Speaker
Description
Summary: Solid-state nanochannels offer unique opportunities for miniaturized biosensing by coupling molecular recognition with iontronic signal transduction. In enzyme-functionalized nanochannels, biochemical reactions can locally modify the chemical environment at the channel interface, thereby altering the surface charge and ionic transport. Here, we experimentally investigate the factors governing iontronic glucose sensing in single bullet-shaped nanochannels functionalized with glucose oxidase (GOx), providing experimental insights into the mechanisms underlying the observed iontronic response.
Background and Motivation: Although enzyme-mediated iontronic sensing in nanochannels has previously been described and theoretically addressed, the experimental contribution of key parameters governing the sensing response remains to be fully elucidated.
Results: The iontronic response is strongly influenced by the local chemical environment generated during GOx-catalyzed glucose oxidation. Increasing the enzyme surface concentration enhances the sensing response, whereas increasing the buffer concentration attenuates it, supporting a proton-mediated transduction mechanism. Furthermore, measurements under different oxygenation conditions reveal a clear dependence of the response on dissolved oxygen availability, consistent with its role in enzymatic turnover. These observations are consistent with a steady-state local proton concentration established near the enzyme-functionalized nanochannel surface, which modulates the protonation state and therefore the surface charge.
Glucose detection was achieved over the 50–5000 µM concentration range, with a characteristic saturation-like response and an apparent Michaelis–Menten constant of approximately 600 µM. The platform exhibited a logarithmic dependence of the iontronic response on glucose concentration and enabled sensing under atmospheric oxygen conditions without external oxygen supplementation.