This dissertation extensively investigates applications of optics in bioresearch and introduces a series of developments in novel optical technology. The developed techniques include optics-based particle manipulation; nanophotonic, device-based gas-sensing; and optical imaging.Fine control and the inherently remote capability of light technologies allow for enormous potential in every facet of modern advanced technologies. By exploiting these advantages and employing the observable photons as information carriers, the optical techniques developed in the physical sciences are now rapidly finding numerous important applications in the research fields of biology, medicine, and soft matters. Some examples are optical manipulation, sensing, and imaging. I have worked on the technological developments to solve issues faced in this interdisciplinary field.This thesis consists of four chapters. The first chapter serves as a brief introduction to each research field of optical manipulation, sensing, and imaging, encompassing the research of this PhD work. Chapter 2 describes three novel, optics-based techniques to manipulate nanoscopic objects: lipid integrated optoelectronic tweezers, optoelectrophoresis in nanofluidic scales, and the plasmonic Brownian Ratchet. Chapter 3 reports the development of a novel explosive gas sensor utilizing an actively excited plasmon nanocavity. Chapter 4 introduces two novel microscopy techniques: the nanowire-based backscattering interference contrast microscope and the axial plane optical microscope. The first of these two reveals the Brownian motion of the anisotropic colloids near a wall, and the latter finds its applications in three-dimensional biological tissue imaging and fluidic lithography.