Abstract
We have proposed a novel microfluidic system, named 'microfluidic reactor array', for parallel and ultra-low volume chemical or biochemical screenings with droplets dispensing and mixing. This system consists of three-dimensional microchamber and microchannel networks, in which nanoliter-sized droplets could be accurately dispensed with the aid of pneumatic pressure and narrow channels called hydrophobic passive valves. By arranging multiple dispensing channels and reaction chambers in parallel, a number of droplets can be dispensed simultaneously only by a single injection of liquid. In this study, two types of microfluidic reactor array have been developed: 'open-channel reactor array' and 'closed-chamber reactor array'. First, we have designed and fabricated microdevices for 'open-channel reactor array', and applied this system to biochemical analysis using enzymatic reactions. Next, we have designed and fabricated microdevices for 'closed-chamber reactor array', in which concentration or pH gradient was precisely generated. For the application of this closed-chamber array, optimization of enzyme reaction condition was performed. These two types of 'microreactor array' will play an important roll in chemical/biochemical screenings for its simplicity in structure and operation, and diverse applicability. In addition, these liquid dispensing technologies display outstanding performances since the dead volume ideally becomes zero, and applied to a new type of microreactor array.
