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Updated: Jan 17, 2026
Rapid Homogeneous Detection of Biological Assays Using Magnetic Modulation Biosensing System
Published on: June 13, 2010
Magnetic MOF-Assisted Radical Polymerization Signal Amplification in Homogeneous System for Ultrasensitive PEC-EC
Huan Wang1, Yiyuan Yang1, Cuicui Du1
1State Key Laboratory of Chemo and Biosensing, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China.
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Enhancing detection sensitivity and reliability is critical in analytical chemistry, particularly for disease diagnosis and biological analysis. Innovative radical polymerization signal amplification strategies, integrated with dual-mode sensing approaches, offer promising avenues for highly sensitive and reliable photoelectrochemical (PEC)-based biosensing. Herein, a novel ultrasensitive PEC-electrochemical (EC) dual-mode biosensing platform was developed for detecting a model analyte of caspase-3, leveraging magnetic metal-organic framework (MOF)-assisted radical polymerization signal amplification in a homogeneous system. Specifically, a magnetic MOF material of MB-UiO-66-NH2 (mMOFs) was employed to load abundant chain-transfer agent (4-cyano-4-(phenylcarbonothioylthio)pentanoic acid, CPAD) to form mMOFs-CPAD, which was immobilized on a 96-well microplate via caspase-3-specific peptides (DEVD peptides). Upon caspase-3 recognition, the DEVD peptides experienced enzymatic cleavage, releasing mMOFs-CPAD. Following magnetic separation, the released mMOFs-CPAD served as a scaffold for grafting poly(ferrocenylmethyl methacrylate) (PFcMMA), thus forming the mMOFs/PFcMMA composite via reversible addition-fragmentation chain-transfer (RAFT) radical polymerization in a homogeneous system. The mMOFs/PFcMMA composite not only effectively suppressed the photocurrent of MWCNTs/PTCA/CdS-modified electrode for PEC assay but also generated an enhanced electrochemical signal for EC assay. Based on the bifunctional polymeric signal probe, the PEC-EC dual-mode biosensing platform exhibited a wide linear detection range of 10-17-10-8 g mL-1 (PEC/EC) and ultralow detection limits of 1.8 ag mL-1 (PEC) and 5.1 ag mL-1 (EC) for ultrasensitive caspase-3 detection. This work pioneers the utilization of RAFT radical polymerization for improving sensitivity and reliability in PEC-based multimode biosensing technologies.
