Overcoming tumor and mucosal barriers through active-loaded nanocarriers: nanoparticles and exosomes

Advances in nanomedicine have led to the development of efficient ways of dosing biologically active molecules through the use of nanocarriers for the treatment of several diseases, such as tumors, diabetes, neurodegenerative diseases, among others; although several studies have shown that the use of nanocarriers has overcome conventional drug delivery limitations, the limited number of nanotechnological drugs available has raised the curiosity of many researchers in the quest for improvements in nanomedicines. Indeed, recent studies have shown that knowledge of human physiological barriers can be useful to improve the design of nano-drugs, optimizing the delivery of active ingredients in situ. Among these barriers are the physiological and pathological differences between animal model specimens and humans, which makes it difficult to transpose in vivo results to the clinical scenario, intra-patient and inter-patient heterogeneity, and other factors. With the various advantages offered by precision or personalized medicine through the use of exosomes and/or nanoparticles designed for the patient, the problems that constitute the physiological barriers have been solved only at the level of the individual, leaving on the other hand the barrier constituted by population heterogeneity. According to several authors, an adequate design of nano-drugs by incorporating targeting complexes on their surface could facilitate the transfer of animal studies to humans, increase the lifetime of the drug in circulation in the body, optimize its specific delivery, and overcome multiple biological barriers at both the individual and population level. In line with the discussion above, this review highlights the importance of novel nanocarrier systems as solutions to overcome biological barriers that limit therapeutic efficacy.