Light-actuated nanoporous membrane based on host-guest complex for electrochemical quantification of exosomal membrane protein

Exosomal membrane protein plays a crucial role due to its distinctive cellular functions and close association with cancer types. Here, gold nanoparticles were in situ assembled on the surface of a nanoporous membrane (NM), forming net-like gold-coated nanoporous membrane (netAu-NM). Benefiting from the high surface area and porous architecture of the gold layer, the prepared netAu-NM exhibited enhanced ion transport through the nanochannels of the NM. A supramolecular assembly has been constructed based on the host-guest interaction between cucurbit[8]uril, benzeneseleninic acid as well as azobenzene-grafted aptamer. Benzeneseleninic acid was applied to anchor the host-guest complex onto the netAu layer via Au–Se bonds. The aptamer oriented on the netAu-NM can specifically recognize and capture CD63 protein on the exosomal surface. Current-potential (I-V) response was utilized to monitor the aptamer-target interaction that occurred on the surface of NM. On this basis, the sensing method could achieve quantitative determination of CD63 protein, with a limit of detection of 3.5 ng·mL⁻¹. Moreover, the aptamer-target bioconjugate could be released under ultraviolet light irradiation, which allowed for the subsequent immobilization of new aptamer. This strategy can be employed for the capture and detection of exosomes. The reusability of the membranes provided a sustainable and cost-effective platform for the detection of other disease biomarkers.