparticles, cancer bioimaging, cancer photothermal and photodynamic therapy

  6. Room-temperature synthesis of gold nanoparticles and nanoplates using Shewanella algae cell extract

    Energy Technology Data Exchange (ETDEWEB)

    Ogi, Takashi; Saitoh, Norizoh; Nomura, Toshiyuki; Konishi, Yasuhiro, E-mail: yasuhiro@chemeng.osakafu-u.ac.j [Osaka Prefecture University, Department of Chemical Engineering (Japan)

    2010-09-15

    Biosynthesis of spherical gold nanoparticles and gold nanoplates was achieved at room temperature and pH 2.8 when cell extract from the metal-reducing bacterium Shewanella algae was used as both a reducing and shape-controlling agent. Cell extract, prepared by sonicating a suspension of S. algae cells, was capable of reducing 1 mol/m{sup 3} aqueous AuCl{sub 4}{sup -} ions into elemental gold within 10 min when H{sub 2} gas was provided as an electron donor. The time interval lapsed since the beginning of the bioreductive reaction was found to be an important factor in controlling the morphology of biogenic gold nanoparticles. After 1 h, there was a large population of well-dispersed, spherical gold nanoparticles with a mean size of 9.6 nm. Gold nanoplates with an edge length of 100 nm appeared after 6 h, and 60% of the total nanoparticle population was due to gold nanoplates with an edge length of 100-200 nm after 24 h. The yield of gold nanoplates prepared with S. algae extract was four times higher than that prepared with resting cells of S. algae. The resulting biogenic gold nanoparticle suspensions showed a large variation in color, ranging from pale pink to purple due to changes in nanoparticle morphology.

  7. Room-temperature synthesis of gold nanoparticles and nanoplates using Shewanella algae cell extract

    International Nuclear Information System (INIS)

    Ogi, Takashi; Saitoh, Norizoh; Nomura, Toshiyuki; Konishi, Yasuhiro

    2010-01-01

    Biosynthesis of spherical gold nanoparticles and gold nanoplates was achieved at room temperature and pH 2.8 when cell extract from the metal-reducing bacterium Shewanella algae was used as both a reducing and shape-controlling agent. Cell extract, prepared by sonicating a suspension of S. algae cells, was capable of reducing 1 mol/m 3 aqueous AuCl 4 - ions into elemental gold within 10 min when H 2 gas was provided as an electron donor. The time interval lapsed since the beginning of the bioreductive reaction was found to be an important factor in controlling the morphology of biogenic gold nanoparticles. After 1 h, there was a large population of well-dispersed, spherical gold nanoparticles with a mean size of 9.6 nm. Gold nanoplates with an edge length of 100 nm appeared after 6 h, and 60% of the total nanoparticle population was due to gold nanoplates with an edge length of 100-200 nm after 24 h. The yield of gold nanoplates prepared with S. algae extract was four times higher than that prepared with resting cells of S. algae. The resulting biogenic gold nanoparticle suspensions showed a large variation in color, ranging from pale pink to purple due to changes in nanoparticle morphology.

  8. Preparation, Physicochemical Characterization and Performance Evaluation of Gold Nanoparticles in Radiotherapy

    Directory of Open Access Journals (Sweden)

    Ali Kamiar

    2013-08-01

    Full Text Available Purpose: The aim of the present study was preparation, physicochemical characterization and performance evaluation of gold nanoparticles (GNPs in radiotherapy. Another objective was the investigation of anti-bacterial efficacy of gold nanoparticle against E. coli clinical strains. Methods: Gold nanoparticles prepared by controlled reduction of an aqueous HAuCl4 solution using Tri sodium citrate. Particle size analysis and Transmission electron microscopy were used for physicochemical characterization. Polymer gel dosimetry was used for evaluation of the enhancement of absorbed dose. Diffusion method in agar media was used for investigation of anti-bacterial effect. Results: Gold nanoparticles synthesized in size range from 57 nm to 346 nm by planning different formulation. Gold nanoparticle in 57 nm size increased radiation dose effectiveness with the magnitude of about 21 %. At the concentration of 400 ppm, Nano gold exhibited significant anti-bacterial effect against E. coli clinical strains. Conclusion: It is concluded that gold nanoparticles can be applied as dose enhancer in radiotherapy. The Investigation of anti-bacterial efficacy showed that gold nanoparticle had significant effect against E. coli clinical strains.

  9. Rapid colorimetric sensing of tetracycline antibiotics with in situ growth of gold nanoparticles

    International Nuclear Information System (INIS)

    Shen, Li; Chen, Jing; Li, Na; He, Pingli; Li, Zhen

    2014-01-01

    Highlights: • Tetracyclines directly reduce aurate into gold nanoparticles. • Gold nanoparticles showed characteristic plamson absorbance at 526 nm. • Quantitative detection of tetracyclines with the colorimetric assay. • Tetracyclines spiked urine samples can be detected with the assay. - Abstract: A colorimetric assay utilizing the formation of gold nanoparticles was developed to detect tetracycline antibiotics in fluidic samples. Tetracycline antibiotics showed the capability of directly reducing aurate salts into atomic gold which form gold nanoparticles spontaneously under proper conditions. The resulted gold nanoparticles showed characteristic plasmon absorbance at 526 nm, which can be visualized by naked eyes or with a spectrophotometer. UV–vis absorbance of the resulted gold nanoparticles is correlated directly with the concentrations of tetracycline antibiotics in the solution, allowing for quantitative colorimetric detection of tetracycline antibiotics. Reaction conditions, such as pH, temperature, reaction time, and ionic strength were optimized. Sensitivity of the colorimetric assay can be enhanced by the addition of gold nanoparticle seeds, a LOD as low as 20 ng mL −1 can be achieved with the help of seed particles. The colorimetric assay showed minimum interference from ethanol, methanol, urea, glucose, and other antibiotics such as sulfonamides, amino glycosides etc. Validity of the method was also evaluated on urine samples spiked with tetracycline antibiotics. The method provides a broad spectrum detection method for rapid and sensitive detection of reductive substances such as tetracycline antibiotics in liquid and biological samples

  10. In situ gold nanoparticles formation: contrast agent for dental optical coherence tomography

    Science.gov (United States)

    Braz, Ana K. S.; Araujo, Renato E. de; Ohulchanskyy, Tymish Y.; Shukla, Shoba; Bergey, Earl J.; Gomes, Anderson S. L.; Prasad, Paras N.

    2012-06-01

    In this work we demonstrate the potential use of gold nanoparticles as contrast agents for the optical coherence tomography (OCT) imaging technique in dentistry. Here, a new in situ photothermal reduction procedure was developed, producing spherical gold nanoparticles inside dentinal layers and tubules. Gold ions were dispersed in the primer of commercially available dental bonding systems. After the application and permeation in dentin by the modified adhesive systems, the dental bonding materials were photopolymerized concurrently with the formation of gold nanoparticles. The gold nanoparticles were visualized by scanning electron microscopy (SEM). The SEM images show the presence of gold nanospheres in the hybrid layer and dentinal tubules. The diameter of the gold nanoparticles was determined to be in the range of 40 to 120 nm. Optical coherence tomography images were obtained in two- and three-dimensions. The distribution of nanoparticles was analyzed and the extended depth of nanosphere production was determined. The results show that the OCT technique, using in situ formed gold nanoparticles as contrast enhancers, can be used to visualize dentin structures in a non-invasive and non-destructive way.

  11. Rapid extra-/intracellular biosynthesis of gold nanoparticles by the fungus Penicillium sp.

    Science.gov (United States)

    Du, Liangwei; Xian, Liang; Feng, Jia-Xun

    2011-03-01

    In this work, the fungus Penicillium was used for rapid extra-/intracellular biosynthesis of gold nanoparticles. AuCl4 - ions reacted with the cell filtrate of Penicillium sp. resulting in extracellular biosynthesis of gold nanoparticles within 1 min. Intracellular biosynthesis of gold nanoparticles was obtained by incubating AuCl4 - solution with fungal biomass for 8 h. The gold nanoparticles were characterized by means of visual observation, UV-Vis absorption spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The extracellular nanoparticles exhibited maximum absorbance at 545 nm in UV-Vis spectroscopy. The XRD spectrum showed Bragg reflections corresponding to the gold nanocrystals. TEM exhibited the formed spherical gold nanoparticles in the size range from 30 to 50 nm with an average size of 45 nm. SEM and TEM revealed that the intracellular gold nanoparticles were well dispersed on the cell wall and within the cell, and they are mostly spherical in shape with an average diameter of 50 nm. The presence of gold was confirmed by EDX analysis.

  12. Rapid colorimetric sensing of tetracycline antibiotics with in situ growth of gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Li [Logistics School, Beijing Wuzi University, Beijing 101149 (China); Chen, Jing; Li, Na [Logistics School, Beijing Wuzi University, Beijing 101149 (China); He, Pingli [State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing 100094 (China); Li, Zhen [State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193 (China)

    2014-08-11

    Highlights: • Tetracyclines directly reduce aurate into gold nanoparticles. • Gold nanoparticles showed characteristic plamson absorbance at 526 nm. • Quantitative detection of tetracyclines with the colorimetric assay. • Tetracyclines spiked urine samples can be detected with the assay. - Abstract: A colorimetric assay utilizing the formation of gold nanoparticles was developed to detect tetracycline antibiotics in fluidic samples. Tetracycline antibiotics showed the capability of directly reducing aurate salts into atomic gold which form gold nanoparticles spontaneously under proper conditions. The resulted gold nanoparticles showed characteristic plasmon absorbance at 526 nm, which can be visualized by naked eyes or with a spectrophotometer. UV–vis absorbance of the resulted gold nanoparticles is correlated directly with the concentrations of tetracycline antibiotics in the solution, allowing for quantitative colorimetric detection of tetracycline antibiotics. Reaction conditions, such as pH, temperature, reaction time, and ionic strength were optimized. Sensitivity of the colorimetric assay can be enhanced by the addition of gold nanoparticle seeds, a LOD as low as 20 ng mL{sup −1} can be achieved with the help of seed particles. The colorimetric assay showed minimum interference from ethanol, methanol, urea, glucose, and other antibiotics such as sulfonamides, amino glycosides etc. Validity of the method was also evaluated on urine samples spiked with tetracycline antibiotics. The method provides a broad spectrum detection method for rapid and sensitive detection of reductive substances such as tetracycline antibiotics in liquid and biological samples.

  13. Environmentally friendly synthesis of highly monodisperse biocompatible gold nanoparticles with urchin-like shape.

    Science.gov (United States)

    Lu, Lehui; Ai, Kelong; Ozaki, Yukihiro

    2008-02-05

    We report a facile and environmentally friendly strategy for high-yield synthesis of highly monodisperse gold nanoparticles with urchin-like shape. A simple protein, gelatin, was first used for the control over shape and orientation of the gold nanoparticles. These nanoparticles, ready to use for biological systems, are promising in the optical imaging-based disease diagnostics and therapy because of their tunable surface plasmon resonance (SPR) and excellent surface-enhanced Raman scattering (SERS) activity.

  14. Deposition of functionalized gold nanoparticles onto modified silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Riskin, A.; Dobbelaere, C. de; Elen, K.; Rul, H. van den; Mullens, J.; Hardy, A. [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Diepenbeek (Belgium); D' Haen, J. [Imecvzw Division IMOMEC, Diepenbeek (Belgium); Electrical and Physical Characterization, Institute for Materials Research, Hasselt University, Diepenbeek (Belgium); Bael, M.K. van [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Diepenbeek (Belgium); Imecvzw Division IMOMEC, Diepenbeek (Belgium)

    2010-04-15

    In this report, an existing phase transfer method for the synthesis of alkylamine- or alkanethiol-functionalized gold nanoparticles (NPs) is investigated. A parameter study shows that the concentration of the gold salt used is important for the stability of the resulting sol, but has little effect on the final average particle size or the size distribution. By adding dodecanethiol before the reduction, the formation of NPs was inhibited, providing evidence for the autocatalytic pathway for the formation of metallic NPs in wet chemical synthesis proposed in the literature. The resulting functionalized gold NPs are deposited onto Si-OH, octadecyltrichlorosilane (OTS) or 3-mercaptopropyltrimethoxysilane modified SiO{sub 2}/Si substrates. scanning electron microscope (SEM) is used to analyze the ordering behavior and surface coverage of the NPs and it is shown that the difference in affinity for the substrate has a profound effect on the deposition behavior. The functionalization of the substrates and of the NPs is confirmed by grazing angle attenuated total reflectance fourier transform infrared spectroscopy (GATR-FTIR). (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  15. Green synthesis of gold nanoparticles using Stevia rebaudiana leaf extracts: Characterization and their stability.

    Science.gov (United States)

    Sadeghi, Babak; Mohammadzadeh, M; Babakhani, B

    2015-07-01

    Various methods invented and developed for the synthesis of gold nanoparticles that increases daily consumed. According to this method, including potential environmental pollution problems and the complexity of the synthesis, in this study, the feasibility of using the leaves extract of Stevia rebaudiana (SR) for the reduction of gold ions to nanoparticles form have been studied. Stevia leaves were used to prepare the aqueous extract for this study. Gold nanoparticles were characterized with different techniques such as UV-vis spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Transmission electron microscopy experiments showed that these nanoparticles are spherical and uniformly distributed and its size is from 5 to 20 nm. FT-IR spectroscopy revealed that gold nanoparticles were functionalized with biomolecules that have primary amine group (NH2), carbonyl group, OH groups and other stabilizing functional groups. X-ray diffraction pattern showed high purity and face centered cubic structure of gold nanoparticles with size of 17 nm. The scanning electron microscopy (SEM) implies the right of forming gold nanoparticles. The results, confirm that gold nanoparticles have synthesized by the leaves extract of S. rebaudiana (SR). Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Green Chemistry Approach for the Synthesis of Gold Nanoparticles Using the Fungus Alternaria sp.

    Science.gov (United States)

    Dhanasekar, Naresh Niranjan; Rahul, Ganga Ravindran; Narayanan, Kannan Badri; Raman, Gurusamy; Sakthivel, Natarajan

    2015-07-01

    The synthesis of gold nanoparticles has gained tremendous attention owing to their immense applications in the field of biomedical sciences. Although several chemical procedures are used for the synthesis of nanoparticles, the release of toxic and hazardous by-products restricts their use in biomedical applications. In the present investigation, gold nanoparticles were synthesized biologically using the culture filtrate of the filamentous fungus Alternaria sp. The culture filtrate of the fungus was exposed to three different concentrations of chloroaurate ions. In all cases, the gold ions were reduced to Au(0), leading to the formation of stable gold nanoparticles of variable sizes and shapes. UV-Vis spectroscopy analysis confirmed the formation of nanoparticles by reduction of Au(3+) to Au(0). TEM analysis revealed the presence of spherical, rod, square, pentagonal, and hexagonal morphologies for 1 mM chloroaurate solution. However, quasi-spherical and spherical nanoparticles/heart-like morphologies with size range of about 7-13 and 15-18 nm were observed for lower molar concentrations of 0.3 and 0.5 mM gold chloride solution, respectively. The XRD spectrum revealed the face-centered cubic crystals of synthesized gold nanoparticles. FT-IR spectroscopy analysis confirmed the presence of aromatic primary amines, and the additional SPR bands at 290 and 230 nm further suggested that the presence of amino acids such as tryptophan/tyrosine or phenylalanine acts as the capping agent on the synthesized mycogenic gold nanoparticles.

  17. A new green chemistry method based on plant extracts to synthesize gold nanoparticles

    Science.gov (United States)

    Montes Castillo, Milka Odemariz

    Extraordinary chemical and physical properties exhibited by nanomaterials, as compared to their bulk counterparts, have made the area of nanotechnology a growing realm in the past three decades. It is the nanoscale size (from 1 to 100 nm) and the morphologies of nanomaterials that provide several properties and applications not possible for the same material in the bulk. Magnetic and optical properties, as well as surface reactivity are highly dependent on the size and morphology of the nanomaterial. Diverse nanomaterials are being widely used in molecular diagnostics as well as in medicine, electronic and optical devices. Among the most studied nanomaterials, gold nanoparticles are of special interest due to their multifunctional capabilities. For instance, spherical gold nanoparticles measuring 15-20 nm in diameter have been studied due to their insulin binding properties. Also, thiol functionalized gold nanoparticles between 5 and 30 nm are used in the detection of DNA. Thus, harnessing the shape and size of gold nanoparticles plays an important role in science and technology. The synthesis of gold nanoparticles via the reduction of gold salts, using citrate or other reducing agents, has been widely studied. In recent years, algae, fungi, bacteria, and living plants have been used to reduce trivalent gold (Au3+) to its zero oxidation state (Au 0) forming gold nanoparticles of different sizes and shapes. In addition, plant biomasses have also been studied for their gold-reducing power and nanoparticle formation. Although there is information about the synthesis of the gold nanoparticles by biologically based materials; to our knowledge, the study of the use of alfalfa extracts has not been reported. This innovation represents a significant improvement; that is an environmentally friendly method that does not use toxic chemicals. Also, the problem of extracting the formed gold nanoparticles from biomaterials is addressed in this research but still remains to be

  18. Production of gold nanoparticles by Streptomyces djakartensis isolate B-5

    Directory of Open Access Journals (Sweden)

    Sara Biglari

    2014-09-01

    Full Text Available  Objective(s: Biosynthesis of gold nanoparticles (NGPs is environmentally safer than chemical and physical procedures. This method requires no use of toxic solvents and synthesis of dangerous products and is environmentally safe. In this study, we report the biosynthesis of NGPs using Streptomyces djakartensis isolate B-5. Materials and Methods: NGPs were biosynthesized by reducing aqueous gold chloride solution via a Streptomyces isolate without the need for any additive for protecting nanoparticles from aggregation. We characterized the responsible Streptomycete; its genome DNA was isolated, purified and 16S rRNA was amplified by PCR. The amplified isolate was sequenced; using the BLAST search tool from NCBI, the microorganism was identified to species level. Results: Treating chloroauric acid solutions with this bacterium resulted in reduction of gold ions and formation of stable NGPs. TEM and SEM electro micrographs of NGPs indicated size range from 2- 25 nm with average of 9.09 nm produced intracellular by the bacterium. SEM electro micrographs revealed morphology of spores and mycelia. The amplified PCR fragment of 16S rRNA gene was cloned and sequenced from both sides; it consisted of 741 nucleotides. According to NCBI GenBank, the bacterium had 97.1% homology with Streptomyces djakartensis strain RT-49. The GenBank accession number for partial 16S rRNA gene was recorded as JX162550. Conclusion: Optimized application of such findings may create applications of Streptomycetes for use as bio-factories in eco-friendly production of NGPs to serve in demanding industries and related biomedical areas. Research in this area should also focus on the unlocking the full mechanism of NGPs biosynthesis by Streptomycetes.

  19. Gold nanoparticle formation in diamond-like carbon using two different methods: Gold ion implantation and co-deposition of gold and carbon

    International Nuclear Information System (INIS)

    Salvadori, M. C.; Teixeira, F. S.; Araújo, W. W. R.; Sgubin, L. G.; Cattani, M.; Spirin, R. E.; Brown, I. G.

    2012-01-01

    We describe work in which gold nanoparticles were formed in diamond-like carbon (DLC), thereby generating a Au-DLC nanocomposite. A high-quality, hydrogen-free DLC thin film was formed by filtered vacuum arc plasma deposition, into which gold nanoparticles were introduced using two different methods. The first method was gold ion implantation into the DLC film at a number of decreasing ion energies, distributing the gold over a controllable depth range within the DLC. The second method was co-deposition of gold and carbon, using two separate vacuum arc plasma guns with suitably interleaved repetitive pulsing. Transmission electron microscope images show that the size of the gold nanoparticles obtained by ion implantation is 3-5 nm. For the Au-DLC composite obtained by co-deposition, there were two different nanoparticle sizes, most about 2 nm with some 6-7 nm. Raman spectroscopy indicates that the implanted sample contains a smaller fraction of sp 3 bonding for the DLC, demonstrating that some sp 3 bonds are destroyed by the gold implantation.

  20. Gold nanoparticles and films produced by a laser ablation/gas deposition (LAGD) method

    International Nuclear Information System (INIS)

    Kawakami, Yuji; Seto, Takafumi; Yoshida, Toshinobu; Ozawa, Eiichi

    2002-01-01

    Gold nanoparticles have great potential for various nanoelectronic applications such as single electron transistors, an infrared absorption sensor and so on. It is very important to understand and control the size distribution of the particles for such a variety of applications. In this paper, we report the size distribution of gold nanoparticles and the relationship between the nanoparticle-films and the electrical property produced by a laser ablation method. Gold nanoparticle-films were prepared by a technique, which sprays nanoparticles on the substrate through a nozzle. We call it a gas deposition method. The nanoparticles were generated by the nanosecond pulsed Nd:YAG laser ablation of a gold substrate under a low-pressure inert gas atmosphere. The ambient pressure was changed to control the average size and their distribution. The particles produced in the generation chamber were transported by a helium carrier gas to the deposition chamber and deposited on a substrate to form the films composed of gold nanoparticles. The electrical resistivity of the generated gold nanoparticle-films on the glass substrates was measured using a four-probe method. The size distribution of the nanoparticles was examined using transmission electron microscopy (TEM) and a low-pressure differential mobility analyzer (LP-DMA). The relationship between the particle size and the electrical properties of each film made by the different synthesis conditions were analyzed. The electrical resistivity changed from the order of 10 -5 to 10 -1 Ω cm depending on the ambient pressure and the size distribution

  1. Coating of gold nanoparticles for medical application: UV-VIS

    Science.gov (United States)

    Martínez Espinosa, Juan Carlos; Ramírez, Nayem Amtanus Chequer; Funes Oliva, Luis Enrique; Córdova Fraga, Teodoro; Bernal Alvarado, Jesús; Reyes Pablo, Aldelmo; Núñez, Anita Rosa Elvira

    2014-11-01

    The use of nanostructured materials has gained strength in recent years in the biomedical area; new applications such as the detection of components in living cells have been used in pharmaceutical area, specifically to study the interaction of various antitumor drugs in living tissues, the detection of genes that are closely related to some type of cancer, as well as the detections of protein biomarkers for diseases also have been studied in various research laboratories around of the world. In this work, we characterize the variation of the absorbance of gold nanoparticles (GNPs) coated with different concentration of Bovine Serum Albumin (BSA) protein. We use GNPS of 60 nm of the trademark-TED PELLA, the BSA protein trademark of Sigma Aldrich and based on that proposed protocol by Chithrani et al., 2009 with purposes to obtain an alternative model to determine the optimal stability of the nanoparticles coated with the protein. The colloidal solutions were prepared with BSA at different concentrations (0.25, 0.5, 0.75 and 1% M/V), and were centrifuged at 15,000 rpm for 90 minutes (centrifuge Model Z383K) and a constant temperature of 25 °C. All the spectra sets were obtained within the range from 400 to 700 nm using an UV-VIS spectrophotometer (Thermo Scientific Model 51118650). The results showed a R2 of 0.99 for an exponential curve correlation between the concentration of BSA, and the absorbance measured. We found at higher concentrations of BSA, there is a decrease in the intensity of the absorption spectra in the plasmon resonance. This preliminary model obtained can be used in the stabilization of gold nanoparticles with different proteins of biomedical interest in future experiments and support for functionalization of GNPs with specific membrane markers.

  2. Surface plasmon enhancement in gold nanoparticles in the presence of an optical gain medium: an analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sathiyamoorthy, K; Sreekanth, K V; Sidharthan, R; Murukeshan, V M [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Xing Bengang, E-mail: mmurukeshan@ntu.edu.sg [Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 (Singapore)

    2011-10-26

    The localized surface plasmon (LSP) enhancement in a gold nanoparticle is demonstrated in this paper. The enhancement of LSP is influenced by both size and the dielectric gain medium surrounding the nanoparticles. The nanoparticle is found to induce plasmonic enhancement of varying degrees depending on its size, and it is inferred that a gold nanoparticle of size 60 nm exhibits the maximum LSP for 532 nm excitation. Singularity due to cancellation of SP loss by an infinite gain medium and LSP enhancement are studied using a pump-probe Rayleigh scattering experiment. Gold nanoparticles of average size 60 nm exhibit the lowest threshold power to observe Rayleigh scattering. Furthermore, compared with the bare nanoparticles, a 12.5 fold enhancement of LSP is observed when the nanoparticle of average size 60 nm is kept in the gain medium.

  3. Colorimetric As (V) detection based on S-layer functionalized gold nanoparticles.

    Science.gov (United States)

    Lakatos, Mathias; Matys, Sabine; Raff, Johannes; Pompe, Wolfgang

    2015-11-01

    Herein, we present simple and rapid colorimetric and UV/VIS spectroscopic methods for detecting anionic arsenic (V) complexes in aqueous media. The methods exploit the aggregation of S-layer-functionalized spherical gold nanoparticles of sizes between 20 and 50 nm in the presence of arsenic species. The gold nanoparticles were functionalized with oligomers of the S-layer protein of Lysinibacillus sphaericus JG-A12. The aggregation of the nanoparticles results in a color change from burgundy-red for widely dispersed nanoparticles to blue for aggregated nanoparticles. A detailed signal analysis was achieved by measuring the shift of the particle plasmon resonance signal with UV/VIS spectroscopy. To further improve signal sensitivity, the influence of larger nanoparticles was tested. In the case of 50 nm gold nanoparticles, a concentration of the anionic arsenic (V) complex lower than 24 ppb was detectable. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Gold nanoparticles delivery in mammalian live cells: a critical review

    Directory of Open Access Journals (Sweden)

    Raphaël Lévy

    2010-02-01

    Full Text Available Functional nanomaterials have recently attracted strong interest from the biology community, not only as potential drug delivery vehicles or diagnostic tools, but also as optical nanomaterials. This is illustrated by the explosion of publications in the field with more than 2,000 publications in the last 2 years (4,000 papers since 2000; from ISI Web of Knowledge, ‘nanoparticle and cell’ hit. Such a publication boom in this novel interdisciplinary field has resulted in papers of unequal standard, partly because it is challenging to assemble the required expertise in chemistry, physics, and biology in a single team. As an extreme example, several papers published in physical chemistry journals claim intracellular delivery of nanoparticles, but show pictures of cells that are, to the expert biologist, evidently dead (and therefore permeable. To attain proper cellular applications using nanomaterials, it is critical not only to achieve efficient delivery in healthy cells, but also to control the intracellular availability and the fate of the nanomaterial. This is still an open challenge that will only be met by innovative delivery methods combined with rigorous and quantitative characterization of the uptake and the fate of the nanoparticles. This review mainly focuses on gold nanoparticles and discusses the various approaches to nanoparticle delivery, including surface chemical modifications and several methods used to facilitate cellular uptake and endosomal escape. We will also review the main detection methods and how their optimum use can inform about intracellular localization, efficiency of delivery, and integrity of the surface capping. Raphaël Lévy is a BBSRC David Phillips Research Fellow at the University of Liverpool. He graduated in Physics at the University Louis Pasteur in Strasbourg (France. In 2002, after a Master in Soft Condensed Matter Physics, he obtained a PhD in Physics at the University Louis Pasteur. He then moved to

  5. Concentration Dependence of Gold Nanoparticles for Fluorescence Enhancement

    Science.gov (United States)

    Solomon, Joel; Wittmershaus, Bruce

    Noble metal nanoparticles possess a unique property known as surface plasmon resonance in which the conduction electrons oscillate due to incoming light, dramatically increasing their absorption and scattering of light. The oscillating electrons create a varying electric field that can affect nearby molecules. The fluorescence and photostability of fluorophores can be enhanced significantly when they are near plasmonic nanoparticles. This effect is called metal enhanced fluorescence (MEF). MEF from two fluorescence organic dyes, Lucifer Yellow CH and Riboflavin, was measured with different concentrations of 50-nm colloidal gold nanoparticles (Au-NP). The concentration range of Au-NP was varied from 2.5 to 250 pM. To maximize the interaction, the dyes were chosen so their emission spectra had considerable overlap with the absorption spectra of the Au-NP, which is common in MEF studies. If the dye molecules are too close to the surface of Au-NP, fluorescence quenching can occur instead of MEF. To try to observe this difference, silica-coated Au-NP were compared to citrate-based Au-NP; however, fluorescence quenching was observed with both Au-NP. This material is based upon work supported by the National Science Foundation under Grant Number NSF-ECCS-1306157.

  6. Rapid and ultrasensitive colorimetric detection of mercury(II) by chemically initiated aggregation of gold nanoparticles

    International Nuclear Information System (INIS)

    Chen, Yinji; Chen, Wei; Yao, Li; Deng, Yi; Pan, Daodong; Cao, Jinxuan; Ogabiela, Edward; Adeloju, Samuel B.

