Nanoparticle Assembly via Hydrogen-Bonding: IRS, TEM and AFM Characterizations

2001 ◽  
Vol 635 ◽  
Author(s):  
Li Han ◽  
Mathew M. Maye ◽  
Chuan-Jian Zhong
Keyword(s):  
Gold Nanoparticles ◽  
Hydrogen Bonding ◽  
Morphological Properties ◽  
Nanoparticle Assembly ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Infrared Reflection ◽  
Afm Imaging ◽  
Infrared Reflection Spectroscopy

AbstractThis paper reports results of the characterizations of nanoparticle assembly formed via spontaneous core-shell and shell-shell reactivities at thiolate-capped gold nanoparticles. Gold nanoparticles of two different core sizes and thiols with carboxylic acid terminals are exploited as a model system. The reactivities involve covalent Au-thiolate bonding and non-covalent hydrogen-bonding with anisotropic linking character. We employed infrared reflection spectroscopy (IRS), atomic force microscopy (AFM) and transmission electron microscopy (TEM) for the characterizations. While IRS provides structural assessment, TEM and AFM imaging measurements probe the morphological properties.

scholarly journals Caffeic Acid: Potential Applications in Nanotechnology as a Green Reducing Agent for Sustainable Synthesis of Gold Nanoparticles

2015 ◽  
Vol 10 (4) ◽  
pp. 1934578X1501000
Author(s):  
Yu Seon Seo ◽  
Song-Hyun Cha ◽  
Seonho Cho ◽  
Hye-Ran Yoon ◽  
Young-Hwa Kang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Caffeic Acid ◽  
Average Diameter ◽  
Reducing Agent ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Potential Applications ◽  
Acid Potential ◽  
Sustainability Initiatives

The sustainable synthesis of gold nanoparticles from gold ions was conducted with caffeic acid as a green reducing agent. The formation of gold nanoparticles was confirmed by spectroscopic and microscopic methods. Spherical nanoparticles with an average diameter of 29.99 ± 7.43 nm were observed in high-resolution transmission electron microscopy and atomic force microscopy images. The newly prepared gold nanoparticles exhibited catalytic activity toward the reduction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. This system enables the preparation of green catalysts using plant natural products as reducing agents, which fulfills the growing need for sustainability initiatives.

Characterization of Different Sequences of DNA on Si Substrate by Atomic Force Microscopy and Gold Nanoparticle Labeling

2007 ◽  
Vol 7 (2) ◽  
pp. 418-423 ◽  
Author(s):  
Rong Jin ◽  
Xiaoxiao He ◽  
Kemin Wang ◽  
Liu Yang ◽  
Huimin Li ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Atomic Force Microscopy ◽  
Single Strand ◽  
Si Substrate ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging ◽  
On Chip ◽  
Micrometer Scale

In this paper, different sequences of single-strand DNA modified on Si substrate were studied taking advantages of the high resolution of atomic force microscopy (AFM) and signal enhancement of gold nanoparticles. Two sequences of single-strand DNA, as a model, were immobilized on Si substrate and hybridized with their sequence-complementary DNA molecules modified respectively with two sizes of gold nanoparticles. The surface of Si substrate was characterized through detecting the size and coverage of gold nanoparticles by AFM. Results demonstrated that different sizes of gold nanoparticles represented different sequences of DNA immobilized on the substrate. Density and distribution of DNA on Si substrate can be investigated by AFM imaging using gold nanoparticles as topographic markers. Compared to other sensitive methods such as fluorescence energy transfer, X-ray photoelectron, and radiolabeling experiments, this approach is advantageous in terms of high spatial resolution in sub-micrometer scale. This new method will be beneficial in the characterization of DNA immobilized on chip surfaces.

scholarly journals Nanoengineering of Gold Nanoparticles: Green Synthesis, Characterization, and Applications

