UC Berkeley

Lab-on-a-chip technologies have seen great advances and development over the past few decades in addressing applications such as biochemical analysis, pharmaceutical development, and point-of-care diagnostics. Miniaturization of biochemical operations performed on lab-on-a-chip platforms benefit from reduced sample, reagent and waste volumes as well as increased parallelization and automation. This enables more cost-effective operations along with higher throughput and sensitivity for faster and more efficient analysis and detection.

The research presented in this dissertation focuses on progress achieved in optoelectrowetting (OEW), an optofluidic technology that allows for the manipulation of discrete droplets. In this work, we present a novel co-planar OEW device for droplet manipulation, which allows for faster droplet movement and a wider range of system integration capabilities than previous generations of OEW devices. First, we discuss the theory and design of the co-planar OEW device and present an optimization model that also accounts for the OEW effect on the droplet’s contact line. The OEW effect is experimentally verified by inspection of the contact angle of the droplet. We demonstrate individual and parallel droplet movement along with basic operations such as droplet merging and mixing with actuation speeds of up to 4.5 cm/s on the co-planar OEW device. Next, we investigate how experimental parameters such as applied voltage, frequency, and light intensity can be tuned for optimized OEW operation. Lastly, to showcase the co-planar OEW’s advantage for more flexible input/output configurations, we integrate the co-planar OEW platform with a droplet-on-demand dispensing system to form large scale droplet arrays with each individual droplet acting as its own unique microreaction chamber. Overall, the co-planar OEW device expands the ability for OEW technologies to serve as a versatile and adaptable lab-on-a-chip platform for a variety of biological and chemical applications.