Limitations of conventional treatment and dosage forms prompted the investigation of novel approaches that combine efficacy, selectivity and fewer adverse effects. These are the main promises of nanomedicine, generally defined as the application of nanotechnology to the biomedical field. Despite the considerable advances over the years and the large number of publications resulting from the growth of nanomedicine, there are still many hurdles and unknown factors limiting its successful translation from promise to reality. These factors range from the lack of standardization in the terminology and regulations, to the lack of understanding of interactions between nanocarriers and the biological system, and their influence on drug pharmacodynamics. In this manuscript, we aim at presenting and discussing concepts and terminologies used in the nanomedicine field and examining the main types of nanocarriers and their effects to modulate biological barriers and aid drug transport, bioavailability and targeting.

Polymeric vesicles known as polymersomes are formed by the self-assemble of amphiphilic block copolymers and have structural organization similar to liposomes. However, polymersomes present higher physicochemical stability and structure versatility due to their polymeric nature. In this review we describe the main aspects related to the structure and applications of these systems for drug delivery.