Revealing the Role of Surface Wettability in Ionic Detection Signals of Nanofluidic-Based Chemical Sensors

The nanofluidic ionic signal is governed by the interactions between ion species and the surface charge, surface wettability, and pore diameter of nanofluidic membranes. However, the effect of surface wettability on the ionic detection signal across the nanofluidic membrane remains poorly explored, limited nanofluidic applications in biochemical sensing. Here, we investigate the effect of surface wettability of the nanofluidic membrane on the ionic signal for the detection of hydrophobic drug molecules using a heterogeneous nanofluidic system. This ionic signal can be tuned by light or the presence of certain ions due to the tailoring of hydrophobic interactions between the ion species and membrane surface. Compared with traditional nanofluidic membranes whose ionic signal is governed by surface charge, the regulation mechanism reported here mainly dependents on specific hydrophobic interactions, which shows a more sensitive ionic signal to environments. By virtue of the mechanism, the selective detection of the three drug molecules was realized owing to their different hydrophobic interactions with membrane surfaces. These findings have implications for understanding mass transport in nanofluidic devices and biological components and porous media involving surface wettability in nanofluidic systems.

Automated summary

The nanofluidic ionic signal is influenced by the interactions between ion species and the surface charge, surface wettability, and pore diameter of nanofluidic membranes. However, the impact of surface wettability on the ionic detection signal remains poorly understood. In this study, the effect of surface wettability on the ionic signal for the detection of hydrophobic drug molecules was investigated, and it was found that this signal could be tuned by light or the presence of certain ions. The regulation mechanism primarily relies on specific hydrophobic interactions, leading to a more sensitive ionic signal compared to traditional nanofluidic membranes.