Development of an Integrated Optofluidic Platform for Droplet and Micro Particle Sensing - Microflow Analyzer for Interrogating Self Aligned Droplets and Droplet Encapsulated Micro Objects

Here we report the development of a micro flow analyser that integrates digital microfluidics technology with optoelectronics for the detection of micron size droplets and particles. Digital microfluidics is employed for the encapsulation of microparticles inside droplets that self-align at the centre of a microchannel thus eliminates the need of complicated 3D focusing. Optoelectronics comprise a laser source and detectors for the measurement of forward scatter (FSC), side scatter (SSC) and fluorescence (FL) signals from the microparticles. The optoelectronics was first used with a simple 2D flow focusing channel to detect microparticles which showed uncertainty in the data due to lack of 3D focusing. The integrated device with digital microfluidics technology and optoelectronics was then used for the enumeration and detection of Rhodamine droplets of different size. Rhodamine droplets of different size were characterized based on FSC, SSC and FL. Finally, the device was used for the detection of fluorescent microbeads encapsulated inside aqueous droplets.