Publications

Polypropylene (PP) surgical meshes, with different knitted architectures, were chemically functionalized with gold nanoparticles (AuNPs) and 4-mercaptothiazole (4-MB) to transform their fibers into a surface enhanced Raman scattering (SERS) detectable plastic material. The application of a thin layer of poly[N-isopropylacrylamide-co-N,N'-methylene bis(acrylamide)] (PNIPAAm-co-MBA) graft copolymer, covalently polymerized to the mesh-gold substrate, caused the conversion of the inert plastic into a thermoresponsive material, resulting in the first PP implantable mesh with both SERS and temperature stimulus responses. AuNPs were homogeneously distributed over the PP yarns, offering a clear SERS recognition together with higher PNIPAAm lower critical solution temperature (LCST ∼ 37 °C) than without the metallic particles (LCST ∼ 32 °C). An infrared thermographic camera was used to observe the polymer-hydrogel folding-unfolding process and to identify the new value of the LCST, connected with the heat generation by plasmonic-resonance gold NPs. The development of SERS PP prosthesis will be relevant for the bioimaging and biomarker detection of the implant by using the plasmonic effect and Raman vibrational spectroscopy for minimally invasive interventions (such as laparoscopy), to prevent patient inflammatory processes. Furthermore, Raman sources have been proved to not damage the cells, like happens with near-infrared irradiation, representing another advantage of moving to SERS approaches. The findings reported here offer unprecedented application possibilities in the biomedical field by extrapolating the material functionalization to other nonabsorbable polymer made devices (e.g., surgical sutures, grapes, wound dressings, among others).

JTD Keywords: gold nanoparticles, poly(n-isopropylacrylamide), polymers, polypropylene, raman-spectroscopy, reduction, resonance, sers spectroscopy, size, surface functionalization, Gold nanoparticles, Polypropylene, Surface functionalization

The use of silver nanoparticles (Ag NPs) in the biomedical field deserves a mindful analysis of the possible inflammatory response which could limit their use in the clinic. Despite the anti-cancer properties of Ag NPs having been widely demonstrated, there are still few studies concerning their involvement in the activation of specific inflammatory pathways. The inflammatory outcome depends on the synthetic route used in the NPs production, in which toxic reagents are employed. In this work, we compared two types of Ag NPs, obtained by two different chemical routes: conventional synthesis using sodium citrate and a green protocol based on leaf extracts as a source of reduction and capping agents. A careful physicochemical characterization was carried out showing spherical and stable Ag NPs with an average size between 20 nm and 35 nm for conventional and green Ag NPs respectively. Then, we evaluated their ability to induce the activation of inflammation in Human Leukemic Monocytes (THP-1) differentiated into M0 macrophages using 1 µM and 2 µM NPs concentrations (corresponded to 0.1 µg/mL and 0.2 µg/mL respectively) and two-time points (24 h and 48 h). Our results showed a clear difference in Nuclear Factor ?B (NF-?b) activation, Interleukins 6–8 (IL-6, IL-8) secretion, Tumor Necrosis Factor-? (TNF-?) and Cyclooxygenase-2 (COX-2) expression exerted by the two kinds of Ag NPs. Green Ag NPs were definitely tolerated by macrophages compared to conventional Ag NPs which induced the activation of all the factors mentioned above. Subsequently, the exposure of breast cancer cell line (MCF-7) to the green Ag NPs showed that they exhibited antitumor activity like the conventional ones, but surprisingly, using the MCF-10A line (not tumoral breast cells) the green Ag NPs did not cause a significant decrease in cell viability. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

JTD Keywords: activation, biosynthesis, gold nanoparticles, green route, inflammation response, mechanism, metal, nanotechnology, physico-chemical properties, raman-spectroscopy, resonance, silver nanoparticles, surface, Biomedical fields, Cell culture, Cell death, Chemical activation, Chemical routes, Conventional synthesis, Diseases, Green route, Inflammation response, Inflammatory response, Macrophages, Metal nanoparticles, Nf-kappa-b, Pathology, Physico-chemical properties, Physicochemical property, Property, Silver nanoparticles, Sodium compounds, Synthetic routes, Toxic reagents