Design Framework for a Low-Cost Optical PDMS-Membrane Microfluidic Pressure Sensor for Blood-Flow Micro-pressure

Pressure measurement within the channels used in microfluidic devices is important for vascular-on-a-chip studies as well as accurate microfluidic measurements at the point of care. Most of the pressure sensors found in microfluidic devices use an expensive imaging system, have complex multi-step fabrication processes, or produce analogue output signals. This article highlights some of the fundamental components in PDMS-based microfluidics, optofluidic pressure sensors, polymer-based photonic membranes, and microfluidic logic circuits. From the review of these concepts, a gap in the literature emerges; there is a lack of simple optical pressure sensors that produce logic level signals with adjustable thresholds. Based on this knowledge, the proposal in this manuscript presents an optical pressure sensor consisting of a PDMS membrane based optical cavity and laser diode/photodiode, followed by threshold logic using a microcontroller. The manuscript discusses the proposed methods and hypotheses.