    2015-01-01

    The article describes a method for rapid and visual determination of Hg(II) ion using unmodified gold nanoparticles (Au-NPs). It involves the addition of Au-NPs to a solution containing Hg(II) ions which, however, does not induce a color change. Next, a solution of lysine is added which induces the aggregation of the Au-NPs and causes the color of the solution to change from wine-red to purple. The whole on-site detection process can be executed in less than 15 min. Other amines (ethylenediamine, arginine, and melamine) were also investigated with respect to their capability to induce aggregation. Notably, only amines containing more than one amino group were found to be effective, but a 0.4 μM and pH 8 solution of lysine was found to give the best results. The detection limits for Hg (II) are 8.4 pM (for instrumental read-out) and 10 pM (for visual read-out). To the best of our knowledge, this LOD is better than those reported for any other existing rapid screening methods. The assay is not interfered by the presence of other common metal ions even if present in 1000-fold excess over Hg(II) concentration. It was successfully applied to the determination of Hg(II) in spiked tap water samples. We perceive that this method provides an excellent tool for rapid and ultrasensitive on-site determination of Hg(II) ions at low cost, with relative ease and minimal operation. (author)

  7. Green synthesis of gold nanoparticles for trace level detection of a hazardous pollutant (nitrobenzene) causing Methemoglobinaemia

    Energy Technology Data Exchange (ETDEWEB)

    Emmanuel, R. [Post Graduate and Research Department of Chemistry, Thiagarajar College, Madurai 625009, Tamil Nadu (India); Karuppiah, Chelladurai [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 106, Taiwan, ROC (China); Chen, Shen-Ming, E-mail: smchen78@ms15.hinet.net [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 106, Taiwan, ROC (China); Palanisamy, Selvakumar [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 106, Taiwan, ROC (China); Padmavathy, S. [Department of Zoology and Microbiology, Thiagarajar College, Madurai 625009, Tamil Nadu (India); Prakash, P., E-mail: kmpprakash@gmail.com [Post Graduate and Research Department of Chemistry, Thiagarajar College, Madurai 625009, Tamil Nadu (India)

    2014-08-30

    Graphical abstract: Schematic representation for green synthesis of Au-NPs and its electroreduction of nitrobenzene. - Highlights: • A green synthesis of size controlled Au-NPs from plant extract. • Trace level detection of nitro benzene, a pollutant causing Methemoglobinaemia, at Au-NPs modified electrode. • Achievement of lower LOD and wider linear response. • The proposed sensor exhibits excellent practicality in various water samples. - Abstract: The present study involves a green synthesis of gold nanoparticles (Au-NPs) using Acacia nilotica twig bark extract at room temperature and trace level detection of one of the hazardous materials, viz. nitrobenzene (NB) that causes Methemoglobinaemia. The synthesis protocol demonstrates that the bioreduction of chloroauric acid leads to the formation of Au-NPs within 10 min, suggesting a higher reaction rate than any other chemical methods involved. The obtained Au-NPs have been characterized by UV–vis spectroscopy, X-ray diffraction, transmission electron microscopy, Energy-Dispersive X-ray Spectroscopy and Fourier Transform Infrared Spectroscopy. The electrochemical detection of NB has been investigated at the green synthesized Au-NPs modified glassy carbon electrode by using differential pulse voltammetry (DPV). The Au-NPs modified electrode exhibits excellent reduction ability toward NB compared to unmodified electrode. The developed NB sensor at Au-NPs modified electrode displays a wide linear response from 0.1 to 600 μM with high sensitivity of 1.01 μA μM{sup −1} cm{sup −2} and low limit of detection of 0.016 μM. The modified electrode shows exceptional selectivity in the presence of ions, phenolic and biologically coactive compounds. In addition, the Au-NPs modified electrode exhibits an outstanding recovery results toward NB in various real water samples.

  8. Green synthesis of gold nanoparticles for trace level detection of a hazardous pollutant (nitrobenzene) causing Methemoglobinaemia

    International Nuclear Information System (INIS)

    Emmanuel, R.; Karuppiah, Chelladurai; Chen, Shen-Ming; Palanisamy, Selvakumar; Padmavathy, S.; Prakash, P.

    2014-01-01

    Graphical abstract: Schematic representation for green synthesis of Au-NPs and its electroreduction of nitrobenzene. - Highlights: • A green synthesis of size controlled Au-NPs from plant extract. • Trace level detection of nitro benzene, a pollutant causing Methemoglobinaemia, at Au-NPs modified electrode. • Achievement of lower LOD and wider linear response. • The proposed sensor exhibits excellent practicality in various water samples. - Abstract: The present study involves a green synthesis of gold nanoparticles (Au-NPs) using Acacia nilotica twig bark extract at room temperature and trace level detection of one of the hazardous materials, viz. nitrobenzene (NB) that causes Methemoglobinaemia. The synthesis protocol demonstrates that the bioreduction of chloroauric acid leads to the formation of Au-NPs within 10 min, suggesting a higher reaction rate than any other chemical methods involved. The obtained Au-NPs have been characterized by UV–vis spectroscopy, X-ray diffraction, transmission electron microscopy, Energy-Dispersive X-ray Spectroscopy and Fourier Transform Infrared Spectroscopy. The electrochemical detection of NB has been investigated at the green synthesized Au-NPs modified glassy carbon electrode by using differential pulse voltammetry (DPV). The Au-NPs modified electrode exhibits excellent reduction ability toward NB compared to unmodified electrode. The developed NB sensor at Au-NPs modified electrode displays a wide linear response from 0.1 to 600 μM with high sensitivity of 1.01 μA μM −1 cm −2 and low limit of detection of 0.016 μM. The modified electrode shows exceptional selectivity in the presence of ions, phenolic and biologically coactive compounds. In addition, the Au-NPs modified electrode exhibits an outstanding recovery results toward NB in various real water samples

  9. Analytical detection and biological assay of antileukemic drug using gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Selvaraj, V. [Department of Chemical Engineering, Alagappa College of Technology, Anna University, Chennai 600025 (India)]. E-mail: rajselva_77@yahoo.co.in; Alagar, M. [Department of Chemical Engineering, Alagappa College of Technology, Anna University, Chennai 600025 (India)]. E-mail: mkalagar@yahoo.com; Hamerton, I. [Chemistry Division, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2006-11-12

    Gold nanoparticles are reported and evaluated as probes for the detection of anticancer drug 6-mercaptopurine (6-MP). The nature of binding between 6-MP and the gold nanoparticles via complexation is investigated using ultraviolet-visible spectrum, cyclic voltammetry, transmission electron microscopy, fluorescence and Fourier transform infrared (FT-IR) spectroscopy. The bound antileukemic drug is fluorescent and the quenching property of gold nanoparticles could be exploited for biological investigations. The 6-MP-colloidal gold complex is observed to have appreciable antibacterial and antifungal activity against Micrococcus luteus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Aspergillus fumigatus, and Aspergillus niger. The experimental studies suggest that gold nanoparticles have the potential to be used as effective carriers for anticancer drugs.

  10. PVA stabilized gold nanoparticles by use of unexplored albeit conventional reducing agent

    Energy Technology Data Exchange (ETDEWEB)

    Khanna, P K [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchwati, Off Pashan Road, Pune 411008 (India); Gokhale, R [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchwati, Off Pashan Road, Pune 411008 (India); Subbarao, V V.V.S. [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchwati, Off Pashan Road, Pune 411008 (India); Vishwanath, A Kasi [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchwati, Off Pashan Road, Pune 411008 (India); Das, B K [Nanomaterials Laboratory, Centre for Materials for Electronics Technology (C-MET), Panchwati, Off Pashan Road, Pune 411008 (India); Satyanarayana, C V.V. [National Chemical Laboratory, Pashan Road, Pune 41108 (India)

    2005-07-15

    Poly(vinyl alcohol) (PVA) stabilized gold nanoparticles have been prepared in aqueous medium using two different reducing viz.; hydrazine hydrate, a stronger reducing agent and sodium formaldehydesulfoxylate (SFS), a slightly weaker reducing agent. SFS is used for first ever time for reduction of gold metal salt. The PVA stabilized gold nanoparticles solutions are wine red to blood red coloured and are stable over a long period of time with no indication of aggregation. The solution shows strong visible light absorptions in the range of 520-540 nm, characteristics of gold nanoparticles. Powder X-ray diffraction patterns of freshly prepared films containing gold nanoparticles indicated particles size to be about 15 nm. Transmission electron microscopy (TEM) of a more than two-week-old sample revealed well-defined non-agglomerated spherical particles of about 50 nm diameter in solutions.

  11. Optimization of components in high-yield synthesis of block copolymer-mediated gold nanoparticles

    International Nuclear Information System (INIS)

    Ray, Debes; Aswal, Vinod Kumar

    2012-01-01

    The optimization to achieve stable and high-yield gold nanoparticles in block copolymer-mediated synthesis has been examined. Gold nanoparticles are synthesized using block copolymer P85 in gold salt HAuCl 4 ·3H 2 O solution. This method usually has a very limited yield which does not simply increase with the increase in the gold salt concentration. We show that the yield can be enhanced by increasing the block copolymer concentration but is limited to the factor by which the concentration is increased. On the other hand, the presence of an additional reductant (trisodium citrate) in 1:1 molar ratio with gold salt enhances the yield by manyfold. In this case (with additional reductant), the stable and high-yield nanoparticles having size about 14 nm can be synthesized at very low block copolymer concentrations. These nanoparticles thus can be efficiently used for their application such as for adsorption of proteins.

  12. Gold nanoparticle arrays directly grown on nanostructured indium tin oxide electrodes: Characterization and electroanalytical application

    International Nuclear Information System (INIS)

    Zhang Jingdong; Oyama, Munetaka

    2005-01-01

    This work describes an improved seed-mediated growth approach for the direct attachment and growth of mono-dispersed gold nanoparticles on nanostructured indium tin oxide (ITO) surfaces. It was demonstrated that, when the seeding procedure of our previously reported seed-mediated growth process on an ITO surface was modified, the density of gold nanospheres directly grown on the surface could be highly improved, while the emergence of nanorods was restrained. By field emission scanning electron microscopy (FE-SEM) and cyclic voltammetry, the growth of gold nanoparticles with increasing growth time on the defect sites of nanostructured ITO surface was monitored. Using a [Fe(China) 6 ] 3- /[Fe(China) 6 ] 4- redox probe, the increasingly facile heterogeneous electron transfer kinetics resulting from the deposition and growth of gold nanoparticle arrays was observed. The as-prepared gold nanoparticle arrays exhibited high catalytic activity toward the electrooxidation of nitric oxide, which could provide electroanalytical application for nitric oxide sensing

  13. PVA stabilized gold nanoparticles by use of unexplored albeit conventional reducing agent

    International Nuclear Information System (INIS)

    Khanna, P.K.; Gokhale, R.; Subbarao, V.V.V.S.; Vishwanath, A. Kasi; Das, B.K.; Satyanarayana, C.V.V.

    2005-01-01

    Poly(vinyl alcohol) (PVA) stabilized gold nanoparticles have been prepared in aqueous medium using two different reducing viz.; hydrazine hydrate, a stronger reducing agent and sodium formaldehydesulfoxylate (SFS), a slightly weaker reducing agent. SFS is used for first ever time for reduction of gold metal salt. The PVA stabilized gold nanoparticles solutions are wine red to blood red coloured and are stable over a long period of time with no indication of aggregation. The solution shows strong visible light absorptions in the range of 520-540 nm, characteristics of gold nanoparticles. Powder X-ray diffraction patterns of freshly prepared films containing gold nanoparticles indicated particles size to be about 15 nm. Transmission electron microscopy (TEM) of a more than two-week-old sample revealed well-defined non-agglomerated spherical particles of about 50 nm diameter in solutions

  14. Eggshell membrane-templated porous gold membranes using nanoparticles as building blocks

    International Nuclear Information System (INIS)

    Ashraf, S.; Khalid, Z. M.; Hussain, I.

    2013-01-01

    Highly porous gold membrane-like structures are formed using eggshell membrane, as such and heat denatured, as a template and gold nanoparticles as building blocks. Gold nanoparticles were produced in-situ on the eggshell membranes without using additional reducing agents. The morphology and loading of gold nanoparticles can easily be controlled by adjusting the pH and thus the redox potential of eggshell membranes. Lower pH favored the formation of irregularly-shaped but dense gold macro/ nanocrystals whereas higher pH(8-9) favored the formation of fairly uniform but less dense gold nanoparticles onto the eggshell membranes. Heat treatment of eggshell membrane-gold nanoparticle composites formed at pH 8-9 led to the formation of highly porous membrane like gold while mimicking the original structure of eggshell membrane. All these materials have been thoroughly characterized using field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), and inductively coupled plasma - atomic emission spectroscopy (ISP-AES). These highly porous membrane-like gold materials may have potential applications in catalysis, biosensors, electrode materials, optically selective coatings, heat dissipation and biofiltration. (author)

  15. A low cost microwave synthesis method for preparation of gold nanoparticles

    International Nuclear Information System (INIS)

    Ngo Vo Ke Thanh; Lam Quang Vinh; Nguyen Dang Giang; Huynh Thanh Dat

    2014-01-01

    The gold nanoparticles (GNPs) in 15-20 nm size range have attention for fabrication of smart sensing devices in biomedical sciences as diagnostic tools. Citrate capped GNPs are negatively charged, which can be exploited for electrostatic interactions with some positively charged biomolecules like antibody. In this study, we are developing a low-cost technique by using a common microwave system with medium power for synthesizing gold nanoparticles with using sodium citrate (Na 3 Ct) reduction in chloroauric acid (HAuCl 4 .3H 2 O). It was found that the comparing with normal thermal method, the reaction by the microwave irradiation was much faster. Besides, the effects the sodium citrate concentration and optical properties of gold nanoparticles were studied. The optical properties of gold nanoparticles suspension were characterized by using transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-Vis absorption spectroscopy (UV-Vis). Maximum absorbance wavelengths (λ max ) for gold nanoparticles are ∼ 518-524 nm with the size of 12-25 nm. The size of gold nanoparticles decreases with increasing concentration of sodium citrate. Besides, the morphology of gold nanoparticles have a spherical shape with face-centered-cubic (fcc) crystalline structure. (author)

  16. Study on the interaction between gold nanoparticles and papain by spectroscopic methods

    International Nuclear Information System (INIS)

    Wang, Gongke; Chen, Ye; Yan, Changling; Lu, Yan

    2015-01-01

    The interaction between gold nanoparticles and papain was studied by fluorescence, UV–vis absorption and synchronous fluorescence spectroscopic techniques under the physiological conditions. The results showed that the binding of gold nanoparticles to papain was a spontaneous binding process. The fluorescence of papain was strongly quenched by gold nanoparticles. The quenching mechanism was probably a static quenching type with the formation of a ground state complex. The Stern–Volmer quenching constants, the binding constants and the number of binding sites in different temperatures were calculated. The corresponding thermodynamic parameters ΔH,ΔS and ΔG indicated that hydrogen bonding and Van der Waals forces played a key role in the interaction process. Additionally, the conformational change of papain induced by gold nanoparticles was analyzed by UV–vis absorption and synchronous fluorescence spectra. - Highlights: • Spherical and monodispersed gold nanoparticles are synthesized. • The fluorescence of papain is quenched by gold nanoparticles under physiological conditions. • Hydrogen bonding and Van der Waals forces may play an essential role in the binding of gold nanoparticles with papain. • This binding interaction is predominantly enthalpy driven

  17. Anthelmintic efficacy of gold nanoparticles derived from a phytopathogenic fungus, Nigrospora oryzae.

    Directory of Open Access Journals (Sweden)

    Pradip Kumar Kar

    Full Text Available Exploring a green chemistry approach, this study brings to the fore, the anthelmintic efficacy of gold nanoparticles, highlighting the plausible usage of myconanotechnology. Gold nanoparticles of ∼6 to ∼18 nm diameter were synthesized by treating the mycelia-free culture filtrate of the phytopathogenic fungus with gold chloride. Their size and morphology were confirmed by UV-Vis spectroscopy, DLS data, AFM and TEM images. The XRD studies reveal a crystalline nature of the nanoparticles, which are in cubic phase. The FTIR spectroscopic studies before and after the formation of nanoparticles show the presence of possible functional groups responsible for the bio-reduction and capping of the synthesized gold nanoparticles. The latter were tested as vermifugal agents against a model cestode Raillietina sp., an intestinal parasite of domestic fowl. Further, ultrastructural and biochemical parameters were used to corroborate the efficacy study.

  18. Gold and silver nanoparticles conjugated with heparin derivative possess anti-angiogenesis properties

    Science.gov (United States)

    Kemp, Melissa M.; Kumar, Ashavani; Mousa, Shaymaa; Dyskin, Evgeny; Yalcin, Murat; Ajayan, Pulickel; Linhardt, Robert J.; Mousa, Shaker A.

    2009-11-01

    Silver and gold nanoparticles display unique physical and biological properties that have been extensively studied for biological and medical applications. Typically, gold and silver nanoparticles are prepared by chemical reductants that utilize excess toxic reactants, which need to be removed for biological purposes. We utilized a clean method involving a single synthetic step to prepare metal nanoparticles for evaluating potential effects on angiogenesis modulation. These nanoparticles were prepared by reducing silver nitrate and gold chloride with diaminopyridinyl (DAP)-derivatized heparin (HP) polysaccharides. Both gold and silver nanoparticles reduced with DAPHP exhibited effective inhibition of basic fibroblast growth factor (FGF-2)-induced angiogenesis, with an enhanced anti-angiogenesis efficacy with the conjugation to DAPHP (Pcancer and inflammatory diseases.

  19. Facile synthesis of biocompatible gold nanoparticles with organosilicone-coated surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Xia Lijin; Yi Sijia; Lenaghan, Scott C.; Zhang Mingjun, E-mail: mjzhang@utk.edu [University of Tennessee, Department of Mechanical, Aerospace and Biomedical Engineering (United States)

    2012-07-15

    In this study, a simple method for one-step synthesis of gold nanoparticles has been developed using an organosilicone surfactant, Silwet L-77, as both a reducing and capping agent. Synthesis of gold nanoparticles using this method is rapid and can be conducted conveniently at ambient temperature. Further refinement of the method, through the addition of sodium hydroxide and/or silver nitrate, allowed fine control over the size of spherical nanoparticles produced. Coated on the surface with organosilicone, the as-prepared gold nanoparticles were biocompatible and stable over the pH range from 5 to 12, and have been proven effective at transportation into MC3T3 osteoblast cells. The proposed method is simple, fast, and can produce size-controlled gold nanoparticles with unique surface properties for biomedical applications.

  20. Facile synthesis of biocompatible gold nanoparticles with organosilicone-coated surface properties

    International Nuclear Information System (INIS)

    Xia Lijin; Yi Sijia; Lenaghan, Scott C.; Zhang Mingjun

    2012-01-01

    In this study, a simple method for one-step synthesis of gold nanoparticles has been developed using an organosilicone surfactant, Silwet L-77, as both a reducing and capping agent. Synthesis of gold nanoparticles using this method is rapid and can be conducted conveniently at ambient temperature. Further refinement of the method, through the addition of sodium hydroxide and/or silver nitrate, allowed fine control over the size of spherical nanoparticles produced. Coated on the surface with organosilicone, the as-prepared gold nanoparticles were biocompatible and stable over the pH range from 5 to 12, and have been proven effective at transportation into MC3T3 osteoblast cells. The proposed method is simple, fast, and can produce size-controlled gold nanoparticles with unique surface properties for biomedical applications.

  1. Facile synthesis of biocompatible gold nanoparticles with organosilicone-coated surface properties

    Science.gov (United States)

    Xia, Lijin; Yi, Sijia; Lenaghan, Scott C.; Zhang, Mingjun

    2012-07-01

    In this study, a simple method for one-step synthesis of gold nanoparticles has been developed using an organosilicone surfactant, Silwet L-77, as both a reducing and capping agent. Synthesis of gold nanoparticles using this method is rapid and can be conducted conveniently at ambient temperature. Further refinement of the method, through the addition of sodium hydroxide and/or silver nitrate, allowed fine control over the size of spherical nanoparticles produced. Coated on the surface with organosilicone, the as-prepared gold nanoparticles were biocompatible and stable over the pH range from 5 to 12, and have been proven effective at transportation into MC3T3 osteoblast cells. The proposed method is simple, fast, and can produce size-controlled gold nanoparticles with unique surface properties for biomedical applications.

  2. Seed Mediated Growth of Gold Nanoparticles Based on Liquid Arc Discharge

    International Nuclear Information System (INIS)

    Ashkarran, Ali Akbar

    2013-01-01

    We report studies on the growth of gold nanoparticles by a seed-mediated approach in solution. The synthetic method is adapted from one we published earlier (Ashkarran et al. Appl. Phys. A 2009, 96, 423). The synthesized gold nanoparticles were characterized by X-ray diffraction (XRD), dynamic light scattering (DLS), UV-Vis spectroscopy, optical imaging and atomic force microscopy (AFM). Optical absorption spectroscopy of the prepared samples at 15 A arc current in HAuCl 4 solution shows a surface plasmon resonance around 520 nm. It is found that sodium citrate acts as a stabilizer and surface capping agent of the colloidal nanoparticles. The intensity of the plasmonic peak of the prepared gold nanoparticles for 1 minute arc duration gradually increases due to seed mediation for up to 6 hours. The formation time of gold nanoparticles at higher seed concentrations is less than that at lower seed concentrations. (plasma technology)

  3. Durable PROX catalyst based on gold nanoparticles and hydrophobic silica

    KAUST Repository

    Laveille, Paco; Guillois, Kevin; Tuel, Alain; Petit, Corine; Basset, Jean-Marie; Caps, Valerie

    2016-01-01

    3 nm gold nanoparticles (Au NP) obtained by direct chemical reduction of AuPPh3Cl in the presence of methyl-terminated silica exhibit superior durability for low temperature CO oxidation in the presence of hydrogen (PROX). The activity of hydrophobic Au/SiO2-R972 indeed appears much more stable with time-on-stream than those of the OH-terminated, hydrophilic Au/TiO2 and Au/Al2O3 catalysts, with similar Au NP size. This enhanced stability is attributed to the peculiar catalyst surface of Au/SiO2-R972. Not only may the support hydrophobicity concentrate and facilitate reactant adsorption and product desorption over Au NP, but methyl-terminated SiO2-R972 likely also inhibits carbonatation of the Au/support interface. Hence, at a temperature at which H2/H2O “cleaning” of the carbonate-contaminated Au/Al2O3 and Au/TiO2 surface is inefficient (< 100°C), passivated Au/SiO2-R972 displays much more stable PROX activity. Besides, the virtual absence of surface hydroxyl groups, which provide sites for water formation in H2/O2 atmospheres, can also account for the improved PROX selectivity (>85%) observed over Au/SiO2-R972. This new example, of CO oxidation activity of gold nanoparticles dispersed over a hydrophobic, “inert” support, clearly emphasizes the role of hydrogen as a promoter for the gold-catalyzed oxidation of CO at low temperature. Unlike support-mediated oxygen activation, hydrogen-only mediated oxygen activation takes full advantage of the hydrophobic surface, which is much more resistant against CO2 and thus remains free of poisonous carbonate species, as compared with hydroxyl-terminated catalysts. Hence, although the absence of surface hydroxyl groups prevents the hydrophobic Au/SiO2-R972 catalyst to reach the state-of-the-art activities initially displayed by Au/TiO2 and Au/Al2O3, it brings long-term stability with time-on-stream and superior selectivity, which opens up promising perspectives in the development of viable PROX catalysts based on gold.

  4. Durable PROX catalyst based on gold nanoparticles and hydrophobic silica

    KAUST Repository

    Laveille, Paco

    2016-01-20

    3 nm gold nanoparticles (Au NP) obtained by direct chemical reduction of AuPPh3Cl in the presence of methyl-terminated silica exhibit superior durability for low temperature CO oxidation in the presence of hydrogen (PROX). The activity of hydrophobic Au/SiO2-R972 indeed appears much more stable with time-on-stream than those of the OH-terminated, hydrophilic Au/TiO2 and Au/Al2O3 catalysts, with similar Au NP size. This enhanced stability is attributed to the peculiar catalyst surface of Au/SiO2-R972. Not only may the support hydrophobicity concentrate and facilitate reactant adsorption and product desorption over Au NP, but methyl-terminated SiO2-R972 likely also inhibits carbonatation of the Au/support interface. Hence, at a temperature at which H2/H2O “cleaning” of the carbonate-contaminated Au/Al2O3 and Au/TiO2 surface is inefficient (< 100°C), passivated Au/SiO2-R972 displays much more stable PROX activity. Besides, the virtual absence of surface hydroxyl groups, which provide sites for water formation in H2/O2 atmospheres, can also account for the improved PROX selectivity (>85%) observed over Au/SiO2-R972. This new example, of CO oxidation activity of gold nanoparticles dispersed over a hydrophobic, “inert” support, clearly emphasizes the role of hydrogen as a promoter for the gold-catalyzed oxidation of CO at low temperature. Unlike support-mediated oxygen activation, hydrogen-only mediated oxygen activation takes full advantage of the hydrophobic surface, which is much more resistant against CO2 and thus remains free of poisonous carbonate species, as compared with hydroxyl-terminated catalysts. Hence, although the absence of surface hydroxyl groups prevents the hydrophobic Au/SiO2-R972 catalyst to reach the state-of-the-art activities initially displayed by Au/TiO2 and Au/Al2O3, it brings long-term stability with time-on-stream and superior selectivity, which opens up promising perspectives in the development of viable PROX catalysts based on gold.

  5. Extracellular biosynthesis of monodispersed gold nanoparticles by a SAM capping route

    Energy Technology Data Exchange (ETDEWEB)

    Wen Li [Xiamen University, Department of Chemistry, College of Chemistry and Chemical Engineering (China); Lin Zhonghua [Xiamen University, State Key Laboratory of Physical Chemistry of Solid Surfaces (China); Gu Pingying [Xiamen University, Department of Chemistry, College of Chemistry and Chemical Engineering (China); Zhou Jianzhang [Xiamen University, State Key Laboratory of Physical Chemistry of Solid Surfaces (China); Yao Bingxing [Xiamen University, School of Life Sciences (China); Chen Guoliang; Fu Jinkun, E-mail: wenli_1976@163.co [Xiamen University, Department of Chemistry, College of Chemistry and Chemical Engineering (China)

    2009-02-15

    Monodispersed gold nanoparticles capped with a self-assembled monolayer of dodecanethiol were biosynthesized extracellularly by an efficient, simple, and environmental friendly procedure, which involved the use of Bacillus megatherium D01 as the reducing agent and the use of dodecanethiol as the capping ligand at 26 {sup o}C. The kinetics of gold nanoparticle formation was followed by transmission electron microscope (TEM) and UV-vis spectroscopy. It was shown that reaction time was an important parameter in controlling the morphology of gold nanoparticles. The effect of thiol on the shape, size, and dispersity of gold nanoparticles was also studied. The results showed that the presence of thiol during the biosynthesis could induce the formation of small size gold nanoparticles (<2.5 nm), hold the shape of spherical nanoparticles, and promote the monodispersity of nanoparticles. Through the modulation of reaction time and the use of thiol, monodispersed spherical gold nanoparticles capped with thiol of 1.9 {+-} 0.8 nm size were formed by using Bacillus megatherium D01.

  6. Acute toxicity and pharmacokinetics of 13 nm-sized PEG-coated gold nanoparticles

    International Nuclear Information System (INIS)

    Cho, Wan-Seob; Cho, Minjung; Jeong, Jinyoung; Choi, Mina; Cho, Hea-Young; Han, Beom Seok; Kim, Sheen Hee; Kim, Hyoung Ook; Lim, Yong Taik; Chung, Bong Hyun; Jeong, Jayoung

    2009-01-01

    In general, gold nanoparticles are recognized as being as nontoxic. Still, there have been some reports on their toxicity, which has been shown to depend on the physical dimension, surface chemistry, and shape of the nanoparticles. In this study, we carry out an in vivo toxicity study using 13 nm-sized gold nanoparticles coated with PEG (MW 5000). In our findings the 13 nm sized PEG-coated gold nanoparticles were seen to induce acute inflammation and apoptosis in the liver. These nanoparticles were found to accumulate in the liver and spleen for up to 7 days after injection and to have long blood circulation times. In addition, transmission electron microscopy showed that numerous cytoplasmic vesicles and lysosomes of liver Kupffer cells and spleen macrophages contained the PEG-coated gold nanoparticles. These findings of toxicity and kinetics of PEG-coated gold nanoparticles may have important clinical implications regarding the safety issue as PEG-coated gold nanoparticles are widely used in biomedical applications

  7. Extracellular biosynthesis of monodispersed gold nanoparticles by a SAM capping route

    International Nuclear Information System (INIS)

    Wen Li; Lin Zhonghua; Gu Pingying; Zhou Jianzhang; Yao Bingxing; Chen Guoliang; Fu Jinkun

    2009-01-01

    Monodispersed gold nanoparticles capped with a self-assembled monolayer of dodecanethiol were biosynthesized extracellularly by an efficient, simple, and environmental friendly procedure, which involved the use of Bacillus megatherium D01 as the reducing agent and the use of dodecanethiol as the capping ligand at 26 o C. The kinetics of gold nanoparticle formation was followed by transmission electron microscope (TEM) and UV-vis spectroscopy. It was shown that reaction time was an important parameter in controlling the morphology of gold nanoparticles. The effect of thiol on the shape, size, and dispersity of gold nanoparticles was also studied. The results showed that the presence of thiol during the biosynthesis could induce the formation of small size gold nanoparticles (<2.5 nm), hold the shape of spherical nanoparticles, and promote the monodispersity of nanoparticles. Through the modulation of reaction time and the use of thiol, monodispersed spherical gold nanoparticles capped with thiol of 1.9 ± 0.8 nm size were formed by using Bacillus megatherium D01.

