• Nanovettori

Nanovectors for drug delivery can significantly improve the effectiveness and stability of encapsulated cargos, also prolonging circulating times and drug release kinetics. In particular they can promote the transport across biological barriers such as the blood-brain barrier. The blood-brain barrier, indeed, limits the delivery of systemically administered therapies to the brain, and poses a significant challenge to drug development efforts for such treatments. Polymeric Reverse Micelles (PRMs) are nanostructures with a polar core and a hydrophobic shell, resulting from the spontaneous self-assembly of amphiphilic copolymers in an organic solvent. The design of PRMs provides an optimal strategy for encapsulating and delivering therapeutic hydrophilic compounds.
In this experimental thesis project, stabilized polymeric reverse micelles (PRMs) have been developed which can be utilized as nanocarriers for the intranasal delivery of hydrophilic drugs to the central nervous system (CNS).
For the synthesis of PRMs, an amphiphilic copolymer composed of methoxy-polyethylene glycol-block-poly(lactide-co-glycolide) (mPEG-b-PLGA) was employed, a biocompatible polymer approved
by the Food and Drug Administration for various clinical applications. The synthesis was conducted as detailed in the work by Gagliardi et al. (Stabilized Reversed Polymeric Micelles as Nanovector for Hydrophilic Compounds; Polymers 2023, 15: 946). The chemical-physical characterization, including size, surface charge, and stability of the PRMs was performed using Dynamic Light
Scattering (DLS) analysis.
The biocompatibility of the PRMs was assessed through in vitro proliferation and vitality assays. Tests were conducted on cell lines relevant for potential intranasal administration: human neuroblastoma cells (SH-SY5Y) and human nasal epithelial cells (RPMI 2650). Proliferation was evaluated using a colorimetric assay, while cellular vitality was assessed through live cell imaging and fluorescent dyes. In addition to the empty PRMs, PRMs were also generated marked with a fluorophore: the mPEG-block-PLGA copolymer was conjugated with the fluorescent dye ATTO 488.
These PRM-488s were employed to study cellular internalization and the fate of the nanovectors within the cells. The study was conducted by treating human nasal epithelial cells RPMI 2650 with
various concentrations of PRM-488 at different time points and visualizing them through confocal microscopy.
In conclusion, the present work demonstrates that PRMs are stable, biocompatible, and capable of internalizing into cells in vitro, making them valid candidates for intranasal delivery of hydrophilic drugs (such as antisense oligonucleotides, RNA) to the CNS.