by Keyword: Poly(n-isopropylacrylamide)

Lanzalaco, S, Sánchez, X, Alemán, C, Weis, C, Traeger, KA, Turon, P, Armelin, E, (2023). Thermo/Pressure-Sensitive Self-Fixation Surgical Meshes: The Role of Adhesive Hydrogels in Interface Attachment Acs Applied Polymer Materials 5, 9898-9908

Herein, an innovative self- and pressure-adhesive biomedical implant was developed. Tissue adhesion was achieved with a thermosensitive hydrogel based on poly-(N-isopropylacrylamide-co-acrylamide), PNIPAAm-co-PAAm, grafted on a substrate composed of knitted fibers of isotactic polypropylene mesh (PP), used as surgical mesh implants. The in vitro studies, carried out with porcine skin, showed an important role of the inclusion of acrylamide-based comonomer (AAm) in the thermosensitive hydrogel PNIPAAm matrix. The bonding, peeling, and shearing energies obtained for PNIPAAm-co-PAAm increased exponentially up to three, two, and six times, respectively, compared to the gel without AAm. The physisorption and mechanical interlocking mechanisms are responsible for such improvement due to the simultaneous creation of hydrophobic and hydrophilic interactions of the thermosensitive hydrogel at temperatures higher than the lower critical solution temperature (LCST), with the porcine tissue. In addition, our bioadhesives present excellent interfacial toughness (similar to 100 J/m(2)) when compared to commercial bioglues (similar to 50 J/m(2) or lower). The results obtained represent a very promising adhesive material that is extensible to other medical devices that require atraumatic fixation to avoid chronic pain related to other fixation approaches.

JTD Keywords: Bioadhesive, Complications, Hernia-repair, Interface adhesion, Mechanicalinterlocking, Physisorption, Poly(n-isopropylacrylamide), Polypropylene mesh, Surgicalmesh, Thermosensitive hydrogel

Mingot J, Benejam N, Víllora G, Alemán C, Armelin E, Lanzalaco S, (2023). Multimodal Biomedical Implant with Plasmonic and Simulated Body Temperature Responses Macromolecular Bioscience 23, e2300118

This work presents a novel nanoparticle-based thermosensor implant able to reveal the precise temperature variations along the polymer filaments, as it contracts and expands due to changes in the macroscale local temperature. The multimodal device is able to trace the position and the temperature of a polypropylene mesh, 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 nanoparticles, based on gold stabilized by a chitosan-shell, already charged with the Raman reporter (RaR) molecules, to the robust prosthesis, without the need of chemical linkers. The SERS enhanced effect observed is potentiated by the presence of a quite thick layer of the copolymer (poly(N-isopropylacrylamide)-co-poly(acrylamide)) hydrogel. At temperatures above the LCST of PNIPAAm-co-PAAm, the water molecules are expulsed and the hydrogel layer contracts, leaving the RaR molecules more accessible to the Raman source. In vitro studies with fibroblast cells reveal that the functionalized surgical mesh is biocompatible and no toxic substances are leached in the medium. The mesh sensor opens new frontiers to semi-invasive diagnosis and infection prevention in hernia repair by using SERS spectroscopy. It also offers new possibilities to the functionalization of other healthcare products.© 2023 Wiley-VCH GmbH.

JTD Keywords: adhesion, blends, chitosan, gold nanoparticles, poly(n-isopropylacrylamide), polypropylene mesh, polypropylene meshes, repair, scattering, silver, surgical implants, thermosensitive hydrogels, toxicity, Chitosan, Gold nanoparticles, Polypropylene meshes, Surgical implants, Thermosensitive hydrogels

Lanzalaco, S, Weis, C, Traeger, KA, Turon, P, Alemán, C, Armelin, E, (2023). Mechanical Properties of Smart Polypropylene Meshes: Effects of Mesh Architecture, Plasma Treatment, Thermosensitive Coating, and Sterilization Process Acs Biomaterials Science & Engineering 9, 3699-3711

Smart polypropylene (PP) hernia meshes were proposed to detect surgical infections and to regulate cell attachment-modulated properties. For this purpose, lightweight and midweight meshes were modified by applying a plasma treatment for subsequent grafting of a thermosensitive hydrogel, poly(N-isopropylacrylamide) (PNIPAAm). However, both the physical treatment with plasma and the chemical processes required for the covalent incorporation of PNIPAAm can modify the mechanical properties of the mesh and thus have an influence in hernia repair procedures. In this work, the mechanical performance of plasma-treated and hydrogel-grafted meshes preheated at 37 °C has been compared with standard meshes using bursting and the suture pull out tests. Furthermore, the influence of the mesh architecture, the amount of grafted hydrogel, and the sterilization process on such properties have been examined. Results reveal that although the plasma treatment reduces the bursting and suture pull out forces, the thermosensitive hydrogel improves the mechanical resistance of the meshes. Moreover, the mechanical performance of the meshes coated with the PNIPAAm hydrogel is not influenced by ethylene oxide gas sterilization. Micrographs of the broken meshes evidence the role of the hydrogel as reinforcing coating for the PP filaments. Overall, results confirm that the modification of PP medical textiles with a biocompatible thermosensitive hydrogel do not affect, and even improve, the mechanical requirements necessary for the implantation of these prostheses in vivo.

JTD Keywords: biomaterials, bursting test, etox sterilization, hernia repair, hydrogels, infection, poly(n-isopropylacrylamide), pull outtest, surgical mesh, Abdominal-wall, Biomedical implant, Bursting test, Etox sterilization, Poly(n-isopropylacrylamide), Pull out test, Surgical mesh

Lanzalaco, S, Mingot, J, Torras, J, Alemán, C, Armelin, E, (2023). Recent Advances in Poly(N-isopropylacrylamide) Hydrogels and Derivatives as Promising Materials for Biomedical and Engineering Emerging Applications Advanced Engineering Materials 25,

Lanzalaco, S, Gil, P, Mingot, J, Agueda, A, Alemán, C, Armelin, E, (2022). Dual-Responsive Polypropylene Meshes Actuating as Thermal and SERS Sensors Acs Biomaterials Science & Engineering 8, 3329-3340

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