  8. Biofabrication of gold and silver nanoparticles for pharmaceutical applications

    Directory of Open Access Journals (Sweden)

    Hamed Barabadi

    2016-02-01

    Full Text Available Biofabrication by using fungi is an exciting recent interest to develop an eco-friendly production of metallic nanoparticles (NPs for pharmaceutical applications. This study aimed to synthesize and characterize gold (Au and silver (Ag NPs by using Penicillium simplisimum. The fungus was grown in fluid czapek dox broth on shaker at 28 ºC and 200 rpm for ten days. Then the supernatant was separated from the mycelia to convert HAuCl4 and AgNO3 solution into Au and Ag NPs separately. After 24 hours, synthesized Au and Ag NPs were characterized by using UV-Visible Spectroscopy as well as Photon Correlation spectroscopy (PCS involves Polydispersity Index (PDI and zeta potential. The UV-Visible Spectroscopy analysis revealed a plasmon bond peak around 533 nm and 400 nm suggesting formation of Au and Ag NPs, respectively. Furthermore, the PCS analysis showed an average diameter of 68 nm and 76 nm with PDI value of 0.2 and 0.23 for Au and Ag NPs, successively, which demonstrated that the nanoparticles formed with fairly well-defined dimensions and good monodispersity. Besides, a negative zeta potential were found for nanoparticles indicating their stability in the solution. The current approach suggests that the rapid synthesis of nanoparticles would be suitable for developing a green process for mass scale production. Besides, we believe that development of eco-friendly process for the formulation of metallic NPs is an important step in the field of application of nanotechnology and its optimization may make it a potential procedure for industrial production of NPs.

  9. Gold core@silver semishell Janus nanoparticles prepared by interfacial etching

    Science.gov (United States)

    Chen, Limei; Deming, Christopher P.; Peng, Yi; Hu, Peiguang; Stofan, Jake; Chen, Shaowei

    2016-07-01

    Gold core@silver semishell Janus nanoparticles were prepared by chemical etching of Au@Ag core-shell nanoparticles at the air/water interface. Au@Ag core-shell nanoparticles were synthesized by chemical deposition of a silver shell onto gold seed colloids followed by the self-assembly of 1-dodecanethiol onto the nanoparticle surface. The nanoparticles then formed a monolayer on the water surface of a Langmuir-Blodgett trough, and part of the silver shell was selectively etched away by the mixture of hydrogen peroxide and ammonia in the water subphase, where the etching was limited to the side of the nanoparticles that was in direct contact with water. The resulting Janus nanoparticles exhibited an asymmetrical distribution of silver on the surface of the gold cores, as manifested in transmission electron microscopy, UV-vis absorption, and X-ray photoelectron spectroscopy measurements. Interestingly, the Au@Ag semishell Janus nanoparticles exhibited enhanced electrocatalytic activity in oxygen reduction reactions, as compared to their Au@Ag and Ag@Au core-shell counterparts, likely due to a synergistic effect between the gold cores and silver semishells that optimized oxygen binding to the nanoparticle surface.Gold core@silver semishell Janus nanoparticles were prepared by chemical etching of Au@Ag core-shell nanoparticles at the air/water interface. Au@Ag core-shell nanoparticles were synthesized by chemical deposition of a silver shell onto gold seed colloids followed by the self-assembly of 1-dodecanethiol onto the nanoparticle surface. The nanoparticles then formed a monolayer on the water surface of a Langmuir-Blodgett trough, and part of the silver shell was selectively etched away by the mixture of hydrogen peroxide and ammonia in the water subphase, where the etching was limited to the side of the nanoparticles that was in direct contact with water. The resulting Janus nanoparticles exhibited an asymmetrical distribution of silver on the surface of the gold

  10. Feasibility of MR imaging in evaluating breast cancer lymphangiogenesis using Polyethylene glycol-GoldMag nanoparticles

    International Nuclear Information System (INIS)

    Yang, H.; Zou, L.G.; Zhang, S.; Gong, M.F.; Zhang, D.; Qi, Y.Y.; Zhou, S.W.; Diao, X.W.

    2013-01-01

    Aim: To investigate the feasibility of evaluating tumour lymphangiogenesis using magnetic resonance imaging (MRI) in vivo. Materials and methods: Water-soluble polyethylene glycol (PEG)-GoldMag nanoparticles were obtained by combining GoldMag with PEG. The PEG-GoldMag nanoparticles were bound to anti-podoplanin antibody (PodAb) to construct PEG-GoldMag-pod molecular probes targeting lymphatic endothelial cells (LECs). The characteristics of the PEG-GoldMag-pod nanoparticles were tested. Using these nanoparticles, tumour lymphangiogenesis was evaluated using MRI in vitro and in vivo. Results: The average size of PEG-GoldMag nanoparticles was about 66.8 nm, and the nanoparticles were stably dispersed in the liquid phase for at least 15 days. After incubation for 24 h at different iron concentrations ranging from 5–45 μg/ml, the LECs were labelled with PEG-GoldMag-pod nanoparticles, in particular the breast cancer LECs. Dose-dependence was observed in the labelling efficiencies and MRI images of the labelled cells. In vitro, the labelling efficiencies and MRI images showed that the nanoparticles could detect podoplanin expression in LECs. In induced rat models of breast cancer, PEG-GoldMag-pod nanoparticles combined with lymphatic vessels were significantly detectable at MRI 60 min after nanoparticle administration, the signal intensity was negatively correlated with the lymphatic vessel density of breast cancer (r = −0.864, P = 0.000). Conclusions: The present study proves the feasibility of evaluating tumour lymphangiogenesis with MRI in vivo

  11. Deposition of gold nanoparticles from colloid on TiO2 surface

    Science.gov (United States)

    Rehacek, Vlastimil; Hotovy, Ivan

    2017-11-01

    In this paper, experimental results are presented on the deposition of colloidal gold nanoparticles on the surfaces of TiO2 prepared on silicon/silicon dioxide. Important procedures, such as titanium dioxide surface hydrophilization as well as functionalization by an organosilane coupling agent (3-aminopropyl) trimethoxysilane and (3-mercaptopropyl) trimethoxysilane were investigated in order to obtain a metal oxide surface with the most convenient properties for immobilization of gold nanoparticles having a dense and uniform distribution. TiO2 nanotips prepared by reactive ion etching of oxide surface covered with self-mask gold nanoparticles are demonstrated.

  12. Preparation of gold nanoparticles by γ-ray irradiation method using polyvinyl pyrrolidone (PVP) as stabilizer

    International Nuclear Information System (INIS)

    Nguyen Tan Man; Le Hai; Le Huu Tu; Tran Thu Hong; Tran Thi Tam; Pham Thi Le Ha; Pham Thi Sam

    2011-01-01

    Gold nanoparticles were prepared from (Au 3+ ) aqueous solution by the method of γ-ray irradiation using polyvinylpyrrolidone (PVP) as stabilizer. The saturated conversion dose (Au 3+ --> Au o ) determined by UV-Vis spectroscopy was found to be about 5 kGy. The UV-Vis spectrum showed that an absorption peak at λ max =524 nm due to surface plasmon resonance. The image of transmission electron microscopy (TEM) showed that the gold nanoparticles are mostly spherical in shape and have an average diameter of ≅20 nm. The prepared colloidal gold nanoparticles solution is good stability for 6 months of storage. (author)

  13. Gold-coated iron nanoparticles in transparent Si3N4 matrix thin films

    Science.gov (United States)

    Sánchez-Marcos, J.; Céspedes, E.; Jiménez-Villacorta, F.; Muñoz-Martín, A.; Prieto, C.

    2013-06-01

    A new method to prepare thin films containing gold-coated iron nanoparticles is presented. The ternary Fe-Au-Si3N4 system prepared by sequential sputtering has revealed a progressive variation of microstructures from Au/Fe/Au/Si3N4 multilayers to iron nanoparticles. Microstructural characterization by transmission electron microscopy, analysis of the magnetic properties and probing of the iron short-range order by X-ray absorption spectroscopy confirm the existence of a gold-coated iron nanoparticles of 1-2 nm typical size for a specific range of iron and gold contents per layer in the transparent silicon nitride ceramic matrix.

  14. Electrochemical extraction of gold from wastes as nanoparticles stabilized by phospholipids.

    Science.gov (United States)

    Moriwaki, Hiroshi; Yamada, Kotaro; Usami, Hisanao

    2017-02-01

    A simple one-step method for the extraction of gold from wastes as nanoparticles stabilized by phospholipids is demonstrated. This is achieved by applying an AC voltage for 5s to the gold-containing wastes, which act as the electrodes in a buffer solution containing a dispersed phospholipid (1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC). This is an environmentally friendly and rapid method for recovering gold from wastes. The extracted gold nanoparticles have significant potential as a catalyst or biomedical material. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Polyelectrolyte-modified cowpea mosaic virus for the synthesis of gold nanoparticles.

    Science.gov (United States)

    Aljabali, Alaa A A; Evans, David J

    2014-01-01

    Polyelectrolyte surface-modified cowpea mosaic virus (CPMV) can be used for the templated synthesis of narrowly dispersed gold nanoparticles. Cationic polyelectrolyte, poly(allylamine) hydrochloride, is electrostatically bound to the external surface of the virus capsid. The polyelectrolyte-coated CPMV promotes adsorption of aqueous gold hydroxide anionic species, prepared from gold(III) chloride and potassium carbonate, that are easily reduced to form CPMV-templated gold nanoparticles. The process is simple and environmentally benign using only water as solvent at ambient temperature.

  16. Gold nanoparticles for cancer theranostics — A brief update

    Directory of Open Access Journals (Sweden)

    Ning Zhao

    2016-07-01

    Full Text Available Gold nanoparticles (AuNPs exhibit superior optical and physical properties for more effective treatment of cancer through incorporating both diagnostic and therapeutic functions into one single platform. The ability to passively accumulate on tumor cells provides AuNPs the opportunity to become an attractive contrast agent for X-ray based computed tomography (CT imaging in vivo. Because of facile surface modification, various size and shape of AuNPs have been extensively functionalized and applied as active nanoprobes and drug carriers for cancer targeted theranostics. Moreover, their capabilities on producing photoacoustic (PA signals and photothermal effects have been used to image and treat tumor progression, respectively. Herein, we review the developments of AuNPs as cancer diagnostics and chemotherapeutic drug vector, summarizing strategies for tumor targeting and their applications in vitro and in vivo.

  17. Linker-mediated assembly of gold nanoparticles into multimeric motifs

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, Mateusz; Cieplak, Marek [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668 Warsaw (Poland); Szymczak, Piotr [Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ulica Hoza 69, 00-681 Warsaw (Poland); Thompson, Damien, E-mail: mc@ifpan.edu.pl [Tyndall National Institute, Lee Maltings, University College Cork, Cork (Ireland)

    2011-11-04

    We present a theoretical description of linker-mediated self-assembly of gold nanoparticles (Au-NP). Using mesoscale simulations with a coarse-grained model for the Au NPs and dirhenium-based linker molecules, we investigate the conditions under which large clusters can grow and construct a phase diagram that identifies favorable growth conditions in terms of floating and bound linker concentrations. The findings can be considered as generic, as we expect other NP-linker systems to behave in a qualitatively similar way. In particular, we also discuss the case of antibody-functionalised Au NPs connected by the C-reactive proteins (CRPs). We extract some general rules for NP linking that may aid the production of size- and shape-specific NP clusters for technology applications.

  18. Cyclodextrin-Based [1]Rotaxanes on Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yanli Zhao

    2012-08-01

    Full Text Available Transformation of mechanically interlocked molecules (e.g., rotaxanes and catenanes into nanoscale materials or devices is an important step towards their real applications. In our current work, an azobenzene-modified β-cyclodextrin (β-CD derivative that can form a self-inclusion complex in aqueous solution was prepared. The self-included β-CD derivative was then functionalized onto a gold nanoparticle (AuNP surface via a ligand-exchange reaction in aqueous solution, leading to the formation of AuNP-[1]rotaxane hybrids. Corresponding non-self-included β-CD derivative functionalized AuNPs were also developed in a DMF/H2O mixture solution for control experiments. These hybrids were fully characterized by UV-vis and circular dichroism spectroscopies, together with transmission electron microscopy (TEM. The competitive binding behavior of the hybrids with an adamantane dimer was investigated.

  19. Signal amplification for impedimetric genosensing using gold-streptavidin nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bonanni, A.; Esplandiu, M.J. [Sensors and Biosensors Group, Department of Chemistry, Universitat Autonoma de Barcelona, Edifici Cn, 08193 Bellaterra, Barcelona (Spain); Valle, M. del [Sensors and Biosensors Group, Department of Chemistry, Universitat Autonoma de Barcelona, Edifici Cn, 08193 Bellaterra, Barcelona (Spain)], E-mail: manel.delvalle@uab.es

    2008-04-20

    Streptavidin-coated gold nanoparticles (strept-AuNPs) were used in this work to amplify the impedimetric signal generated in a biosensor detecting the DNA hybridization event. Probe oligomer was adsorbed onto a graphite epoxy composite (GEC) electrode surface and the impedance measurement was performed in a solution containing the redox marker ferrocyanide/ferricyanide. The biotinylated complementary oligomer was used as target. The change of interfacial charge transfer resistance (R{sub ct}), experimented by the redox marker, was recorded to confirm the hybrid formation. The addition of strept-AuNPs, binding to the target due to the strong streptavidin-biotin interaction, led to a further increment of R{sub ct} thus obtaining significant signal amplification. Strept-AuNPs on the electrode surface were observed by scanning electron microscopy (SEM) after silver enhancement treatment. A competitive binding assay was also performed using unlabelled DNA target to demonstrate its applicability to real sample analysis.

  20. Gold nanoparticle cellular uptake, toxicity and radiosensitisation in hypoxic conditions

    International Nuclear Information System (INIS)

    Jain, Suneil; Coulter, Jonathan A.; Butterworth, Karl T.; Hounsell, Alan R.; McMahon, Stephen J.; Hyland, Wendy B.; Muir, Mark F.; Dickson, Glenn R.; Prise, Kevin M.; Currell, Fred J.; Hirst, David G.; O’Sullivan, Joe M.

    2014-01-01

    Background and purpose: Gold nanoparticles (GNPs) are novel agents that have been shown to cause radiosensitisation in vitro and in vivo. Tumour hypoxia is associated with radiation resistance and reduced survival in cancer patients. The interaction of GNPs with cells in hypoxia is explored. Materials and methods: GNP uptake, localization, toxicity and radiosensitisation were assessed in vitro under oxic and hypoxic conditions. Results: GNP cellular uptake was significantly lower under hypoxic than oxic conditions. A significant reduction in cell proliferation in hypoxic MDA-MB-231 breast cancer cells exposed to GNPs was observed. In these cells significant radiosensitisation occurred in normoxia and moderate hypoxia. However, in near anoxia no significant sensitisation occurred. Conclusions: GNP uptake occurred in hypoxic conditions, causing radiosensitisation in moderate, but not extreme hypoxia in a breast cancer cell line. These findings may be important for the development of GNPs for cancer therapy

  1. One-pot synthesis of gold nanoparticles using tetradentate porphyrins

    International Nuclear Information System (INIS)

    Canitez, Fatma K.; Yavuz, Mustafa S.; Ozturk, Ramazan

    2011-01-01

    In this study, the meso-tetra (p-hydroxyphenyl) porphyrin and meso-tetra (m-hydroxyphenyl) porphyrin were coated on to gold nanoparticles (AuNPs) via thioacetate anchors which easily dissociate to form S–Au bonds. 4-tert-butyl phenyl thioacetate-AuNPs were prepared and used as a monodentate passivant to control the size of the tetradentate porphyrin-AuNPs. The porphyrin-coated AuNPs were characterized by UV–Vis, TEM, XRD, and XPS analyses. The tetradentate porphyrin-AuNPs size is within a range of 5–15 nm in diameter with exotic shapes. The plausible network formation for AuNP-p-TPP-SAc and the capping structure of the AuNP-m-TPP-SAc have been suggested.

  2. Fluidic Manufacture of Star-Shaped Gold Nanoparticles.

    Science.gov (United States)

    Silvestri, Alessandro; Lay, Luigi; Psaro, Rinaldo; Polito, Laura; Evangelisti, Claudio

    2017-07-21

    Star-shaped gold nanoparticles (StarAuNPs) are extremely attractive nanomaterials, characterized by localized surface plasmon resonance which could be potentially employed in a large number of applications. However, the lack of a reliable and reproducible synthetic protocols for the production of StarAuNPs is the major limitation to their spreading. For the first time, here we present a robust protocol to manufacture reproducible StarAuNPs by exploiting a fluidic approach. Star-shaped AuNPs have been synthesized by means of a seed-less protocol, employing ascorbic acid as reducing agent at room temperature. Moreover, the versatility of the bench-top microfluidic protocol has been exploited to afford hydrophilic, hydrophobic and solid-supported engineered StarAuNPs, by avoiding intermediate NP purifications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Synthesis of tungsten oxide, silver, and gold nanoparticles by radio frequency plasma in water

    International Nuclear Information System (INIS)

    Hattori, Yoshiaki; Nomura, Shinfuku; Mukasa, Shinobu; Toyota, Hiromichi; Inoue, Toru; Usui, Tomoya

    2013-01-01

    Highlights: •RF plasma in water was used for nanoparticle synthesis. •Nanoparticles were produced from erosion of metallic electrode. •Rectangular and spherical tungsten oxide nanoparticles were produced. •No oxidations of the silver and gold spherical nanoparticles were produced. -- Abstract: A process for synthesis of nanoparticles using plasma in water generated by a radio frequency of 27.12 MHz is proposed. Tungsten oxide, silver, and gold nanoparticles were produced at 20 kPa through erosion of a metallic electrode exposed to plasma. Characterization of the produced nanoparticles was carried out by XRD, absorption spectrum, and TEM. The nanoparticle sizes were compared with those produced by a similar technique using plasma in liquid

  4. Facile method for the synthesis of gold nanoparticles using an ion coater

    Science.gov (United States)

    Lee, Seung Han; Jung, Hyun Kyu; Kim, Tae Cheol; Kim, Chang Hee; Shin, Chang Hwan; Yoon, Tae-Sik; Hong, A.-Ra; Jang, Ho Seong; Kim, Dong Hun

    2018-03-01

    Herein we report a metal nanoparticle synthesis method based on a physical vapor deposition process instead of the conventional wet process of chemical reactions in liquids. A narrow size distribution of synthesized gold nanoparticles was obtained using an ion coater on glycerin at low vapor pressure. The nanoparticle size could be modulated by controlling the sputtering conditions especially the discharge current. Due to the formation of gold nanoparticles, a surface plasmon resonance peak appeared at ∼530 nm in the absorption spectrum. The surface plasmon resonance peak exhibited red-shift with increasing size of the gold nanoparticles. Our results provide a simple, environmental friendly method for the synthesis of metal nanoparticles by combine low-cost deposition apparatus and a liquid medium, which is free from toxic reagents.

  5. Targeting and molecular imaging of HepG2 cells using surface-functionalized gold nanoparticles

    International Nuclear Information System (INIS)

    Rathinaraj, Pierson; Lee, Kyubae; Choi, Yuri; Park, Soo-Young; Kwon, Oh Hyeong; Kang, Inn-Kyu

    2015-01-01

    Mercaptosuccinic acid (M)-conjugated gold nanoparticles (GM) were prepared and characterized by transmission electron microscope and dynamic light scattering. M was used to improve the monodispersity and non-specific intracellular uptake of nanoparticles. Lactobionic acid (L) was subsequently conjugated to the GM to target preferentially HepG2 cells (liver cancer cells) that express asialoglycoprotein receptors (ASGPR) on their membrane surfaces and facilitate the transit of nanoparticles across the cell membrane. The mean size of lactobionic acid-conjugated gold nanoparticle (GL) was approximately 10 ± 0.2 nm. Finally, the Atto 680 dye (A6) was coupled to the nanoparticles to visualize their internalization into HepG2 cells. The interaction of surface-modified gold nanoparticles with HepG2 cells was studied after culturing cells in media containing the GM or L-conjugated GM (GL)

  6. Targeting and molecular imaging of HepG2 cells using surface-functionalized gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rathinaraj, Pierson [Auckland University of Technology, Institute of Biomedical Technologies (New Zealand); Lee, Kyubae; Choi, Yuri; Park, Soo-Young [Kyungpook National University, School of Applied Chemical Engineering, Graduate School (Korea, Republic of); Kwon, Oh Hyeong [Kumoh National Institute of Technology, Department of Polymer Science and Engineering (Korea, Republic of); Kang, Inn-Kyu, E-mail: ikkang@knu.ac.kr [Kyungpook National University, School of Applied Chemical Engineering, Graduate School (Korea, Republic of)

    2015-07-15

    Mercaptosuccinic acid (M)-conjugated gold nanoparticles (GM) were prepared and characterized by transmission electron microscope and dynamic light scattering. M was used to improve the monodispersity and non-specific intracellular uptake of nanoparticles. Lactobionic acid (L) was subsequently conjugated to the GM to target preferentially HepG2 cells (liver cancer cells) that express asialoglycoprotein receptors (ASGPR) on their membrane surfaces and facilitate the transit of nanoparticles across the cell membrane. The mean size of lactobionic acid-conjugated gold nanoparticle (GL) was approximately 10 ± 0.2 nm. Finally, the Atto 680 dye (A6) was coupled to the nanoparticles to visualize their internalization into HepG2 cells. The interaction of surface-modified gold nanoparticles with HepG2 cells was studied after culturing cells in media containing the GM or L-conjugated GM (GL)

  7. Biosynthesis of silver and gold nanoparticles by novel sundried Cinnamomum camphora leaf

    International Nuclear Information System (INIS)

    Huang Jiale; Li Qingbiao; Sun Daohua; Lu Yinghua; Su Yuanbo; Yang Xin; Wang Huixuan; Wang Yuanpeng; Shao Wenyao; He Ning; Hong Jinqing; Chen Cuixue

    2007-01-01

    The synthesis of nanocrystals is in the limelight in modern nanotechnology. Biosynthesis of nanoparticles by plant extracts is currently under exploitation. Not only could silver nanoparticles ranging from 55 to 80 nm in size be fabricated, but also triangular or spherical shaped gold nanoparticles could be easily modulated by reacting the novel sundried biomass of Cinnamomum camphora leaf with aqueous silver or gold precursors at ambient temperature. The marked difference of shape control between gold and silver nanoparticles was attributed to the comparative advantage of protective biomolecules and reductive biomolecules. The polyol components and the water-soluble heterocyclic components were mainly responsible for the reduction of silver ions or chloroaurate ions and the stabilization of the nanoparticles, respectively. The sundried leaf in this work was very suitable for simple synthesis of nanoparticles

  8. Microreactors for Gold Nanoparticles Synthesis: From Faraday to Flow

    Directory of Open Access Journals (Sweden)

    Md. Taifur Rahman

    2014-06-01

    Full Text Available The seminal work of Michael Faraday in 1850s transmuted the “Alchemy of gold” into a fascinating scientific endeavor over the millennia, particularly in the past half century. Gold nanoparticles (GNPs arguably hold the central position of nanosciences due to their intriguing size-and-shape dependent physicochemical properties, non-toxicity, and ease of functionalization and potential for wide range of applications. The core chemistry involved in the syntheses is essentially not very different from what Michael Faraday resorted to: transforming ions into metallic gold using mild reducing agents. However, the process of such reduction and outcome (shapes and sizes are intricately dependent on basic operational parameters such as sequence of addition and efficiency of mixing of the reagents. Hence, irreproducibility in synthesis and maintaining batch-to-batch quality are major obstacles in this seemingly straightforward process, which poses challenges in scaling-up. Microreactors, by the virtue of excellent control over reagent mixing in space and time within narrow channel networks, opened a new horizon of possibilities to tackle such problems to produce GNPs in more reliable, reproducible and scalable ways. In this review, we will delineate the state-of-the-art of GNPs synthesis using microreactors and will discuss in length how such “flask-to-chip” paradigm shift may revolutionize the very concept of nanosyntheses.

  9. Gold Nanoparticles in Photonic Crystals Applications: A Review.

    Science.gov (United States)

    Venditti, Iole

    2017-01-24

    This review concerns the recently emerged class of composite colloidal photonic crystals (PCs), in which gold nanoparticles (AuNPs) are included in the photonic structure. The use of composites allows achieving a strong modification of the optical properties of photonic crystals by involving the light scattering with electronic excitations of the gold component (surface plasmon resonance, SPR) realizing a combination of absorption bands with the diffraction resonances occurring in the body of the photonic crystals. Considering different preparations of composite plasmonic-photonic crystals, based on 3D-PCs in presence of AuNPs, different resonance phenomena determine the optical response of hybrid crystals leading to a broadly tunable functionality of these crystals. Several chemical methods for fabrication of opals and inverse opals are presented together with preparations of composites plasmonic-photonic crystals: the influence of SPR on the optical properties of PCs is also discussed. Main applications of this new class of composite materials are illustrated with the aim to offer the reader an overview of the recent advances in this field.

  10. Gold Nanoparticles in Photonic Crystals Applications: A Review

    Directory of Open Access Journals (Sweden)

    Iole Venditti

    2017-01-01

    Full Text Available This review concerns the recently emerged class of composite colloidal photonic crystals (PCs, in which gold nanoparticles (AuNPs are included in the photonic structure. The use of composites allows achieving a strong modification of the optical properties of photonic crystals by involving the light scattering with electronic excitations of the gold component (surface plasmon resonance, SPR realizing a combination of absorption bands with the diffraction resonances occurring in the body of the photonic crystals. Considering different preparations of composite plasmonic-photonic crystals, based on 3D-PCs in presence of AuNPs, different resonance phenomena determine the optical response of hybrid crystals leading to a broadly tunable functionality of these crystals. Several chemical methods for fabrication of opals and inverse opals are presented together with preparations of composites plasmonic-photonic crystals: the influence of SPR on the optical properties of PCs is also discussed. Main applications of this new class of composite materials are illustrated with the aim to offer the reader an overview of the recent advances in this field.

  11. Selective growth of gold onto copper indium sulfide selenide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Witt, Elena; Parisi, Juergen; Kolny-Olesiak, Joanna [Oldenburg Univ. (Germany). Inst. of Physics, Energy and Semiconductor Research

    2013-05-15

    Hybrid nanostructures are interesting materials for numerous applications in chemistry, physics, and biology, due to their novel properties and multiple functionalities. Here, we present a synthesis of metal-semiconductor hybrid nanostructures composed of nontoxic I-III-VI semiconductor nanoparticles and gold. Copper indium sulfide selenide (CuInSSe) nanocrystals with zinc blende structure and trigonal pyramidal shape, capped with dodecanethiol, serve as an original semiconductor part of a new hybrid nanostructure. Metallic gold nanocrystals selectively grow onto vertexes of these CuInSSe pyramids. The hybrid nanostructures were studied by transmission electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, and UV-Vis-absorption spectroscopy, which allowed us conclusions about their growth mechanism. Hybrid nanocrystals are generated by replacement of a sacrificial domain in the CuInSSe part. At the same time, small selenium nanocrystals form that stay attached to the remaining CuInSSe/Au particles. Additionally, we compare the synthesis and properties of CuInSSe-based hybrid nanostructures with those of copper indium disulfide (CuInS{sub 2}). CuInS{sub 2}/Au nanostructures grow by a different mechanism (surface growth) and do not show any selectivity. (orig.)

  12. Synthesis and antimicrobial activity of gold nanoparticle conjugates with cefotaxime

    Science.gov (United States)

    Titanova, Elena O.; Burygin, Gennady L.

