Atomic Force Microscopy Data

We employed three types of atomic force microscopy (AFM) data collection. The first type consisted of images of 200 nm to 1 mm, such as the one in Fig. 2, on which the protein molecules, 13 nm in size were clearly detectable. Calibration of the microscope was verified by determining the spacing of molecules along a densely, packed direction in the lattice and the thickness of the top crystalline layer. As Fig. 2 reveals, the respective numbers for one of the systems, used for the studies...

Biomolecular Templated NW Assembly

The steady trend in the electronics industry toward components having ever-smaller dimensions has stimulated the development of alternative bottom-up fabrication technologies to compete with conventional micro- and nano- lithography, which are expected to become extremely expensive as the feature sizes of future electronic circuits approach the limits of optical lithography (112). Bottom-up approaches, which rely on self-assembly (or self-organization) that often utilizes biological molecules,...

SERS as a Tool for Detection of Single Molecules

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...

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...

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...

References

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...