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1.
Surface enhanced Raman scattering (SERS) was used to study phospholipid monolayers transferred by the Langmuir-Blodgett (LB) technique to SERS active substrates. These substrates, which were constituted of gold colloidal nanoparticles bound to polysilane films grafted onto glass plates, showed a uniform and homogeneous layer with strong interacting particles as revealed from UV-visible extinction spectra and atomic force microscopy images. Laser excitation at 632.8 nm within the red part of the localized surface plasmon resonance leads to intense and reproducible SERS spectra of trans-1,2-bis(4-pyridyl)ethylene (BPE). From SERS measurements at different pHs it was possible to determine the apparent pK(a) of BPE adsorbed on gold-coated silanized substrates in the absence and presence of one LB monomolecular layer of phospholipids. These SERS titrations allowed the estimation of the pH at the metal-LB film interface. 相似文献
2.
Hybrid spheres containing peptides and gold nanoparticles have been simultaneously synthesized in water using AG4 (NPSSLFRYLPSD) peptides that acted as a reducing agent to guide the nucleation and growth of gold nanoparticles and a precursor to form sphere-like structure by self-assembly where the size of hybrid spheres is precisely controlled by adjusting the operating temperature. The self-assembled peptide spheres remain stable even after selective removal of the gold nanoparticles by iodide etching. The amino acids containing the aromatic functional group in the peptide sequence significantly affect the construction of sphere structures. The surface of gold nanoparticles containing hybrid spheres has been functionalized using the thiol group linked to biomolecules. The ability to synthesize nanoparticle and self-assembled peptide structures with controlled size and composition in an environmental benign way will allow us to fabricate a new class of multifunctional organic-inorganic hybrid superstructures for various biomedical and electronic applications. 相似文献
3.
Tahereh Makiabadi Audrey Bouvrée Victor Le Nader Hélène Terrisse Guy Louarn 《Plasmonics (Norwell, Mass.)》2010,5(1):21-29
Generally, the immobilization of two-dimensional nanoparticles in immersion procedures is time-consuming (over 24 h). In this
paper, we report a very effective and simple method to fabricate two-dimensional gold nanoparticle patterns over large areas
with high regularity for surface-enhanced Raman scattering (SERS). We achieved a highly sensitive SERS colloid surface by
optimizing temperature and immersion time. The surfaces were characterized by X-ray photoelectron spectroscopy, UV–Vis, atomic
force microscopy, and scanning electron microscopy. The SERS activity of surfaces was compared by using two techniques: “dip”
and “dip and dry” in an aqueous solution of 10−6 M crystal violet. The influence of the morphology of the surface was investigated with both the dip and dip and dry techniques. 相似文献
4.
Katrin Quester Miguel Avalos-Borja Alfredo Rafael Vilchis-Nestor Marco Antonio Camacho-López Ernestina Castro-Longoria 《PloS one》2013,8(10)
Surface-enhanced Raman scattering (SERS) is a surface-sensitive technique that enhances Raman scattering by molecules adsorbed on rough metal surfaces. It is known that metal nanoparticles, especially gold and silver nanoparticles, exhibit great SERS properties, which make them very attractive for the development of biosensors and biocatalysts. On the other hand, the development of ecofriendly methods for the synthesis of metallic nanostructures has become the focus of research in several countries, and many microorganisms and plants have already been used to biosynthesize metallic nanostructures. However, the majority of these are pathogenic to plants or humans. Here, we report gold nanoparticles with good SERS properties, biosynthesized by Neurospora crassa extract under different environmental conditions, increasing Raman signals up to 40 times using methylene blue as a target molecule. Incubation of tetrachloroauric acid solution with the fungal extract at 60°C and a pH value of a) 3, b) 5.5, and c) 10 resulted in the formation of gold nanoparticles of a) different shapes like triangles, hexagons, pentagons etc. in a broad size range of about 10-200 nm, b) mostly quasi-spheres with some different shapes in a main size range of 6-23 nm, and c) only quasi-spheres of 3-12 nm. Analyses included TEM, HRTEM, and EDS in order to corroborate the shape and the elemental character of the gold nanoparticles, respectively. The results presented here show that these ‘green’ synthesized gold nanoparticles might have potential applicability in the field of biological sensing. 相似文献
5.
