No abstract

Nanoparticles (NPs) in the biomedical field are known for many decades as carriers for drugs that are used to overcome biological barriers and reduce drug doses to be administrated. Some types of NPs can interact with external stimuli, such as electromagnetic radiations, promoting interesting effects (e.g., hyperthermia) or even modifying the interactions between electromagnetic field and the biological system (e.g., electroporation). For these reasons, at present these nanomaterial applications are intensively studied, especially for drugs that manifest relevant side effects, for which it is necessary to find alternatives in order to reduce the effective dose. In this review, the main electromagnetic-induced effects are deeply analyzed, with a particular focus on the activation of hyperthermia and electroporation phenomena, showing the enhanced biological performance resulting from an engineered/tailored design of the nanoparticle characteristics. Moreover, the possibility of integrating these nanofillers in polymeric matrices (e.g., electrospun membranes) is described and discussed in light of promising applications resulting from new transdermal drug delivery systems with controllable morphology and release kinetics controlled by a suitable stimulation of the interacting systems (nanofiller and interacting cells).

Two non-commercial metallic Au-based complexes were tested against one of the most aggressive malignant melanomas of the skin (MeWo cells), through cell viability and time-lapse live-cell imaging system assays. The tests with the complexes were carried out both in the form of free metallic complexes, directly in contact with the MeWo cell line culture, and embedded in fibers of Polycaprolactone (PCL) membranes produced by the electrospinning technique. Membranes functionalized with complexes were prepared to evaluate the efficiency of the membranes against the melanoma cells and therefore their feasibility in the application as an antitumoral patch for topical use. Both series of tests highlighted a very effective antitumoral activity, manifesting a very relevant cell viability inhibition after both 24 h and 48 h. In the case of the AuM1 complex at the concentration of 20 mM, melanoma cells completely died in this short period of time. A mortality of around 70% was detected from the tests performed using the membranes functionalized with AuM1 complex at a very low concentration (3 wt.%), even after 24 h of the contact period. The synthesized complexes also manifest high selectivity with respect to the MeWo cells. The peculiar structural and morphological organization of the nanofibers constituting the membranes allows for a very effective antitumoral activity in the first 3 h of treatment. Experimental points of the release profiles were perfectly fitted with theoretical curves, which easily allow interpretation of the kinetic phenomena occurring in the release of the synthesized complexes in the chosen medium.

Membranes based on poly(ε-caprolactone)/poly(3-hydroxybutyrate) blends (PCL/PHB at 50 wt%) were obtained by electrospinning and curcumin encapsulated at 1 wt% as active agent, as drug delivery systems for biomedical applications. PCL and PHB were also separately electrospinned and loaded with 1 wt% of curcumin. The processing parameters of PHB were drastically different from PCL and the blend PCL/PHB; in fact, the temperature used was 40 °C, and the distance injector–collector was 28 cm. Different conditions were used for PCL: lower temperature (i.e., 25 °C) and shorter distance injector–collector (i.e., 18 cm). The blend was processed in the same conditions of PCL. The fibers obtained with PHB showed diameters in the order of magnitude of micron (i.e., ≈ 3.45 µm), while the PCL mats is composed of fiber of nanometric dimensions (i.e., ≈ 340 nm). PCL/PHB blend allowed to obtain nanometric fibers (i.e., ≈520 nm). Same trend of results was obtained for the fibers’ porosity. The morphology, thermal, mechanical and barrier properties (sorption and diffusion) through water vapor were evaluated on all the electrospun fibers, as well as the release behavior of curcumin, and correlated to the processing parameter and the fibers’ morphologies.

Nowadays, continuous development of soft-electronics and wearable devices opens to the development needs of stretchable and flexible materials able to interface with the human body. In this scenario, biopolymers are particularly intriguing materials given their biocompatibility and biodegradability. For the application in this specific field the material requires several properties such as biological and mechanical performance and thermal stability. In this study, membranes able to fulfill some of these requirements are described. The electrospun membranes, composed of a blend of polycaprolactone (PCL) and gelatin (GN), have been produced in various configurations. The results show how blend or coaxial systems have different effects on both the interactions between the polymers and their thermal and mechanical properties. An important result of the chosen experimental conditions is the narrow dimensional distribution of the nanofiber diameters constituting the electrospun membranes. Thermal and mechanical tests evidenced that, by properly choosing the material composition and the method of the electrospinning process, membranes capable of withstanding high strain values before the failure can be obtained. In particular, optimizing the electrospinning process and using a blend PCL/GN with a mass ratio of 80/20, it is possible to increase the thermal stability up to 310 °C and confer to the sample the ability to reach a percentage of strain up to 350%.