Visiting Speaker in Chemistry ~ Professor Laura B. Sagle

Event Date: Wednesday, November 30, 2016

Professor Laura B. Sagle
Department of Chemistry
University of Cincinnati

will present a talk entitled:

Adventures in Combining Plasmonic Particles and Lipids for Biosensing and Spectrocopy

Abstract:
  This presentation will highlight two platforms recently developed in the Sagle group which combine lipids and gold nanoparticles.  The first platform involves interfacing a gold nanodisc array with solid supported lipid bilayers for label-free biosensing of membrane-associated proteins.  This platform is shown to have superior sensitivity due to elongated gold nanodics (exhibiting greater sensitivity than typical nanoparticle arrays) and an ultrathin silica layer above the nanodiscs, enabling the lipid bilayer to reside close to the nanoparticle surface.  The second platform involves sandwiching a liposome between a planar gold surface and a gold nanostar to generate a biocompatible, highly enhancing surface enhanced Raman spectroscopy (SERS) substrate.  Our initial characterization of these novel substrates investigates substrate stability, temperature inside the liposome component, and SERS activity, mechanism and reproducibility.  The substrates are shown to be stable to laser irradiation and exhibit a temperature increase of only 20 degrees Celsius inside the liposome component.  Surprisingly, the SERS enhancement of dye residing in the liposome component was found to be 4 x 10⁶, much higher than expected considering the dye molecules are at least 4 nm from either gold surface.  Finite Difference Time Domain (FDTD) calculations reveal that our excitation wavelength, 633 nm, is not exciting the dipole mode, but rather a multipole mode, which leads not only to higher SERS enhancement, but also long range coupling.  Lastly, these substrates show greater reproducibility than the SERS generated from dye residing directly on nanoparticle surfaces, and are expected to allow for the non-perturbative measurement of biological molecules in their native state, freely diffusing in solution.

Visiting Speaker in Chemistry ~ Professor Laura B. Sagle