Rapid prototyping of glass microfluidic chips based on autonomous capillary networks for physiological solutions

Abstract

In this work, a technological solution is proposed for the fast and low cost realization of autonomous capillary systems that can operate with saline solutions typically used for the implementation of bioanalytical protocols. In order to develop and test the technological process, a simple microfluidic network has been designed. The network includes elementary structures as mixers, T-junctions and capillary pumps for studying the behavior of the fluid inside the test chips. The proposed microfluidic network is made in SU-8 deposited on glass substrate and the microchannels are sealed using a glass cover. A novel procedure has been implemented for the fabrication of devices using low-pressure and low-temperature bonding avoiding the risk of breaking the glass slides while ensuring a very good sealing of the microchannels. The fabricated devices showed strong capillary force and successful mixing of colored physiological solutions. Thanks to the chemical inertia of the used materials and to their mechanical properties, the chip can be easily reused after a chemical rinse, high pressure air blow and thermal treatment.