SERS as a Tool for Detection of SingleMolecules
There have been several reports of single-molecule detection using SERS in recent years 4-7,113,136,137 . A critical factor in these milestone studies has been the development of exceptional SERS substrates. Most of the reports of single-molecule SERS detection have involved the use of metal colloids in suspensions. For example, Kneipp et al. demonstrated single-molecule detection of crystal violet in both silver 5,6 and colloid suspensions 7 . In these studies, an effective cross-section of...
Peixuan Guo Summary
A controllable, 30-nm imitating DNA-packaging motor was constructed. The motor is driven by six synthetic adenosine triphosphate ATP -binding RNA packaging RNA pRNA monomers, similar to the driving of a bolt with a hex nut. Conformational change and sequential action of the RNA with fivefold viral capsid sixfold pRNA hexamer mismatch could ensure continuous rotation of the motor with ATP as energy. In the presence of ATP and magnesium, a 5- lm synthetic DNA was packaged using this motor. On...
Chemical Stability
Improved chemical stability is also possible. Studies have shown that antibodies immobilized via the sol-gel route better retained their ability to bind antigen after exposure to acid compared with antibodies immobilized via traditional surface attachment. After exposure to 0.01 N HCl pH approx 2.0 for 24 h, sol-gel-encapsulated antitrinitrotoluene anti-TNT antibodies experienced essentially no loss in their ability to bind TNT, whereas antibodies immobilized via traditional surface attachment...
NSOM SERS Probes
NSOM is a methodology for obtaining subwavelength resolution 20-200 nm with the spectroscopic information afforded by conventional optical spectro- scopic techniques 131,132 . The high spatial resolution of NSOM permits spectroscopic studies of individual biomolecules in high-density systems such as encountered in in vivo experiments 8,133,134 . In this respect, NSOM combined with a Raman microscope is particularly attractive. So far, this novel scanning probe technique has been restricted to...
With Microfluidics ChipBased Protein Mobility Shift
Electrophoretic mobility shift analysis EMSA is a well-characterized and widely employed technique for the analysis of protein-DNA interaction and of transcription factor combinatorics. As currently implemented, EMSA generally involves the use of radiolabeled DNA and PAGE. We have noted 20 that this technique could be effectively implemented with microfluidics chips designed for the separation of DNA fragments. To accomplish this, samples were run on a 2100 Bioanalyzer Agilent using a DNA 500...
Protein Structure The Basic Building Blocks
Proteins are long chains of molecules consisting of polymers assembled from a large number of amino acids like beads on a necklace. The sequence of the amino acids in the polymer backbone is the primary structure of any given protein. There are 20 normal amino acids. Typical polypeptide chains contain about 100 to 600 amino acid molecules and have a molecular weight of about 15,000 to 70,000. Since amino acids have hydrophilic, hydrophobic, and amphilic groups, in an aqueous environment they...
Development of Solid SERS Substrates Based on Metallic Nanostructures
In addition to immobilized colloids, researchers have developed a variety of solid surface-based SERS substrates that are produced entirely from solid materials, as depicted schematically in Fig. 1. In contrast to immobilized colloids, the solid SERS-based probes described subsequently exhibit a high degree of reproducibility. In addition, nanoshells with a dielectric core and a metallic shell e.g., Au SiO2 , or a metallic core and a dielectric shell e.g., Au core SiO2 shell , or a metallic...
Introduction An Historical Perspective on Nanotechnology
Nanotechnology involves research and development on materials and species at length scales between 1 and 100 nm. The term nano is derived from the Greek word meaning dwarf. In dimensional scaling, nano refers to 10-9, i.e., one billionth of a unit. Thus, a nanometer is 10-9 m 0.000000001 m , or about the size of a molecule such as benzene. Nanotechnology therefore, refers to the techniques and methods for studying, designing, and fabricating things at the nanometer scale. The initial concept of...
References Jqe
1. Fleischmann, M., Hendra, P. J., and McQuillan, A. J. 1974 Raman-spectra of pyridine adsorbed at a silver electrode. Chem. Phys. Lett. 26, 163-166. 2 Jeanmaire, D. L. and Van Duyne, R. P. 1977 Surface Raman spectro-electro-chemistry. 1. Heterocyclic, aromatic, and aliphatic-amines adsorbed on anod-ized silver electrode. J. Electroanal. Chem. 84, 1-20. 3. Albrecht, M. G. and Creighton, J. A. 1977 Anomalously intense Raman-spectra of pyridine at a silver electrode. J. Am. Chem. Soc. 99,...
SERS Gene Probes
There has been a great deal of interest in the development of optical techniques for genomics analysis such as nonradioactive DNA probes for use in biomedical diagnostics, pathogen detection, gene identification, gene mapping, and DNA sequencing. Hybridization of a nucleic acid probe to DNA biotargets e.g., gene sequences, bacteria, viral DNA permits a very high degree of accuracy in identifying DNA sequences complementary to that probe. The possibility of using SERS for low-level detection of...
Materials Iva
Dimyristoyl phosphatidyl choline DMPC , dioleoyl phosphatidyl choline DOPC , and octyl glucoside were purchased from Sigma St. Louis, MO . iminodiacetic acid succinyl DOGS was purchased from Aventi Polar Lipids. Cis- PtCl2 NH3 2 was kindly provided by Johnson Matthey London, UK . DPDPB was provided by Pierce Rockford, IL . DPDPB is insoluble in aqueous buffers and was first dissolved in dimethyl sulfoxide DMSO 20 mM before dilution. Oligonucleotides were provided by Eurogentec. Surface plasmon...
Protein Nanotechnology
Protocols, Instrumentation, and Applications Director, Center for Advanced Biomedical Photonics, Oak Ridge National Laboratory, Oak Ridge, TN 2005 Humana Press Inc. 999 Riverview Drive, Suite 208 Totowa, New Jersey 07512 All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise without written permission from the Publisher. Methods in Molecular...