Nanomedicine: the future for advancing medicine and neuroscience

Considering the last half century, the delivery of pharmacologically active substances, such as synthetic drugs, natural compounds, gene material and many other pharmaceutical products, has been widely studied and investigated [1]. Scientists working on the field of pharmacological active substances easily understood that the main problem of such molecules is represented by their wide and non-specific biodistribution once administered in the human body. This reflect in an increase in toxicity and contemporaneously in both a decreased patient’s compliance and decreased benefit-risk ratio. Another critical issue consists of the tremendous difficulty of such drugs and active molecules in crossing biological barriers [2]. In this view, the development of drug delivery systems (DDS) is aimed to create carriers able to improve the pharmacokinetic profile of drugs. Along with this purpose, the carriers could protect the body from the exposure of a great amount of drugs thus decreasing the circulating doses. Taken together, these aspects surely represent one of the most innovative improvement of the last decade of pharmaceutical research. This strategy took the smart name of “Nanomedicine”, mainly based on the use of lipid-based (liposomes, LPs), polymer-based (nanoparticles, NPs) nanocarriers or metal-based nanovectors. The last example of nanocarriers (i.e. super-paramagnetic nanoparticles) are currently applied in medicine in order to improve the quality and the specificity of body/cell imaging and diagnostic. These carriers are usually made of gold or iron, featured by a core-shell able to be visualized in body depth, thus allowing the physician to obtain better defined contrast and diagnostic images. Some examples are Resovist ® (Shering, Berlin, Germany) and Endorem/Lumirem ® (Advanced Magnetics, Guebert, France) used for liver tumor imaging. Considering the drug delivery and drug targeting aim deputed to Nanomedicine, the main advantages of nanocarriers rely on the protection of the active molecule from the metabolism and degradation, the possibility of governing the drug release over time and the ability in reaching target site (mainly organ or tissue) by using passive-route. Despite these applications, which encourages highlights from the researches, the main limits that may hamper the development of such nanocarriers could be recognized in the lack of selectivity and specificity of DDS. Thus, in order to maximize the therapeutic effect, the new “smart” DDS need to be further engineered to obtain “stable and ultra-selective” carriers able to deliver the drugs not only to the target organ or tissue but also to the target cell. In fact, in the last 10 years, the research in Nanomedicine strongly focused on the use of specific ligands (antibodies, peptides, substrates of receptors, and many others) to be conjugated onto the surface of NPs and LPs, thus enabling nanocarriers to specifically target cell population or to cross virtually impermeable barriers, as the Blood Brain Barrier [2].Some important focuses should be considered when approaching to Nanomedicine, such as its development in comparison with other innovative approaches (i.e. personalized medicine) and its application to the most difficult-to-treat diseases (i.e. neurodegenerative and neurological disorders).