    2016-04-01

    Gold nanoparticles (GNPs) have attracted significant interest as a novel platform for various applications to nanobiotechnology and biomedicine. The conjugates of GNPs with antibiotics and antibodies were also used for selective photothermal killing of protozoa and bacteria. Also the conjugates of some antibiotics with GNPs decreased the number of bacterial growing cells. In this work was made the procedure optimization for conjugation of cefotaxime (a third-generation cephalosporin antibiotic) with GNPs (15 nm) and we examined the antimicrobial properties of this conjugate to bacteria culture of E. coli K-12. Addition of cefotaxime solution to colloidal gold does not change their color and extinction spectrum. For physiologically active concentration of cefotaxime (3 μg/mL), it was shown that the optimum pH for the conjugation was more than 9.5. A partial aggregation of the GNPs in saline medium was observed at pH 6.5-7.5. The optimum concentration of K2CO3 for conjugation cefotaxime with GNPs-15 was 5 mM. The optimum concentration of cefotaxime was at 0.36 μg/mL. We found the inhibition of the growth of E. coli K12 upon application cefotaxime-GNP conjugates.

  13. Facile synthesis of chondroitin sulfate-stabilized gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Li Wei, E-mail: weilixj8510@163.com [School of Science, Henan Agricultural University, No. 95 Wenhua Road, Zhengzhou, Henan 450002 (China); Li Xin; Su Hui; Zhao Shiju; Li Yanyun; Hu Jiandong [School of Science, Henan Agricultural University, No. 95 Wenhua Road, Zhengzhou, Henan 450002 (China)

    2011-02-15

    A facile and simple method for the synthesis of biocompatible gold nanoparticles (AuNPs) at room temperature has been developed by using sodium borohydride as the reducing agent and employing an inexpensive water-soluble chondroitin sulfate (CS) biopolymer as the stabilizing agent. The as-prepared AuNPs were characterized with ultraviolet-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). Additionally, the stability of AuNPs in aqueous solution was investigated as a function of the electrolyte sodium chloride concentration. The experimental results showed that even high sodium chloride concentration (1 M) also did not destabilize the colloidal gold solution. So it could be speculated that the high stability of AuNPs should be attributed to the electrostatic repulsion and steric hindrance between the AuNPs stabilized by CS molecules, which wrapped around the surface of as-prepared AuNPs and prevented their agglomeration, and simultaneously improve biocompatibility of AuNPs as well.

  14. Facile synthesis of chondroitin sulfate-stabilized gold nanoparticles

    International Nuclear Information System (INIS)

    Li Wei; Li Xin; Su Hui; Zhao Shiju; Li Yanyun; Hu Jiandong

    2011-01-01

    A facile and simple method for the synthesis of biocompatible gold nanoparticles (AuNPs) at room temperature has been developed by using sodium borohydride as the reducing agent and employing an inexpensive water-soluble chondroitin sulfate (CS) biopolymer as the stabilizing agent. The as-prepared AuNPs were characterized with ultraviolet-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). Additionally, the stability of AuNPs in aqueous solution was investigated as a function of the electrolyte sodium chloride concentration. The experimental results showed that even high sodium chloride concentration (1 M) also did not destabilize the colloidal gold solution. So it could be speculated that the high stability of AuNPs should be attributed to the electrostatic repulsion and steric hindrance between the AuNPs stabilized by CS molecules, which wrapped around the surface of as-prepared AuNPs and prevented their agglomeration, and simultaneously improve biocompatibility of AuNPs as well.

  15. Direct Electrochemistry of Horseradish Peroxidase-Gold Nanoparticles Conjugate

    Directory of Open Access Journals (Sweden)

    Chanchal K. Mitra

    2009-02-01

    Full Text Available We have studied the direct electrochemistry of horseradish peroxidase (HRP coupled to gold nanoparticles (AuNP using electrochemical techniques, which provide some insight in the application of biosensors as tools for diagnostics because HRP is widely used in clinical diagnostics kits. AuNP capped with (i glutathione and (ii lipoic acid was covalently linked to HRP. The immobilized HRP/AuNP conjugate showed characteristic redox peaks at a gold electrode. It displayed good electrocatalytic response to the reduction of H2O2, with good sensitivity and without any electron mediator. The covalent linking of HRP and AuNP did not affect the activity of the enzyme significantly. The response of the electrode towards the different concentrations of H2O2 showed the characteristics of Michaelis Menten enzyme kinetics with an optimum pH between 7.0 to 8.0. The preparation of the sensor involves single layer of enzyme, which can be carried out efficiently and is also highly reproducible when compared to other systems involving the layer-by-layer assembly, adsorption or encapsulation of the enzyme. The immobilized AuNP-HRP can be used for immunosensor applications

  16. Green Synthesis, Characterization and Application of Proanthocyanidins-Functionalized Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Linhai Biao

    2018-01-01

    Full Text Available Green synthesis of gold nanoparticles using plant extracts is one of the more promising approaches for obtaining environmentally friendly nanomaterials for biological applications and environmental remediation. In this study, proanthocyanidins-functionalized gold nanoparticles were synthesized via a hydrothermal method. The obtained gold nanoparticles were characterized by ultraviolet and visible spectrophotometry (UV-Vis, Fourier transform infrared spectroscopy (FTIR, transmission electron microscopy (TEM and X-ray diffraction (XRD measurements. UV-Vis and FTIR results indicated that the obtained products were mainly spherical in shape, and that the phenolic hydroxyl of proanthocyanidins had strong interactions with the gold surface. TEM and XRD determination revealed that the synthesized gold nanoparticles had a highly crystalline structure and good monodispersity. The application of proanthocyanidins-functionalized gold nanoparticles for the removal of dyes and heavy metal ions Ni2+, Cu2+, Cd2+ and Pb2+ in an aqueous solution was investigated. The primary results indicate that proanthocyanidins-functionalized gold nanoparticles had high removal rates for the heavy metal ions and dye, which implies that they have potential applications as a new kind of adsorbent for the removal of contaminants in aqueous solution.

  17. Bio-synthesis of gold nanoparticles by human epithelial cells, in vivo

    International Nuclear Information System (INIS)

    Larios-Rodriguez, E; Rangel-Ayon, C; Herrera-Urbina, R; Castillo, S J; Zavala, G

    2011-01-01

    Healthy epithelial cells, in vivo, have the ability to synthesize gold nanoparticles when aqueous tetrachloroauric acid is made to react with human skin. Neither a reducing agent nor a protecting chemical is needed for this bio-synthesis method. The first indication of gold nanoparticle formation is the staining of the skin, which turns deep purple. Stereoscopic optical micrographs of human skin tissue in contact with aqueous tetrachloroauric acid clearly show the staining of the epithelial cells. The UV-Vis spectrum of these epithelial cells shows an absorption band with a maximum at 553 nm. This absorption peak is within the wavelength region where the surface plasmon resonance (SPR) band of aqueous colloidal gold exhibits a maximum. Transmission electron micrographs show that gold nanoparticles synthesized by epithelial cells have sizes between 1 and 100 nm. The electron diffraction pattern of these nanoparticles reveals a crystalline structure whose interplanar distances correspond to fcc metallic gold. Transmission electron micrographs of ultra-thin (70 nm thick) slices of epithelial cells clearly and undoubtedly demonstrate that gold nanoparticles are inside the cell. According to high resolution transmission electron micrographs of intracellular single gold nanoparticles, they have the shape of a polyhedron.

  18. Directing self-assembly of gold nanoparticles in diblock copolymer scaffold

    Science.gov (United States)

    Li, Qifang; He, Jinbo; Glogowski, Elizabeth; Emrick, Todd; Russell, Thomas

    2007-03-01

    A versatile hierarchical approach for directing self -assembly of gold nanostructures with size 2-3nm in diblock copolymer scaffolds is found. Diblock copolymer polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) is used to form a regular scaffold of highly anisotropic, stripe-like domains, and controlled differential wetting by dichloromethane and thermal annealing guides gold nanoparticles with half hydrophilic ligand to aggregate selectively along the scaffold, producing highly organized metal nanostructures. In as-cast block-copolymer and gold nanoparticles thin films, micelle structure and gold nanoparticles random distribution on scaffold are typically observed. However, samples annealed in dichloromethane exhibit well-defined short-range ordered nanostructure with gold nanoparticles located at the interface of PS and P2VP nanoscale domain. After annealing at 170 C, the gold nanoparticles at interface migrated into the middle of P2VP phase and exhibited long-range ordered hierarchical structures. Synergistic interactions between the gold nanoparticles and the PS-b-P2VP caused an orientation of the microdomains normal to the film surface.

  19. Bio-synthesis of gold nanoparticles by human epithelial cells, in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Larios-Rodriguez, E; Rangel-Ayon, C; Herrera-Urbina, R [Departamento de Ingenieria Quimica y Metalurgia, Universidad de Sonora, Rosales y Luis Encinas S/N, Hermosillo, Sonora, C.P. 83000 (Mexico); Castillo, S J [Departamento de Investigacion en Fisica, Universidad de Sonora, Rosales y Luis Encinas S/N, Hermosillo, Sonora, C.P. 83000 (Mexico); Zavala, G, E-mail: elarios@polimeros.uson.mx [Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos (Mexico)

    2011-09-02

    Healthy epithelial cells, in vivo, have the ability to synthesize gold nanoparticles when aqueous tetrachloroauric acid is made to react with human skin. Neither a reducing agent nor a protecting chemical is needed for this bio-synthesis method. The first indication of gold nanoparticle formation is the staining of the skin, which turns deep purple. Stereoscopic optical micrographs of human skin tissue in contact with aqueous tetrachloroauric acid clearly show the staining of the epithelial cells. The UV-Vis spectrum of these epithelial cells shows an absorption band with a maximum at 553 nm. This absorption peak is within the wavelength region where the surface plasmon resonance (SPR) band of aqueous colloidal gold exhibits a maximum. Transmission electron micrographs show that gold nanoparticles synthesized by epithelial cells have sizes between 1 and 100 nm. The electron diffraction pattern of these nanoparticles reveals a crystalline structure whose interplanar distances correspond to fcc metallic gold. Transmission electron micrographs of ultra-thin (70 nm thick) slices of epithelial cells clearly and undoubtedly demonstrate that gold nanoparticles are inside the cell. According to high resolution transmission electron micrographs of intracellular single gold nanoparticles, they have the shape of a polyhedron.

  20. In Situ Gold Nanoparticle Gradient Formation in a 3D Meso- and Macroporous Polymer Matrix.

    Science.gov (United States)

    Penders, Jelle; Rajasekharan, Anand K; Hulander, Mats; Andersson, Martin

    2017-08-01

    Herein, the development and characterization of a 3D gradient structure of gold nanoparticles is described. The gradient of gold nanoparticles is made in situ in a macroporous nonionic block copolymer hydrogel matrix, through gold ion diffusion control. The polymer provides a matrix for diffusion of gold ions, acts as a template for controlling nanoparticle growth, and facilitates the in situ reduction of gold ions to gold nanoparticles. A clear gradient in gold nanoparticles is observed across the 3D space of the polymer matrix using scanning electron microscopy, fluorescence microscopy, atomic force microscopy, and thermogravimetric analysis. The particle gradient is further functionalized with both hydrophobic and hydrophilic groups via thiol-gold linkage to demonstrate the ability to form gradients with different chemical functionalities. Using additive manufacturing, the polymer can also be printed as a porous network with possible applications for 3D cell culturing in, e.g., biomaterials research. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Green synthesis of anisotropic gold nanoparticles for photothermal therapy of cancer.

    Science.gov (United States)

    Fazal, Sajid; Jayasree, Aswathy; Sasidharan, Sisini; Koyakutty, Manzoor; Nair, Shantikumar V; Menon, Deepthy

    2014-06-11

    Nanoparticles of varying composition, size, shape, and architecture have been explored for use as photothermal agents in the field of cancer nanomedicine. Among them, gold nanoparticles provide a simple platform for thermal ablation owing to its biocompatibility in vivo. However, the synthesis of such gold nanoparticles exhibiting suitable properties for photothermal activity involves cumbersome routes using toxic chemicals as capping agents, which can cause concerns in vivo. Herein, gold nanoparticles, synthesized using green chemistry routes possessing near-infrared (NIR) absorbance facilitating photothermal therapy, would be a viable alternative. In this study, anisotropic gold nanoparticles were synthesized using an aqueous route with cocoa extract which served both as a reducing and stabilizing agent. The as-prepared gold nanoparticles were subjected to density gradient centrifugation to maximize its NIR absorption in the wavelength range of 800-1000 nm. The particles also showed good biocompatibility when tested in vitro using A431, MDA-MB231, L929, and NIH-3T3 cell lines up to concentrations of 200 μg/mL. Cell death induced in epidermoid carcinoma A431 cells upon irradiation with a femtosecond laser at 800 nm at a low power density of 6 W/cm(2) proved the suitability of green synthesized NIR absorbing anisotropic gold nanoparticles for photothermal ablation of cancer cells. These gold nanoparticles also showed good X-ray contrast when tested using computed tomography (CT), proving their feasibility for use as a contrast agent as well. This is the first report on green synthesized anisotropic and cytocompatible gold nanoparticles without any capping agents and their suitability for photothermal therapy.

  2. Biosynthesis, structural characterization and antimicrobial activity of gold and silver nanoparticles.

    Science.gov (United States)

    Ahmad, Tokeer; Wani, Irshad A; Manzoor, Nikhat; Ahmed, Jahangeer; Asiri, Abdullah M

    2013-07-01

    An eco friendly simple biosynthetic route was used for the preparation of monodisperse and highly crystalline gold and silver nanoparticles using cell free extract of fungus, Candida albicans. Transmission electron microscopic studies show the formation of gold and silver nanocrystals of average size of 5 nm and 30 nm with the specific surface areas of 18.9 m(2)/g and 184.4 m(2)/g respectively. The interaction of gold and silver nanoparticles with proteins has been formulated by FT-IR spectroscopy and thermal gravimetric analysis. The formation of gold and silver nanoparticles was also confirmed by the appearance of a surface plasmon band at 540 nm and 450 nm respectively. The antimicrobial activity of the synthesized gold and silver nanoparticles was investigated against both Staphylococcus aureus and Escherichia coli. The results suggest that these nanoparticles can be used as effective growth inhibitors against the test microorganisms. Greater bactericidal activity was observed for silver nanoparticles. The E. coli, a gram negative bacterium was found to be more susceptible to gold and silver nanoparticles than the S. aureus, a gram positive bacterium. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Shape-controlled synthesis of NIR absorbing branched gold nanoparticles and morphology stabilization with alkanethiols

    International Nuclear Information System (INIS)

    Van de Broek, B; Frederix, F; Bonroy, K; Jans, H; Jans, K; Borghs, G; Maes, G

    2011-01-01

    Gold nanoparticles are ideal candidates for clinical applications if their plasmon absorption band is situated in the near infrared region (NIR) of the electromagnetic spectrum. Various parameters, including the nanoparticle shape, strongly influence the position of this absorption band. The aim of this study is to produce stabilized NIR absorbing branched gold nanoparticles with potential for biomedical applications. Hereto, the synthesis procedure for branched gold nanoparticles is optimized varying the different synthesis parameters. By subsequent electroless gold plating the plasmon absorption band is shifted to 747.2 nm. The intrinsic unstable nature of the nanoparticles' morphology can be clearly observed by a spectral shift and limits their use in real applications. However, in this article we show how the stabilization of the branched structure can be successfully achieved by exchanging the initial capping agent for different alkanethiols and disulfides. Furthermore, when using alkanethiols/disulfides with poly(ethylene oxide) units incorporated, an increased stability of the gold nanoparticles is achieved in high salt concentrations up to 1 M and in a cell culture medium. These achievements open a plethora of opportunities for these stabilized branched gold nanoparticles in nanomedicine.

  4. Effects of Gold Nanoparticles on the Response of Phenol Biosensor Containing Photocurable Membrane with Tyrosinase

    Directory of Open Access Journals (Sweden)

    Ahmad Musa

    2008-10-01

    Full Text Available The role of incorporation of gold nanoparticles (50-130 nm in diameter into a series of photocurable methacrylic-acrylic based biosensor membranes containing tyrosinase on the response for phenol detection was investigated. Membranes with different hydrophilicities were prepared from 2-hydroxyethyl methacrylate and n-butyl acrylate via direct photocuring. A range of gold nanoparticles concentrations from 0.01 to 0.5 % (w/w was incorporated into these membranes during the photocuring process. The addition of gold nanoparticles to the biosensor membrane led to improvement in the response time by a reduction of approximately 5 folds to give response times of 5-10 s. The linear response range of the phenol biosensor was also extended from 24 to 90 mM of phenol. The hydrophilicities of the membrane matrices demonstrated strong influence on the biosensor response and appeared to control the effect of the gold nanoparticles. For less hydrophilic methacrylic-acrylic membranes, the addition of gold nanoparticles led to a poorer sensitivity and detection limit of the biosensor towards phenol. Therefore, for the application of gold nanoparticles in the enhancement of a phenol biosensor response, the nanoparticles should be immobilized in a hydrophilic matrix rather than a hydrophobic material.

  5. Characterization and antimicrobial application of biosynthesized gold and silver nanoparticles by using Microbacterium resistens.

    Science.gov (United States)

    Wang, Chao; Singh, Priyanka; Kim, Yeon Ju; Mathiyalagan, Ramya; Myagmarjav, Davaajargal; Wang, Dandan; Jin, Chi-Gyu; Yang, Deok Chun

    2016-11-01

    Various microorganisms were found to be cable of synthesizing gold and silver nanoparticles when gold and silver salts were supplied in the reaction system. The main objective of this study was to evaluate the extracellular synthesis of gold and silver nanoparticles by the type strain Microbacterium resistens(T) [KACC14505]. The biosynthesized gold and silver nanoparticles were characterized by ultraviolet-visible spectroscopy (UV-Vis), field emission transmission electron micrograph (FE-TEM), energy dispersive X-ray spectroscopy (EDX), elemental mapping, and dynamic light scattering (DLS). Moreover, the nanoparticles were evaluated for antimicrobial potential against various pathogenic microorganisms such as Vibrio parahaemolyticus [ATCC 33844], Salmonella enterica [ATCC 13076], Staphylococcus aureus [ATCC 6538], Bacillus anthracis [NCTC 10340], Bacillus cereus [ATCC 14579], Escherichia coli [ATCC 10798], and Candida albicans [KACC 30062]. The silver nanoparticles were found as a potent antimicrobial agent whereas gold nanoparticles not showed any ability. Therefore, the current study describes the simple, green, and extracellular synthesis of gold and silver nanoparticles by the type strain Microbacterium resistens(T) [KACC14505].

  6. Effect of gold nanoparticle on stability of the DNA molecule: A study of molecular dynamics simulation.

    Science.gov (United States)

    Izanloo, Cobra

    2017-09-02

    An understanding of the mechanism of DNA interactions with gold nanoparticles is useful in today medicine applications. We have performed a molecular dynamics simulation on a B-DNA duplex (CCTCAGGCCTCC) in the vicinity of a gold nanoparticle with a truncated octahedron structure composed of 201 gold atoms (diameter ∼1.8 nm) to investigate gold nanoparticle (GNP) effects on the stability of DNA. During simulation, the nanoparticle is closed to DNA and phosphate groups direct the particles into the major grooves of the DNA molecule. Because of peeling and untwisting states that are occur at end of DNA, the nucleotide base lies flat on the surface of GNP. The configuration entropy is estimated using the covariance matrix of atom-positional fluctuations for different bases. The results show that when a gold nanoparticle has interaction with DNA, entropy increases. The results of conformational energy and the hydrogen bond numbers for DNA indicated that DNA becomes unstable in the vicinity of a gold nanoparticle. The radial distribution function was calculated for water hydrogen-phosphate oxygen pairs. Almost for all nucleotide, the presence of a nanoparticle around DNA caused water molecules to be released from the DNA duplex and cations were close to the DNA.

  7. Plasmonic properties and enhanced fluorescence of gold and dye-doped silica nanoparticle aggregates

    Science.gov (United States)

    Green, Nathaniel Scott

    The development of metal-enhanced fluorescence has prompted a great interest in augmenting the photophysical properties of fluorescent molecules with noble metal nanostructures. Our research efforts, outlined in this dissertation, focus on augmenting properties of fluorophores by conjugation with gold nanostructures. The project goals are split into two separate efforts; the enhancement in brightness of fluorophores and long distance non-radiative energy transfer between fluorophores. We believe that interacting dye-doped silica nanoparticles with gold nanoparticles can facilitate both of these phenomena. Our primary research interest is focused on optimizing brightness, as this goal should open a path to studying the second goal of non-radiative energy transfer. The two major challenges to this are constructing suitable nanomaterials and functionalizing them to promote plasmonically active complexes. The synthesis of dye-doped layered silica nanoparticles allows for control over the discrete location of the dye and a substrate that can be surface functionalized. Controlling the exact location of the dye is important to create a silica spacer, which promotes productive interactions with metal nanostructures. Furthermore, the synthesis of silica nanoparticles allows for various fluorophores to be studied in similar environments (removing solvent and other chemo-sensitive issues). Functionalizing the surface of silica nanoparticles allows control over the degree of silica and gold nanoparticle aggregation in solution. Heteroaggregation in solution is useful for producing well-aggregated clusters of many gold around a single silica nanoparticle. The dye-doped surface functionalized silica nanoparticles can than be mixed efficiently with gold nanomaterials. Aggregating multiple gold nanospheres around a single dye-doped silica nanoparticle can dramatically increase the fluorescent brightness of the sample via metal-enhanced fluorescence due to increase plasmonic

  8. Optical effects in artificial opals infiltrated with gold nanoparticles

    Science.gov (United States)

    Comoretto, Davide; Morandi, Valentina; Marabelli, Franco; Amendola, Vincenzo; Meneghetti, Moreno

    2006-04-01

    Polystyrene artificial opals are directly grown with embedded gold nanoparticles (NpAu) in their interstices. Reflectance spectra of samples having different sphere diameters and nanoparticles load clearly show a red shift of the photonic band gap as well as a reduction of its width without showing direct evidence of NpAu absorption. The case of transmission spectra is instead more complicated: here, overlapped to a broad NpAu absorption, a structure having unusual lineshape is detected. The infiltration of opal with NpAu removes the polarization dependence of the photonic band structure observed in bare opals. The lineshape of the absorption spectra suggest a spatial localization of the electromagnetic field in the volume where NpAu are confined thus enhancing its local intensity. This effect seems to be effective to stimulate optical nonlinearities of NpAu. Nanosecond transient absorption measurements on NpAu infiltrated opals indicate that a variation of transmission of about 10% is observed. Since this effect takes place within the pump pulse and since NpAu photoluminescence has been subtracted to the signal, we attribute it to an optical switching process.

  9. Ferritin as a photocatalyst and scaffold for gold nanoparticle synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Keyes, Jeremiah D.; Hilton, Robert J. [Brigham Young University, Department of Chemistry and Biochemistry (United States); Farrer, Jeffrey [Brigham Young University, Department of Physics and Astronomy (United States); Watt, Richard K., E-mail: rwatt@chem.byu.edu [Brigham Young University, Department of Chemistry and Biochemistry (United States)

    2011-06-15

    The ferrihydrite mineral core of ferritin is a semi-conductor capable of catalyzing oxidation/reduction reactions. This report shows that ferritin can photoreduce AuCl{sub 4}{sup -} to form gold nanoparticles (AuNPs). An important goal was to identify innocent reaction conditions that prevented formation of AuNPs unless the sample was illuminated in the presence of ferritin. TRIS buffer satisfied this requirement and produced AuNPs with spherical morphology with diameters of 5.7 {+-} 1.6 nm and a surface plasmon resonance (SPR) peak at 530 nm. Size-exclusion chromatography of the AuNP-ferritin reaction mixture produced two fractions containing both ferritin and AuNPs. TEM analysis of the fraction close to where native ferritin normally elutes showed that AuNPs form inside ferritin. The other peak eluted at a volume indicating a particle size much larger than ferritin. TEM analysis revealed AuNPs adjacent to ferritin molecules suggesting that a dimeric ferritin-AuNP species forms. We propose that the ferritin protein shell acts as a nucleation site for AuNP formation leading to the AuNP-ferritin dimeric species. Ferrihydrite nanoparticles ({approx}10 nm diameter) were unable to produce soluble AuNPs under identical conditions unless apo ferritin was present indicating that the ferritin protein shell was essential for stabilizing AuNPs in aqueous solution.

  10. Smart dual-mode fluorescent gold nanoparticle agents.

    Science.gov (United States)

    Kang, Kyung A; Wang, Jianting

    2014-01-01

    Fluorophore-mediated, molecular sensing is one of the most popular and important technique in biomedical studies. As in any sensing technique, the two most important factors in this sensing are the sensitivity and specificity. Since the fluorescence of a fluorophore is emitted in the process of fluorophore electrons returning from their excited to ground state, a tool that can locally manipulate the electron state can be useful to maximize the sensitivity and specificity. A good tool candidate for this purpose is nanosized metal particles that can form an electromagnetic (EM) field at a sufficiently strong level, upon receiving a particular wavelength that fits the excitation wavelength of the fluorophore to be used. There are several metal nanoparticle types that can generate a sufficiently strong EM field for this purpose. Nevertheless, for the biomedical studies, which require minimal toxicity, gold nanoparticles (GNPs) are known to be the most suitable. In this article, various methods for fluorescence alteration using GNPs, which can be beneficially utilized for biomarker-specific, highly sensitive molecular sensing and imaging, are discussed. For further resources related to this article, please visit the WIREs website. The authors have declared no conflicts of interest for this article. © 2014 Wiley Periodicals, Inc.

  11. Microstructural characterization of gold nanoparticles synthesized by solution plasma processing

    International Nuclear Information System (INIS)

    Cho, Sung-Pyo; Bratescu, Maria Antoaneta; Takai, Osamu; Saito, Nagahiro

    2011-01-01

    Microstructural characteristics of gold nanoparticles (Au NPs) fabricated by solution plasma processing (SPP) in reverse micelle solutions have been studied by high-resolution transmission electron microscopy (HRTEM). The synthesized Au NPs, with an average size of 6.3 ± 1.4 nm, have different crystal characteristics; fcc single-crystalline particles, multiply twinned particles (MTPs), and incomplete MTPs (single-nanotwinned fcc configuration). The crystal structure characteristics of the Au NPs synthesized by the SPP method were analyzed and compared with similar-size Au NPs obtained by the conventional chemical reduction synthesis (CRS) method. The TEM analysis results show that the Au NPs synthesized by the CRS method have shapes and crystal structures similar to those nanoparticles obtained by the SPP method. However, from the detailed HRTEM analysis, the relative number of the Au MTPs and incomplete MTPs to the total number of the Au NPs synthesized by the SPP method was observed to be around 94%, whereas the relative number of these kinds of crystal structures fabricated by the CRS method was about 63%. It is most likely that the enhanced formation of the Au MTPs is due to the fact that the SPP method generates highly reaction-activated species under low environmental temperature conditions.

  12. Visible luminescence in polyaniline/(gold nanoparticle) composites

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Renata F. S. [Universidade Federal de Pernambuco, Pos-Graduacao em Ciencia de Materiais (Brazil); Andrade, Cesar A. S. [Universidade Federal de Pernambuco, Departamento de Bioquimica (Brazil); Santos, Clecio G. dos [Instituto de Educacao, Ciencia e Tecnologia de Pernambuco (Brazil); Melo, Celso P. de, E-mail: celso@df.ufpe.br [Universidade Federal de Pernambuco, Pos-Graduacao em Ciencia de Materiais (Brazil)

    2013-01-15

    We describe the use of solution chemistry methods to prepare polyaniline/(gold nanoparticles)-PANI/AuNPs-composites as colloidal particles that exhibit an intense green fluorescence after excitation in the ultraviolet region. Measurements of the relative fluorescence quantum yield indicate that the intensity of the observed luminescence of these nanocomposites is a few orders of magnitude higher than the corresponding fluorescence of either the isolated polymer or the pure AuNPs. Hence, cooperative effects between the conducting polymer chains and the metallic particles must dominate the emission behavior of these materials. Transmission electron microscopy reveals the existence of metal nanoparticle aggregates with sizes in the 2-3 nm range dispersed in the polymer matrix. By implementing an experimental planning, we have been able to change the preparation parameters so as to vary in a controlled manner the intensity and the profile of the luminescence spectrum as well as the size and aggregation characteristics of the colloidal particles. We also show that when the pH of the medium is varied, the dielectric properties (such as the degree of conductivity) of the PANI/AuNPs colloidal solutions and the intensity of their luminescence change in a consistent manner. Due to the polycation nature of the doped PANI chains, we suggest that these composites may find interesting applications as fluorescent markers of biologic molecules.