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 612 ◽  
Author(s):  
Nancy Tepale ◽  
Víctor V. A. Fernández-Escamilla ◽  
Clara Carreon-Alvarez ◽  
Valeria J. González-Coronel ◽  
Adan Luna-Flores ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Green Synthesis ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Fundamental Study ◽  
X Ray ◽  
Force Microscopy ◽  
X Ray Scattering ◽  
Atomic Force ◽  
Transmission Electron

The fundamental aspects of the manufacturing of gold nanoparticles (AuNPs) are discussed in this review. In particular, attention is devoted to the development of a simple and versatile method for the preparation of these nanoparticles. Eco-friendly synthetic routes, such as wet chemistry and biosynthesis with the aid of polymers, are of particular interest. Polymers can act as reducing and/or capping agents, or as soft templates leading to hybrid nanomaterials. This methodology allows control of the synthesis and stability of nanomaterials with novel properties. Thus, this review focus on a fundamental study of AuNPs properties and different techniques to characterize them, e.g., Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), UV-Visible spectroscopy, Dynamic Light Scattering (DLS), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy, Small-angle X-Ray Scattering (SAXS), and rheology. Recently, AuNPs obtained by “green” synthesis have been applied in catalysis, in medicine, and as antibacterials, sensors, among others.

scholarly journals Enzyme-Free Electrochemical Nano-Immunosensor Based on Graphene Quantum Dots and Gold Nanoparticles for Cardiac Biomarker Determination

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 578
Author(s):  
Bhargav D. Mansuriya ◽  
Zeynep Altintas
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Gold Nanoparticles ◽  
Troponin I ◽  
Electrochemical Techniques ◽  
Graphene Quantum Dots ◽  
High Specificity ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

An ultrasensitive enzyme-free electrochemical nano-immunosensor based on a screen-printed gold electrode (SPGE) modified with graphene quantum dots (GQDs) and gold nanoparticles (AuNPs) was engineered to detect cardiac troponin-I (cTnI) for the early diagnosis of acute myocardial infarction (AMI). The GQDs and in-house synthesized AuNPs were implanted onto the SPGE and allowed for anti-cTnI immobilization prior to quantifying cTnI. The biomarker could be determined in a wide concentration range using square-wave voltammetry (SWV), cyclic voltammetry (CV), electron impedance spectroscopy (EIS) and amperometry. The analyses were performed in buffer, as well as in human serum, in the investigation ranges of 1–1000 and 10–1000 pg mL−1, respectively. The detection time ranged from 10.5–13 min, depending on the electrochemical method employed. The detection limit was calculated as 0.1 and 0.5 pg mL−1 for buffer and serum, respectively. The sensitivity of the immunosensor was found to be 6.81 µA cm−2 pg mL−1, whereas the binding affinity was determined to be <0.89 pM. The sensor showed high specificity for cTnI with slight responses for nonspecific biomolecules. Each step of the sensor fabrication was characterized using CV, SWV, EIS and atomic force microscopy (AFM). Moreover, AuNPs, GQDs and their nanocomposites were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). This is the first immunosensor that represents the successful determination of an analyte using four different electrochemical techniques. Such a sensor could demonstrate a promising future for on-site detection of AMI with its sensitivity, cost-effectiveness, rapidity and specificity.

Antibody-Mediated Self-Limiting Self-Assembly for Quantitative Analysis of Nanoparticle Surfaces by Atomic Force Microscopy

2011 ◽  
Vol 17 (2) ◽  
pp. 206-214 ◽  
Author(s):  
Carly Lay A. Geronimo ◽  
Robert I. MacCuspie
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Lower Cost ◽  
Synthesis Method ◽  
Force Microscopy ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron ◽  
Afm Imaging ◽  
Induced Aggregation

