writer：Qu, Zhenyuan; Xu, Hong; Xu, Ping; Chen, Kaimin; Mu, Rong; Fu, Jianping; Gu, Hongchen
keywords：无
source：期刊
specific source：Analytical Chemistry, 2014, 86(19), 9367-9371
Issue time：2014年
Improving the detection sensitivity of ELISA (ELISA) is of utmost importance for meeting the demand of early disease diagnosis. Herein we report an ultrasensitive ELISA system using horseradish peroxidase (HRP)-loaded nanospherical poly(acrylic acid) brushes (SPAABs) as labels. HRP was covalently immobilized in SPAABs with high capacity and activity via an efficient "chem. conjugation after electrostatic entrapment" (CCEE) process, thus endowing SPAABs with high amplification capability as labels. The periphery of SPAAB-HRP was further utilized to bind a layer of antibody with high d. for efficient capture of analytes owing to the three-dimensional architecture of SPAABs. Using human chorionic gonadotrophin (hCG) as a model analyte, the SPAAB-amplified system drastically boosted the detection limit of ELISA to 0.012 mIU mL-1, a 267-fold improvement as compared to conventional ELISA systems.