3D mapping of microfluidic flow in laboratory-on-a-chip structures using optical tweezers

Accurate measurement of flow in microfluidic systems is both challenging and important, providing information that can be used to better understand flow fields within laboratory-on-a-chip devices and validate computational simulations. Here, we use optical tweezers within a microfluidic system to measure the velocity vectors of flow fields in two and three dimensions around a microstructures including both molded features within channels and cells. The experimental results are compared to a complex fluid dynamics model showing an agreement between the two of better than 3 mu m/s. This measurement is highly reproducible and minimally invasive, which in the future could be used to provided more in-depth studies of the rheological properties of biological cells and microstructures in laboratory-on-a-chip devices.