Plasmon Coupling Correlation Spectroscopy

Trustees Of Boston University, Boston

Investigators

Abstract

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry and the Biomaterials Program in the Division of Materials Research, Professor Reinhard and his team at Boston University are developing optical spectroscopic techniques to investigate the structure and movement of biomolecules at the single molecule level. Single molecule measurements provide information about each molecules that move at a fast rate or rare events that would otherwise be buried by bulk measurements. To monitor the movement and structural changes of biomolecules at such a small scale, Professor Reinhard makes a molecular ruler based on optical interaction of gold nanoparticles (NPs). Fast and subtle changes in biomolecular structure and movements lead to changes in the spectral signature of these gold NPs, which can be captured at fast speed and be used to understand the behavior of biomolecules. The developed technique could elucidate the role of structural fluctuations of proteins and other biomolecules in complex biological systems, which could lead to new advances in biological, biomedical, and environmental research. Professor Reinhard works with his graduate and undergraduate students on the project, providing them an opportunity to work at the interface between biophysical chemistry, bioplasmonics, and biomaterials. Professor Reinhard also organizes workshops, offers research internships, and develops web-modules to share with the general public of his research outcomes. A particular emphasis of his outreach activities is to attract members of groups that are underrepresented in science and engineering to the research of this project. Professor Reinhard is developing a localized surface plasmon resonance (LSPR) based correlation spectroscopy. He utilizes distance-dependent near-field coupling between plasmonic NPs that cause spectral fluctuations in the far-field to monitor interparticle separations which would allow him to obtain long-time signal correlation studies of individual biopolymer molecules entirely without blinking artefacts. In this project, Professor Reinhard uses plasmon coupling correlation spectroscopy (PCCS) to measure the effect of nanoconfinement on the mechanical properties of DNA and experimentally test the validity of conventional polymer models under nano-confinement. He also works on understanding the structural dynamics of intrinsically disordered proteins (IDPs) by providing an accurate characterization of the structural fluctuations over a broad frequency range in order to develop predictive function models based on structural dynamics. The ability to elucidate the role of structural fluctuations for the function of disordered proteins and other biopolymers is important and necessary to develop a fundamental understanding of their working mechanism, which remains enigmatic. The project involves testing how spatial nanoconfinement, which is ubiquitous in biological systems, effects and potentially changes the structural dynamics of biopolymers. Besides the research goals, Professor Reinhard is working on a series of educational and outreach activities to actively mentoring students in interdisciplinary research and encourage the participation of underrepresented groups in science and engineering. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.