Implications of intracellular distribution of nanovesicles for bioimaging studies

An ever increasing number of diverse nanomaterials for biopharmaceutical applications is emerging, ranging from liposomes, niosomes, micelles, nanoemulsions, dendrimers, nanocells, cell ghosts, lipoproteins to solid nanoparticles and quantum dots. Several of these nanomaterials have been brought from the bench into the clinic over the last three decades giving raise to "Nanomedicine", a term implying the application of nanotechnology for therapy and diagnosis. Though pharmaceutical nanoparticular carriers have been successfully established as devices for enhancing the therapeutic index of clinically approved and experimental drugs, their utilization for imaging and monitoring biological functions has just began to materialize. The development of the effective carrier mechanism does not only mean the execution of delivery, but also the positive confirmation of the correct and specific delivery the cargo. Consequently, the ability to track and image the fate of any nanomedicine starting from the systemic down to the sub-cellular level becomes essential. In unison, the importance of monitoring any desired or undesired cellular and subcellular morphological and functional alterations subsequent to or indicative of therapeutic delivery is gaining increasingly attention. Focusing on selected pharmaceutical nanomaterials, this review tries to illustrate the interconnectivity between therapeutic applications of nanocarriers and their use for imaging and monitoring cellular and subcellular functions.