Sialic acids (SAs), anionic monosaccharides, are commonly found at the termini of brain gangliosides on cell membranes. The ubiquitous existence of SAs promote the aggregation and cytotoxicity of amyloid-β (Aβ) protein in neuronal membranes, suggesting the important mediators that SAs work as in the pathological process of Alzheimer’s disease (AD). We first report a highly sensitive and selective electrochemical biosensor based on a unique stimuli-responsive copolymer for the detection of SAs and further successfully apply it to evaluate the dynamic change of SAs level in live brain of mice with AD by combining with in vivo microdialysis. Our results have shown that this novel stimuli-responsive copolymer modified on the electrode surface has not only demonstrated remarkable recognition ability but also greatly enhanced the electrochemical performance by inducing favorable wettability switching. The described method can quantify SAs as low as 0.4 pM and show good selectivity over other biomolecules in the complex brain system. Furthermore, this study has first reported the accurate concentrations of SAs in different brain regions of live mice with AD, which are beneficial to the exploration of the roles that SAs play in pathological and physiological events in the brain. Considering the compositional diversity of the copolymer, this work has also provided a methodology to design new electrochemical sensors for the detection of other molecules in the central nervous system and can thereby open up a new sensing platform to understand brain chemistry.

Highly sensitive and selective electrochemical biosensor for monitoring sialic acid in live brain of mice with Alzheimer's disease based on wettability switching of a stimuli-responsive copolymer

253rd National Meeting (2017)

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