MICROFLUIDIC DROPLET CONSISTENCY MONITORING AND ENCAPSULATED CELL DETECTION VIA LASER EXCITATION

Abstract

Microfluidic droplets formed in emulsions are used in a variety of analytical techniques and hold great potential for future scientific and commercial applications. Our experiments present a microdroplet generation and consistency monitoring system with laser optics excitation and detection. We also demonstrate the detection of cancer cells encapsulated within aqueous microdroplets in continuous oil phase flow. The custom setup analyzes each droplet with sub-millisecond signal resolution and single photon accuracy, and is compatible with process-monitoring methods. To demonstrate the consistency of microdroplet generation over time, we measure and examine the mean frequency of aqueous plug-shaped droplet (microplug) formation in oil phase, as well as the mean length and interval between consecutive droplets. Two-channel optical monitoring allows for the simultaneous and independent inspection of both microdroplet generation and identification of green fluorescent protein-labeled cancer cells within the droplets. A precise, quantitative approach as utilized in these experiments may be helpful in the development of microfluidic concepts that require exacting reproducibility and would benefit from automated consistency monitoring techniques.