NER: Detection of Specific Biomolecule Adsoption in Ionically Self-Assembled Monolayers via Second Harmonic Generation
Project Information
| Principal Investigator | Kevin E. Van Cott |
| Institution | Virginia Polytechnic Institute and State University |
| Project URL | View |
| Relevance to Implications | Marginal |
| Class of Nanomaterial | Generic |
| Impact Sector | Human Health |
| Broad Research Categories |
Hazard Characterization |
| NNI identifier |
Funding Information
| Country | USA |
| Anticipated Total Funding | $99,999.00 |
| Annual Funding | $49,999.50 |
| Funding Source | NSF |
| Funding Mechanism | Extramural |
| Funding Sector | Government |
| Start Year | 2001 |
| Anticipated End Year | 2003 |
Abstract/Summary
Nanotechnology has had a profound impact on biosensor development. The understanding and exploitation of specific biomolecular interactions has led to new applications in medical diagnostics, environmental monitoring, and genomic science. The objective of this research is to use second harmonic generation (SHG) to detect specific adsorption of unlabeled biological molecules (e.g., proteins, DNA) at a surface, and thus develop a new biosensor platform that will have significant advantages over conventional sensor platforms. SHG is the creation of light at twice the frequency of the light with which the material is being irradiated, and occurs only in materials that are noncentrosymmetric - that is, materials comprised of molecules arranged in a non-random fashion. It has been shown previously that ionically self assembled monolayers (ISAMs) of polyelectrolytes can be used to make nanometer-thick, noncentrosymmetric monolayers that exhibit a large SHG signal. The ISAM technique involves the alternant adsorption of oppositely-charged polyelectrolyte layers via electrostatic attraction. During the course of those investigations, it was found that adsorption of a ‘capping’ layer of a polyelectrolyte of opposite charge onto an SHG-active monolayer results in a dramatic decrease in the measured SHG signal. This indicates a change in the net orientation of the molecules in the pre-adsorbed film towards a more centrosymmetric configuration. This project will extend this concept to the development of a sensor that detects specific adsorption of biomolecules. Nanoscale ISAM films will be designed and fabricated in which specific adsorption of an unlabeled target biomolecule will induce a substantial change in the net orientation of molecules in the film. Important parameters will be determined that control how the sensor is constructed, the sensitivity, the dynamic range, the effect of non-specific adsorption of sample contaminants and results will be evaluated in order to compare with other biosensor systems.
