A packaging technique for polymer microfluidic platforms

A new technique, resin-gas injection, has been developed for bonding and surface modification of polymer microfluidic devices. This method can easily bond biochips with complex flow patterns. A cascade micromixer and a multichannel DNA sequencing chip were demonstrated experimentally. By adding surface modification agents, the interfacial free energy of the substrate with water can be controlled. Local modification of the channel surface can also be achieved through sequential resin-gas injection in conjunction with a masking technique. For application, this technique is used to form a layer of dry monolithic stationary hydrogel on the walls of a microchannel, serving as a sieving material for electrophoresis separation of DNA fragments. The reagent loading and the electrophoresis separation efficiency of this technique were compared experimentally with the conventional linear polymer solution method used in the microchannel-based DNA sequencing process. It is found that our method has the advantages of more user-friendly operation, easier and faster sample loading, but slightly less separation efficiency.