  13. Photofragmentation of colloidal solutions of gold nanoparticles under femtosecond laser pulses in IR and visible ranges

    International Nuclear Information System (INIS)

    Danilov, P A; Zayarnyi, D A; Ionin, A A; Kudryashov, S I; Makarov, S V; Rudenko, A A; Saraeva, I N; Yurovskikh, V I; Lednev, V N; Pershin, S M

    2015-01-01

    The specific features of photofragmentation of sols of gold nanoparticles under focused femtosecond laser pulses in IR (1030 nm) and visible (515 nm) ranges is experimentally investigated. A high photofragmentation efficiency of nanoparticles in the waist of a pulsed laser beam in the visible range (at moderate radiation scattering) is demonstrated; this efficiency is related to the excitation of plasmon resonance in nanoparticles on the blue shoulder of its spectrum, in contrast to the regime of very weak photofragmentation in an IR-laser field of comparable intensity. Possible mechanisms of femtosecond laser photofragmentation of gold nanoparticles are discussed. (extreme light fields and their applications)

  14. Implementing atomic force microscopy (AFM) for studying kinetics of gold nanoparticle's growth

    DEFF Research Database (Denmark)

    Georgiev, P.; Bojinova, A.; Kostova, B.

    2013-01-01

    In a novel experimental approach Atomic Force Microscopy (AFM) was applied as a tool for studying the kinetics of gold nanoparticle growth. The gold nanoparticles were obtained by classical Turkevich citrate synthesis at two different temperatures. From the analysis of AFM images during...... the synthesis process the nanoparticle s' sizes were obtained. To demonstrate the applicability and the reliability of the proposed experimental approach we studied the nanoparticles growth at two different temperatures by spectrophotometric measurements and compared them with the results from AFM experimental...

  15. Electrochemical Determination of Food Preservative Nitrite with Gold Nanoparticles/p-Aminothiophenol-Modified Gold Electrode.

    Science.gov (United States)

    Üzer, Ayşem; Sağlam, Şener; Can, Ziya; Erçağ, Erol; Apak, Reşat

    2016-08-02

    Due to the negative impact of nitrate and nitrite on human health, their presence exceeding acceptable levels is not desired in foodstuffs. Thus, nitrite determination at low concentrations is a major challenge in electroanalytical chemistry, which can be achieved by fast, cheap, and safe electrochemical sensors. In this work, the working electrode (Au) was functionalized with p-aminothiophenol (p-ATP) and modified with gold nanoparticles (Au-NPs) to manufacture the final (Au/p-ATP-Aunano) electrode in a two-step procedure. In the first step, p-ATP was electropolymerized on the electrode surface to obtain a polyaminothiophenol (PATP) coating. In the second step, Au/p-ATP-Aunano working electrode was prepared by coating the surface with the use of HAuCl₄ solution and cyclic voltammetry. Determination of aqueous nitrite samples was performed with the proposed electrode (Au/p-ATP-Aunano) using square wave voltammetry (SWV) in pH 4 buffer medium. Characteristic peak potential of nitrite samples was 0.76 V, and linear calibration curves of current intensity versus concentration was linear in the range of 0.5-50 mg·L(-1) nitrite with a limit of detection (LOD) of 0.12 mg·L(-1). Alternatively, nitrite in sausage samples could be colorimetrically determined with high sensitivity by means of p-ATP‒modified gold nanoparticles (AuNPs) and naphthylethylene diamine as coupling agents for azo-dye formation due to enhanced charge-transfer interactions with the AuNPs surface. The slopes of the calibration lines in pure NO₂(-) solution and in sausage sample solution, to which different concentrations of NO₂(-) standards were added, were not significantly different from each other, confirming the robustness and interference tolerance of the method. The proposed voltammetric sensing method was validated against the colorimetric nanosensing method in sausage samples.

  16. Highly stable, protein capped gold nanoparticles as effective drug delivery vehicles for amino-glycosidic antibiotics

    International Nuclear Information System (INIS)

    Rastogi, Lori; Kora, Aruna Jyothi; Arunachalam, J.

    2012-01-01

    A method for the production of highly stable gold nanoparticles (Au NP) was optimized using sodium borohydride as reducing agent and bovine serum albumin as capping agent. The synthesized nanoparticles were characterized using UV–visible spectroscopy, transmission electron microscopy, X‐ray diffraction (XRD) and dynamic light scattering techniques. The formation of gold nanoparticles was confirmed from the appearance of pink colour and an absorption maximum at 532 nm. These protein capped nanoparticles exhibited excellent stability towards pH modification and electrolyte addition. The produced nanoparticles were found to be spherical in shape, nearly monodispersed and with an average particle size of 7.8 ± 1.7 nm. Crystalline nature of the nanoparticles in face centered cubic structure is confirmed from the selected‐area electron diffraction and XRD patterns. The nanoparticles were functionalized with various amino-glycosidic antibiotics for utilizing them as drug delivery vehicles. Using Fourier transform infrared spectroscopy, the possible functional groups of antibiotics bound to the nanoparticle surface have been examined. These drug loaded nanoparticle solutions were tested for their antibacterial activity against Gram-negative and Gram-positive bacterial strains, by well diffusion assay. The antibiotic conjugated Au NP exhibited enhanced antibacterial activity, compared to pure antibiotic at the same concentration. Being protein capped and highly stable, these gold nanoparticles can act as effective carriers for drugs and might have considerable applications in the field of infection prevention and therapeutics. - Highlights: ► Method for NaBH 4 reduced and BSA capped gold nanoparticle was standardized. ► Nanoparticles were spherical and nearly monodispersed with a size of 7.8 nm. ► Nanoparticles are extremely stable towards pH modification and electrolyte addition. ► Antibiotic conjugated nanoparticles exhibited enhanced antibacterial activity

  17. A green chemistry approach for synthesizing biocompatible gold nanoparticles

    Science.gov (United States)

    Gurunathan, Sangiliyandi; Han, JaeWoong; Park, Jung Hyun; Kim, Jin-Hoi

    2014-05-01

    Gold nanoparticles (AuNPs) are a fascinating class of nanomaterial that can be used for a wide range of biomedical applications, including bio-imaging, lateral flow assays, environmental detection and purification, data storage, drug delivery, biomarkers, catalysis, chemical sensors, and DNA detection. Biological synthesis of nanoparticles appears to be simple, cost-effective, non-toxic, and easy to use for controlling size, shape, and stability, which is unlike the chemically synthesized nanoparticles. The aim of this study was to synthesize homogeneous AuNPs using pharmaceutically important Ganoderma spp . We developed a simple, non-toxic, and green method for water-soluble AuNP synthesis by treating gold (III) chloride trihydrate (HAuCl4) with a hot aqueous extract of the Ganoderma spp . mycelia. The formation of biologically synthesized AuNPs (bio-AuNPs) was characterized by ultraviolet (UV)-visible absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Furthermore, the biocompatibility of as-prepared AuNPs was evaluated using a series of assays, such as cell viability, lactate dehydrogenase leakage, and reactive oxygen species generation (ROS) in human breast cancer cells (MDA-MB-231). The color change of the solution from yellow to reddish pink and strong surface plasmon resonance were observed at 520 nm using UV-visible spectroscopy, and that indicated the formation of AuNPs. DLS analysis revealed the size distribution of AuNPs in liquid solution, and the average size of AuNPs was 20 nm. The size and morphology of AuNPs were investigated using TEM. The biocompatibility effect of as-prepared AuNPs was investigated in MDA-MB-231 breast cancer cells by using various concentrations of AuNPs (10 to 100 μM) for 24 h. Our findings suggest that AuNPs are non-cytotoxic and biocompatible. To the best of our knowledge

  18. Fabrication of conducting polymer-gold nanoparticles film on electrodes using monolayer protected gold nanoparticles and its electrocatalytic application

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, Palanisamy [Department of Chemistry, Gandhigram Rural University, Gandhigram 624 302, Dindigul (India); School of Chemical and Biomedical Engineering, N1.3, B4-01, 70 Nanyang Drive, Nanyang Technological University, Singapore 637457 (Singapore); John, S. Abraham, E-mail: abrajohn@yahoo.co.in [Department of Chemistry, Gandhigram Rural University, Gandhigram 624 302, Dindigul (India)

    2011-08-01

    We wish to report a simple and new strategy for the fabrication of gold nanoparticles-conducting polymer film on glassy carbon (GC) and indium tin oxide (ITO) surfaces using 5-amino-2-mercapto-1,3,4-thiadiazole capped gold nanoparticles (AMT-AuNPs) in 0.01 M H{sub 2}SO{sub 4} by electropolymerization. The presence of amine groups on the surface of the AuNPs was responsible for the deposition of the AMT-AuNPs film on the electrode surface. The atomic force microscopy (AFM) studies reveal that the fabricated p-AMT-AuNPs film showed homogeneously distributed AuNPs with a spherical shape of {approx}8 nm diameter. The XPS spectrum shows the binding energies at 83.8 and 87.5 eV in the Au 4f region corresponding to 4f{sub 7/2} and 4f{sub 5/2}, respectively. The position and difference between these two peaks (3.7 eV) exactly match the value reported for Au{sup 0}. The N1s XPS showed three binding energies at 396.7, 399.6 and 403.3 eV, corresponding to the =NH, -NH- and -N{sup +}H-, respectively, confirming that the electropolymerization proceeded through the oxidation of -NH{sub 2} groups present on the periphery of the AMT-AuNPs. The application of the present p-AMT-AuNPs modified electrode was demonstrated by studying the electro reduction of oxygen at pH 7.2. The p-AMT-AuNPs film enhanced the oxygen reduction current more than three times than that of p-AMT film prepared under identical conditions.

  19. Fluorescence behavior and singlet oxygen generating abilities of aluminum phthalocyanine in the presence of anisotropic gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mthethwa, Thandekile; Nyokong, Tebello, E-mail: t.nyokong@ru.ac.za

    2015-01-15

    Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs. - Highlights: • Gold nanoparticles (spheres, rods and bipyramids) were synthesized. • Gold nanoparticles were then conjugated to a quaternized ClAl phthalocyanine. • Conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields. • An increase in the singlet oxygen quantum yields was observed for the phthalocyanine in the presence of nanoparticles.

  20. Gold nanoparticle growth control - Implementing novel wet chemistry method on silicon substrate

    KAUST Repository

    Al-Ameer, Ammar; Katsiev, Habib; Sinatra, Lutfan; Hussein, Irshad; Bakr, Osman

    2013-01-01

    Controlling particle size, shape, nucleation, and self-assembly on surfaces are some of the main challenges facing electronic device fabrication. In this work, growth of gold nanoparticles over a wide range of sizes was investigated by using a novel

  1. Gold Nanoparticles: An Efficient Antimicrobial Agent against Enteric Bacterial Human Pathogen

    Directory of Open Access Journals (Sweden)

    Shahzadi Shamaila

    2016-04-01

    Full Text Available Enteric bacterial human pathogens, i.e., Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae, are the major cause of diarrheal infections in children and adults. Their structure badly affects the human immune system. It is important to explore new antibacterial agents instead of antibiotics for treatment. This project is an attempt to explain how gold nanoparticles affect these bacteria. We investigated the important role of the mean particle size, and the inhibition of a bacterium is dose-dependent. Ultra Violet (UV-visible spectroscopy revealed the size of chemically synthesized gold nanoparticle as 6–40 nm. Atomic force microscopy (AFM analysis confirmed the size and X-ray diffractometry (XRD analysis determined the polycrystalline nature of gold nanoparticles. The present findings explained how gold nanoparticles lyse Gram-negative and Gram-positive bacteria.

  2. Mimusops elengi bark extract mediated green synthesis of gold nanoparticles and study of its catalytic activity

    Science.gov (United States)

    Majumdar, Rakhi; Bag, Braja Gopal; Ghosh, Pooja

    2016-04-01

    The bark extract of Mimusops elengi is rich in different types of plant secondary metabolites such as flavonoids, tannins, triterpenoids and saponins. The present study shows the usefulness of the bark extract of Mimusops elengi for the green synthesis of gold nanoparticles in water at room temperature under very mild conditions. The synthesis of the gold nanoparticles was complete within a few minutes without any extra stabilizing or capping agents and the polyphenols present in the bark extract acted as both reducing as well as stabilizing agents. The synthesized colloidal gold nanoparticles were characterized by HRTEM, surface plasmon resonance spectroscopy and X-ray diffraction studies. The synthesized gold nanoparticles have been used as an efficient catalyst for the reduction of 3-nitrophenol and 4-nitrophenol to their corresponding aminophenols in water at room temperature.

  3. Preparation of porous polymer monoliths featuring enhanced surface coverage with gold nanoparticles

    KAUST Repository

    Lv, Yongqin; Alejandro, Fernando Maya; Frechet, Jean; Švec, František

    2012-01-01

    monoliths. The materials were then analyzed using both energy dispersive X-ray spectroscopy and thermogravimetric analysis. We found that the quantity of attached gold was dependent on the size of nanoparticles, with the maximum attachment of more than 60

  4. Biomedical Applications of Gold Nanoparticles Functionalized Using Hetero-Bifunctional Poly(ethylene glycol) Spacer

    National Research Council Canada - National Science Library

    Fu, Wei; Shenoy, Dinesh; Li, Jane; Crasto, Curtis; Jones, Graham; Dimarzio, Charles; Sridhar, Srinivas; Amiji, Mansoor

    2005-01-01

    To increase the targeting potential, circulation time, and the flexibility of surface-attached biomedically-relevant ligands on gold nanoparticles, hetero-bifunctional poly(ethylene glycol) (PEG, MW 1,500...

  5. Fluorogenic dansyl-ligated gold nanoparticles for the detection of sulfur mustard by displacement assay.

    Science.gov (United States)

    Knighton, Richard C; Sambrook, Mark R; Vincent, Jack C; Smith, Simon A; Serpell, Christopher J; Cookson, James; Vickers, Matthew S; Beer, Paul D

    2013-03-21

    The dansyl fluorophore ligated to gold nanoparticles via imidazole and amine groups affords conjugates capable of detecting micromolar concentrations of the chemical warfare agent sulfur mustard by a fluorescence switching 'ON' displacement assay.

  6. Nanostructured Membranes Functionalized with Gold Nanoparticles for Separation and Recovery of Monoclonal Antibodies

    KAUST Repository

    Soldan, Giada

    2017-01-01

    chromatography has gained attention as possible substituent of the common used protein A affinity chromatography for bioseparations. In this scenario, gold nanoparticles can be used as means for offering affinity, mainly because of their biocompatible

  7. Efficient light extraction from GaN LEDs using gold-coated ZnO nanoparticles

    KAUST Repository

    Alhadidi, A.

    2015-11-01

    We experimentally demonstrate the effect of depositing gold-coated ZnO nanoparticles on the surface of GaN multi-quantum well LED structures. We show that this method can significantly increase the amount of extracted light.

  8. Synthesis and characterization of thiolated pectin stabilized gold coated magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Varun, E-mail: varun.arora3986@gmail.com [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Sector 16-C, Dwarka, New Delhi 110078 (India); Sood, Ankur, E-mail: ankursood02@gmail.com [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Sector 16-C, Dwarka, New Delhi 110078 (India); Shah, Jyoti, E-mail: shah.jyoti1@gmail.com [National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Kotnala, R.K., E-mail: rkkotnala@nplindia.org [National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Jain, Tapan K., E-mail: tapankjain@gmail.com [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Sector 16-C, Dwarka, New Delhi 110078 (India)

    2016-04-15

    Core–shell nanoparticles, magnetic core and gold shell, were synthesized by reduction of gold chloride on the surface of magnetic nanoparticles; using tyrosine as a reducing agent. The formation of gold shell on magnetic nanoparticles was confirmed by X-ray diffraction (XRD) and UV-Visible spectroscopy. The core–shell nanoparticles (CSn) were conjugated with thiolated pectin to form a stable aqueous dispersion. The hydrodynamic size of thiolated pectin stabilized core–shell nanoparticles (TP-CSn) measured by Dynamic light scattering (DLS) was 160.5 nm with a poly dispersity index (PDI) of 0.302, whereas the mean particle size of TP-CSn calculated by high resolution transmission electron microscopy (HRTEM) was 10.8 ± 2.7 nm. The value of zeta potential for TP-CSn was −13.6 mV. There was a decrease in the value of saturation magnetization upon formation of the gold shell on magnetic nanoparticles. The amount of thiolated pectin bound to the surface of core–shell nanoparticles, calculated using Thermogravimetric analysis (TGA), was 6% of sample weight. - Highlights: • Use of side group of tyrosine (phenol) as a pH dependent reducing agent to synthesize gold coated magnetic nanoparticles. • Successful coating of gold shell on magnetic nanoparticles core. • Synthesis of thiolated pectin and stabilization of aqueous dispersion of core–shell nanoparticles with thiolated pectin. • The superparamagnetic behaviour of magnetic nanoparticles is retained after shell formation.

  9. Ultrathin free-standing close-packed gold nanoparticle films: Conductivity and Raman scattering enhancement

    Science.gov (United States)

    Yu, Qing; Huang, Hongwen; Peng, Xinsheng; Ye, Zhizhen

    2011-09-01

    A simple filtration technique was developed to prepare large scale free-standing close-packed gold nanoparticle ultrathin films using metal hydroxide nanostrands as both barrier layer and sacrificial layer. As thin as 70 nm, centimeter scale robust free-standing gold nanoparticle thin film was obtained. The thickness of the films could be easily tuned by the filtration volumes. The electronic conductivities of these films varied with the size of the gold nanoparticles, post-treatment temperature, and thickness, respectively. The conductivity of the film prepared from 20 nm gold nanoparticles is higher than that of the film prepared from 40 nm gold nanoparticle by filtering the same filtration volume of their solution, respectively. Their conductivities are comparable to that of the 220 nm thick ITO film. Furthermore, these films demonstrated an average surface Raman scattering enhancement up to 6.59 × 105 for Rhodamine 6 G molecules on the film prepared from 40 nm gold nanoparticles. Due to a lot of nano interspaces generated from the close-packed structures, two abnormal enhancements and relative stronger intensities of the asymmetrical vibrations at 1534 and 1594 cm-1 of R6G were observed, respectively. These robust free-standing gold nanoparticle films could be easily transferred onto various solid substrates and hold the potential application for electrodes and surface enhanced Raman detectors. This method is applicable for preparation of other nanoparticle free-standing thin films.A simple filtration technique was developed to prepare large scale free-standing close-packed gold nanoparticle ultrathin films using metal hydroxide nanostrands as both barrier layer and sacrificial layer. As thin as 70 nm, centimeter scale robust free-standing gold nanoparticle thin film was obtained. The thickness of the films could be easily tuned by the filtration volumes. The electronic conductivities of these films varied with the size of the gold nanoparticles, post

  10. Seed-mediated shape evolution of gold nanomaterials: from spherical nanoparticles to polycrystalline nanochains and single-crystalline nanowires

    International Nuclear Information System (INIS)

    Qiu Penghe; Mao Chuanbin

    2009-01-01

    We studied the kinetics of the reduction of a gold precursor (HAuCl 4 ) and the effect of the molar ratio (R) of sodium citrate, which was introduced from a seed solution, and the gold precursor on the shape evolution of gold nanomaterials in the presence of preformed 13 nm gold nanoparticles as seeds. The reduction of the gold precursor by sodium citrate was accelerated due to the presence of gold seeds. Nearly single-crystalline gold nanowires were formed at a very low R value (R = 0.16) in the presence of the seeds as a result of the oriented attachment of the growing gold nanoparticles. At a higher R value (R = 0.33), gold nanochains were formed due to the non-oriented attachment of gold nanoparticles. At a much higher R value (R = 1.32), only larger spherical gold nanoparticles grown from the seeds were found. In the absence of gold seeds, no single-crystalline nanowires were formed at the same R value. Our results indicate that the formation of the 1D nanostructures (nanochains and nanowires) at low R values is due to the attachment of gold nanoparticles along one direction, which is driven by the surface energy reduction, nanoparticle attraction, and dipole-dipole interaction between adjacent nanoparticles.

  11. Optimal energy for cell radiosensitivity enhancement by gold nanoparticles using synchrotron-based monoenergetic photon beams.

    Science.gov (United States)

    Rahman, Wan Nordiana; Corde, Stéphanie; Yagi, Naoto; Abdul Aziz, Siti Aishah; Annabell, Nathan; Geso, Moshi

    2014-01-01

    Gold nanoparticles have been shown to enhance radiation doses delivered to biological targets due to the high absorption coefficient of gold atoms, stemming from their high atomic number (Z) and physical density. These properties significantly increase the likelihood of photoelectric effects and Compton scattering interactions. Gold nanoparticles are a novel radiosensitizing agent that can potentially be used to increase the effectiveness of current radiation therapy techniques and improve the diagnosis and treatment of cancer. However, the optimum radiosensitization effect of gold nanoparticles is strongly dependent on photon energy, which theoretically is predicted to occur in the kilovoltage range of energy. In this research, synchrotron-generated monoenergetic X-rays in the 30-100 keV range were used to investigate the energy dependence of radiosensitization by gold nanoparticles and also to determine the photon energy that produces optimum effects. This investigation was conducted using cells in culture to measure dose enhancement. Bovine aortic endothelial cells with and without gold nanoparticles were irradiated with X-rays at energies of 30, 40, 50, 60, 70, 81, and 100 keV. Trypan blue exclusion assays were performed after irradiation to determine cell viability. Cell radiosensitivity enhancement was indicated by the dose enhancement factor which was found to be maximum at 40 keV with a value of 3.47. The dose enhancement factor obtained at other energy levels followed the same direction as the theoretical calculations based on the ratio of the mass energy absorption coefficients of gold and water. This experimental evidence shows that the radiosensitization effect of gold nanoparticles varies with photon energy as predicted from theoretical calculations. However, prediction based on theoretical assumptions is sometimes difficult due to the complexity of biological systems, so further study at the cellular level is required to fully characterize the effects

  12. Bubble template synthesis of hollow gold nanoparticles and their applications as theranostic agents

    Science.gov (United States)

    Huang, Chienwen

    Hollow gold nanoparticle with a sub-30nm polycrystalline shell and a 50 nm hollow core has been successfully synthesized through the reduction of sodium gold sulfite by electrochemically evolved hydrogen. Such hollow gold nanoparticles exhibit unique plasmonic properties. They strongly scatter and absorb near infrared light. In this thesis we seek to understand the formation mechanism of hollow gold nanoparticles in this new synthesis process and their plasmonic properties. Also, we explore their biomedical applications as theranostic agents (therapeutic and diagnostic imaging). A lithographically patterned electrode consisting of Ag stripes on a glass substrate was used to investigate the formation process of hollow gold nanoparticles. Ag stripes served as working electrode for electrochemically evolution of hydrogen, and adjacent glass areas provided supporting surface for hydrogen nanobubbles nucleation and growth. Hydrogen nanobubbles served as both templates and reducing agents to trigger the autocatalytic disproportionation reaction of sodium gold sulfite. The effects of applied potential and the additives in the electrolyte have been studied. It has been found that the size and size distribution of hollow gold nanoparticle are directly relative to the applied potential, i.e. the hydrogen evolution rate. It has also been found the addition of Ni2+ ions can greatly improve the size distribution of hollow gold nanoparticles that can be contributed to that the newly electrodeposited nickel metal can enhance the hydrogen evolution efficiency. Another additive, ethylenediamine (EDA) can suppress the autocatalytic reaction of gold sulfite to increase the stability of sodium gold sulfite electrolyte. To capture such electrochemically evolved hydrogen nanobubbles, and subsequently to generate hollow gold nanoparticles in large numbers, alumina membranes were placed on the top of the working electrode. Anodic alumina membrane consists of ~200 nm pores, which provides

  13. Enhanced relative biological effectiveness of proton radiotherapy in tumor cells with internalized gold nanoparticles

    International Nuclear Information System (INIS)

    Polf, Jerimy C.; Gillin, Michael; Bronk, Lawrence F.; Driessen, Wouter H. P.; Arap, Wadih; Pasqualini, Renata

    2011-01-01

    The development and use of sensitizing agents to improve the effectiveness of radiotherapy have long been sought to improve our ability to treat cancer. In this letter, we have studied the relative biological effectiveness of proton beam radiotherapy on prostate tumor cells with and without internalized gold nanoparticles. The effectiveness of proton radiotherapy for the killing of prostate tumor cells was increased by approximately 15%-20% for those cells containing internalized gold nanoparticles.

  14. Enhanced relative biological effectiveness of proton radiotherapy in tumor cells with internalized gold nanoparticles

    Science.gov (United States)

    Polf, Jerimy C.; Bronk, Lawrence F.; Driessen, Wouter H. P.; Arap, Wadih; Pasqualini, Renata; Gillin, Michael

    2011-01-01

    The development and use of sensitizing agents to improve the effectiveness of radiotherapy have long been sought to improve our ability to treat cancer. In this letter, we have studied the relative biological effectiveness of proton beam radiotherapy on prostate tumor cells with and without internalized gold nanoparticles. The effectiveness of proton radiotherapy for the killing of prostate tumor cells was increased by approximately 15%–20% for those cells containing internalized gold nanoparticles. PMID:21915155

  15. Selfassembly of gold nanoparticles onto the surface of multiwall carbon nanotubes functionalized with mercaptobenzene moieties

    International Nuclear Information System (INIS)

    Shi Jin; Wang Zhe; Li Hulin

    2006-01-01

    We have developed a new and effective method to robustly self-assemble gold nanoparticles onto the surface of multiwall carbon nanotubes (MWNTs) functionalized with mercaptobenzene moieties. Fourier transform infrared and electron diffraction spectroscopy were used to verify whether or not the mercaptobenzene moieties have been attached to the π-conjugated body of MWNTs. Transmission electron microscope images give direct evidences for the success of selfassembly of gold nanoparticles onto the functionalized MWNTs

  16. Gold nanoparticle catalyzed oxidation of alcohols - From biomass to commodity chemicals

    DEFF Research Database (Denmark)

    Taarning, Esben; Christensen, Claus H.

    2007-01-01

    and glycerol are rich in alcohol functionalities. Thus, a key step in utilizing these resources lies in the conversion of this functional group. Benign oxidations involving oxygen as the stoichiometric oxidant are important from both an environmental and economical perspective. Recently, it has become clear...... that supported gold nanoparticles are highly active catalysts for oxidizing alcohols and aldehydes using oxygen as the oxidant. This perspective will focus on the use of gold nanoparticles in the oxidation of renewables....

  17. Gold Nanoparticles with Externally Controlled, Reversible Shifts of Local Surface Plasmon Resonance Bands

    Science.gov (United States)

    Yavuz, Mustafa S.; Jensen, Gary C.; Penaloza, David P.; Seery, Thomas A. P.; Pendergraph, Samuel A.; Rusling, James F.; Sotzing, Gregory A.

    2010-01-01

    We have achieved reversible tunability of local surface plasmon resonance in conjugated polymer functionalized gold nanoparticles. This property was facilitated by the preparation of 3,4-ethylenedioxythiophene (EDOT) containing polynorbornene brushes on gold nanoparticles via surface-initiated ring-opening metathesis polymerization. Reversible tuning of the surface plasmon band was achieved by electrochemically switching the EDOT polymer between its reduced and oxidized states. PMID:19839619

  18. Comparative study of gum arabic and PVP as stabilizing agents for synthesis of gold nanoparticles

    International Nuclear Information System (INIS)

    Silva, Andressa A.; Leal, Jessica; Geraldes, Adriana N.; Lugao, Ademar B.

    2015-01-01

    Use Colloidal metallic nanoparticles such as gold nanoparticles have received a great attention, due in part to their specific properties and potential applications. Control of size and uniformity of nanoparticles is important to prevent aggregation. High-molecular-weight polymers were used as stabilizer agents. Natural polymers, such as gum Arabic, are used as stabilizer because of capping nanoparticles behavior and present advantages such as solubility, non- toxicity and its compatibility for pharmaceutical and biomedical applications. Previous studies showed that the hydrophilic group of Poly(vinyl pyrrolidone) (PVP) caused repulsion on gold nanoparticles surface because steric interactions with polymer, for this reason this kind of polymers could be used as stabilizer agent. The aim of this work is to study the synthesis and stabilization of gold nanoparticles with PVP and gum Arabic using gamma radiation. The results obtained by samples analysis using UV-Visible showed that the gamma irradiation doses influenced the nanoparticles formation by PVP but that is not the case with the GA, because for smaller quantity of Arabic gum in different doses produced and stabilized nanoparticles. The samples were observed for 20 days and showed stability. We have obtained preliminary results showed that the use of radiation is applicable to the formation of gold nanoparticles. (author)

  19. Comparative study of gum arabic and PVP as stabilizing agents for synthesis of gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Andressa A.; Leal, Jessica; Geraldes, Adriana N.; Lugao, Ademar B., E-mail: andressa_alvess@yahoo.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Use Colloidal metallic nanoparticles such as gold nanoparticles have received a great attention, due in part to their specific properties and potential applications. Control of size and uniformity of nanoparticles is important to prevent aggregation. High-molecular-weight polymers were used as stabilizer agents. Natural polymers, such as gum Arabic, are used as stabilizer because of capping nanoparticles behavior and present advantages such as solubility, non- toxicity and its compatibility for pharmaceutical and biomedical applications. Previous studies showed that the hydrophilic group of Poly(vinyl pyrrolidone) (PVP) caused repulsion on gold nanoparticles surface because steric interactions with polymer, for this reason this kind of polymers could be used as stabilizer agent. The aim of this work is to study the synthesis and stabilization of gold nanoparticles with PVP and gum Arabic using gamma radiation. The results obtained by samples analysis using UV-Visible showed that the gamma irradiation doses influenced the nanoparticles formation by PVP but that is not the case with the GA, because for smaller quantity of Arabic gum in different doses produced and stabilized nanoparticles. The samples were observed for 20 days and showed stability. We have obtained preliminary results showed that the use of radiation is applicable to the formation of gold nanoparticles. (author)

  20. Effect of surface roughness on substrate-tuned gold nanoparticle gap plasmon resonances.

    Science.gov (United States)

    Lumdee, Chatdanai; Yun, Binfeng; Kik, Pieter G

    2015-03-07

    The effect of nanoscale surface roughness on the gap plasmon resonance of gold nanoparticles on thermally evaporated gold films is investigated experimentally and numerically. Single-particle scattering spectra obtained from 80 nm diameter gold particles on a gold film show significant particle-to-particle variation of the peak scattering wavelength of ±28 nm. The experimental results are compared with numerical simulations of gold nanoparticles positioned on representative rough gold surfaces, modeled based on atomic force microscopy measurements. The predicted spectral variation and average resonance wavelength show good agreement with the measured data. The study shows that nanometer scale surface roughness can significantly affect the performance of gap plasmon-based devices.

