Label free sensing platform for amyloid fibrils effect on living cells

• A multiparametric label-free analysis for real-time monitoring of cellular response to amyloid compounds is proposed.
• Both analysis of SPR reflectivity and EIS are deployed providing enhanced resolution on cell-surface and cell–cell interactions.
• A new method for cell assessment based on analysis of SPR dip is discussed.
• Times series of SPR angle, SPR dip assays and EIS data are analyzed and discussed in conjunction with cell dynamics.

This study presents a multiparametric label-free analysis gathering surface plasmon resonance (SPR) and electrical impedance spectroscopy (EIS) for monitoring the progress of a model epithelial cell culture (Madin Darbey Canine Kidney – MDCK) exposed to a peptide with high bio-medical relevance, amyloid β (Aβ42). The approach surpasses the limitations in using the SPR angle for analyzing confluent cell monolayers and proposes a novel quantitative analysis of the SPR dip combined with advanced EIS as a tool for dynamic cell assessment.Long, up to 48 h time series of EIS and SPR data reveal a biphasic cellular response upon Aβ42 exposure corresponding to changes in cell-substrate adherence, cell–cell tightening or cytoskeletal remodeling.The equivalent circuit used for fitting the EIS spectra provided substantiation of SPR analysis on the progress of cell adhesion as well as insight on dynamics of cell–cell junction.Complementary endpoint assays: western blot analysis and atomic force microscopy experiments have been performed for validation.The proposed label free sensing of nonlethal effect of model amyloid protein at cellular level provides enhanced resolution on cell-surface and cell–cell interactions modulated by membrane related protein apparatus, applicable as well to other adherent cell types and amyloid compounds.