Irreversible, self-aligned microfluidic packaging for chronic implant applications

Packaging is an often overlooked component in microfluidic devices for biomedical implant applications. Robust and reliable connectors to interface microscale and macroscale features are especially critical for chronic implant applications. Existing microfluidic packaging methods are incompatible with emerging polymeric materials designed to enhance device integration with the surrounding tissue. A microfluidic connector scheme was developed to promote compatibility with novel materials and implant applications. The connectors and an adhesive wax were printed on a scaffold via additive manufacturing processes. The low-temperature packaging process entailed bonding the connector to a polymer nanocomposite-based intracortical microfluidic probe using an adhesive wax. The robustness of the packaging was assessed by measuring the tensile and shear bond strengths of the connector-adhesive wax-polymer film interface. After soak testing for 4 weeks, the bond strength continued to exceed the force required to infuse fluids through the microfluidic channel. Further, the shear bond strength exceeded typical probe insertion forces by at least 10-fold. These results support the use of the connector and thermal bonding method as a viable option for chronic implant applications.