  1. NON-INVASIVE RADIOFREQUENCY ABLATION OF CANCER TARGETED BY GOLD NANOPARTICLES

    Science.gov (United States)

    Cardinal, Jon; Klune, John Robert; Chory, Eamon; Jeyabalan, Geetha; Kanzius, John S.; Nalesnik, Michael; Geller, David A.

    2008-01-01

    Introduction Current radiofrequency ablation (RFA) techniques require invasive needle placement and are limited by accuracy of targeting. The purpose of this study was to test a novel non-invasive radiowave machine that uses RF energy to thermally destroy tissue. Gold nanoparticles were designed and produced to facilitate tissue heating by the radiowaves. Methods A solid state radiowave machine consisting of a power generator and transmitting/receiving couplers which transmit radiowaves at 13.56 MHz was used. Gold nanoparticles were produced by citrate reduction and exposed to the RF field either in solutions testing or after incubation with HepG2 cells. A rat hepatoma model using JM-1 cells and Fisher rats was employed using direct injection of nanoparticles into the tumor to focus the radiowaves for select heating. Temperatures were measured using a fiber-optic thermometer for real-time data. Results Solutions containing gold nanoparticles heated in a time- and power-dependent manner. HepG2 liver cancer cells cultured in the presence of gold nanoparticles achieved adequate heating to cause cell death upon exposure to the RF field with no cytotoxicity attributable to the gold nanoparticles themselves. In vivo rat exposures at 35W using gold nanoparticles for tissue injection resulted in significant temperature increases and thermal injury at subcutaneous injection sites as compared to vehicle (water) injected controls. Discussion These data show that non-invasive radiowave thermal ablation of cancer cells is feasible when facilitated by gold nanoparticles. Future studies will focus on tumor selective targeting of nanoparticles for in vivo tumor destruction. PMID:18656617

  2. Efficient Production of Hydrogen from Decomposition of Formic Acid over Zeolite Incorporated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Gallas-Hulin, Agata; Mielby, Jerrik Jørgen; Kegnæs, Søren

    2016-01-01

    Formic acid has a great potential as a safe and convenient source of hydrogen for sustainable chemical synthesis and renewable energy storage. Here, we report a heterogeneous gold nanoparticles catalyst for efficient production of hydrogen from vapor phase decomposition of formic acid using zeolite...... incorporated gold nanoparticles. The catalyst is prepared by pressure assisted impregnation and reduction (PAIR), which results in a uniform distribution of small gold nanoparticles that are incorporated into zeolite silicalite-1 crystals. Consequently, the incorporated nanoparticles exhibit increased...... sintering stability. Based on these results, we believe that incorporation of metal nanoparticles in zeolites may find use as highly active and selective heterogeneous catalysts for the production of hydrogen in future renewable energy applications....

  3. Centrifuge Controlled Shape Tuning of Biosynthesized Gold Nanoparticles Obtained from Plumbago zeylanica Leaf Extract.

    Science.gov (United States)

    Ankamwar, Balaprasad; Pansare, Sachin; Sur, Ujjal Kumar

    2017-02-01

    Development of cost-efficient and eco-friendly biogenic synthetic protocols for the green synthesis of biocompatible metal nanoparticles has become popular among researchers in recent years. The biogenic synthesis of these nanoparticles and their potential biomedical applications introduces the concept of nanobiotechnology, which has become the latest fascinating area of research. The lower cost and lesser side effects as compare to chemical methods of synthesis are the main advantages of biosynthesis. In the present investigation, aqueous leaf extract of Plumbago zeylanica had been used to synthesize anisotropic gold nanoparticles. The as-synthesized gold nanoparticles were centrifuged at 5000 and 10000 rpm and compared both pellets using UV-visible spectroscopy, XRD, FTIR and TEM techniques. We have studied here the effect of speed of centrifugation on the yield, shape, size as well as size distribution of as synthesized gold nanoparticles.

  4. Gold nanoparticles synthesized by gamma radiation and stabilized by bovine serum albumin

    International Nuclear Information System (INIS)

    Leal, Jessica; Silva, Andressa A.; Geraldes, Adriana N.; Lugao, Ademar B.; Grasselli, Mariano

    2015-01-01

    Gold nanoparticles (AuNPs) are a new option for pharmaceutical and cosmetic industries due to their interesting chemical, electrical and catalytic properties. Research for cancer treatments have been developed using this promising radiotherapy agent. The challenge of gold nanoparticles is to keep them stable, due to metallic behavior. It is know that surface plasma resonance promotes agglomeration of metallic nanoparticles, but they are not stable. Stabilizers have been used to reduce agglomeration. The aim of this work is reduction of HAuCl 4 salt to AuNPs performed by gamma radiation 60 Co source and the stabilization of gold nanoparticles using bovine serum albumin (BSA) fraction V as stabilizer agent. AuNPs were characterized by UV-visible to verify the nanoparticles formation. Samples containing BSA and samples obtained by the conventional method (without stabilizer) were monitored for two weeks and analyzed. Results were compared. (author)

  5. DNA hydrogel as a template for synthesis of ultrasmall gold nanoparticles for catalytic applications.

    Science.gov (United States)

    Zinchenko, Anatoly; Miwa, Yasuyuki; Lopatina, Larisa I; Sergeyev, Vladimir G; Murata, Shizuaki

    2014-03-12

    DNA cross-linked hydrogel was used as a matrix for synthesis of gold nanoparticles. DNA possesses a strong affinity to transition metals such as gold, which allows for the concentration of Au precursor inside a hydrogel. Further reduction of HAuCl4 inside DNA hydrogel yields well dispersed, non-aggregated spherical Au nanoparticles of 2-3 nm size. The average size of these Au nanoparticles synthesized in DNA hydrogel is the smallest reported so far for in-gel metal nanoparticles synthesis. DNA hybrid hydrogel containing gold nanoparticles showed high catalytic activity in the hydrogenation reaction of nitrophenol to aminophenol. The proposed soft hybrid material is promising as environmentally friendly and sustainable material for catalytic applications.

  6. Gold nanoparticles synthesized by gamma radiation and stabilized by bovine serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Jessica; Silva, Andressa A.; Geraldes, Adriana N.; Lugao, Ademar B., E-mail: jessicaleal@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Grasselli, Mariano, E-mail: mariano.grasselli@gmail.com [Departamento de Ciencia y Tecnologia, Universidad Nacional de Quilmes, Bernal (Argentina)

    2015-07-01

    Gold nanoparticles (AuNPs) are a new option for pharmaceutical and cosmetic industries due to their interesting chemical, electrical and catalytic properties. Research for cancer treatments have been developed using this promising radiotherapy agent. The challenge of gold nanoparticles is to keep them stable, due to metallic behavior. It is know that surface plasma resonance promotes agglomeration of metallic nanoparticles, but they are not stable. Stabilizers have been used to reduce agglomeration. The aim of this work is reduction of HAuCl{sub 4} salt to AuNPs performed by gamma radiation {sup 60}Co source and the stabilization of gold nanoparticles using bovine serum albumin (BSA) fraction V as stabilizer agent. AuNPs were characterized by UV-visible to verify the nanoparticles formation. Samples containing BSA and samples obtained by the conventional method (without stabilizer) were monitored for two weeks and analyzed. Results were compared. (author)

  7. Conductometric gas sensors based on metal oxides modified with gold nanoparticles: a review

    International Nuclear Information System (INIS)

    Korotcenkov, Ghenadii; Cho, Beong K.; Brinzari, Vladimir

    2016-01-01

    This review (with 170 refs.) discusses approaches towards surface functionalizaton of metal oxides by gold nanoparticles, and the application of the resulting nanomaterials in resistive gas sensors. The articles is subdivided into sections on (a) methods for modification of metal oxides with gold nanoparticles; (b) the response of gold nanoparticle-modified metal oxide sensors to gaseous species, (c) a discussion of the limitations of such sensors, and (d) a discussion on future tasks and trends along with an outlook. It is shown that, in order to achieve significant improvements in sensor parameters, it is necessary to warrant a good control the size and density of gold nanoparticles on the surface of metal oxide crystallites, the state of gold in the cluster, and the properties of the metal oxide support. Current challenges include an improved reproducibility of sensor preparation, better long-term stabilities, and a better resistance to sintering and poisoning of gold clusters during operation. Additional research focused on better understanding the role of gold clusters and nanoparticles in gas-sensing effects is also required. (author)

  8. Preparation of gold nanoparticles and determination of their particles size via different methods

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad; Usanase, Gisele [University of Lyon, University Lyon-1, CNRS, UMR-5007, LAGEP, F-69622 Villeurbanne (France); Oulmi, Kafia; Aberkane, Fairouz; Bendaikha, Tahar [Laboratory of Chemistry and Environmental Chemistry(LCCE), Faculty of Science, Material Science Department, University of Batna, 05000 (Algeria); Fessi, Hatem [University of Lyon, University Lyon-1, CNRS, UMR-5007, LAGEP, F-69622 Villeurbanne (France); Zine, Nadia [Institut des Sciences Analytiques (ISA), Université Lyon, Université Claude Bernard Lyon-1, UMR-5180, 5 rue de la Doua, F-69100 Villeurbanne (France); Agusti, Géraldine [University of Lyon, University Lyon-1, CNRS, UMR-5007, LAGEP, F-69622 Villeurbanne (France); Errachid, El-Salhi [Institut des Sciences Analytiques (ISA), Université Lyon, Université Claude Bernard Lyon-1, UMR-5180, 5 rue de la Doua, F-69100 Villeurbanne (France); Elaissari, Abdelhamid, E-mail: elaissari@lagep.univ-lyon1.fr [University of Lyon, University Lyon-1, CNRS, UMR-5007, LAGEP, F-69622 Villeurbanne (France)

    2016-07-15

    Graphical abstract: Preparation of gold nanoparticles via NaBH{sub 4} reduction method, and determination of their particle size, size distribution and morphology by using different techniques. - Highlights: • Gold nanoparticles were synthesized by NaBH{sub 4} reduction method. • Excess of reducing agent leads to tendency of aggregation. • The particle size, size distribution and morphology were investigated. • Particle size was determined both experimentally as well as theoretically. - Abstract: Gold nanoparticles have been used in various applications covering both electronics, biosensors, in vivo biomedical imaging and in vitro biomedical diagnosis. As a general requirement, gold nanoparticles should be prepared in large scale, easy to be functionalized by chemical compound of by specific ligands or biomolecules. In this study, gold nanoparticles were prepared by using different concentrations of reducing agent (NaBH{sub 4}) in various formulations and their effect on the particle size, size distribution and morphology was investigated. Moreover, special attention has been dedicated to comparison of particles size measured by various techniques, such as, light scattering, transmission electron microscopy, UV spectrum using standard curve and particles size calculated by using Mie theory and UV spectrum of gold nanoparticles dispersion. Particle size determined by various techniques can be correlated for monodispersed particles and excess of reducing agent leads to increase in the particle size.

  9. Attenuated effects of chitosan-capped gold nanoparticles on LPS-induced toxicity in laboratory rats

    International Nuclear Information System (INIS)

    Stefan, Marius; Melnig, Viorel; Pricop, Daniela; Neagu, Anca; Mihasan, Marius; Tartau, Liliana; Hritcu, Lucian

    2013-01-01

    The impact of nanoparticles in medicine and biology has increased rapidly in recent years. Gold nanoparticles (AuNP) have advantageous properties such as chemical stability, high electron density and affinity to biomolecules. However, the effects of AuNP on human body after repeated administration are still unclear. Therefore, the purpose of the present study was to evaluate the effects of gold-11.68 nm (AuNP1, 9.8 μg) and gold-22.22 nm (AuNP2, 19.7 μg) nanoparticles capped with chitosan on brain and liver tissue reactivity in male Wistar rats exposed to lipopolysaccharide (LPS from Escherichia coli serotype 0111:B4, 250 μg) upon 8 daily sessions of intraperitoneal administration. Our results suggest that the smaller size of chitosan-capped AuNP shows the protective effects against LPS-induced toxicity, suggesting a very high potential for biomedical applications. - Highlights: ► Smaller size of chitosan-capped gold nanoparticles acts against LPS-induced toxicity. ► Larger size of chitosan-capped gold nanoparticles agglomerated inside neurons and induced toxicity in combination with LPS. ► Chitosan has excellent biocompatible proprieties. ► Smaller size of chitosan-capped gold nanoparticles demonstrates great potential in biomedical applications.

  10. Effect of gold nanoparticles on adipogenic differentiation of human mesenchymal stem cells

    International Nuclear Information System (INIS)

    Kohl, Yvonne; Gorjup, Erwin; Katsen-Globa, Alisa; Büchel, Claudia; Briesen, Hagen von; Thielecke, Hagen

    2011-01-01

    Gold nanoparticles are very attractive for biomedical products. However, there is a serious lack of information concerning the biological activity of nanosized gold in human tissue cells. An influence of nanoparticles on stem cells might lead to unforeseen consequences to organ and tissue functions as long as all cells arising from the initial stem cell might be subsequently damaged. Therefore the effect of negatively charged gold nanoparticles (9 and 95 nm), which are certified as reference material for preclinical biomedical research, on the adipogenic differentiation of human mesenchymal stem cells (hMSCs) is investigated here. Bone marrow hMSCs are chosen as differentiation model since bone marrow hMSCs are well characterized and their differentiation into the adipogenic lineage shows clear and easily detectable differentiation. In this study effects of gold nanoparticles on adipogenic differentiation are analyzed regarding fat storage and mitochondrial activity after different exposure times (4–21 days). Using time lapse microscopy the differentiation progress under chronically gold nanoparticle treatment is continuously investigated. In this preliminary study, chronically treatment of adipogenic differentiating hMSCs with gold nanoparticles resulted in a reduced number and size of lipid vacuoles and reduced mitochondrial activity depending on the applied concentration and the surface charge of the particles.

  11. Effect of gold nanoparticles on adipogenic differentiation of human mesenchymal stem cells

    Science.gov (United States)

    Kohl, Yvonne; Gorjup, Erwin; Katsen-Globa, Alisa; Büchel, Claudia; von Briesen, Hagen; Thielecke, Hagen

    2011-12-01

    Gold nanoparticles are very attractive for biomedical products. However, there is a serious lack of information concerning the biological activity of nanosized gold in human tissue cells. An influence of nanoparticles on stem cells might lead to unforeseen consequences to organ and tissue functions as long as all cells arising from the initial stem cell might be subsequently damaged. Therefore the effect of negatively charged gold nanoparticles (9 and 95 nm), which are certified as reference material for preclinical biomedical research, on the adipogenic differentiation of human mesenchymal stem cells (hMSCs) is investigated here. Bone marrow hMSCs are chosen as differentiation model since bone marrow hMSCs are well characterized and their differentiation into the adipogenic lineage shows clear and easily detectable differentiation. In this study effects of gold nanoparticles on adipogenic differentiation are analyzed regarding fat storage and mitochondrial activity after different exposure times (4-21 days). Using time lapse microscopy the differentiation progress under chronically gold nanoparticle treatment is continuously investigated. In this preliminary study, chronically treatment of adipogenic differentiating hMSCs with gold nanoparticles resulted in a reduced number and size of lipid vacuoles and reduced mitochondrial activity depending on the applied concentration and the surface charge of the particles.

  12. Preparation of gold nanoparticles and determination of their particles size via different methods

    International Nuclear Information System (INIS)

    Iqbal, Muhammad; Usanase, Gisele; Oulmi, Kafia; Aberkane, Fairouz; Bendaikha, Tahar; Fessi, Hatem; Zine, Nadia; Agusti, Géraldine; Errachid, El-Salhi; Elaissari, Abdelhamid

    2016-01-01

    Graphical abstract: Preparation of gold nanoparticles via NaBH_4 reduction method, and determination of their particle size, size distribution and morphology by using different techniques. - Highlights: • Gold nanoparticles were synthesized by NaBH_4 reduction method. • Excess of reducing agent leads to tendency of aggregation. • The particle size, size distribution and morphology were investigated. • Particle size was determined both experimentally as well as theoretically. - Abstract: Gold nanoparticles have been used in various applications covering both electronics, biosensors, in vivo biomedical imaging and in vitro biomedical diagnosis. As a general requirement, gold nanoparticles should be prepared in large scale, easy to be functionalized by chemical compound of by specific ligands or biomolecules. In this study, gold nanoparticles were prepared by using different concentrations of reducing agent (NaBH_4) in various formulations and their effect on the particle size, size distribution and morphology was investigated. Moreover, special attention has been dedicated to comparison of particles size measured by various techniques, such as, light scattering, transmission electron microscopy, UV spectrum using standard curve and particles size calculated by using Mie theory and UV spectrum of gold nanoparticles dispersion. Particle size determined by various techniques can be correlated for monodispersed particles and excess of reducing agent leads to increase in the particle size.

  13. A spectroscopic study on the interaction between gold nanoparticles and hemoglobin

    International Nuclear Information System (INIS)

    Garabagiu, Sorina

    2011-01-01

    Highlights: ► The interaction was studied using UV–vis and fluorescence spectroscopy. ► Gold nanoparticles quench the fluorescence emission of hemoglobin solution. ► The binding and thermodynamic constants were calculated. ► Major impact: electrochemical applications of the complex onto a substrate. -- Abstract: The interaction between horse hemoglobin and gold nanoparticles was studied using optical spectroscopy. UV–vis and fluorescence spectra show that a spontaneous binding process occurred between hemoglobin and gold nanoparticles. The Soret band of hemoglobin in the presence of gold nanoparticles does not show significant changes, which proves that the protein retained its biological function. A shift to longer wavelengths appears in the plasmonic band of gold nanoparticles upon the attachment of hemoglobin molecules. Gold nanoparticles quench the fluorescence emission of tryptophan residues in the structure of hemoglobin. The Stern–Volmer quenching constant, the binding constant and the number of binding sites were also calculated. Thermodynamic parameters indicate that the binding was mainly due to hydrophobic interactions.

  14. Bringing Catalysis with Gold Nanoparticles in Green Solvents to Graduate Level Students

    Science.gov (United States)

    Raghuwanshi, Vikram Singh; Wendt, Robert; O'Neill, Maeve; Ochmann, Miguel; Som, Tirtha; Fenger, Robert; Mohrmann, Marie; Hoell, Armin; Rademann, Klaus

    2017-01-01

    We demonstrate here a novel laboratory experiment for the synthesis of gold nanoparticles (AuNPs) by using a low energy gold-sputtering method together with a modern, green, and biofriendly deep eutectic solvent (DES). The strategy is straightforward, economical, ecofriendly, rapid, and clean. It yields uniform AuNPs of 5 nm in diameter with high…

  15. Fabrication of gold-nanoparticle arrays using photolithography and thermal dewetting

    NARCIS (Netherlands)

    de Vreede, Lennart; Göeken, Kristian; Göeken, Kristian; Gill, Ron; Gill, Ron; van den Berg, Albert; Eijkel, Jan C.T.; Zengerle, R.

    2013-01-01

    We demonstrate a new manufacturing method using only basic cleanroom techniques to produce an array of 106 100 nm diameter gold-nanoparticles (GNPs) of equal shape and 5 μm spacing on a fused silica surface. Photolithography and sputtering are used to produce gold islets, followed by a simple

  16. Polymer-templated self-assembly of a 2-dimensional gold nanoparticle network

    DEFF Research Database (Denmark)

    Hansen, Christian Rein; Westerlund, Fredrik; Moth-Poulsen, Kasper

    2008-01-01

    We here report on the formation of well-ordered 2D gold nanostructures at the air/water interface. Spreading a mixture of alkanethiol-capped gold nanoparticles (AuNPs) and an amphiphilic poly(p-phenylene) on a water surface and compressing the mixture to a surface pressure of 40 mN/m lead...

  17. Organosilane oxidation by water catalysed by large gold nanoparticles in a membrane reactor

    NARCIS (Netherlands)

    Gitis, V.; Beerthuis, R.; Shiju, N.R.; Rothenberg, G.

    2014-01-01

    We show that gold nanoparticles catalyse the oxidation of organosilanes using water as oxidant at ambient conditions. Remarkably, monodispersions of small gold particles (3.5 nm diameter) and large ones (6-18 nm diameter) give equally good conversion rates. This is important because separating large

  18. High-resolution chemical imaging of gold nanoparticles using hard x-ray ptychography

    DEFF Research Database (Denmark)

    Hoppe, R.; Reinhardt, J.; Hofmann, G.

    2013-01-01

    We combine resonant scattering with (ptychographic) scanning coherent diffraction microscopy to determine the chemical state of gold nanoparticles with high spatial resolution. Ptychographic images of the sample are recorded for a series of energies around the gold L3 absorption edge. From these ...

  19. Gold micro- and nano-particles for surface enhanced vibrational spectroscopy of pyridostigmine bromide

    DEFF Research Database (Denmark)

    Dolgov, Leonid; Fesenko, Olena; Kavelin, Vladyslav

    2017-01-01

    Triangular gold microprisms and spherical silica nanoparticles with attached gold nano-islands were examined as an active nanostructures for the surface enhanced Raman and infrared spectroscopy. These particles were probed for the detection of pyridostigmine bromide as a safe analog of military c...

  20. Basic metal carbonate supported gold nanoparticles: enhanced performance in aerobic alcohol oxidation

    NARCIS (Netherlands)

    Yang, J.; Guan, Y.; Verhoeven, M.W.G.M.; Santen, van R.A.; Li, Can; Hensen, E.J.M.

    2009-01-01

    Gold nanoparticles supported by basic hydrozincite or bismuth carbonate are excellent catalysts for liquid-phase aerobic alcohol oxidation: the performance of a series of metal (Zn, Bi, Ce, La, Zr) carbonate supported gold catalysts depends strongly on the basicity of the support material.

  1. Preparation of gold nanoparticles by microwave heating and application of spectroscopy to study conjugate of gold nanoparticles with antibody E. coli O157:H7

    International Nuclear Information System (INIS)

    Ngo, Vo Ke Thanh; Nguyen, Hoang Phuong Uyen; Huynh, Trong Phat; Tran, Nguyen Nguyen Pham; Lam, Quang Vinh; Huynh, Thanh Dat

    2015-01-01

    Gold nanoparticles (AuNPs) of 15–20 nm size range have attracted attention for producing smart sensing devices as diagnostic tools in biomedical sciences. Citrate capped AuNPs are negatively charged, which can be exploited for electrostatic interactions with some positively charged biomolecules like antibodies. In this paper we describe a method for the low cost synthesis of gold nanoparticles using sodium citrate (Na_3Ct) reduction in chloroauric acid (HAuCl_4.3H_2O) by microwave heating (diameter about 13–15 nm). Gold nanoparticles were functionalized with surface activation by 3-mercaptopropionic acid for attaching antibody. These nanoparticles were then reacted with anti-E. coli O157:H7, using N-hydroxy succinimide (NHS) and carbondimide hydrochloride (EDC) coupling chemistry. The product was characterized with UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and zeta potential. In addition, the binding of antibody-gold nanoparticles conjugates to E. coli O157:H7 was demonstrated using transmission electron microscopy (TEM). (paper)

  2. Characterization and Biocompatibility of Chitosan Gels with Silver and Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    C. Sámano-Valencia

    2014-01-01

    Full Text Available The presence of bacterial resistance to antibiotics is a very important issue and the search of new alternatives is necessary. In this work, a combination of chitosan gel with silver or gold nanoparticles was prepared and characterized using thermal, rheology, bactericide, and biocompatibility analyses. ESEM images were also taken to visualize the incorporation of the nanoparticles into the gel matrix. Thermal analysis showed a better thermal stability in the chitosan-gold nanoparticles gels compared to the chitosan-silver nanoparticles gels. Rheology analyses showed that the viscosity of the gels decreased when velocity increased and there were differences in viscosity when silver and gold nanoparticles concentrations change. ESEM images showed the presence of agglomerates of silver and gold nanoparticles into the gel matrix with a good distribution; in some cases the formation of microstructures was found. Bactericide results show that these materials present an antibacterial activity against S. aureus, S. mutans, and E. coli. The biocompatibility test showed neither negative reaction nor wound healing delay after the application of the gels in an in vivo test. The gels with silver and gold nanoparticles could be used to treat wound infections in oral or skin applications.

  3. Application of gold nanoparticles for improved drug efficiency

    Science.gov (United States)

    Shittu, K. O.; Bankole, M. T.; Abdulkareem, A. S.; Abubakre, O. K.; Ubaka, A. U.

    2017-09-01

    Due to increasing resistance of microorganisms towards current antibiotics, there is a need for new or enhanced antibiotics. Nanotechnology is a technology that enhances the use of gold nanoparticles (AuNP) in area of medical applications, especially as a drug carrier for targeted drug delivery. In this research, AuNPs was synthesized using biological method via bioreduction of Piper guineense aqueous leaf extract on tetra gold chloride, characterized using UV-Vis spectrophometer, DLS, TEM/EDS and FTIR. The synthesized AuNPs was covalently functionalized with polyethylene glycol and encapsulated with Lincomycin and in vitro dissolution methods was used to evaluate the potential performance of the formulated nanodrug. The nanodrug has highest release efficiency at the 9th minutes (23.4 mg ml-1 for 40 °C) and (29.5 mg ml-1 for 60 °C) compared with the non-nanodrug. The antibacterial potential of the nanodrug was seen on the gram-positive bacteria of Staphylococcus aureus and Streptococcus pyogenes with highest inhibitions of 18 mm (at 40 °C) and 16 mm (at 60 °C) for S. aureus, and 16 mm for S. pyogenes (both at 40 °C and 60 °C). The bacteria growth inhibition continued and lasted for 15 min, while that of non-nanodrug lasted for 9 min with lesser growth inhibition compared to the formulated nanodrug. This work shows that the presence of the AuNPs increased the release efficiency of lincomycin even at a lower concentration and also bacteria growth inhibition thereby suggesting the effectiveness of the nanodrug formulation.

  4. A novel bacterial isolate Stenotrophomonas maltophilia as living factory for synthesis of gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Shekhawat G

    2009-07-01

    Full Text Available Abstract Background The synthesis of gold nanoparticles (GNPs has received considerable attention with their potential applications in various life sciences related applications. Recently, there has been tremendous excitement in the study of nanoparticles synthesis by using some natural biological system, which has led to the development of various biomimetic approaches for the growth of advanced nanomaterials. In the present study, we have demonstrated the synthesis of gold nanoparticles by a novel bacterial strain isolated from a site near the famous gold mines in India. A promising mechanism for the biosynthesis of GNPs by this strain and their stabilization via charge capping was investigated. Results A bacterial isolate capable of gold nanoparticle synthesis was isolated and identified as a novel strain of Stenotrophomonas malophilia (AuRed02 based on its morphology and an analysis of its 16S rDNA gene sequence. After 8 hrs of incubation, monodisperse preparation of gold nanoparticles was obtained. Gold nanoparticles were characterized and found to be of ~40 nm size. Electrophoresis, Zeta potential and FTIR measurements confirmed that the particles are capped with negatively charged phosphate groups from NADP rendering them stable in aqueous medium. Conclusion The process of synthesis of well-dispersed nanoparticles using a novel microorganism isolated from the gold enriched soil sample has been reported in this study, leading to the development of an easy bioprocess for synthesis of GNPs. This is the first study in which an extensive characterization of the indigenous bacterium isolated from the actual gold enriched soil was conducted. Promising mechanism for the biosynthesis of GNPs by the strain and their stabilization via charge capping is suggested, which involves an NADPH-dependent reductase enzyme that reduces Au3+ to Au0 through electron shuttle enzymatic metal reduction process.

