Multimodal Biomedical Implant with Plasmonic and Simulated Body Temperature Responses.

This work presents a novel nanoparticle-based thermosensor implant able to reveal the precise minute temperature variations along the polymer filaments, as it contracts and expands due to an increase or a decrease in the macroscale local temperature. The multimodal device is able to trace the position and the temperature of a high density polypropylene mesh, the most common type of plastic textile employed in abdominal hernia repair, by combining plasmon resonance and Raman spectroscopy with hydrogel responsive system. The novelty relies on the attachment of the biocompatible plasmon nanoparticles, based on gold stabilized by a chitosan-shell, already charged with the Raman reporter (RaR) molecules, to the robust prosthesis (polypropylene based), without the need of chemical linkers. The great SERS enhanced effect observed was potentiated by the presence of a quite thick layer of the copolymer (poly(N-isopropylacrylamide)-co-poly(acrylamide), PNIPAAm-co-PAAm) hydrogel. At temperatures above the LCST of PNIPAAm-co-PAAm (38.5°C), the water molecules are expulsed and the hydrogel layer contracts, leaving the RaR molecules (4-mercaptobenzonitrile, 4-MB) more accessible to the Raman source. In vitro studies with fibroblast cells (COS-1) revealed that the functionalized surgical mesh is biocompatible and no toxic substances are leached in the culture media after 24 h and 7 days. The PP mesh multimodal sensor opens new frontiers to semi-invasive diagnosis and infection prevention in hernia repair by using SERS spectroscopy. It also offers new possibilities to extrapolate the material functionalization to other healthcare products. This article is protected by copyright. All rights reserved.