Rapid lectin detection via nanoconfined polysaccharide-protein agglutination in an iontronic nanopore sensor

Concanavalin A (Con A) is a glycoprotein binding lectin which involves cytotoxicity, cell death and cancer diagnosis. An iontronic sensor was designed using nano-confined polysaccharide-protein complexation. Dextran was functionalized onto conical track-etched nanopore surface as a lectin probe. When tetramer Con A agglutinate with dextran inside the conical nanopores, the nanopore is effectively blocked by steric hindrance, enabling a molecularly gated response that results in an amplified decrease of ionic conductance. Subsequent elution removes Con A and reopens the channel, allowing the sensor to be regenerated and reused. In 1 mol/L KCl PBS buffer (pH 7.4), the sensor achieved an ultra-low detection limit of 0.19 ng/mL and exhibited a broad linear range from 10 ng/mL to 100 mg/mL, with channel conductivity showing clear logarithmic dependence on Con A concentration. The sensor exhibits excellent selectivity toward Con A and maintains stable performance for 20 days. With its label-free design, simple structure, reusability and successful application in real samples, this iontronic nanopore sensing platform offers a highly promising tool for lectin monitoring and related bioanalytical applications.