In the last fifty years, the miniaturization of computer chips has revolutionized technological industries. The advantages of being small in size and fast in operation for chips are clearly necessary elements that made superpower computers and microelectronic devices possible. A parallel development process is now being seen in chemical and biochemical technology industries. Research laboratories are undergoing revolutionary changes in terms of automation and parallelization of daily experiments.Microfluidic reaction devices require microliter or even less solutions and minute amounts of samples for chemical and biochemical reactions. Due to their small sizes, these devices enable automation and miniaturization of experiments. As a consequence, a large number of experiments, traditionally done on a one-by-one basis, can be performed simultaneously to provide tremendous amounts of information at an unprecedented rate and a much reduced cost. Many forms of microfluidic devices have been developed for isolation and analysis of biomolecules; few these devices are suitable for chemical synthesis. In collaboration with Dr. Xiaochuan Zhou (Atactic Technologies Inc., Houston) and Professor Erdogan Gulari (University of Michigan), we have developed microfluidic chips for chemical synthesis and bioassays (Figure 6). Since the volume per reaction in a microfluidic chip is less than one nanoliter, the device is called microfluidic PicoArray reactor.

Figure 6. Schematic illustration of PicoArray reactor for combinatorial parallel synthesis. The main features of the reactor include: a two layer structure by annealed silicon and glass, designed microfluidic dimensions suitable for various reaction and/or assay needs, uniform fluid distribution through solution distribution channels, highly parallel isolated reaction chambers, high density of reaction chambers per unit area (thousands/cm2). The PicoArray reactor enables digital chemistry by programmable light projection to selected reaction chambers and PGA controlled reactions occur within light-irradiated reaction sites.

The microfluidic devices such as those shown in Figure 6 can be conveniently connected to a conventional fluidic delivery instrument such as a regular DNA synthesizer for synthesis or a peristaltic pump for binding assays of nucleic acids or protein/antibodies. The images of the chip can be acquired on a regular image capture instrument such as a laser scanner.

We expect a broad applications of microfluidic platform based devices and the creation of integrated, miniaturized and efficient processes for chemical and biochemical applications.