%0 Journal Article
%T In Situ Monitoring the Aggregation Dynamics of Amyloid-¦Â Protein A¦Â42 in Physiological Media via a Raman-Based Frequency Shift Method
%J -
%D 2018
%R https://doi.org/10.1021/acsabm.8b00257
%X Amyloid-¦Â protein (A¦Â) is a major biomarker candidate for the diagnosis of Alzheimer¡¯s disease (AD). It is known that the core segment of A¦Â42 tends to aggregate into neurotoxic soluble oligomeric species and finally into fibrillar structures associated with AD; however, much remains to be learned about the conformational changes and dynamic aggregation processes of A¦Â protein in solution. Herein we exploit the selectivity of affinity peptides, singled out by biopanning a phage display library, to recognize and capture A¦Â42 and its fibers. The sensitivity of surface-enhanced Raman spectroscopy (SERS) to subtle electronic changes of a Raman reporter upon A¦Â42 binding, that is, the frequency shift SERS assay, is employed to develop a reliable sensor for both in situ A¦Â42 aggregation monitoring and A¦Â42 monomers and fibers detection. Atomic force microscope (AFM) imaging is used to investigate the dynamic aggregation processes of A¦Â42 on mica and confirms the conclusions of the SERS studies. Finally sensing of A¦Â42 and its fibers in fetal bovine serum (FBS) solution is shown to have a limit of detection of ¡«10¨C9 mol/L
%U https://pubs.acs.org/doi/10.1021/acsabm.8b00257