An Electrochemiluminescence Biosensing Platform Based on a Hydrogel-AAO Nanochannel Membrane for GFAP Detection

Electrochemiluminescence (ECL) biosensors are widely used for ultrasensitive bioanalysis; however, their practical application is often limited by insufficient interface stability under complex detection conditions. Herein, an integrated hydrogel-AAO membrane (HAM) as a novel composite ion-exchange membrane is developed for constructing stable ECL biosensing interfaces. In the HAM architecture, the agarose hydrogel provides a three-dimensional, biocompatible matrix for antibody immobilization and target recognition, while the highly ordered AAO nanochannels serve as an efficient ion-transport and signal transduction pathway. The composite membrane enables effective coupling between interfacial biorecognition events and ECL signal modulation while physically separating the recognition layer from the ECL reaction region. Using glial fibrillary acidic protein (GFAP), a clinically relevant biomarker for Alzheimer's disease, as the model analyte, the proposed sensor achieved a detection limit of 191.6 fg/mL with a linear range from 1 pg/mL to 100 ng/mL. The sensor further demonstrated reliable quantification of GFAP in human serum samples, showing good agreement with a commercial ELISA kit. This work establishes the HAM as a versatile composite ion-exchange membrane for ECL biosensing and provides a general design framework for developing stable and sensitive ECL biosensors for clinical analysis.