Preparation and Characterization of Functionalized Surgical Meshes for Early Detection of Bacterial Infections

Free-standing, flexible and conformable bilayered polymeric nanomembranes modified with gold nanomaterials as electronic skin sensors

Skin is a barrier that protects us against physical, chemical and biological agents. However, any damage to the skin can disrupt this barrier and therefore compromise its function leading to sometimes catastrophic consequences like sepsis. Thus, methods to detect early signs of infection are necessary. In this work, we have developed a straightforward method for producing 2D nanomembranes with regularly spaced 1D metallic nanostructures integrating sensing capabilities to pH and NADH (nicotinamide adenine dinucleotide), which are critical analytes revealing infection. To achieve this, we have successfully fabricated a bilayered nanomembrane combining a pH-responsive polyaniline (PANI) layer and a nanoperforated poly(lactic acid) (PLA) layer containing gold nanowires (Au NWs) as NADH sensing element. SEM, FTIR, Raman and AFM techniques revealed the formation of the bilayered PANI/PLA nanomembrane and the successful incorporation of the Au NWs inside the nanoperforations. The resulting bilayered nanomembrane showed significant flexibility and conformability onto different substrates due to the softness of the polymers and the ultrathin thickness with stiffness values similar to human skin. These nanomembranes also exhibited remarkable electrochemical sensing performance towards pH and NADH detection. Thus, the nanomembrane displayed linearity with good sensitivity (47 mV pH-1) in the critical pH range 4-10 and fast response time (10 s). On the other hand, PANI/PLA-Au nanomembranes also allowed the quantitative sensing of NADH with a limit of detection of 0.39 mM and a sensitivity of 1 µA cm-2 mM-1 in the concentration range 0-5 mM.

Infection-Resistant Polypropylene Hernia Mesh: Vision & Innovations

The surgical repair of hernias, a prevalent condition affecting millions worldwide, has traditionally relied on polypropylene (PP) mesh due to its favorable mechanical properties and biocompatibility. However, postoperative infections remain a significant complication, underscoring the need for the development of infection-resistant hernia meshes. This study provides a comprehensive analysis of current advancements and innovative strategies aimed at enhancing the infection resistance of PP mesh. It presents an overview of various research efforts focused on the integration of antimicrobial agents, surface modifications, and the development of bioactive coatings to prevent bacterial colonization and biofilm formation. Additionally, the synergistic effects of novel material designs and the role of nanotechnology in optimizing the anti-infective properties of PP mesh are explored. Recent clinical outcomes and in vitro studies are critically examined, highlighting challenges and potential future directions in the development of next-generation hernia meshes. Emphasis is placed on the importance of interdisciplinary approaches in advancing surgical materials with the ultimate goal of improving patient outcomes in hernia repair.

Electrochemical techniques for label-free and early detection of growing microbial cells and biofilms

Over the past decades, the misuse or abuse of antimicrobial agents to prevent and/or control infections has led to increased resistance of microbes to treatments, and antimicrobial resistance is now a subject of major global concern. In some cases, microbes possess the capacity to attach to biotic or abiotic surfaces, and to produce a protective polymeric matrix, forming biofilms of higher resistance and virulence compared to planktonic forms. To avoid further excessive and inappropriate use of antimicrobials, and to propose new effective treatments, it is very important to detect planktonic microbes and microbial biofilms in their early growth stage and at the point of need. In this review, we provide an overview of currently available electrochemical techniques, in particular impedimetric and voltamperometric methods, highlighting recent advances in the field and illustrating with examples in antibiotic susceptibility testing and microbial biofilm monitoring.

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

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.