The field of lab-on-a-chip offers exciting new capabilities for chemical and biological assays, including increased automation, higher throughput, heightened sensitivity of detection, and reduced sample and reagent usage. This area of study has seen remarkable progress in the last decade, with applications ranging from drug development to point-of-care diagnostics. The research presented herein focuses on the development of semiconductor-based optoelectrowetting (OEW) and optoelectronic tweezers (OET) platforms, which can respectively perform operations on droplets and cells/particles. This thesis discusses progress achieved on both OEW and OET platforms. For OEW, a novel optimization model has been developed to accurately predict the interaction of droplets, semiconductor layers, and a programmable DLP-based optical source. Consequently, parallel and arrayed droplet manipulation is now possible over a large operational area (cm × cm). In addition, critical droplet operations such as mixing, splitting, and dispensing have been demonstrated. As a biological application of OEW, this work will discuss the parallel, real-time, isothermal polymerase chain reaction detection of Herpes Simplex Virus Type 1 in droplet arrays. For OET, the effort in long-term culture of adherent mammalian single cells into clonal colonies will be discussed; OET surface functionalization enables large (0.5-mm-diameter) growth patches in which positioned single cells can adhere and proliferate. Lastly, the link between the OEW and OET devices and how both droplet and particle manipulation can be enabled on a unified platform will be presented.