Smart materials for optothermal gating of nanopore

We present an innovative method for optically gating solid-state nanopores through plasmonic heating, offering significant applications in biosensing and drug delivery. By integrating temperature-responsive polymers such as poly(N-isopropylacrylamide) (PNIPAM) inside nanopores, we achieve thermal gating as the temperature goes above the lower critical solution temperature of PNIAM. Our approach combines plasmonic structure with PNIPAM within the nanopore architecture, enabling optical control of individual or multiple nanopores with micrometer spatial resolution and rapid gating speed of a few milliseconds through thermo-plasmonic effects. We attain rapid temperature changes of 40 kelvin per millisecond, confirmed by ionic conductivity measurement and COMSOL, allowing selective activation of nanopores in an array. Moreover, this selective gating allows for a distinct ionic conductance level—low, medium, and high ("0," "1," and "2")—facilitating different logical gating controlled by optical signals. This advancement paves the way for smart nanofluidic devices with multifunctional applications such as biosensing, targeted drug delivery, and fluidic mixing.