  5. Transplacental clastogenic and epigenetic effects of gold nanoparticles in mice

    Energy Technology Data Exchange (ETDEWEB)

    Balansky, Roumen [National Center of Oncology, Sofia (Bulgaria); Longobardi, Mariagrazia [Department of Health Sciences, University of Genoa, Genoa (Italy); Ganchev, Gancho; Iltcheva, Marietta [National Center of Oncology, Sofia (Bulgaria); Nedyalkov, Nikolay; Atanasov, Petar [Institute of Electronics, Bulgarian Academy of Sciences, Sofia (Bulgaria); Toshkova, Reneta [Institute of Experimental Morphology, Pathology and Anthropology with Museum, Bulgarian Academy of Sciences, Sofia (Bulgaria); De Flora, Silvio [Department of Health Sciences, University of Genoa, Genoa (Italy); Izzotti, Alberto, E-mail: izzotti@unige.it [Department of Health Sciences, University of Genoa, Genoa (Italy)

    2013-11-15

    Highlights: • We evaluated transplacental genotoxicity of 40 nm- and 100 nm-gold nanoparticles. • AuNP-100 nm significantly enhanced MN PCE in fetal liver and blood. • In fetal lung, out of 1281 miRNA analyzed, 28 were significantly altered in their expression. • In fetal liver, 5 miRNA were significantly altered in their expression. • Altered miRNAs are involved in cell proliferation, apoptosis, transcription, stress response. - Abstract: The broad application of nanotechnology in medicine, biology, and pharmacology is leading to a dramatic increase of the risk of direct contact of nanoproducts, among which gold nanoparticles (AuNP), with the human organism. The present study aimed at evaluating in vivo the genotoxicity of AuNPs with average size of 40 nm and 100 nm. A single intraperitoneal treatment of adult male and female Swiss mice (strain H) with AuNPs, at a dose of 3.3 mg/kg body weight, had no effect on the frequency of micronucleated polychromatic erythrocytes (MN PCEs) in bone marrow. Conversely, the transplacental treatment with AuNP-100 nm, but not with AuNP-40 nm, applied intraperitoneally at a dose of 3.3 mg/kg to pregnant mice on days 10, 12, 14, and 17 of gestation, resulted in a significant increase in the frequency of MN PCEs in both liver and peripheral blood of mouse fetuses. In parallel, the same treatment with AuNP-100 nm, but not with AuNP-40 nm, produced significant changes in microRNA expression. In particular, out of 1281 mouse microRNAs analyzed, 28 were dys-regulated more than two-fold and to a statistically significant extent in fetus lung, and 5 were up-regulated in fetal liver. Let-7a and miR-183 were significantly up-regulated in both organs. The data presented herein demonstrate for the first time the transplacental size-dependent clastogenic and epigenetic effects of AuNPs in mouse fetus, thus highlighting new aspects concerning the putative genotoxicity of AuNPs during a vulnerable period of life.

  6. Transplacental clastogenic and epigenetic effects of gold nanoparticles in mice

    International Nuclear Information System (INIS)

    Balansky, Roumen; Longobardi, Mariagrazia; Ganchev, Gancho; Iltcheva, Marietta; Nedyalkov, Nikolay; Atanasov, Petar; Toshkova, Reneta; De Flora, Silvio; Izzotti, Alberto

    2013-01-01

    Highlights: • We evaluated transplacental genotoxicity of 40 nm- and 100 nm-gold nanoparticles. • AuNP-100 nm significantly enhanced MN PCE in fetal liver and blood. • In fetal lung, out of 1281 miRNA analyzed, 28 were significantly altered in their expression. • In fetal liver, 5 miRNA were significantly altered in their expression. • Altered miRNAs are involved in cell proliferation, apoptosis, transcription, stress response. - Abstract: The broad application of nanotechnology in medicine, biology, and pharmacology is leading to a dramatic increase of the risk of direct contact of nanoproducts, among which gold nanoparticles (AuNP), with the human organism. The present study aimed at evaluating in vivo the genotoxicity of AuNPs with average size of 40 nm and 100 nm. A single intraperitoneal treatment of adult male and female Swiss mice (strain H) with AuNPs, at a dose of 3.3 mg/kg body weight, had no effect on the frequency of micronucleated polychromatic erythrocytes (MN PCEs) in bone marrow. Conversely, the transplacental treatment with AuNP-100 nm, but not with AuNP-40 nm, applied intraperitoneally at a dose of 3.3 mg/kg to pregnant mice on days 10, 12, 14, and 17 of gestation, resulted in a significant increase in the frequency of MN PCEs in both liver and peripheral blood of mouse fetuses. In parallel, the same treatment with AuNP-100 nm, but not with AuNP-40 nm, produced significant changes in microRNA expression. In particular, out of 1281 mouse microRNAs analyzed, 28 were dys-regulated more than two-fold and to a statistically significant extent in fetus lung, and 5 were up-regulated in fetal liver. Let-7a and miR-183 were significantly up-regulated in both organs. The data presented herein demonstrate for the first time the transplacental size-dependent clastogenic and epigenetic effects of AuNPs in mouse fetus, thus highlighting new aspects concerning the putative genotoxicity of AuNPs during a vulnerable period of life

  7. Multifunctional DNA-gold nanoparticles for targeted doxorubicin delivery.

    Science.gov (United States)

    Alexander, Colleen M; Hamner, Kristen L; Maye, Mathew M; Dabrowiak, James C

    2014-07-16

    In this report we describe the synthesis, characterization, and cytotoxic properties of DNA-capped gold nanoparticles having attached folic acid (FA), a thermoresponsive polymer (p), and/or poly(ethylene glycol) (PEG) oligomers that could be used to deliver the anticancer drug doxorubicin (DOX) in chemotherapy. The FA-DNA oligomer used in the construction of the delivery vehicle was synthesized through the reaction of the isolated folic acid N-hydroxysuccinimide ester with the amino-DNA and the conjugated DNA product was purified using high performance liquid chromatography (HPLC). This approach ultimately allowed control of the amount of FA attached to the surface of the delivery vehicle. Cytotoxicity studies using SK-N-SH neuroblastoma cells with drug loaded delivery vehicles were carried out using a variety of exposure times (1-48 h) and recovery times (1-72 h), and in order to access the effects of varying amounts of attached FA, in culture media deficient in FA. DOX loaded delivery vehicles having 50% of the DNA strands with attached FA were more cytotoxic than when all of the strands contained FA. Since FA stimulates cell growth, the reduced cytotoxicity of vehicles fully covered with FA suggests that the stimulatory effects of FA can more than compensate for the cytotoxic effects of the drug on the cell population. While attachment of hexa-ethylene glycol PEG(18) to the surface of the delivery vehicle had no effect on cytotoxicity, 100% FA plus the thermoresponsive polymer resulted in IC50 = 0.48 ± 0.01 for an exposure time of 24 h and a recovery time of 1 h, which is an order of magnitude more cytotoxic than free DOX. Confocal microscopic studies using fluorescence detection showed that SK-N-SH neuroblastoma cells exposed to DOX-loaded vehicles have drug accumulation inside the cell and, in the case of vehicles with attached FA and thermoresponsive polymer, the drug appears more concentrated. Since the biological target of DOX is DNA, the latter

  8. On the formation of protected gold nanoparticles from AuCl4- by the reduction using aromatic amines

    International Nuclear Information System (INIS)

    Subramaniam, Chandramouli; Tom, Renjis T.; Pradeep, T.

    2005-01-01

    Amines are used extensively as reductants and subsequent capping agents in the synthesis of metal nanoparticles, especially gold, due to its affinity to nitrogen. Taking 2-methyl aniline as an example, we show that metal reduction is followed by polymerization of the amine, while part of it covers the nanoparticle surface another fraction deposits in the solution. It is found that the oxidative polymerization of the amine goes in step with the formation of gold nanoparticles. The gold nanoparticles thus formed have a mean diameter of 20 nm. The polymerized amine encapsulates the gold nanoparticle forming a robust shell of about 5 nm thickness, making the gold core inert towards mineralizing agents such as chloroform, bromoform, sodium cyanide, benzylchloride, etc. which react with the naked gold nanoparticles. The deposited polymer is largely protonated, taking up protons from the medium during its formation. Similar results have been observed in the case of aniline also. The materials have been fully characterized by spectroscopy and microscopy

  9. Substrate Size-Selective Catalysis with Zeolite-Encapsulated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Laursen, Anders Bo; Højholt, Karen Thrane; Lundegaard, L.F.

    2010-01-01

    The Dark Crystal: A hybrid material is reported that is comprised of 1-2 nm sized gold nanoparticles, accessible only through zeolite micropores in a silicalite-1 crystal, as shown by three-dimensional TEM tomography (see picture). Calcination experiments indicate that the embedded nanoparticles...

  10. Fluorescence quenching of dye molecules near gold nanoparticles: radiative and nonradiative effects

    NARCIS (Netherlands)

    Dulkeith, E.; Morteani, A.C.; Niedereichholz, T.; Klar, T.A.; Feldman, J.; Levi, S.; van Veggel, F.C.J.M.; Reinhoudt, David; Möller, M.; Gittins, D.I.

    2002-01-01

    The radiative and nonradiative decay rates of lissamine dye molecules, chemically attached to differently sized gold nanoparticles, are investigated by means of time-resolved fluorescence experiments. A pronounced fluorescence quenching is observed already for the smallest nanoparticles of 1  nm

  11. Reversible modulation of CsPbBr3 perovskite nanocrystal/gold nanoparticle heterostructures.

    Science.gov (United States)

    Chen, Shanshan; Lyu, Danya; Ling, Tao; Guo, Weiwei

    2018-04-19

    A facile strategy is illustrated to reversibly modulate CsPbBr3 perovskite nanocrystal/Au nanoparticle heterostructures with the reversible formation and fragmentation of gold nanoparticles anchored to the corners and surface of CsPbBr3 perovskite nanocrystals. The modulation process was performed under ambient conditions and could be conducted for cycles.

  12. Determining the composition of gold nanoparticles: a compilation of shapes, sizes, and calculations using geometric considerations

    International Nuclear Information System (INIS)

    Mori, Taizo; Hegmann, Torsten

    2016-01-01

    Size, shape, overall composition, and surface functionality largely determine the properties and applications of metal nanoparticles. Aside from well-defined metal clusters, their composition is often estimated assuming a quasi-spherical shape of the nanoparticle core. With decreasing diameter of the assumed circumscribed sphere, particularly in the range of only a few nanometers, the estimated nanoparticle composition increasingly deviates from the real composition, leading to significant discrepancies between anticipated and experimentally observed composition, properties, and characteristics. We here assembled a compendium of tables, models, and equations for thiol-protected gold nanoparticles that will allow experimental scientists to more accurately estimate the composition of their gold nanoparticles using TEM image analysis data. The estimates obtained from following the routines described here will then serve as a guide for further analytical characterization of as-synthesized gold nanoparticles by other bulk (thermal, structural, chemical, and compositional) and surface characterization techniques. While the tables, models, and equations are dedicated to gold nanoparticles, the composition of other metal nanoparticle cores with face-centered cubic lattices can easily be estimated simply by substituting the value for the radius of the metal atom of interest.Graphical abstract

  13. Determining the composition of gold nanoparticles: a compilation of shapes, sizes, and calculations using geometric considerations

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Taizo, E-mail: MORI.Taizo@nims.go.jp; Hegmann, Torsten, E-mail: thegmann@kent.edu [Kent State University, Chemical Physics Interdisciplinary Program, Liquid Crystal Institute (United States)

    2016-10-15

    Size, shape, overall composition, and surface functionality largely determine the properties and applications of metal nanoparticles. Aside from well-defined metal clusters, their composition is often estimated assuming a quasi-spherical shape of the nanoparticle core. With decreasing diameter of the assumed circumscribed sphere, particularly in the range of only a few nanometers, the estimated nanoparticle composition increasingly deviates from the real composition, leading to significant discrepancies between anticipated and experimentally observed composition, properties, and characteristics. We here assembled a compendium of tables, models, and equations for thiol-protected gold nanoparticles that will allow experimental scientists to more accurately estimate the composition of their gold nanoparticles using TEM image analysis data. The estimates obtained from following the routines described here will then serve as a guide for further analytical characterization of as-synthesized gold nanoparticles by other bulk (thermal, structural, chemical, and compositional) and surface characterization techniques. While the tables, models, and equations are dedicated to gold nanoparticles, the composition of other metal nanoparticle cores with face-centered cubic lattices can easily be estimated simply by substituting the value for the radius of the metal atom of interest.Graphical abstract.

  14. Synthesis and bioconjugation of gold nanoparticles as potential molecular probes for light-based imaging techniques

    NARCIS (Netherlands)

    Rayavarapu, R.G.; Petersen, Wilhelmina; Ungureanu, C.; Post, Janine Nicole; van Leeuwen, Ton; Manohar, Srirang

    2007-01-01

    We have synthesized and characterized gold nanoparticles (spheres and rods) with optical extinction bands within the “optical imaging window.” The intense plasmon resonant driven absorption and scattering peaks of these nanoparticles make them suitable as contrast agents for optical imaging

  15. The detection of HBV DNA with gold-coated iron oxide nanoparticle gene probes

    International Nuclear Information System (INIS)

    Xi Dong; Luo Xiaoping; Lu Qianghua; Yao Kailun; Liu Zuli; Ning Qin

    2008-01-01

    Gold-coated iron oxide nanoparticle Hepatitis B virus (HBV) DNA probes were prepared, and their application for HBV DNA measurement was studied. Gold-coated iron oxide nanoparticles were prepared by the citrate reduction of tetra-chloroauric acid in the presence of iron oxide nanoparticles which were added as seeds. With a fluorescence-based method, the maximal surface coverage of hexaethiol 30-mer oligonucleotides and the maximal percentage of hybridization strands on gold-coated iron oxide nanoparticles were (120 ± 8) oligonucleotides per nanoparticle, and (14 ± 2%), respectively, which were comparable with those of (132 ± 10) and (22 ± 3%) in Au nanoparticle groups. Large network aggregates were formed when gold-coated iron oxide nanoparticle HBV DNA gene probe was applied to detect HBV DNA molecules as evidenced by transmission electron microscopy and the high specificity was verified by blot hybridization. Our results further suggested that detecting DNA with iron oxide nanoparticles and magnetic separator was feasible and might be an alternative effective method

  16. Gold nanoparticles applications in natural polymer modified for UV protection

    International Nuclear Information System (INIS)

    Silva, Iris O. da; Ladchumananandasivam, Rasiah; Nascimento, Jose H. O. do; Silva, Francisco C. da; Sa, Christiane S. de A.

    2015-01-01

    The protein-based polymers such as milk, such as polylactic acid (PLA) and soya can be cited as examples of substrates used in various fields of engineering, mainly due to its character of biodegradability, generating low environmental impact when compared to chemical polymers to petroleum-based, which take years to decompose in nature. Among these, soy fiber has great application potential because it is a manufactured material base of a residue obtained from the existing folder in the soybean seeds after oil extraction, using resins and chemicals for structural modification. In this work, soy mesh was used to develop a material with ultraviolet protection properties, through the use of nanotechnology. Thus, to connect the gold nanoparticles (NPAu), the fabric had a surface charge modified with the use of chitosan, using 20% of the weight of the material, followed by nanomaterials exhaust process. The NPAu were synthesized via chemical synthesis with sodium nitrate as reducing and stabilizing agent. The analysis of the solution samples were evaluated by absorbance spectroscopy and solid materials through diffuse reflectance spectroscopy and XRD X-ray diffraction. The size of NPAu was evaluated in equipment Zetasizer nanoseries / nanoZ, finding nanoparticles with an average size of 34.59 nm, and also underlined plasmon resonance phenomenon, with peaks between 530 nm and red coloration, and good results from the soundness washes, compared to conventional dyeing. It was found that soy polymer treated with NPAu presented an excellent property with ultraviolet protection factor (UPF) of +50, considered excellent, proving its potential application in the biomedical field. (author)

  17. Biomimetic High-Density Lipoproteins from a Gold Nanoparticle Template

    Science.gov (United States)

    Luthi, Andrea Jane

    For hundreds of years the field of chemistry has looked to nature for inspiration and insight to develop novel solutions for the treatment of human diseases. The ability of chemists to identify, mimic, and modifiy small molecules found in nature has led to the discovery and development of many important therapeutics. Chemistry on the nanoscale has made it possible to mimic natural, macromolecular structures that may also be useful for understanding and treating diseases. One example of such a structure is high-density lipoprotein (HDL). The goal of this work is to use a gold nanoparticle (Au NP) as a template to synthesize functional mimics of HDL and characterize their structure and function. Chapter 1 details the structure and function of natural HDL and how chemistry on the nanoscale provides new strategies for mimicking HDL. This Chapter also describes the first examples of using nanoparticles to mimic HDL. Chapter 2 reports the synthesis and characterization of biomimetic HDL using different sizes of Au NPs and different surface chemistries and how these variables can be used to tailor the properties of biomimetic HDL. From these studies the optimal strategy for synthesizing biomimetic HDL was determined. In Chapter 3, the optimization of the synthesis of biomimetic HDL is discussed as well as a full characterization of its structure. In addition, the work in this chapter shows that biomimetic HDL can be synthesized on a large scale without alterations to its structure or function. Chapter 4 focuses on understanding the pathways by which biomimetic HDL accepts cholesterol from macrophage cells. The results of these studies demonstrate that biomimetic HDL is able to accept cholesterol by both active and passive pathways of cholesterol efflux. In Chapter 5 the preliminary results of in vivo studies to characterize the pharmacokinetics and pharmacodynamics of biomimetic HDL are presented. These studies suggest that biomimetic HDL traffics through tissues prone to

  18. Merely Measuring the UV-Visible Spectrum of Gold Nanoparticles Can Change Their Charge State.

    Science.gov (United States)

    Navarrete, Jose; Siefe, Chris; Alcantar, Samuel; Belt, Michael; Stucky, Galen D; Moskovits, Martin

    2018-02-14

    Metallic nanostructures exhibit a strong plasmon resonance at a wavelength whose value is sensitive to the charge density in the nanostructure, its size, shape, interparticle coupling, and the dielectric properties of its surrounding medium. Here we use UV-visible transmission and reflectance spectroscopy to track the shifts of the plasmon resonance in an array of gold nanoparticles buried under metal-oxide layers of varying thickness produced using atomic layer deposition (ALD) and then coated with bulk layers of one of three metals: aluminum, silver, or gold. A significant shift in the plasmon resonance was observed and a precise value of ω p , the plasmon frequency of the gold comprising the nanoparticles, was determined by modeling the composite of gold nanoparticles and metal-oxide layer as an optically homogeneous film of core-shell particles bounded by two substrates: one of quartz and the other being one of the aforementioned metals, then using a Maxwell-Garnett effective medium expression to extract ω p for the gold nanoparticles before and after coating with the bulk metals. Under illumination, the change in the charge density of the gold nanoparticles per particle determined from the change in the values of ω p is found to be some 50-fold greater than what traditional electrostatic contact electrification models compute based on the work function difference of the two conductive materials. Moreover, when using bulk gold as the capping layer, which should have resulted in a negligible charge exchange between the gold nanoparticles and the bulk gold, a significant charge transfer from the bulk gold layer to the nanoparticles was observed as with the other metals. We explain these observations in terms of the "plasmoelectric effect", recently described by Atwater and co-workers, in which the gold nanoparticles modify their charge density to allow their resonant wavelength to match that of the incident light, thereby achieving, a lower value of the

  19. Polyaniline nanowires-gold nanoparticles hybrid network based chemiresistive hydrogen sulfide sensor

    Science.gov (United States)

    Shirsat, Mahendra D.; Bangar, Mangesh A.; Deshusses, Marc A.; Myung, Nosang V.; Mulchandani, Ashok

    2009-02-01

    We report a sensitive, selective, and fast responding room temperature chemiresistive sensor for hydrogen sulfide detection and quantification using polyaniline nanowires-gold nanoparticles hybrid network. The sensor was fabricated by facile electrochemical technique. Initially, polyaniline nanowires with a diameter of 250-320 nm bridging the gap between a pair of microfabricated gold electrodes were synthesized using templateless electrochemical polymerization using a two step galvanostatic technique. Polyaniline nanowires were then electrochemically functionalized with gold nanoparticles using cyclic voltammetry technique. These chemiresistive sensors show an excellent limit of detection (0.1 ppb), wide dynamic range (0.1-100 ppb), and very good selectivity and reproducibility.

  20. Colorimetric and ratiometric aggregation assay for streptomycin using gold nanoparticles and a new and highly specific aptamer

    International Nuclear Information System (INIS)

    Soheili, Vahid; Taghdisi, Seyed Mohammad; Khayyat, Mohammad Hassanzadeh; Abnous, Khalil; Bazzaz, BiBi Sedigheh Fazly; Ramezani, Mohammad

    2016-01-01

    Aptamers specific for the antibiotic streptomycin were identified by a modified SELEX procedure that employs magnetic beads. After eight rounds of selection, twenty-six aptamers were identified and clustered into seven groups according to similarities in their sequences. The binding constant of three sequences from different groups were determined by colorimetric assays using unmodified gold nanoparticles (AuNPs). These most suitable aptamers were then truncated, and finally a 23-base sequence was identified that has the highest affinity (K_d = 132.3 nM) and selectivity. The assay was employed to analyze streptomycin residue in raw milk samples by ratiometric spectrophotometry at 520 and 660 nm, respectively. The analytical range extends from 180 to 1000 nM, and the LOD is 47.2 nM which is better than that of HPLC (4 μM). The interaction between aptamer and streptomycin was studied by molecular modeling. In our perception, this colorimetric assay provides a viable method for fast analysis of streptomycin in raw milk. (author)

  1. Cytotoxic Induction and Photoacoustic Imaging of Breast Cancer Cells Using Astaxanthin-Reduced Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Subramaniyan Bharathiraja

    2016-04-01

    Full Text Available Astaxanthin, a kind of photosynthetic pigment, was employed for gold nanoparticle formation. Nanoparticles were characterized using Ulteraviolet-Visible (UV-Vis spectroscopy, transmission electron microscopy, and X-ray diffraction, and the possible presence of astaxanthin functional groups were analyzed by Fourier transform infrared spectroscopy (FTIR. The cytotoxic effect of synthesized nanoparticles was evaluated against MDA-MB-231 (human breast cancer cells using a tetrazolium-based assay, and synthesized nanoparticles exhibited dose-dependent toxicity. The morphology upon cell death was differentiated through fluorescent microscopy using different stains that predicted apoptosis. The synthesized nanoparticles were applied in ultrasound-coupled photoacoustic imaging to obtain good images of treated cells. Astaxanthin-reduced gold nanoparticle has the potential to act as a promising agent in the field of photo-based diagnosis and therapy.

  2. Plectranthus amboinicus-mediated silver, gold, and silver-gold nanoparticles: phyto-synthetic, catalytic, and antibacterial studies

    Science.gov (United States)

    Purusottam Reddy, B.; Mallikarjuna, K.; Narasimha, G.; Park, Si-Hyun

    2017-08-01

    Bio-based green nanotechnology aims to characterize compounds from natural sources and establish efficient routes for the preparation of nontoxic materials that have applicability in biodegradable and biocompatible devices. The present study has investigated the use of Plectranthus amboinicus leaf extracts as reducing and capping materials for the green fabrication of silver, gold, and silver-gold (Ag, Au, and Ag/Au) metal and bimetallic nanoparticles. The catalytic behavior of these phyto-inspired nanoparticles was then assessed in terms of the reduction of 4-nitrophenol. Transmission electron microscopy was used to investigate the shape, morphology, distribution, and diameter of the phytomolecules capped with Ag, Au, and Ag/Au metal nanoparticles. The nature of the crystallinity of the nanoparticles was studied by small area electron diffraction (SAED) and x-ray diffraction analysis (XRD), and Fourier transform infrared (FTIR) spectroscopy was used to study the reduction and stabilizing involvement of the phyto-organic moieties in aqueous medium. The phyto-inspired Ag and Ag/Au nanoparticles demonstrated good antibacterial properties toward Gram-negative Escherichia coli and Pseudomonas spp. and Gram-positive Bacillus spp. and Staphylococcus spp. microorganisms using the well diffusion method. Notably, the Ag nanoparticles were shown to possess effective antibacterial properties.

  3. Colorimetric detection of manganese(II) ions using gold/dopa nanoparticles.

    Science.gov (United States)

    Narayanan, Kannan Badri; Park, Hyun Ho

    2014-10-15

    We report here a one-pot, greener, eco-friendly strategy for the synthesis of gold nanoparticles using L-dopa. The as-prepared dopa-functionalized gold nanoparticles (AuNPs/dopa) can detect low concentrations of manganese(II) metal ions in aqueous solution. The binding forces between dopa and Mn(2+) ions cause dopa-functionalized gold nanoparticles to come closer together, decreasing the interparticle distance and aggregating it with a change in color of colloidal solution from red to purplish-blue. Dynamic light scattering (DLS) analysis showed a decreased surface charge on the surface of gold nanoparticles when exposed to Mn(2+) ions, which caused cross-linking aggregation. Transmission electron microscopic (TEM) images also revealed the aggregation of gold nanoparticles with the addition of Mn(2+) ions. The extinction ratio of absorbance at 700-550nm (A700/A550) was linear against the concentration of [Mn(2+)] ions. Thus, the optical absorption spectra of gold colloidal solution before and after the addition of Mn(2+) ions reveal the concentration of Mn(2+) ions in solution. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Rapid colorimetric sensing of tetracycline antibiotics with in situ growth of gold nanoparticles.

    Science.gov (United States)

    Shen, Li; Chen, Jing; Li, Na; He, Pingli; Li, Zhen

    2014-08-11

    A colorimetric assay utilizing the formation of gold nanoparticles was developed to detect tetracycline antibiotics in fluidic samples. Tetracycline antibiotics showed the capability of directly reducing aurate salts into atomic gold which form gold nanoparticles spontaneously under proper conditions. The resulted gold nanoparticles showed characteristic plasmon absorbance at 526 nm, which can be visualized by naked eyes or with a spectrophotometer. UV-vis absorbance of the resulted gold nanoparticles is correlated directly with the concentrations of tetracycline antibiotics in the solution, allowing for quantitative colorimetric detection of tetracycline antibiotics. Reaction conditions, such as pH, temperature, reaction time, and ionic strength were optimized. Sensitivity of the colorimetric assay can be enhanced by the addition of gold nanoparticle seeds, a LOD as low as 20 ng mL(-1) can be achieved with the help of seed particles. The colorimetric assay showed minimum interference from ethanol, methanol, urea, glucose, and other antibiotics such as sulfonamides, amino glycosides etc. Validity of the method was also evaluated on urine samples spiked with tetracycline antibiotics. The method provides a broad spectrum detection method for rapid and sensitive detection of reductive substances such as tetracycline antibiotics in liquid and biological samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Cytotoxicity evaluation of gold nanoparticles on microalga Dunaliella salina in microplate test system

    Science.gov (United States)

    Chumakov, Daniil; Prilepskii, Artur; Dykman, Lev; Khlebtsov, Boris; Khlebtsov, Nikolai; Bogatyrev, Vladimir

    2018-04-01

    Gold nanoparticles are intensively studied in biomedicine. Assessment of their biocompatibility is highly important. Currently there is lack of evidence, concerning nanotoxicity of ultrasmall gold nanoparticles < 5 nm. Existing data are rather contradictory. The aim of that study was to evaluate the toxicity of 2 nm colloidal gold, using microalga Dunaliella salina. Cellular barriers of that microalga are very similar to animal cells so it might be considered as a valuable model for nanotoxicity testing. Chlorophyll content as a test-function was used. Spectrophotometric method for chlorophyll determination in vivo in suspensions of D.salina cultures was applied. Calculated EC50 48h value of ionic gold was 25.8 +/- 0.3 mg Au/L. EC50 value of phosphine-stabilized gold nanoclusters was 32.2 +/-1.1 mg Au/L. It was not possible to calculate EC50 for 15 nm citrate gold nanoparticles, as they were non-toxic at all concentrations tested. These results are confirmed by fluorescent -microscopic monitoring of the same probes. It was shown that 10-fold growth of phosphine-stabilized gold nanoparticles (from 2.3 +/- 0.9 nm to 21.1 +/- 7.5 nm) led to 7-fold decrease of their toxicity.

