Integration of optoelectronics and microfluidics for biological and chemical sensing

Over the past decade, rapid advances in microfluidics have led to the creation of valves, pumps, mixers, multiplexers, along with a large variety of other devices. This technology has allowed for many fluidics applications to be performed on a chip that is approximately an inch square in area. Such applications include cell sorting, PCR on chip, crystal growth, combinatorial mixing and many others. Although the complexity of these devices may seem overwhelming, they are based on simple process called multilayer soft lithography, which uses a silicone-based elastomer to create these amazing devices. However, with the current state of technology, the applications are somewhat limited. New devices need to be created to further such fields as fluidic logic and biomimetics. Another major issue that challenges true acceptance of microfluidics is the need for a typically large interrogation setup to determine what is actually happening in the flow cell. In general, a microfluidic chip is placed under a bench top optical microscope in order to perform either colorimetric, absorption, or luminescence spectroscopy. Through these methods everything from cells to chemicals can be identified; however, a true lab-on-a-chip must not rely on something as cumbersome as a microscope. Integrated sensors must be developed to truly make lab-on-a-chip reasonable. Through this thesis, several approaches for realization of integrated optoelectronic microfluidic systems are presented. The systems are capable of performing optical interrogation of analyte, from both outside of the flow cell as well as directly inside a flow channel. Also, some novel microfluidic devices which should pave the way for greater advancement in the field of microfluidics are discussed. Through the technologies presented, true lab-on-a-chip systems should be even closer to realization.