Electrochemiluminescent Aptamer-sensor for Alpha Synuclein Oligomer Based on Metal-organic Frameworks
Alpha synuclein (α-syn) oligomer is one of the biomarkers for early diagnosis of Parkinson’s disease. In this paper, two electrochemiluminescent (ECL) biosensors with aptamer as recognition element for α-syn oligomer detection were prepared. Functioned indium tin oxide (ITO) glass with metal-organic frameworks (MOFs) materials provides adequate sensing platform. Here the gold nanoparticles/MOFs composite (AuNPs@MOFs) using 3-aminopropyltrimethoxysilane as binding agent, or to connect MOFs onto the ITO directly via glutaraldehyde, both make strong ECL emission of luminol even under weak alkaline condition. Thereafter, the thiolated or carboxylated aptamer was coalesced onto the MOFs material functioned electrode by Au-S bond or amide bond via the classic EDC-NHS coupling, respectively. Thus the ECL emission of the sensors significantly reduced after the specific binding of α-syn oligomer to aptamer. The good linear relationship of ECL sensing signals upon the logarithm of α-syn oligomer concentration were established, from 2.43 fM to 0.486 pM or 1.39 fM to 0.243 pM, and the limit of detection can reach down to 0.42 fM or 0.38 fM, for these two sensors. Both obtained sensors have advantages of high sensitivity and selectivity, reproducibility and being capable of detecting target in human serum.