(112c) Novel Valving and Packaging Designs for Protein Containing Biochips

Protein binding occurs everywhere in protein containing microfluidics. In this paper, two major issues were discussed: valving and packaging. Capillary valve (CV) is a widely used passive valve used to control the fluid flow in microfluidics. Many designs and applications have been based on the capillary valve including the compact-disk microfluidic platform technology. However, the valve loses its function when being used to hold the protein solutions or subject to protein solution that is applied to treat the surface for non-specific binding. A novel “fishbone” micro-valving design based on the concept of super-hydrophobicity was developed in this study. The experimental results showed that the valve remains its function even after protein blocking of the channel surface. Its application on the CD microfluidic platform was demonstrated. Moreover, in order to avoid the denature of the preloaded protein, two novel bonding techniques were evaluated, i.e., interstitial bonding and CO2 bonding. In interstitial bonding, UV curable monomer was loaded into the gap between the cover and the chip via capillary force, which will not contaminate the channel surface. Using CO2 to enhance the diffusion of polymer molecules at the joining interface, the bonding is achieved at room temperature via an inter-layer. Both methods were approved to have no influence on the antibody activity after bonding.