Intracellular drug delivery has been of interest in recent years after the development of drugs targeting intracellular components. Delivery of exogenous material into cytosol has a variety of applications including cellular studies, therapies and diagnostics. Nanoparticle-mediated photoporation is novel platform technology, which enables intracellular delivery through transient cell membrane pore formation. In this thesis, we have explored the effects of changes in cellular microenvironment on cellular responses. Specifically, we highlight the role of nanoparticle and associated transient parameters, investigate cell responses to the presence of serum during photoporation and, provide operating conditions for enhanced macromolecular delivery for in vitro applications.Ph.D