(363b) Application Of Surface Enhanced Raman Spectroscopy For Detection Of Beta Amyloid Mediated By Sialic Acid

Alzheimer's disease (AD) is a neurodegenerative disease that gradually destroys a person's memory and ability to learn, make judgments, communicate and carry out daily activities. Currently 4.5 million Americans are diagnosed with AD which is double the amount since 1980. It is expected that in the year 2030, when the baby boom generation is over the age of 65, the number of people with AD will soar to 16 million. At the present time there is no cure, definitive diagnosis, or concrete understanding of the mechanism of AD. Beta amyloid (Aβ) is the primary protein component in senile plaques linked with Alzheimer's disease and is believe to play a significant role in the associated neurotoxicity. Aβ may be a useful marker for disease progression.

The strategy under investigation in this work aims to develop a detection platform that is specific to the toxic Aβ species. Due to low concentrations of Aβ in the cerebral spinal fluid, we propose to use a surface enhanced raman (SERS) based platform for the high sensitivity required. We have investigated this hypothesis using a gold nanosphere layer deposited either on a glass or a gold slide which has been chemically modified in order to mimic neuron cell surfaces. These chemically modified nanospheres will act as the substrate for our SERS sensor platform. The nanospheres are made by Nanospectra Biosciences and are composed of a dielectric sphere surrounded by a thin gold shell. We have been able to show success in the ability to functionalize the gold nanospheres with sialic acid which mediates the Aβ substrate specificity. We have also been able to show that the SERS response allows for detection of concentrations well into the picomolar range. It is our hope that this research will someday aid the early detection of AD and provide insight to the relationship between Aβ and disease progression.