The manipulation of fluids in channels with dimensions of tens of micrometres — microfluidics — has emerged as a distinct new field. Microfluidics has the potential to influence subject areas from chemical synthesis and biological analysis to optics and information technology. But the field is still at an early stage of development. Even as the basic science and technological demonstrations develop, other problems must be addressed: choosing and focusing on initial applications, and developing strategies to complete the cycle of development, including commercialization. The solutions to these problems will require imagination and ingenuity.
What is microfluidics? It is the science and technology of systems that process or manipulate small (10-9 to 10-18 litres) amounts of fluids, using channels with dimensions of tens to hundreds of micrometres. The first applications of microfluidic technologies have been in analysis, for which they offer a number of useful capabilities: the ability to use very small quantities of samples and reagents, and to carry out separations and detections with high resolution and sensitivity; low cost; short times for analysis; and small footprints for the analytical devices1. Microfluidics exploits both its most obvious characteristic — small size — and less obvious characteristics of fluids in microchannels, such as laminar flow. It offers fundamentally new capabilities in the control of concentrations of molecules in space and time.
As a technology, microfluidics seems almost too good to be true: it offers so many advantages and so few disadvantages (at least in its major applications in analysis). But it has not yet become widely used. Why not? Why is every biochemistry laboratory not littered with ‘labs on chips’? Why does every patient not monitor his or her condition using microfluidic home-test systems? The answers are not yet clear. I am convinced that microfluidic technology will become a major theme in the analysis, and perhaps synthesis, of molecules: the advantages it offers are too compelling to let pass. Having said that, the answers to questions concerning the time and circumstances required for microfluidics to develop into a major new technology are important not just for this field, but also for other new technologies struggling to make it into the big time.