AbstractQuantification of very low density molecular coatings on large (60 nm) gold nanoparticles (AuNPs) is demonstrated via the use of antibody-mediated self-limiting self-assembly of small and large AuNPs into raspberry-like structures subsequently imaged by atomic force microscopy (AFM). AFM imaging is proposed as an automated, lower-cost, higher-throughput alternative to immunostaining and imaging by transmission electron microscopy. Synthesis of large AuNPs, containing one of three ligand molecules in one of three stoichiometries (1, 2, or 10 ligands per AuNP), and small probe AuNPs with one of three antibody molecules in a one antibody per AuNP ratio, enabled a range of predicted self-limiting self-assembled structures. A model predicting the probability of observing a given small to large AuNP ratio based on a topography measurement such as AFM is described, in which random orientational deposition is assumed and which accounts for the stochastic synthesis method of the library AuNPs with varied ligand ratios. Experimental data were found to agree very well with the predictive models when using an established AFM sample preparation method that avoids drying-induced aggregation.

First Stages of the Platinum Electroless Deposition on Silicon (100) from Hf Solutions.

1995 ◽  
Vol 402 ◽  
Author(s):  
P. Gorostiza ◽  
J. Servat ◽  
J. R. Morante ◽  
F. Sanz
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electroless Deposition ◽  
Chemical Nature ◽  
Metal Salt ◽  
Morphological Properties ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Influence Of Ph

AbstractElectroless metal deposition based upon the addition of fluoride anions to the metal salt aqueous solution have been developed recently on the assumption that the cleanness of the substrate will be guaranteed and the deposit will be of high purity. In this work, platinum is deposited on silicon (100) from fluorinated solution at two different pH's. The influence of pH is analyzed using Tapping Mode Atomic Force Microscopy (TMAFM) to characterize the main morphological properties of the deposit. Combined TMAFM and Transmission Electron Microscopy (TEM) images are presented and X-ray Photoelectron Spectroscopy (XPS) allows us to identify the chemical nature of the silicon surface.

scholarly journals Microscopic Techniques for the Analysis of Micro and Nanostructures of Biopolymers and Their Derivatives

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 512 ◽  
Author(s):  
Abhilash Venkateshaiah ◽  
Vinod V.T. Padil ◽  
Malladi Nagalakshmaiah ◽  
Stanisław Waclawek ◽  
Miroslav Černík ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Decisive Role ◽  
Environmental Safety ◽  
Vital Role ◽  
Morphological Properties ◽  
Synthesis Of Nanoparticles ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Microscopic Techniques

Natural biopolymers, a class of materials extracted from renewable sources, is garnering interest due to growing concerns over environmental safety; biopolymers have the advantage of biocompatibility and biodegradability, an imperative requirement. The synthesis of nanoparticles and nanofibers from biopolymers provides a green platform relative to the conventional methods that use hazardous chemicals. However, it is challenging to characterize these nanoparticles and fibers due to the variation in size, shape, and morphology. In order to evaluate these properties, microscopic techniques such as optical microscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM) are essential. With the advent of new biopolymer systems, it is necessary to obtain insights into the fundamental structures of these systems to determine their structural, physical, and morphological properties, which play a vital role in defining their performance and applications. Microscopic techniques perform a decisive role in revealing intricate details, which assists in the appraisal of microstructure, surface morphology, chemical composition, and interfacial properties. This review highlights the significance of various microscopic techniques incorporating the literature details that help characterize biopolymers and their derivatives.

Site-Specific Attachment of Gold Nanoparticles to DNA Templates

2001 ◽  
Vol 635 ◽  
Author(s):  
Karen A. Stevenson ◽  
Govindarajan Muralidharan ◽  
Leon Maya ◽  
Jack C. Wells ◽  
Jacob Barhen
Keyword(s):  
Gold Nanoparticles ◽  
Amino Groups ◽  
Dna Templates ◽  
Force Microscopy ◽  
Atomic Force ◽  
Carbodiimide Hydrochloride ◽  
Transmission Electron ◽  
Specific Attachment ◽  
Chemical Technique ◽  
Dna Template

AbstractDNA was used as a scaffold for the binding of gold nanoparticles using a standard chemical technique. A DNA template was designed with amino-modified thymines located every 3.7 nm, which would allow the attachment of the carboxylic acid functionalized gold nanoparticles. The gold particles were covalently bound to the amino groups on the DNA using standard 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) chemistry in the presence of a competitor to block excess gold binding sites. The products were analyzed by transmission electron microscopy (TEM) and atomic force microscopy (AFM).