  6. Mammalian cell growth on gold nanoparticle-decorated substrates is influenced by the nanoparticle coating

    Directory of Open Access Journals (Sweden)

    Christina Rosman

    2014-12-01

    Full Text Available In this work, we study epithelial cell growth on substrates decorated with gold nanorods that are functionalized either with a positively charged cytotoxic surfactant or with a biocompatible polymer exhibiting one of two different end groups, resulting in a neutral or negative surface charge of the particle. Upon observation of cell growth for three days by live cell imaging using optical dark field microscopy, it was found that all particles supported cell adhesion while no directed cell migration and no significant particle internalization occurred. Concerning cell adhesion and spreading as compared to cell growth on bare substrates after 3 days of incubation, a reduction by 45% and 95%, respectively, for the surfactant particle coating was observed, whereas the amino-terminated polymer induced a reduction by 30% and 40%, respectively, which is absent for the carboxy-terminated polymer. Furthermore, interface-sensitive impedance spectroscopy (electric cell–substrate impedance sensing, ECIS was employed in order to investigate the micromotility of cells added to substrates decorated with various amounts of surfactant-coated particles. A surface density of 65 particles/µm2 (which corresponds to 0.5% of surface coverage with nanoparticles diminishes micromotion by 25% as compared to bare substrates after 35 hours of incubation. We conclude that the surface coating of the gold nanorods, which were applied to the basolateral side of the cells, has a recognizable influence on the growth behavior and thus the coating should be carefully selected for biomedical applications of nanoparticles.

  7. Extracellular synthesis of silver and gold nanoparticles by Sporosarcina koreensis DC4 and their biological applications.

    Science.gov (United States)

    Singh, Priyanka; Singh, Hina; Kim, Yeon Ju; Mathiyalagan, Ramya; Wang, Chao; Yang, Deok Chun

    2016-05-01

    The present study highlights the microbial synthesis of silver and gold nanoparticles by Sporosarcina koreensis DC4 strain, in an efficient way. The synthesized nanoparticles were characterized by ultraviolet-visible spectrophotometry, which displayed maximum absorbance at 424nm and 531nm for silver and gold nanoparticles, respectively. The spherical shape of nanoparticles was characterized by field emission transmission electron microscopy. The energy dispersive X-ray spectroscopy and elemental mapping were displayed the purity and maximum elemental distribution of silver and gold elements in the respective nanoproducts. The X-ray diffraction spectroscopy results demonstrate the crystalline nature of synthesized nanoparticles. The particle size analysis demonstrate the nanoparticles distribution with respect to intensity, volume and number of nanoparticles. For biological applications, the silver nanoparticles have been explored in terms of MIC and MBC against pathogenic microorganisms such as Vibrio parahaemolyticus, Escherichia coli, Salmonella enterica, Bacillus anthracis, Bacillus cereus and Staphylococcus aureus. Moreover, the silver nanoparticles in combination with commercial antibiotics, such as vancomycin, rifampicin, oleandomycin, penicillin G, novobiocin, and lincomycin have been explored for the enhancement of antibacterial activity and the obtained results showed that 3μg concentration of silver nanoparticles sufficiently enhance the antimicrobial efficacy of commercial antibiotics against pathogenic microorganism. Furthermore, the silver nanoparticles potential has been reconnoitered for the biofilm inhibition by S. aureus, Pseudomonas aeruginosa and E. coli and the results revealed sufficient activity at 6μg concentration. In addition, gold nanoparticles have been applied for catalytic activity, for the reduction of 4-nitrophenol to 4-aminophenol using sodium borohydride and positive results were attained. Copyright © 2016 Elsevier Inc. All

  8. Measurement of discrete energy-level spectra in individual chemically synthesized gold nanoparticles

    DEFF Research Database (Denmark)

    Kuemmeth, Ferdinand; Bolotin, Kirill I; Shi, Su-Fei

    2008-01-01

    We form single-electron transistors from individual chemically synthesized gold nanoparticles, 5-15 nm in diameter, with monolayers of organic molecules serving as tunnel barriers. These devices allow us to measure the discrete electronic energy levels of individual gold nanoparticles that are......, by virtue of chemical synthesis, well-defined in their composition, size and shape. We show that the nanoparticles are nonmagnetic and have spectra in good accord with random-matrix-theory predictions taking into account strong spin-orbit coupling....

  9. Anomalous complete opaqueness in a sparse array of gold nanoparticle chains

    International Nuclear Information System (INIS)

    Bai Benfeng; Li Xiaowei; Vartiainen, Ismo; Lehmuskero, Anni; Turunen, Jari; Kuittinen, Markku; Vahimaa, Pasi; Kang Guoguo

    2011-01-01

    We report on an anomalous polarization-switching extinction effect in a sparse array of gold nanoparticle chains: under normal incidence of light, the array is almost transparent for one polarization; whereas it is fully opaque (with nearly zero transmittance) for the orthogonal polarization within a narrow band, even though the nanoparticles cover only a tiny fraction (say, 3.5%) of the transparent substrate surface. We reveal that the strong polarization-dependent short-range dipolar coupling and long-range radiative coupling of gold nanoparticles in this highly asymmetric array is responsible for this extraordinary effect.

  10. Synthesis of Gold Nanoparticles Using Garcinia Indica Fruit Rind Extract

    Science.gov (United States)

    Krishnaprabha, M.; Pattabi, Manjunatha

    2016-10-01

    This report presents the easily reproducible biosynthesis of gold nanoparticles (AuNPs) at room temperature with extract prepared using three year old dried Garcinia Indica (GI) fruit rind. Due to the presence of two major bioactive compounds garcinol and hydroxy citric acid, rinds of GI fruit exhibit anti-cancer and anti-obesity properties. The quantity of fruit rind extract directed the morphology of the as synthesized particles. The nucleation and growth of AuNPs and catalytic activity are studied using UV-Vis spectroscopy. The crystalline nature of biosynthesized AuNPs is corroborated by X-ray Diffraction techniques. The morphology is studied using field emission scanning electron microscopy (FESEM). Fourier transform infra-red (FTIR) spectroscopy analysis revealed that biomolecules were involved in the synthesis and capping of AuNPs. As the Fermi potential of noble metal NPs becomes more negative, they are used in various electron transfer processes. The AuNPs produced using GI extract showed excellent catalytic activity when used as a catalyst in the reduction of well-known toxic pollutant 4-Nitrophenol (4-NP) to 4-Aminophenol (4-AP) in the presence of excess sodium borohydride.

  11. Roadmap to Clinical Use of Gold Nanoparticles for Radiation Sensitization

    Energy Technology Data Exchange (ETDEWEB)

    Schuemann, Jan, E-mail: jschuemann@mgh.harvard.edu [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Berbeco, Ross [Department of Radiation Oncology, Brigham and Women' s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts (United States); Chithrani, Devika B. [Department of Physics, Ryerson University, Toronto, Ontario (Canada); Cho, Sang Hyun [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kumar, Rajiv [Nanomedicine Science and Technology Center, Northeastern University, Boston, Massachusetts (United States); Department of Radiation Oncology, Harvard Medical School, Boston, Massachusetts (United States); McMahon, Stephen J. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Centre for Cancer Research and Cell Biology, Queen' s University Belfast, Belfast, Northern Ireland (United Kingdom); Sridhar, Srinivas [Nanomedicine Science and Technology Center, Northeastern University, Boston, Massachusetts (United States); Department of Radiation Oncology, Harvard Medical School, Boston, Massachusetts (United States); Krishnan, Sunil [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2016-01-01

    The past decade has seen a dramatic increase in interest in the use of gold nanoparticles (GNPs) as radiation sensitizers for radiation therapy. This interest was initially driven by their strong absorption of ionizing radiation and the resulting ability to increase dose deposited within target volumes even at relatively low concentrations. These early observations are supported by extensive experimental validation, showing GNPs' efficacy at sensitizing tumors in both in vitro and in vivo systems to a range of types of ionizing radiation, including kilovoltage and megavoltage X rays as well as charged particles. Despite this experimental validation, there has been limited translation of GNP-mediated radiation sensitization to a clinical setting. One of the key challenges in this area is the wide range of experimental systems that have been investigated, spanning a range of particle sizes, shapes, and preparations. As a result, mechanisms of uptake and radiation sensitization have remained difficult to clearly identify. This has proven a significant impediment to the identification of optimal GNP formulations which strike a balance among their radiation sensitizing properties, their specificity to the tumors, their biocompatibility, and their imageability in vivo. This white paper reviews the current state of knowledge in each of the areas concerning the use of GNPs as radiosensitizers, and outlines the steps which will be required to advance GNP-enhanced radiation therapy from their current pre-clinical setting to clinical trials and eventual routine usage.

  12. Integration of capillary electrophoresis with gold nanoparticle-based colorimetry.

    Science.gov (United States)

    Li, Tong; Wu, Zhenglong; Qin, Weidong

    2017-12-01

    A method integrating capillary electrophoresis (CE) and gold nanoparticle aggregation-based colorimetry (AuNP-ABC) was described. By using a dual-sheath interface, the running buffer was isolated from the colorimetric reaction solution so that CE and AuNP-ABC would not interfere with each other. The proof-of-concept was validated by assay of polyamidoamine (PAMAM) dendrimers that were fortified in human urine samples. The factors influencing the CE-AuNP-ABC performances were investigated and optimized. Under the optimal conditions, the dendrimers were separated within 8 min, with detection limits of 0.5, 1.2 and 2.6 μg mL -1 for PAMAM G1.0, G2.0 and G3.0, respectively. The sensitivity of CE-AuNP-ABC was comparable to or even better than those of liquid chromatography-fluorimetry and liquid chromatography-mass spectrometry. The results suggested that the proposed strategy can be applied to facile and quick determination of analytes of similar properties in complex matrices. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Labeling and tracking exosomes within the brain using gold nanoparticles

    Science.gov (United States)

    Betzer, Oshra; Perets, Nisim; Barnoy, Eran; Offen, Daniel; Popovtzer, Rachela

    2018-02-01

    Cell-to-cell communication system involves Exosomes, small, membrane-enveloped nanovesicles. Exosomes are evolving as effective therapeutic tools for different pathologies. These extracellular vesicles can bypass biological barriers such as the blood-brain barrier, and can function as powerful nanocarriers for drugs, proteins and gene therapeutics. However, to promote exosomes' therapy development, especially for brain pathologies, a better understanding of their mechanism of action, trafficking, pharmacokinetics and bio-distribution is needed. In this research, we established a new method for non-invasive in-vivo neuroimaging of mesenchymal stem cell (MSC)-derived exosomes, based on computed tomography (CT) imaging with glucose-coated gold nanoparticle (GNP) labeling. We demonstrated that the exosomes were efficiently and directly labeled with GNPs, via an energy-dependent mechanism. Additionally, we found the optimal parameters for exosome labeling and neuroimaging, wherein 5 nm GNPs enhanced labeling, and intranasal administration produced superior brain accumulation. We applied our technique in a mouse model of focal ischemia. Imaging and tracking of intranasally-administered GNP-labeled exosomes revealed specific accumulation and prolonged presence at the lesion area, up to 24 hrs. We propose that this novel exosome labeling and in-vivo neuroimaging technique can serve as a general platform for brain theranostics.

  14. Fungal biosynthesis of gold nanoparticles: mechanism and scale up.

    Science.gov (United States)

    Kitching, Michael; Ramani, Meghana; Marsili, Enrico

    2015-11-01

    Gold nanoparticles (AuNPs) are a widespread research tool because of their oxidation resistance, biocompatibility and stability. Chemical methods for AuNP synthesis often produce toxic residues that raise environmental concern. On the other hand, the biological synthesis of AuNPs in viable microorganisms and their cell-free extracts is an environmentally friendly and low-cost process. In general, fungi tolerate higher metal concentrations than bacteria and secrete abundant extracellular redox proteins to reduce soluble metal ions to their insoluble form and eventually to nanocrystals. Fungi harbour untapped biological diversity and may provide novel metal reductases for metal detoxification and bioreduction. A thorough understanding of the biosynthetic mechanism of AuNPs in fungi is needed to reduce the time of biosynthesis and to scale up the AuNP production process. In this review, we describe the known mechanisms for AuNP biosynthesis in viable fungi and fungal protein extracts and discuss the most suitable bioreactors for industrial AuNP biosynthesis. © 2014 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  15. Mechanism of large optical nonlinearity in gold nanoparticle films.

    Science.gov (United States)

    Mirza, I; McCloskey, D; Blau, W J; Lunney, J G

    2018-04-01

    The Z-scan technique, using femtosecond (fs) laser pulses at 1480 nm laser pulses, was used to measure the nonlinear optical properties of gold (Au) nanoparticle (NP) films made by both nanosecond (ns) and fs pulsed laser deposition (PLD) in vacuum. At irradiance levels of 1×10 12   Wm -2 , the ns-PLD films displayed induced absorption with β=4×10 -5   mW -1 , and a negative lensing effect with n 2 =-4.7×10 -11   m 2  W -1 with somewhat smaller values for the fs-PLD films. These values of n 2 imply an unphysically large change in the real part of the refractive index, demonstrating the need to take account of nonlinear changes of the Fresnel coefficients and multiple beam interference in Z-scan measurements on nanoscale films. Following this approach, the Z-scan observations were analyzed to determine the effective complex refractive index of the NP film at high irradiance. It appears that at high irradiance the NP film behaves as a metal, while at low irradiance it behaves as a low-loss dielectric. Thus, it is conjectured that, for high irradiance near the waist of the Z-scan laser beam, laser driven electron tunneling between NPs gives rise to metal-like optical behavior.

  16. The deposition of gold nanoparticles in MWCNT forests

    Science.gov (United States)

    de Jong, Franciscus; Buffet, Adeline; Schlueter, Michael

    2015-11-01

    The deposition, i.e. transport and attachment, of small-sized particles is a basic process, on which many applications are based. The innumerable applications range from biology and medicine to engineering. Due to their promising mechanical properties multi-walled carbon nanotubes (MWCNTs) have gained increasing popularity in the past decade. A large number of dense packed vertically aligned MWCNTs form a so-called MWCNT forest. In our study we functionalized the MWCNT forest to filter gold nanoparticles from a colloidal suspension. An experimental investigation was carried out in which the particle deposition kinetics was locally determined with small-angle X-ray scattering (SAXS). Furthermore, inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to verify the local observations. It was concluded that both, SAXS and ICP-AES investigations shows very good agreement. Furthermore, an analytical deposition model was developed based on the DLVO-theory. The experimental and theoretical investigation presented here give insight in the deposition kinetics within a MWCNT forest. The results open up pathways to optimize MWCNT forests for filtering purposes.

  17. Anisotropic gold nanoparticles: synthesis, properties, applications, and toxicity.

    Science.gov (United States)

    Li, Na; Zhao, Pengxiang; Astruc, Didier

    2014-02-10

    Anisotropic gold nanoparticles (AuNPs) have attracted the interest of scientists for over a century, but research in this field has considerably accelerated since 2000 with the synthesis of numerous 1D, 2D, and 3D shapes as well as hollow AuNP structures. The anisotropy of these nonspherical, hollow, and nanoshell AuNP structures is the source of the plasmon absorption in the visible region as well as in the near-infrared (NIR) region. This NIR absorption is especially sensitive to the AuNP shape and medium and can be shifted towards the part of the NIR region in which living tissue shows minimum absorption. This has led to crucial applications in medical diagnostics and therapy ("theranostics"), especially with Au nanoshells, nanorods, hollow nanospheres, and nanocubes. In addition, Au nanowires (AuNWs) can be synthesized with longitudinal dimensions of several tens of micrometers and can serve as plasmon waveguides for sophisticated optical devices. The application of anisotropic AuNPs has rapidly spread to optical, biomedical, and catalytic areas. In this Review, a brief historical survey is given, followed by a summary of the synthetic modes, variety of shapes, applications, and toxicity issues of this fast-growing class of nanomaterials. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Cancer-selective, single agent chemoradiosensitising gold nanoparticles

    Science.gov (United States)

    Grellet, Sophie; Tzelepi, Konstantina; Roskamp, Meike; Williams, Phil; Sharif, Aquila; Slade-Carter, Richard; Goldie, Peter; Whilde, Nicky; Śmiałek, Małgorzata A.; Mason, Nigel J.

    2017-01-01

    Two nanometre gold nanoparticles (AuNPs), bearing sugar moieties and/or thiol-polyethylene glycol-amine (PEG-amine), were synthesised and evaluated for their in vitro toxicity and ability to radiosensitise cells with 220 kV and 6 MV X-rays, using four cell lines representing normal and cancerous skin and breast tissues. Acute 3 h exposure of cells to AuNPs, bearing PEG-amine only or a 50:50 ratio of alpha-galactose derivative and PEG-amine resulted in selective uptake and toxicity towards cancer cells at unprecedentedly low nanomolar concentrations. Chemotoxicity was prevented by co-administration of N-acetyl cysteine antioxidant, or partially prevented by the caspase inhibitor Z-VAD-FMK. In addition to their intrinsic cancer-selective chemotoxicity, these AuNPs acted as radiosensitisers in combination with 220 kV or 6 MV X-rays. The ability of AuNPs bearing simple ligands to act as cancer-selective chemoradiosensitisers at low concentrations is a novel discovery that holds great promise in developing low-cost cancer nanotherapeutics. PMID:28700660

  19. Application of Gold Nanoparticles for Electrochemical DNA Biosensor

    Directory of Open Access Journals (Sweden)

    Ahmed Mishaal Mohammed

    2014-01-01

    Full Text Available An electrochemical DNA biosensor was successfully fabricated by using (3-aminopropyltriethoxysilane (APTES as a linker molecule combined with the gold nanoparticles (GNPs on thermally oxidized SiO2 thin films. The SiO2 thin films surface was chemically modified with a mixture of APTES and GNPs for DNA detection in different time periods of 30 min, 1 hour, 2 hours, and 4 hours, respectively. The DNA immobilization and hybridization were conducted by measuring the differences of the capacitance value within the frequency range of 1 Hz to 1 MHz. The capacitance values for DNA immobilization were 160 μF, 77.8 μF, 70 μF, and 64.6 μF, respectively, with the period of time from 30 min to 4 hours. Meanwhile the capacitance values for DNA hybridization were 44 μF, 54 μF, 55 μF, and 61.5 μF, respectively. The capacitance value of bare SiO2 thin film was 0.42 μF, which was set as a base line for a reference in DNA detection. The differences of the capacitance value between the DNA immobilization and hybridization revealed that the modified SiO2 thin films using APTES and GNPs were successfully developed for DNA detection.

  20. Gold nanoparticles cellular toxicity and recovery: adipose Derived Stromal cells.

    Science.gov (United States)

    Mironava, Tatsiana; Hadjiargyrou, Michael; Simon, Marcia; Rafailovich, Miriam H

    2014-03-01

    Gold nanoparticles (AuNPs) are currently used in numerous medical applications. Herein, we describe their in vitro impact on human adipose-derived stromal cells (ADSCs) using 13 nm and 45 nm citrate-coated AuNPs. In their non-differentiated state, ADSCs were penetrated by the AuNPs and stored in vacuoles. The presence of the AuNPs in ADSCs resulted in increased population doubling times, decreased cell motility and cell-mediated collagen contraction. The degree to which the cells were impacted was a function of particle concentration, where the smaller particles required a sevenfold higher concentration to have the same effect as the larger ones. Furthermore, AuNPs reduced adipogenesis as measured by lipid droplet accumulation and adiponectin secretion. These effects correlated with transient increases in DLK1 and with relative reductions in fibronectin. Upon removal of exogenous AuNPs, cellular NP levels decreased and normal ADSC functions were restored. As adiponectin helps regulate energy metabolism, local fluctuations triggered by AuNPs can lead to systemic changes. Hence, careful choice of size, concentration and clinical application duration of AuNPs is warranted.

  1. Effect of gold nanoparticles on postoperative peritoneal adhesions in rats

    Directory of Open Access Journals (Sweden)

    Amir Hooshang Mohammadpour

    2015-07-01

    Full Text Available Objective(s: Abdominal adhesions are one of the most important problems, occurring after intra-abdominal surgery in more than 90% of cases. This condition is the leading cause of bowel obstruction, infertility, and abdominal/pelvic pain. Gold nanoparticles (GNPs have been shown to be non-toxic and exhibit anti-inflammatory, anti-angiogenic and antioxidant activities. The purpose of this study was to determine the effect of intraperitoneal lavage with GNP solutions on the development of postoperative peritoneal adhesion (PPA. Materials and Methods:In the current experimental study, thirty-five male Wistar rats were randomly assigned to seven groups of five rats. After a standardized peritoneal injury, GNP solutions in different concentrations (1, 2.5, 5, 10, 50 and 100 ng/ml were locally administered through nebulization; normal saline (NS was administered to the control group. Two weeks later, the rats were sacrificed and cecum and peritoneal samples were harvested for histopathological assessment. Blood samples were obtained to determine serum concentrations of inflammatory biomarkers including tumor necrosis factor alpha (TNF-α, interleukin-1 beta (IL-1β and vascular endothelial growth factor (VEGF. Results: The rats treated with GNPs had significantly lower microscopic and macroscopic peritoneal adhesion scores, compared to the control group (P

  2. Interactions between citrate-capped gold nanoparticles and polymersomes

    Science.gov (United States)

    Zhang, Xiaohan; Lopez, Anand; Liu, Yibo; Wang, Feng; Liu, Juewen

    2018-06-01

    Polymersomes are vesicles formed by self-assembled amphiphilic block copolymers. Polymersomes generally have better stability than liposomes and they have been widely used in making drug delivery vehicles. In this work, the interaction between two types of polymersomes and citrate-capped gold nanoparticles (AuNPs) was studied. The following two polymers: poly(2-methyloxazoline-b-dimethylsiloxane-b-2-methyloxazoline) (called P1) and poly(butadiene-b-ethylene oxide) (called P2) were respectively used to form polymersomes. While P1 only formed spherical vesicle structures, worm-like structures were also observed with P2 as indicated by cryo-TEM. Both polymersomes adsorbed AuNPs leading to their subsequent aggregation. A lower polymersome concentration produced more obvious aggregation of AuNPs as judged from the color change. Capping AuNPs with glutathione inhibited adsorption of AuNPs. Considering the surface property of the polymers, the interaction with AuNPs was likely due to van der Waals forces. P1 polymersomes encapsulated calcein stably and AuNPs did not induce leakage. The P1/AuNP complex was more efficiently internalized by HeLa cells compared to free P1 polymersomes, further indicating a stable adsorption under cell culture conditions. In summary, this work indicates citrate-capped AuNPs form stable adsorption complexes with these polymersomes and their interactions have been explored.

  3. Gold nanoparticles-based colorimetric and visual creatinine assay

    International Nuclear Information System (INIS)

    He, Yi; Zhang, Xianhui; Yu, Haili

    2015-01-01

    We demonstrate a selective and sensitive method for determination of creatinine using citrate-stabilized gold nanoparticles (AuNPs) as a colorimetric probe. It is based on a direct cross-linking reaction that occurs between creatinine and AuNPs that causes aggregation of AuNPs and results in a color change from wine red to blue. The absorption peak is shifted from 520 to 670 nm. Under the optimized conditions, the shift in the absorption peak is related the logarithm of the creatinine concentration in the 0.1 to 20 mM range, and the instrumental detection limit (LOD) is 80 μM. This LOD is about one order of magnitude better than that that of the Jaffé method (720 μM). The assay displays good selectivity over interfering substances including various inorganic ions, organic small compounds, proteins, and biothiols. It was successfully employed to the determination of creatinine in spiked human urine. (author)

  4. Colorimetric determination of neomycin using melamine modified gold nanoparticles

    International Nuclear Information System (INIS)

    Xiao, Can; Liu, Junfeng; Yang, Ankang; Zhao, Hong; He, Yujian; Li, Xiangjun; Yuan, Zhuobin

    2015-01-01

    The colorimetric assay for neomycin presented here is based on melamine-modified gold nanoparticles (mel-AuNPs) and the finding that hydrogen bonding between melamine and neomycin results in the aggregation of mel-AuNPs. This results in a change in the color of the solution from wine red to blue and in a red-shift of the absorption maximum of the mel-AuNPs. The concentration of neomycin can be determined by spectrophotometry. The ratio of absorptions at 680 nm and 520 nm is linearly related to the logarithm of the concentration of neomycin in the 0.1 to 5.0 nM range and in the 5 to 100 nM range, with regression coefficients of 0.997 and 0.999, respectively. The detection limit (at an S/N ratio of 3) is 30 pM. This is far below the usual safety limit. The method was applied to the detection of trace levels of neomycin in milk samples and gave recoveries between 98 and 105 %. (author)

  5. Cancer-selective, single agent chemoradiosensitising gold nanoparticles.

    Directory of Open Access Journals (Sweden)

    Sophie Grellet

    Full Text Available Two nanometre gold nanoparticles (AuNPs, bearing sugar moieties and/or thiol-polyethylene glycol-amine (PEG-amine, were synthesised and evaluated for their in vitro toxicity and ability to radiosensitise cells with 220 kV and 6 MV X-rays, using four cell lines representing normal and cancerous skin and breast tissues. Acute 3 h exposure of cells to AuNPs, bearing PEG-amine only or a 50:50 ratio of alpha-galactose derivative and PEG-amine resulted in selective uptake and toxicity towards cancer cells at unprecedentedly low nanomolar concentrations. Chemotoxicity was prevented by co-administration of N-acetyl cysteine antioxidant, or partially prevented by the caspase inhibitor Z-VAD-FMK. In addition to their intrinsic cancer-selective chemotoxicity, these AuNPs acted as radiosensitisers in combination with 220 kV or 6 MV X-rays. The ability of AuNPs bearing simple ligands to act as cancer-selective chemoradiosensitisers at low concentrations is a novel discovery that holds great promise in developing low-cost cancer nanotherapeutics.

  6. Summary of gold nanoparticles obtained by reduction Au3+

    International Nuclear Information System (INIS)

    Corzo Lucioni, Alberto

    2012-01-01

    In the present investigation were synthesized nanoparticles (NPs) of gold by oxidation-reduction reactions at boiling temperature, starting from dilute solutions of acid tetrachloroauric: H[AuCl 4 ].3H 2 O as a precursor in the presence of organic reducing agents such as trisodium citrate: Na 3 C 6 H 5 O 7 .2H 2 O; potassium sodium tartrate: KNaC 4 H 4 O 6 .4H 2 O and sodium borohydride: inorganic reducing agent NaBH 4 . With the aim of evaluating the particle size according to the type of reducing agent, is designed a series of experiments in which the reducing agent is changed, keeping it constant concentrations, but varying the concentration of H[AuCl 4 ]. The particle size and the absorbance of the plasmon Au were measured in a particle size analyzer and a UV - visible, respectively. In turn, the effect of pH variation on the size of the NP Au, maintaining concentrations of H [AuCl 4 ] constant and reducing agent trisodium citrate, at different pH values under the same conditions. (author).

  7. Preparation of porous polymer monoliths featuring enhanced surface coverage with gold nanoparticles

    KAUST Repository

    Lv, Yongqin

    2012-10-01

    A new approach to the preparation of porous polymer monoliths with enhanced coverage of pore surface with gold nanoparticles has been developed. First, a generic poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith was reacted with cystamine followed by the cleavage of its disulfide bonds with tris(2-carboxylethyl)phosphine, which liberated the desired thiol groups. Dispersions of gold nanoparticles with sizes varying from 5 to 40. nm were then pumped through the functionalized monoliths. The materials were then analyzed using both energy dispersive X-ray spectroscopy and thermogravimetric analysis. We found that the quantity of attached gold was dependent on the size of nanoparticles, with the maximum attachment of more than 60. wt% being achieved with 40. nm nanoparticles. Scanning electron micrographs of the cross sections of all the monoliths revealed the formation of a non-aggregated, homogenous monolayer of nanoparticles. The surface of the bound gold was functionalized with 1-octanethiol and 1-octadecanethiol, and these monolithic columns were used successfully for the separations of proteins in reversed phase mode. The best separations were obtained using monoliths modified with 15, 20, and 30. nm nanoparticles since these sizes produced the most dense coverage of pore surface with gold. © 2012 Elsevier B.V.

  8. Porous silicon photoluminescence modification by colloidal gold nanoparticles: Plasmonic, surface and porosity roles

    International Nuclear Information System (INIS)

    Mora, M.B. de la; Bornacelli, J.; Nava, R.; Zanella, R.; Reyes-Esqueda, J.A.

    2014-01-01

    Metal nanoparticles on semiconductors are of interest because of the tunable effect of the surface plasmon resonance on the physical properties of the semiconductor. In this work, colloidal gold nanoparticles obtained by two different methods, with an average size of 6.1±2.0 nm and 5.0±2.0 nm, were added to luminescent porous silicon by drop casting. The gold nanoparticles interact with porous silicon by modifying its optical properties such as photoluminescence. That being said, plasmon effects are not the only to be taken into account; as shown in this work, surface chemical modification and porosity also play a key role in the final performance of photoluminescence of a porous silicon–gold nanoparticle hybrid system. -- Highli