The channel open/close valves are among the most important fluidic components that allow integration of various operations into fluidic circuits. While many types of valves have been developed and established for microfluidics [2], integration of valves into much smaller nanofluidic channels present a considerable challenge. Passive valves for nanofluidic control have been developed but they permit only single-use [3-4]. Active valves based on glass deformation enables reversible operations [5] but it is not compatible with NSM read-out that requires rigid and mechanically stable architectures. Recently, a promising approach exploiting a thermo-responsive polymer ‘grafted to’ a predefined zone of a nanofluidic channel was reported [6]. By heating and cooling of the whole device, the polymer undergoes reversible phase transition associated with the volume change and thus enabling opening and closing the nanochannel. However, the response time is much slower (several minutes) than the response time required to efficiently “catch” the fast diffusing molecules (in the order of miliseconds). In addition, the temperature is changed in the bulk volume of the chip (using a thermoplate interfaced with the device), which is not applicable in biomolecular studies that often requires stable and specifically defined temperatures. In order to allow for rapid and spatially confined temperature control, this project proposes to employ the principles of optically controlled heating via plasmonic nanoparticles [7]. Thermo-responsive polymer architectures actuated by plasmonic heating have been actively studied and already found various applications in colloidal actuation, tunable plasmonics, or biosensing [8]. The ability to rapidly morph miniature structures prepared from thermo-responsive polymers makes them a promising candidate to achieve the ambitious goal of this project.

With respect to the above, the specific objectives are: