Wirelessly powered and remotely controlled valve-array for highly multiplexed analytical assay automation on a centrifugal microfluidic platform

Abstract

In this paper we present a wirelessly powered array of 128 centrifugo-pneumatic valves that can be thermally actuated on demand during spinning. The valves can either be triggered by a predefined protocol, wireless signal transmission via Bluetooth, or in response to a sensor monitoring parameters like temperature or homogeneity of the dispersion. Upon activation of a resistive heater, a low-melting membrane (ParafilmTM) is removed to vent an entrapped gas pocket, thus letting the incoming liquid wet an intermediate dissolvable film and thus open the valve. The proposed system allows up to 12 heaters to be activated in parallel with a response time below 3 seconds, potentially, resulting in 128 actuated valves in under 30 seconds. We demonstrate with three examples of common and standard procedures how the proposed technology could become a powerful tool for implementing diagnostic assays on Lab-on-a-Disc. First, we implement wireless actuation of 64 valves during rotation in a freely programmable sequence, or upon user input in real time. Then, we show a closed-loop centrifugal flow control sequence where the state of mixing between reagents evaluated from stroboscopically recorded images triggers the opening of valves. In our last experiment valving and closed-loop control are used to facilitate centrifugal processing of whole blood.