Chitosan selectively promotes adhesion of myoblasts over fibroblasts

Abdominal wall hernia repair: from prosthetic meshes to smart materials

Hernia reconstruction is one of the most frequently practiced surgical procedures worldwide. Plastic surgery plays a pivotal role in reestablishing desired abdominal wall structure and function without the drawbacks traditionally associated with general surgery as excessive tension, postoperative pain, poor repair outcomes, and frequent recurrence. Surgical meshes have been the preferential choice for abdominal wall hernia repair to achieve the physical integrity and equivalent components of musculofascial layers. Despite the relevant progress in recent years, there are still unsolved challenges in surgical mesh design and complication settlement. This review provides a systemic summary of the hernia surgical mesh development deeply related to abdominal wall hernia pathology and classification. Commercial meshes, the first-generation prosthetic materials, and the most commonly used repair materials in the clinic are described in detail, addressing constrain side effects and rational strategies to establish characteristics of ideal hernia repair meshes. The engineered prosthetics are defined as a transit to the biomimetic smart hernia repair scaffolds with specific advantages and disadvantages, including hydrogel scaffolds, electrospinning membranes, and three-dimensional patches. Lastly, this review critically outlines the future research direction for successful hernia repair solutions by combing state-of-the-art techniques and materials.

Multimodal Biomedical Implant with Plasmonic and Simulated Body Temperature Responses

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.

The Use of Collagen Methacrylate in Actuating Polyethylene Glycol Diacrylate-Acrylic Acid Scaffolds for Muscle Regeneration

After muscle loss or injury, skeletal muscle tissue has the ability to regenerate and return its function. However, large volume defects in skeletal muscle tissue pose a challenge to regenerate due to the absence of regenerative elements such as biophysical and biochemical cues, making the development of new treatments necessary. One potential solution is to utilize electroactive polymers that can change size or shape in response to an external electric field. Poly(ethylene glycol) diacrylate (PEGDA) is one such polymer, which holds great potential as a scaffold for muscle tissue regeneration due to its mechanical properties. In addition, the versatile chemistry of this polymer allows for the conjugation of new functional groups to enhance its electroactive properties and biocompatibility. Herein, we have developed an electroactive copolymer of PEGDA and acrylic acid (AA) in combination with collagen methacrylate (CMA) to promote cell adhesion and proliferation. The electroactive properties of the CMA + PEGDA:AA constructs were investigated through actuation studies. Furthermore, the biological properties of the hydrogel were investigated in a 14-day in vitro study to evaluate myosin light chain (MLC) expression and metabolic activity of C2C12 mouse myoblast cells. The addition of CMA improved some aspects of material bioactivity, such as MLC expression in C2C12 mouse myoblast cells. However, the incorporation of CMA in the PEGDA:AA hydrogels reduced the sample movement when placed under an electric field, possibly due to steric hindrance from the CMA. Further research is needed to optimize the use of CMA in combination with PEGDA:AA as a potential scaffold for skeletal muscle tissue engineering.

Towards bioengineered skeletal muscle: recent developments in vitro and in vivo

Skeletal muscle is a functional tissue that accounts for approximately 40% of the human body mass. It has remarkable regenerative potential, however, trauma and volumetric muscle loss, progressive disease and aging can lead to significant muscle loss that the body cannot recover from. Clinical approaches to address this range from free-flap transfer for traumatic events involving volumetric muscle loss, to myoblast transplantation and gene therapy to replace muscle loss due to sarcopenia and hereditary neuromuscular disorders, however, these interventions are often inadequate. The adoption of engineering paradigms, in particular materials engineering and materials/tissue interfacing in biology and medicine, has given rise to the rapidly growing, multidisciplinary field of bioengineering. These methods have facilitated the development of new biomaterials that sustain cell growth and differentiation based on bionic biomimicry in naturally occurring and synthetic hydrogels and polymers, as well as additive fabrication methods to generate scaffolds that go some way to replicate the structural features of skeletal muscle. Recent advances in biofabrication techniques have resulted in significant improvements to some of these techniques and have also offered promising alternatives for the engineering of living muscle constructs ex vivo to address the loss of significant areas of muscle. This review highlights current research in this area and discusses the next steps required towards making muscle biofabrication a clinical reality.

Bioinspired Hydrogel Coating Based on Methacryloyl Gelatin Bioactivates Polypropylene Meshes for Abdominal Wall Repair

Considering the potential of hydrogels to mimic the cellular microenvironment, methacryloyl gelatin (GelMA) and methacryloyl mucin (MuMA) were selected and compared as bioinspired coatings for commercially available polypropylene (PP) meshes for ventral hernia repair. Thin, elastic hydrated hydrogel layers were obtained through network-forming photo-polymerization, after immobilization of derivatives on the surface of the PP fibers. Fourier transform infrared spectroscopy (FTIR) proved the successful coating while the surface morphology and homogeneity were investigated by scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). The stability of the hydrogel layers was evaluated through biodynamic tests performed on the coated meshes for seven days, followed by inspection of surface morphology through SEM and micro-CT. Taking into account that platelet-rich plasma (PRP) may improve healing due to its high concentration of growth factors, this extract was used as pre-treatment for the hydrogel coating to additionally stimulate cell interactions. The performed advanced characterization proved that GelMA and MuMA coatings can modulate fibroblasts response on PP meshes, either as such or supplemented with PRP extract as a blood-derived bioactivator. GelMA supported the best cellular response. These findings may extend the applicative potential of functionalized gelatin opening a new path on the research and engineering of a new generation of bioactive meshes.

Emerging Trends in Abdominal Wall Reinforcement: Bringing Bio-Functionality to Meshes

Abdominal wall hernia is a recurrent issue world-wide and requires the implantation of over 1 million meshes per year. Because permanent meshes such as polypropylene and polyester are not free of complications after implantation, many mesh modifications and new functionalities have been investigated over the last decade. Indeed, mesh optimization is the focus of intense development and the biomaterials utilized are now envisioned as being bioactive substrates that trigger various physiological processes in order to prevent complications and to promote tissue integration. In this context, it is of paramount interest to review the most relevant bio-functionalities being brought to new meshes and to open new avenues for the innovative development of the next generation of meshes with enhanced properties for functional abdominal wall hernia repair.