Robust Interconnects and Packaging for Microfluidic Elastomeric Chips

A stable, rugged, and easy-to-use microfluidic platform has been developed and evaluated. The system is based on multilayer silicone elastomer chips with integrated flow channels and active components, such as pressure-actuated valves. The silicone chips and stainless steel interconnect tubes are embedded in a block of an epoxy resin to give the chip and the interconnects outstanding mechanical stability. Full optical accessibility of the chip for demanding optical detection and manipulation applications, such as fluorescence and bright-field microscopy and optical tweezing, is achieved through the use of an optically transparent epoxy resin and microscope cover glasses as the packaging materials. Furthermore, this packaging technique uses a purely mechanical seal between the elastomer and cover glass, enabling applications that use chemically functionalized glass surfaces as the bottom of the flow channels. In addition, a socket was developed in which the microfluidic chips can be plugged in to provide all external connections for reagent delivery and pressure control of the integrated valves. The utility of these devices is demonstrated by showing that single DNA molecules can be attached to protein-coated walls of the flow channels and manipulated with optical tweezers.