A microarray approach based on surface-enhanced Raman spectroscopic (SERS) was developed for detection of spotted peptide, peptide-protein or protein-antibody interaction. The procedure involves the attachment of peptide-capped gold nanoparticles followed by silver deposition for signal enhancement. The attachment of the gold nanoparticles is achieved by standard avidin-biotin chemistry. The well-known biomolecular recognition pairs, IgG/protein A and biotin/avidin, were used to demonstrate proof-of-concept of the SERS assay. Detection limits of 10 and 100 fg per microarray spot were obtained respectively for the peptide and protein arrays. For the protein in solution, a limit of 0.1 microg/mL is reported. Furthermore, enzyme activity of the kinase (PKA) is also detected with high specificity for an established peptide substrate (kemptide) on the microarray spots. 相似文献
6.
Immobilized pH gradient isoelectric focusing as a first-dimension separation in shotgun proteomics. 总被引:4,自引:0,他引:4
Benjamin J Cargile Joel R Sevinsky Amal S Essader James L Stephenson Jonathan L Bundy 《Journal of biomolecular techniques》2005,16(3):181-189
Shotgun proteomics, where a tryptic digest of a complex proteome sample is directly analyzed by either single dimensional or multidimensional liquid chromatography tandem mass spectrometry, has gained acceptance in the proteomics community at large and is widely used in core facilities. Here we review the development in our laboratory of an alternative first-dimension separation technique for shotgun proteomics, immobilized pH gradient isoelectric focusing (IPG-IEF). The key advantages of the technology over other multidimensional separation formats (simplicity, high resolution, and high sensitivity) are discussed. The concept of using peptide pI to filter large shotgun proteomics datasets generated by the IPG-IEF technique to minimize false positives and negatives is also introduced. Finally, an account of the comparison of the technique with the established gold standard for multidimensional separation of peptides, strong cation exchange chromatography, is presented, along with the prospects for the use of peptide pI along with accurate mass measurement for the identification of peptides. 相似文献
7.
The cyanobacteria Phormidium valderianum, P. tenue and Microcoleus chthonoplastes and the green algae Rhizoclonium fontinale, Ulva intestinalis, Chara zeylanica and Pithophora oedogoniana were exposed to hydrogen tetrachloroaurate solution and were screened for their suitability for producing nano‐gold. All three cyanobacteria genera and two of the green algae (Rhizoclonium fontinale and Ulva intestinalis) produced gold nanoparticles intracellularly, confirmed by purple colouration of the thallus within 72?h of treatment at 20°C. Extracted nanoparticle solutions were examined by UV‐vis spectroscopy, transmission electron microscopy (TEM) and X‐ray diffractometry (XRD). XRD confirmed the reduction of Au (III) to Au (0). UV‐vis spectroscopy and TEM studies indicated the production of nanoparticles having different shapes and sizes. Phormidium valderianum synthesized mostly spherical nanoparticles, along with hexagonal and triangular nanoparticles, at basic and neutral pHs (pH 9 and pH 7, respectively). Medicinally important gold nanorods were synthesized (together with gold nanospheres) only by P. valderianum at acidic pH (pH 5); this was initially determined by two surface plasmon bands in UV‐vis spectroscopy and later confirmed by TEM. Spherical to somewhat irregular particles were produced by P. tenue and Ulva intestinalis (TEM studies). The UV‐vis spectroscopy of the supernatant of other algal extracts indicated the formation of mostly spherical particles. Production of gold nanoparticles by algae is more ecofriendly than purely chemical synthesis. However, the choice of algae is important: Chara zeylanica and Pithophora oedogoniana were found to be unable to produce nanoparticles. 相似文献
8.
9.
