A high density microchannel network with integrated valves and photodiodes

We have realised a microchannel network with integrated valves, which allows parallel processing of nanoparticles with very high throughput. With the latest prototype, we could show for the first time that integrated photodiodes are capable of detecting particles moving through the channels. In previous work, we have shown that manipulation of particles is possible. The system is designed for the manipulation of particles with a size between a few 100 nm and a few microns, which allows using the system for applications demanding the manipulation of biological cells or bacteria. Compared to related work on microvalve arrays with valve densities of around 16 valves cm(-2) our systems feature densities of up to 330 valves cm(-2). This was achieved with a 3 mum thick silicone valve membrane. This is a factor of 10 less than thicknesses achieved in related work on thermopneumatic actuation with silicone rubber membranes. (C) 2002 Elsevier Science B.V. All rights reserved.