Nanotechnology: Concepts and Potential Applications in Medicine

Nanocarriers have gained enormous highlight as a platform for drug delivery. These systems are often prepared with a variety of either natural or synthetic lipid, polymeric and inorganic materials. Preparation protocols include different bottom-up and top-down strategies, depending on the physicochemical characteristics of the raw materials and drugs. Moreover, the physicochemical properties of nanocarriers can be investigated with different analytical techniques, including dynamic light scattering, electron microscopy, differential scanning calorimetry, etc. The great interest for these nanocarriers is owing to their advantages for drug delivery, such as the protection of the encapsulated drug against degradation, the possibility of sustained release, higher solubility of lipophilic drugs, improved pharmacokinetics, prolonged circulation, passive targeting to solid tumors, based on the enhanced permeability and retention (EPR) effect. Also, these nanocarriers can be actively targeted to disease sites through functionalization using moieties such as peptides, folate, monoclonal antibodies and others. Altogether, these characteristics lead to improved efficacy of drugs in the treatment of a variety of diseases, with reduced side effects. Furthermore, nanocarriers have been successfully demonstrated as effective for diagnosis of diseases and have been also employed as theranostic agents. The application of nanocarriers for both treatment and diagnosis of diseases has been thoroughly investigated both in vitro, in cell culture experiments and in vivo, using xenograft animal models, for cancer, for example. However, nanocarriers are promising for application in other conditions, including inflammatory, infectious and degenerative diseases. Finally, many clinical trials have confirmed the efficacy and safety of nanocarriers, and nowadays, there is a variety of formulations available in the market, particularly liposomes. In the next years, many more nanocarriers are expected to move from bench to bedside, particularly in the field of cancer therapy.