本文以结晶紫作为探针分子,研究了以金溶胶膜、pH =6以及 pH =13的金溶胶溶液为活性基底的表面增强拉曼光谱的增强效果。采用化学还原法制备金溶胶,加入氢氧化钠改变其 pH 值,并以自组装法制备金溶胶膜。通过比较金溶胶膜、pH =6及 pH =13时金溶胶溶液的增强因子以及在这三种金溶胶基底上结晶紫的检测限,分析不同活性基底增强效果的差异。三种活性基底的增强因子分别可达到5.9×103、1.5×105、2.3×107,pH =13的金溶胶溶液有最佳的增强效果。以这三种金溶胶为基底对结晶紫进行表面增强拉曼光谱探测,可得到检测限为70.7 nmol/L、9.6 nmol/L、1.8 nmol/L。结果表明,金溶胶溶液的增强效果明显优于金溶胶膜,而通过改变金溶胶体系的 pH 值可以改变金纳米颗粒的聚合程度及对探测物的吸附特性从而获得更高灵敏度的活性基底。 相似文献
10.
Mishra A Tripathy SK Wahab R Jeong SH Hwang I Yang YB Kim YS Shin HS Yun SI 《Applied microbiology and biotechnology》2011,92(3):617-630
Microorganisms, their cell filtrates, and live biomass have been utilized for synthesizing various gold nanoparticles. The
shape, size, stability as well as the purity of the bio synthesized nanoparticles become very essential for application purpose.
In the present study, gold nanoparticles have been synthesized from the supernatant, live cell filtrate, and biomass of the
fungus Penicillium brevicompactum. The fungus has been grown in potato dextrose broth which is also found to synthesize gold nanoparticles. The size of the
particles has been investigated by Bio-TEM before purification, following purification and after storing the particles for
3 months under refrigerated condition. Different characterization techniques like X-ray diffraction, Fourier transform infrared
spectroscopy, and UV–visible spectroscopy have been used for analysis of the particles. The effect of reaction parameters
such as pH and concentration of gold salt have also been monitored to optimize the morphology and dispersity of the synthesized
gold nanoparticles. A pH range of 5 to 8 has favored the synthesis process whereas increasing concentration of gold salt (beyond
2 mM) has resulted in the formation of bigger sized and aggregated nanoparticles. Additionally, the cytotoxic nature of prepared
nanoparticles has been analyzed using mouse mayo blast cancer C2C12 cells at different time intervals (24, 48, and 72 h) of incubation period. The cells are cultivated in Dulbecco’s modified
Eagle’s medium supplemented with fetal bovine serum with antibiotics (streptopenicillin) at 37°C in a 5% humidified environment
of CO2. The medium has been replenished every other day, and the cells are subcultured after reaching the confluence. The viability
of the cells is analyzed with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide method. 相似文献
11.
A. G. Laman A. O. Shepelyakovskaya Kh. M. Boziev G. V. Savinov F. A. Brovko V. A. Nesmeyanov 《Russian Journal of Bioorganic Chemistry》2010,36(2):157-163
A method for the preparation of peptide mimetics of GMDP which could exhibit adjuvant activity without the negative effects
of GMDP is described. The search for peptides with GMDP-like adjuvant activity was performed using highly specific monoclonal
antibodies against GMDP and combinatorial peptide libraries in the format of phage display. Various elution methods were used
for the immunoaffinity enrichment of the libraries during the course of the preparation of highly active and specific peptides.
A sole peptide Arg-Val-Pro-Pro-Arg-Tyr-His-Ala-Lys-Ile-Ser-Pro-Met-Val-Asn (RN) was obtained by the elution of phage particles
from the immunosorbent with a 1 μM solution of the natural ligand (GMDP). Elution with a buffer with a low pH value (0.1 M
glycine-HCl, pH 2.2) gave two other peptides: Ser-Gly-Arg-Val-Ala-Val-Ser-Pro-Asp-Ser-Pro-Leu-Phe-Tyr-Pro (SP) and Arg-Tyr-Gly-Gly-Ser-Val-Leu-Asn-Ile-Glu-Cys-Gln-Phe-Tyr-Gly
(RG). Affinity constants for the RN and SP peptides proved to be 3.6 × 108 and 3.5 × 108 M−1, respectively. The specificity of the interaction with the monoclonal antibodies was checked by the competitive displacement
of the peptides from the antigen-antibody complex by GMDP. The RN peptide exhibited adjuvant activity similar to that of GMDP,
but had no pyrogenic effect characteristic of GMDP. The described method could be used for the search for mimetics of biologically
active low-molecular compounds. 相似文献
12.
