Green microfluidics made of corn proteins

Petroleum-based polymer such as Poly(dimethylsiloxane) has been widely used to make mesoscale and microscale fluidic devices. The main drawback of such devices in disposable applications is the potential environmental pollution since they are not biodegradable. Biodegradable microfluidic devices have been fabricated out of zein, a prolamin protein found in corn, that can be utilized as disposable health and environmental-friendly micro-chips. Using stereo lithography and soft lithography, micro-chambers and micro-channels features have been replicated on zein films and enclosed zein microfluidic devices are created by bonding to glass substrate using a simple vapor-deposition method. The bonding strength of the zein microfluidic devices has been found to exceed the tensile strength of the zein film and hydraulic pressure, and fluid flow through large-area complex microfluidic designs shows no leakage or distortion. High optical clarity and fluorescent imaging in the zein microfluidic devices are demonstrated by visualizing micro-particles and Rhodamine B. Zein microfluidic devices enable truly disposable microfluidics with intrinsic biocompatibility and biodegradability that can be fabricated using existing techniques.