Physicochemical analysis of nanosystems for biomedical applications

Summary Nanotechnology uses the basic principles of chemistry, biology, physics, and engineering to design and develop nanoscale devices for various applications, including many of biomedical interest. One of the medical fields in which nanotechnologies can exert a significant impact is that of drug delivery. In fact, nanoscale devices that can deliver drugs (nanocarriers) could encapsulate a large variety of drugs or biologically active molecules. Numerous nanosystems have been adopted to improve the bioavailability of such drugs. Recent advances in nanomedicine and biomaterials have provided promising new tools for in vitro models and targeted drug delivery in vivo, with the aim of increasing efficacy while limiting side effects. Nanosized drug delivery systems are designed to modify the biodistribution of therapeutic agents and increase their accumulation at diseased site. Biocompatible nanoparticles, polymeric nanotherapeutics, and lipid–based nanomaterials can improve the stability and targeted delivery of small molecule, as well as nucleic acids and therapeutic proteins. Precise control of key physicochemical properties of nanocarriers, such as size, drug loading, and functionality, enables effective barrier permeability and effective release at the target site. Nanomedicine has recently established itself as an exciting field that could help solve some of the problems associated with the unsatisfactory therapeutic effects of so–called “old drugs”. These problems are caused by insufficient biodistribution after drug administration, which not only limits the therapeutic effect, but also causes several side effects in healthy organs. This thesis provides a general overview on the physicochemical characterization and applications of existing nanosystems. Dissertation outlines This doctoral thesis deals with different nanosystems, including aggregates of vital dyes, hybrid nanoparticles and liposomes containing molecules used in cell differentiation. In this context, a special emphasis was placed on nanosystems preparation, characterization, and potential applications for improving the bioavailability of drugs. In particular, this thesis is structured into four chapters. Chapter 1 is composed of three paragraphs in which the main notions on nanosystems are introduced, together with the experimental techniques used for the physicochemical characterization and the applications of nanosystems used in the clinical field. Experimental results and discussion are reported in the three following chapters. In Chapter 2 vital dyes are described, considering their main optical properties and characteristics. Chapter 3 illustrates the characteristics of hybrid nanoparticle formulations and their use for the development of a patch to be used in tissue regeneration. Finally, Chapter 4 reports the study focused on the analysis of the effects of two different formulations of liposomes containing all–trans retinoic acid (ATRA) on the differentiation of neuroblastoma tumor cells.