Advancement in fluid handling strategies for ultra-thin microfluidic devices

In this Perspective, we discuss the utility and flexibility of elastomeric pneumatic valving strategies and the challenges in applying these approaches to ultra-thin microfluidic devices. We use the strict material requirements for in situ x-ray analysis as a framework for introducing the challenges in leveraging pneumatic valves and highlight a range of capillary-based fluid handling and valving strategies that have been leveraged in x-ray applications as well as point-of-care diagnostics and biomedical applications where ultra-thin devices are critical. Rather than aiming to reproduce the full programmability of elastomeric valve networks, we highlight the ability of these platforms to facilitate event-based fluid control strategies that balance functional utility with manufacturability and robustness.