Peer reviewed article authored by (Sanna V, Pala N, Sechi M). Read article or submit your manuscript for publishing.

Frontal polymerization has been successfully used to synthesize poly(N-isopropylacrylamide) nanocomposite hydrogels containing graphene. The latter was directly achieved by ultrasound treatment of a dispersion of graphite in N-methylpyrrolidone. The dispersion, having the concentration of 2.21 g L⁻¹, was characterized by TEM analysis and mixed with suitable amounts of N-isopropylacrylamide for the synthesis of graphene-containing nanocomposite polymer hydrogels. The nanocomposite hydrogels were analyzed by SEM and Raman spectroscopy, and their swelling and rheological properties were investigated. It was found that graphene strongly influences the swelling ratio, dramatically increasing it, even if present in small amounts. Finally, the rheological properties of the hydrogels were correlated with the graphene content: G′ modulus and complex viscosity were found to increase with increasing nanofiller concentration, thus indicating the occurrence of good interactions between the two phases. Nevertheless, at a high concentration (i.e., 0.13 wt.%), graphene showed a lubrication effect, lowering the rheological parameters and approaching the same pseudoplastic behaviour of the unfilled material.

Docetaxel (Dtx) chemotherapy is the optional treatment in patients with hormone-refractory metastatic prostate cancer, and Dtx-loaded polymeric nanoparticles (NPs) have the potential to induce durable clinical responses. However, alternative formulations are needed to overcome the serious side effects, also due to the adjuvant used, and to improve the clinical efficacy of the drug.In the present study, two novel biodegradable block-copolymers, poly(lactide-co-caprolactone) (PLA-PCL) and poly(lactide-co-caprolactone-co-glycolide) (PLGA-PCL), were explored for the formulation of Dtx-loaded NPs and compared with PLA- and PLGA-NPs. The nanosystems were prepared by an original nanoprecipitation method, using Pluronic F-127 as surfactant agent, and were characterized in terms of morphology, size distribution, encapsulation efficiency, crystalline structure, and in vitro release. To evaluate the potential anticancer efficacy of a nanoparticulate system, in vitro cytotoxicity studies on human prostate cancer cell line (PC3) were carried out. NPs were found to be of spherical shape with an average diameter in the range of 100 to 200 nm and a unimodal particle size distribution. Dtx was incorporated into the PLGA-PCL NPs with higher (p < 0.05) encapsulation efficiency than that of other polymers. Differential scanning calorimetry suggested that Dtx was molecularly dispersed in the polymeric matrices. In vitro drug release study showed that release profiles of Dtx varied on the bases of characteristics of polymers used for formulation. PLA-PCL and PLGA-PCL drug loaded NPs shared an overlapping release profiles, and are able to release about 90% of drug within 6 h, when compared with PLA- and PLGA-NPs. Moreover, cytotoxicity studies demonstrated advantages of the Dtx-loaded PLGA-PCL NPs over pure Dtx in both time- and concentration-dependent manner. In particular, an increase of 20% of PC3 growth inhibition was determined by PLGA-PCL NPs with respect to free drug after 72 h incubation and at all tested Dtx concentration. In summary, PLGA-PCL copolymer may be considered as an attractive and promising polymeric material for the formulation of Dtx NPs as delivery system for prostate cancer treatment, and can also be pursued as a validated system in a more large context.