Dual-Responsive Polypropylene Meshes Actuating as Thermal and SERS Sensors

Abstract

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).

Recent Advances in Poly(N‐isopropylacrylamide) Hydrogels and Derivatives as Promising Materials for Biomedical and Engineering Emerging Applications

“…[ 39 ] Copyright 2018, Springer Nature; Grafting image. [ 133 ] Copyright 2022, American Chemical Society; Free‐radical and crosslinking junctions. [ 189 ] Copyright 2018, American Chemical Society; Metal‐ion image.…”

“…Reproduced with permission. [ 133 ] Copyright 2022, American Chemical Society. On the bottom right, the plot represents the effect of expansion/contraction of PNIPAAm chains, under temperature variations and increasing time, founding an LCST transition of 37 °C, 5 °C higher than the same system without AuNPs/4‐MB).…”

“…For instance, the full conversion of PP meshes, used in hernia repair, modified with PNIPAAm hydrogel and Au NPs (PP‐g‐PNIPAAm@AuNPs), to a spectroscopic detectable material has recently being reported by our group. [ 133 ] With plasma activation and covalently bonded AuNPs we were able to distinguish the presence of 4‐mercaptothiazole (4‐MB), the RaR molecule, inside the layer of PNIPAAm hydrogel and above the PP yarns used as substrates, either using 532 or 785 nm irradiation sources ( Figure ). The complex architecture of the mesh material (textile fabrication, different densities, and pore sizes) did not affect the sensitivity of the analysis.…”

“…Reproduced with permissions: Hydrogen bonding image [39]. Copyright 2018, Springer Nature; Grafting image [133]. Copyright 2022, American Chemical Society; Free-radical and crosslinking junctions [189].…”

Mechanical Properties of Smart Polypropylene Meshes: Effects of Mesh Architecture, Plasma Treatment, Thermosensitive Coating, and Sterilization Process

“…In recent work, the plasma technique was employed to modify the surface polymer prostheses based on the PP matrix for incorporating a coating of the poly­( N -isopropylacrylamide) (PNIPAAm) hydrogel. ,− This strategy provided meshes with enhanced cell attachment and detachment modulated properties. , More recently, Learn et al also demonstrated the advantageous modification of PP meshes with cold plasma, showing that such treatment reduces fibrinogen absorption and bacteria attachment, which are both intrinsically related to the surface oxygen content.…”