Fluorescence sensors for parallel measurements in multichannel microfluidic devices covering the full channel cross sections

Sensitive fluorescence sensors are needed to measure single cell properties in microfluidic devices. Optimizing the parallelizability and the measurement volume are two options enabling high throughput applications. The fluorescence sensor presented is highly parallelizable and, due to MEMS micromirror arrays, several sensors can be integrated in one multichannel microfluidic system. The fluorescence sensor has a detection volume of a few thousand femtoliters, covering the full cross-sections of the microfluidic channels used and can be easily adjusted to other cross-section geometries. By measuring labeled particles with diameters below 10 µm we qualified the applicability of the sensor with different channel geometries. The sensors have measurement volumes fitted to the channel geometries with widths from 20 µm up to 400 µm and reach a decision limit of less than 1790 molecules of equivalent soluble fluorophore.