Research On Tau Protein Biosensor Based On Enhanced Raman Spectroscopy

Tau protein plays an important role in human nervous system,which promotes microtubule stabilization by regulating neuronal microtubule assembly.However,excessively phosphorylated Tau protein will be aggregated to form neurofibrillary tangles which cause neurodegenerative diseases such as Alzheimer's Disease(AD).As one of the biomarkers of AD,the Tau protein levels can reveal the development of diseases.Therefore,it is important to detect Tau protein levels in early screening and intervention in the treatment.This paper designed a biosensor based on surface enhanced Raman scattering(SERS)spectroscopy for fast unlabeled detection of Tau protein.The main contents were as follows:1.Preparation and characterization of SERS substrate.The PVA/Ag NO₃composite film was prepared by spin-coating,and the SERS substrate was prepared by thermal reduction method.The Morphology characterization and chemical composition analysis showed that the substrate had a uniform silver nanostructure with a unique labyrinth shape,which had a thickness of about 100 nm,an area ratio of Ag to substrate of 63%,and an effective surface area of 3.24 cm².2.Enhancement test of SERS substrate.Using melamine as a probe molecule,the substrate exhibited an excellent enhancement characteristics,the enhancement factor could reach 1149,and the minimum detection concentration is 3.85 ng/ml.3.Construction of Tau protein biosensor and Tau protein detection.Tau protein biosensor was constructed with the SERS substrate and Microbree spectroscopy system.The sensor had a good"amount-effective"relationship,better stability and reproducibility in Tau protein detection,and the fitting equation was y=17.99x+291.3(x=10-100 ng/ml),the detection limit is 10 ng/ml.The SERS substrate had a good SERS feature in this biosensor and its preparation method was simple and low,which provides a new idea for the preparation of low-cost SERS substrates;moreover,the biosensor can quantify the Tau protein with low concentration,which has the potential for early screening and diagnosis of AD by detecting Tau protein levels in the patients'Cerebrospinal fluid or blood.