Fabrication of cellophane-based microfluidic devices using laser direct-write approach

Commonly available cellophane, which is low cost and biodegradable, presents itself as a promising substrate for creating microfluidic devices. In this work, we report a simple and rapid laser direct-write (LDW) method for fabricating microfluidic devices in cellophane. The two-step technique involves the deposition of a light-sensitive polymer in a user-defined pattern, followed by its illumination with a continuous wave 405nm laser to cure and define the fluidic device. This method enables the creation of robust and impermeable structures that contain the flow of liquids within the flow channels and allow both pump-free, and pump-driven fluidic transport. As use-case examples, we have successfully demonstrated diffusive-mixing and colorimetric detection of nitrite and microorganisms using laser-patterned cellophane-based devices. The LDW approach provides a simple and cost-effective option for rapid prototyping and mass-manufacturing of affordable microfluidic devices, which are ideally desired for point-of-care testing within resource-constraint settings.