Previous studies have shown that increases in surface-peptide binding affinity result in decreases in peptide matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) ion signals. The present work demonstrates that, with appropriate corrections for peptide ionization efficiency under MALDI conditions, relative surface-peptide binding affinities can be assayed using the MALDI MS methodology. Peptides with a range of pI values are allowed to interact with amine-modified and carboxylic acid-modified polymer surfaces (produced by pulsed radio-frequency plasma polymerization of allyl amine and vinyl acetic acid) in buffered solutions of neutral pH. Because of the net positive and negative charges associated with the peptides and surfaces in solution, both electrostatic and hydrophilic interactions play a role in the surface-peptide interaction. Consistent with expectations, the peptide MALDI ion signals for peptides with net negative charges in solution are smaller than those for peptides with net positive charges in solution when the peptides are allowed to interact with positively charged surfaces. A reversal of the relative peptide MALDI ion signal intensities is observed when the same peptides are allowed to interact with negatively charged surfaces. Cumulatively, the results demonstrate that even modest changes in surface-peptide interactions can be comparatively probed by MALDI mass spectrometry. 相似文献
13.
Zhigang Tu Albert Young Christopher Murphy Jun F. Liang 《Journal of peptide science》2009,15(11):790-795
Many bioactive peptides are featured by their unique amino acid compositions such as argine/lysine‐rich peptides. However, histidine‐rich bioactive peptides are hardly found. In this study, histidine‐containing peptides were constructed by selectively replacing the corresponded lysine residues in a lytic peptide LL‐1 with histidines. Interestingly, all resulting peptides demonstrated pH‐dependent activities. The cell lysis activities of these peptides could be increased up to four times as the solution pHs dropped from pH = 7.4 to pH = 5.5. The pH sensitivity of a histidine‐containing peptide was determined by histidine substitution numbers. Peptide derivatives with more histidines were associated with increased pH sensitivity. Results showed that not the secondary structures but pH‐affected cell affinity changes were responsible for the pH‐dependent activities of histidine‐containing peptides. The histidine substitution approach demonstrated here may present a general strategy to construct bioactive peptides with desired pH sensitivity for various applications. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
14.
15.
Jennifer L. Daniels Troy M. Crawford Oleg A. Andreev Yana K. Reshetnyak 《Biochemistry and Biophysics Reports》2017
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. 相似文献
16.
Jordi Triguero Alejandra Flores‐Ortega David Zanuy Carlos Alemán 《Journal of peptide science》2018,24(1)
The RPAR peptide, a prototype C‐end Rule (CendR) sequence that binds to neuropilin‐1 (NRP‐1), has potential therapeutic uses as internalization trigger in anticancer nanodevices. Recently, the functionalization of gold nanoparticles with CendR peptides has been proved to be a successful strategy to target the NRP‐1 receptor in prostate cancer cells. In this work, we investigate the influence of two gold surface facets, (100) and (111), on the conformational preferences of RPAR using molecular dynamics simulations. Both clustering and conformational analyses revealed that the peptide backbone becomes very rigid upon adsorption onto gold, which is a very fast and favored process, the only flexibility being attributed to the side chains of the two Arg residues. Thus, the different components of RPAR tend to adopt an elongated shape, which is characterized by the pseudo‐extended conformation of both the backbone and the Arg side chains. This conformation is very different from the already known bioactive conformation, indicating that RPAR is drastically affected by the substrate. Interestingly, the preferred conformations of the peptide adsorbed onto gold facets are not stabilized by salt bridges and/or specific intramolecular hydrogen bonds, which represent an important difference with respect to the conformations found in other environments (e.g. the peptide in solution and interacting with NRP‐1 receptor). However, the conformational changes induced by the substrate are not detrimental for the use of gold nanoparticles as appropriate vehicles for the transport and targeted delivery of the RPAR. Thus, once their high affinity for the NRP‐1 receptor induces the targeted delivery of the elongated peptide molecules from the gold nanoparticles, the lack of intramolecular interactions facilitates their evolution towards the bioactive conformation, increasing the therapeutic efficacy of the peptide. 相似文献
17.
