Hybrid-Integrated Biosensor for Express Determination of Protein Markers of Diseases based on Molecular Recognition and Direct Fluorimetric Detection

Abstract

Ways of creating new generation biosensors for multiparametric express diagnostics based on molecular recognition and direct fluorimetric registration of a peptide aptamer — protein marker complex were considered. The biosensor platform comprises a microfluidic channel for delivery sample solutions, coupled with flow-through zones containing covalently attached arrays of peptide probes — aptamers. An outer glass window of the biochip assembly contains a layer of luminophore ZnS:Cu, bound on it via an acrylic lacquer and intended for the re-emitting native fluorescence of bound proteins into the longer wavelength range, more efficient in registering signals with CMOS sensors. The aptamers were designed using "Protein 3D" program for analysis of spatial complementarity of protein structures. The peptide, complementary to Troponin T, was modified by replacement of aromatic amino acid residue while maintaining the spatial configuration. The complementarity of peptide and Troponin T was confirmed using a capillary electrophoresis-on-a-chip. Biosensors are manufactured using thick-film technology and photolithography. The fluorescence of marker proteins was excited using UV-LED with a radiation wavelength of 275 nm. The limit of detection achieved for Troponin T was 6 ng/ml.