Small-molecule triggered cascade enzymatic catalysis in hour-glass shaped nanochannel reactor for glucose monitoring.

Construction of an electrical signal-sensitive nanoreactor in response to small molecule remains a challenge in the developing fields of biomimetic device. Solid nanochannels are considered as promising candidates for constructing smart systems, which is highly sensitive to biochemical stimulus. Here, we report an hourglass shaped nanochannel reactor based on cascade enzymatic catalysis and cation-selective nanochannel system. The employed glucose-specific dual-enzyme combination, glucose oxidase (GOx) and horseradish peroxidase (HRP), ensures the glucose catalytic efficiency and selectivity. Presence of glucose immediately induced the bienzymatic sequential reaction. The yielding gluconic acid decreased the microenvironmental pH in the channel gradually. Different concentration of glucose produced different amount of acid and thus altered the negative charge density inside the nanochannel to different extent. Modification convenience and mechanical robustness also ensure the stability of the test platform. Owing to its unique cation-selective property and high sensitivity toward microenvironmental alteration, this nanodevice shows robust glucose-responsive properties through monitoring ionic current signatures.