High-sensitive Detection Of Protein Based On Interfacial Recognition-induced Transcription Amplification

Sensitive detection of protein biomarkers are of great value in revealing the pathologic process of disease development and early diagnosis of disease.In this study,a novel and universal detection strategy for sensitive detection of proteins was designed by integrating target specific recognition at the solid phase interface and exponential transcription amplification in homogeneous solution.Herein,vascular endothelial growth factor(VEGF)was used as a model target.Firstly,the VEGF was captured on a polyclonal antibody-coated microplate well.Then biotinylated monoclonal antibody was added to form a sandwich immunocomplex,which realized the specific identification of the target.Subsequently,SA was acted as a bridge to bind biotin-labeled DNA(bio-DNA)probes.Finally,the anchored bio-DNA could act as the trigger chain for initiating the homogeneous exponential transcription(HET)process.A large number of single stranded RNA products are produced by efficient exponential amplification at constant temperature.This study could convert per protein recognition events to numerous single-strandedRNA products for highly sensitive fluorescence immunosensing.It showed a strong linear relationship in the range from 0.01 to 1000 pg/mL and the detection limit was as low as 1 fg/mL,which are 3 orders lower than traditional ELISA method.In addition,the method can directly detect the VEGF content in the supernatant of tumor cell culture and the body fluid samples of clinical patients,proving very high sensitivity,high selectivity and low matrix effect.The immunosensing strategy based on interface recognition induced transcription amplification established in this paper is expected to be used for ultra-sensitive detection of low abundance protein biomarkers,which is expected to provide important technical support for early clinical diagnosis,early treatment and prognosis judgment.