Electrochemical Aptameric Recognition System for a Sensitive Protein Assay Based on Specific Target Binding-Induced Rolling Circle Amplification

摘要

A reusable aptameric recognition system was describednfor the electrochemical detection of the protein PDGFBBnbased on the target binding-induced rolling circlenamplification (RCA). A complementary DNA (CDNA),nlinear padlock probe, and primer probe were utilized tonintroduce a RCA process into the aptamer-target bindingnevent while a new aptamer was elegantly designed vianlengthening the original aptamer by the complement tonthe CDNA. The aptameric sensing system facilitates thenintegration of multiple functional elements into a signalingnscheme: a unique electrochemical technique, an attractivenRCA process, reversible DNA hybridization, and desirablenaptameric target recognition. This RCA-based electrochemicalnrecognition system not only exhibits excellentnperformance (e.g., a detection limit of 6.3 × 10-11 M, anlinear dynamic range of 2 orders of magnitude, highnspecificity, and satisfactory repeatability) but alsonovercomes the limitations associated with conventionalnaptameric biosensors (e.g., dependence of signalingntarget binding on specific aptamer sequence or requirementnof sandwich assays for two or more bindingnsites per target molecule). A recovery test demonstratednthe feasibility of the developed target proteinnassay. Given the attractive characteristics, this aptamericnrecognition platform is expected to be a candidatenfor the detection of proteins and other ligands ofninterest in both fundamental and applied research.