The physical properties of non-viral vector/DNA nanoparticles in physiological aqueous solution are poorly understood. A Fluid Particle Image Analyser (FPIA), normally used for analysis of industrial and environmental fluids, was used to visualise individual (Lys)(16)-containing peptide/DNA particles. Eight (Lys)(16)-containing synthetic peptides were used to generate peptide/DNA particles at a constant + to - charge ratio of 2.8:1 with 10 microg/ml of plasmid DNA in phosphate buffered saline. Dynamic Light Scattering (DLS) and gene delivery studies were also performed. We present the first images of non-viral vector/DNA nanoparticles in physiological aqueous solution, together with precise measurements of individual particle size and shape in solution and, for the first time, an accurate measure of particle number. Particle size and shape, particle number, and efficiency for gene delivery varied markedly with different peptides. Under standard conditions for in vitro gene delivery, we estimate approximately 60 peptide/DNA nanoparticles per target cell, each containing approximately 70,000 plasmids. This novel capacity to image individual vector/DNA nanoparticles in solution and to count them accurately will enable a more precise assessment of non-viral gene delivery systems, and a more quantitative interpretation of gene delivery experiments. 相似文献
18.
J. J. Mock S. M. Norton S.-Y. Chen A. A. Lazarides D. R. Smith 《Plasmonics (Norwell, Mass.)》2011,6(1):113-124
We report a morphology-correlated surface-enhanced Raman scattering (SERS) from molecules on the surface of individual clusters
of gold nanoparticles of two types and compare the signal from clusters of two, three, four, and five nanoparticles with the
signal from single particles. Cluster geometry and particle morphology are determined from transmission electron microscopy
for both clusters of 78- to 133-nm nanospheres and clusters of ~250-nm-etched cylindrical particles with crevices and sharp
edges, formed in templates. Scattering from molecules on etched cylinders, but not spheres, is sufficiently strong to allow
spectra to be collected from single particles illuminated at 632.8 nm. SERS intensities from clusters of cylinders are found
to scale linearly with particle number, whereas, for nanospheres, the scaling is non-linear. The linear scaling of SERS from
cylinders is a reflection of the high enhancement provided by the sharp features of the individual particles; whereas, the
non-linear scaling of SERS from clusters of spheres is found to be consistent with the near-field enhancement from inter-particle
coupling simulated for clusters of spheres arranged in representative-observed geometries. 相似文献
19.
Recently, we have developed a high-resolution two-dimensional separation strategy for the analysis of complex peptide mixtures. This methodology employs isoelectric focusing of peptides on immobilized pH gradient (IPG) gels in the first dimension, followed by reversed-phase chromatography in the second dimension, and subsequent tandem mass spectrometry analysis. The traditional approach to this mixture problem employs strong-cation-exchange (SCX) chromatography in the first dimension. Here, we present a direct comparison of these two first-dimensional techniques using complex protein samples derived from the testis of Rattus norvegicus. It was found that the use of immobilized pH gradients (narrow range pH 3.5-4.5) for peptide separation in the first dimension yielded 13% more protein identifications than the optimized off-line SCX approach (employing the entire pI range of the sample). In addition, the IPG technique allows for a much more efficient use on mass spectrometer analysis time. Separation of a tryptic digest derived from a rat testis sample on a narrow range pH gradient (over the 3.5-4.5 pH range) yielded 7626 and 2750 peptides and proteins, respectively. Peptide and protein identification was performed with high confidence using SEQUEST in combination with a data filtering program employing pI and statistical based functions to remove false-positives from the data. 相似文献
20.
Microbial precipitation of gold was achieved using Escherichia coli and Desulfovibrio desulfuricans provided with H2 as the electron donor. No precipitation was observed using H2 alone or with heat-killed cells. Reduction of aqueous AuIII ions by both strains was demonstrated at pH 7 using 2 mM HAuCl4 solution and the concept was successfully applied to recover 100% of the gold from acidic leachate (115 ppm of AuIII) obtained from jewelry waste. Bioreductive recovery of gold from aqueous solution was achieved within 2 h, giving crystalline Au0 particles (20-50 nm), in the periplasmic space and on the cell surface, and small intracellular nanoparticles. The nanoparticle size was smaller (red suspension) at acidic pH (2.0) as compared to that obtained at pH 6.0 and 7.0 (purple) and 9.0 (dark blue). Comparable nanoparticles were obtained from AuIII test solutions and jewelry leachate. 相似文献