| AVS 61st International Symposium & Exhibition | |
| Biomaterial Interfaces | Wednesday Sessions |
| Session BI+AS-WeM |
| Session: | Nonlinear Optical & Vibrational Spectroscopy |
| Presenter: | Patrick Koelsch, University of Washington |
| Authors: | P. Johansson, University of Washington R. Francisco, University of Washington J. Bryers, University of Washington P. Koelsch, University of Washington |
| Correspondent: | Click to Email |
Curli fimbriae are thin, needle-like structures formed by proteins. These so-called amyloid fibrils are typically associated with neurodegenerative conditions such as Alzheimer and Parkinson's disease; however, they can also play a beneficial role in various other processes in nature. Curli fimbriae have been shown to be involved in e.g. the colonization of abiotic surfaces, biofilm formation, and internalization of bacteria into eukaryotic cells. The structure of amyloid fibrils has been studied by IR spectroscopy, far UV CD spectroscopy, NMR, scanning probe techniques, and fluorescent probes that bind to fibrils. What is common to those approaches is the need for labelling or an ex vitro character, typically involving purification steps. Here we show how to use sum-frequency-generation (SFG) spectroscopy to study early stages of amyloid fibrillar formation within biofilms formed by a Pseudomonas strain of the P. fluorescens group. Studies have been performed in vitro, over several days of biofilm formation, under defined environmental conditions, and in real time - without the need for labels or any other disruptive sample preparation. In addition to the wild-type strain, genetically modified P. fluorescence were studied that are either overexpressing fibrils, or for which the fibrillar formation was suppressed. Furthermore, SFG spectra from purified amyloids were used to correlate in vitro and ex vitro results.