Synthesis and Characterization of Surfactant-Free PDEA/PMAA of IPN Nanogel

2014 ◽  
Vol 787 ◽  
pp. 395-400
Author(s):  
Peng Wang ◽  
Jun Li Zhang ◽  
Xue Ting Li ◽  
Qian Wu ◽  
Di Zhao ◽  
...  
Keyword(s):  
Phase Transition ◽  
Hydrogen Bonding ◽  
Chemical Structure ◽  
Aqueous Dispersion ◽  
Ultrapure Water ◽  
Swelling Properties ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Based on the hydrogen bonding between MAA and PDEA, the synthesis of surfactant-free PDEA/PMAA interpenetrating (IPN) nanogels was studied in ultrapure water with N, N-methylene acrylamide (BIS) as a crosslinker, ammonium peroxodisulfate (APS) as an initiator, N,N,N',N'-Tetramethylethylenediamine (TEMED) as an accelerator. First, poly (N, N-diethyl acrylamide) (PDEA) nanogels were synthesized using emulsion precipitation polymerization. As MAA was polymerized in the aqueous dispersion of PDEA nanogels as seeds, PDEA nanogels got interpenetrated with poly (methacrylic acid) (PMAA) due to the effect of the hydrogen bonding between PDEA and PMAA. The chemical structure of the PDEA/PMAA nanogels was studied with Fourier transform infrared (FTIR) spectroscopy. The nanogels morphology was characterized with transmission electron microscopy (TEM) and atomic force microscopy (AFM). And the volume phase transition behaviors and swelling properties were studied with dynamic light scattering (DLS). The experimental results show that the interpenetrating nanogels were very sensitive to temperature. As the amount of MAA increased, the volume of the neutralized PDEA/PMAA nanogels changed less above phase transition temperature and was finally no change. The temperature responsive PDEA/PMAA nanogels will promise to have significant influence on fundamental studies and real applications.

scholarly journals Immunogold Nanoparticles Recognition imaging by Direct Atomic Force Microscopy

2018 ◽  
Vol 6 (4) ◽  
pp. 55
Author(s):  
Yang Cao ◽  
Wenwen Zhang ◽  
Pengfei Yang ◽  
Liping Zhang ◽  
Lili Li ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Phase Image ◽  
Gold Particles ◽  
Virus Identification ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Afm Imaging ◽  
Antibody Conjugates ◽  
Recognition Imaging

<p>We have developed a method that integrated the widely used nanogold immunoassay into direct atomic force microscopy (AFM) imaging and provided a specific morphological technique applying for virus identification. The series of specimens including bare gold particles (Au), antibody-conjugated gold particles (Au-Ab), purified influenza virions (H1N1), antibody-bound virions (H1N1-Ab) and virion-immunogold complex (H1N1- Ab-Au) were investigated by AFM and transmission electron microscopy stepwisely and parallelly. The recognition method of the immuno-AFM technique was constructed by taking the local phase contrast in phase image as main judgment for the existence of immunogold labels and taking the height and amplitude images as auxiliary judgment for viral morphology and positioning. The nanogold-antibody conjugates binding to the H1N1 virions were clearly identified as higher brightness spots from the background biomaterials. Under direct AFM, the topographical image of the scanned biosamples can be easily investigated and reproduced. Our findings achieved the combination of virus morphological features with antibody-antigen specific recognition through the application of antibody-specific nanogold labels and, in principle, the labels for immuno-AFM could be extended to other types of nanomaterials for bio-recognition and localization assay.</p>

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