Liquid flow monitoring at nanoliter/min rates is important for many lab-on-a-chip and stand alone biomedical applications. Several technologies have been investigated to achieve this resolution. The majority require expensive detection systems and fabrication processes. To this end we have developed an injection molded fluidic flow sensor that requires no part-to-part micromachining of silicon, significantly reducing the cost. Further, many of these systems require extensive calibration and rely on phenomena impacted by diffusion (e.g. heat pulses) that quickly lose accuracy as flow rates decrease. To overcome these limitations, bubbles instead of heat are used to mark the passing of fluid. By this means flow measurements down to 10.2Â±.7 nanoliters/min have been achieved with parts that can be manufactured in volume for about one $US.
Project end date: 01/23/08