Microsystems for Blood Cell Counting

This paper presents two biomedical microsystems for blood cell counting, designed and built through MultiMEMS Multi-Project Wafer (MPW) service and the microBUILDER European project. Dies mm in size, made of a micromachined glass-silicon-glass triple stack, host two new kinds of multiple micro-counters, suitable to investigate the feasibility of blood cell differential analysis by means of Coulter principle in a monolithic lab-on-a-chip, which integrates a microfluidic network, sensing metal electrodes and light-guiding structures. Within these devices, impedance method gains some innovative features, both from microsystem technology itself (low consumptions of chemicals, better analytical performances, low dead volumes in multifunctional interconnected networks, parallel high-throughput processing, low-cost mass production) and from new project solutions: self-aligning illumination allows to use compact external sources (i.e, LEDs) and requires no delicate optics. Different working set-ups (ranging from series with fixed control volume to parallel differential) can be achieved by adding only few external components. It is finally possible to combine electrical and optical measurements, oriented to multi-feature classification of cell sub-populations.