Challenges in the physical characterization of lipid nanoparticles

The nano-sized drug transporters have become an efficient approach with considerable commercial values. Nanomedicine is not only limited to drug delivery by means of different ad-ministration routes, such as intravenous, oral, transdermal, nasal, pulmonary, and more, but also a multitude of areas, such as a vaccine, antibacterial, diagnostic and imaging, and gene delivery. This review will focus on lipid nanosystems with a wide range of applications taking into consid-eration their composition, properties and physical parameters. Though, designing of the suitable protocol for physical evaluation of nanoparticles is still conflicting. The main obstacle is concern-ing the sensitivity, reproducibility and reliability of the adopted methodology. Some important techniques have been compared and discussed in this report. Particularly, a comparison between different techniques involved in a) the morphologic characterization, such as Cryo-TEM, SEM and X-ray; b) the size measurement, such as DLS, SdFFF, optical microscopy and c) surface properties, namely zeta potential measurement, is described. In addition, an amperometric tool in order to investigate antioxidant activity and response of nanomaterials towards skin membrane has been presented.