Repair of abdominal wall defects in vitro and in vivo using VEGF sustained-release multi-walled carbon nanotubes (MWNT) composite scaffolds

Nanotechnology approaches in abdominal wall reconstruction: A narrative review about scaffold and meshes

Repairing abdominal wall defects poses challenges for surgeons. Although mesh reinforcement is commonly used for primary repair, nanotechnology has emerged as a promising approach for developing innovative repair techniques. Most research in this area focuses on fabricating scaffolds designed specifically for abdominal wall repair, particularly in cases of hernia. These scaffolds are engineered to replicate the structure and function of the native extracellular matrix. This review aimed to summarize the existing studies on the application of nanotechnology in abdominal wall reconstruction following injury or repair.

Advances on the modification and biomedical applications of acellular dermal matrices

Acellular dermal matrix (ADM) is derived from natural skin by removing the entire epidermis and the cell components of dermis, but retaining the collagen components of dermis. It can be used as a therapeutic alternative to “gold standard” tissue grafts and has been widely used in many surgical fields, since it possesses affluent predominant physicochemical and biological characteristics that have attracted the attention of researchers. Herein, the basic science of biologics with a focus on ADMs is comprehensively described, the modification principles and technologies of ADM are discussed, and the characteristics of ADMs and the evidence behind their use for a variety of reconstructive and prosthetic purposes are reviewed. In addition, the advances in biomedical applications of ADMs and the common indications for use in reconstructing and repairing wounds, maintaining homeostasis in the filling of a tissue defect, guiding tissue regeneration, and delivering cells via grafts in surgical applications are thoroughly analyzed. This review expectedly promotes and inspires the emergence of natural raw collagen-based materials as an advanced substitute biomaterial to autologous tissue transplantation.

Graphical Abstract

Topological Structure Design and Fabrication of Biocompatible PLA/TPU/ADM Mesh with Appropriate Elasticity for Hernia Repair

The meshes for hernia repair result in many problems that are related to complications including chronic pain and limited movement due to inadequate mechanical strength, non-absorbability, or low elasticity. In this study, degradable polylactic acid (PLA), synthetic thermoplastic polyurethane (TPU), and acellular dermal matrix (ADM) powders are combined to prepare a novel PLA/TPU/ADM mesh with three different topological structures (square, circular, and diamond) by 3D printing. The physicochemical properties and structural characteristics of mesh are studied, the results show that the diamond structure mesh with the pore size of 3 mm has sufficient elasticity and tensile strength, which provides the efficient mechanical strength required for hernia repair (16 N cm^-1 ) and the value more than polypropylene(PP) mesh. Besides, in vitro and in vivo experiments demonstrate human umbilical vein endothelial cells could successfully proliferate on the PLA/TPU/ADM mesh whose biocompatibility with the host is shown using a rat model of abdominal wall defect. In conclusion, the results of this study demonstrate that the PLA/TPU/ADM mesh may be considered a good choice for hernia repair as its potential to overcome the elastic and strength challenges associated with a highly flexible abdominal wall, as well as its good biocompatibility.

A smart scaffold composed of three-dimensional printing and electrospinning techniques and its application in rat abdominal wall defects

Background

Biological composite scaffolds are increasingly being used in abdominal wall reconstruction but still have certain shortcomings. The present study describes here a novel three-dimensional (3D) scaffold fabricated by combining 3D printing (3DP) and electrospinning (ESP).

Methods

Biological composite scaffolds are composed of integrated 3DP interconnected macrofiber and random ESP microfiber networks. The 3DP scaffold retains intact 3D architecture and mechanical properties, while the ESP network serves as a cell entrapment system at the extracellular matrix (ECM) scale. Biological composite scaffolds are implanted in a defective rat abdominal wall to detect if it could induce early vascularization and reconstruction of the tissue defect.

Results

SEM analysis reveals a pore diameter of 424.47 ± 58.49 μm and a porosity of 70.46 ± 2.48% for biological composite scaffolds. In the in vitro test of cell proliferation, biological composite scaffolds do not affect rat dermal fibroblast proliferation in a time- and dose-dependent manner. The animal experiments show tissue remodeling and early angiogenesis as compared to 3DP scaffolds.

Conclusions

Our experiment prepares a biological scaffold with both a macro- and microscale structure by ESP and 3DP technology. Thus, the integration of 3DP and ESP techniques provides a new set of smart scaffolds for abdominal wall defect and hernia repair.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-020-02042-6.

Promoting early neovascularization of SIS-repaired abdominal wall by controlled release of bioactive VEGF

Insufficient early neovascularization post-operation is thought to be the main reason of surgical recurrence of porcine small intestinal submucosa (SIS)-repaired abdominal wall defects.

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.

Osteogenic cell differentiation on H-terminated and O-terminated nanocrystalline diamond films

Nanocrystalline diamond (NCD) films are promising materials for bone implant coatings because of their biocompatibility, chemical resistance, and mechanical hardness. Moreover, NCD wettability can be tailored by grafting specific atoms. The NCD films used in this study were grown on silicon substrates by microwave plasma-enhanced chemical vapor deposition and grafted by hydrogen atoms (H-termination) or oxygen atoms (O-termination). Human osteoblast-like Saos-2 cells were used for biological studies on H-terminated and O-terminated NCD films. The adhesion, growth, and subsequent differentiation of the osteoblasts on NCD films were examined, and the extracellular matrix production and composition were quantified. The osteoblasts that had been cultivated on the O-terminated NCD films exhibited a higher growth rate than those grown on the H-terminated NCD films. The mature collagen fibers were detected in Saos-2 cells on both the H-terminated and O-terminated NCD films; however, the quantity of total collagen in the extracellular matrix was higher on the O-terminated NCD films, as were the amounts of calcium deposition and alkaline phosphatase activity. Nevertheless, the expression of genes for osteogenic markers – type I collagen, alkaline phosphatase, and osteocalcin – was either comparable on the H-terminated and O-terminated films or even lower on the O-terminated films. In conclusion, the higher wettability of the O-terminated NCD films is promising for adhesion and growth of osteoblasts. In addition, the O-terminated surface also seems to support the deposition of extracellular matrix proteins and extracellular matrix mineralization, and this is promising for better osteoconductivity of potential bone implant coatings.

Synthesis and bioactivity of gelatin/multiwalled carbon nanotubes/hydroxyapatite nanofibrous scaffolds towards bone tissue engineering

The in vitro bioactivity of scaffolds, and the adhesion, mineralization, viability and proliferation of hFOBs on gelatin/MWNTs/HA nanofibrous scaffolds.

Bioprosthetic tissue matrices in complex abdominal wall reconstruction

Background:

Complex abdominal defects are difficult problems encountered by surgeons in multiple specialties. Although current evidence supports the primary repair of these defects with mesh reinforcement, it is unclear which mesh is superior for any given clinical scenario. The purpose of this review was to explore the characteristics of and clinical relevance behind bioprosthetic tissue matrices in an effort to better clarify their role in abdominal wall reconstruction.

Methods:

We reviewed the peer-reviewed literature on the use of bioprosthetic mesh in human subjects. Basic science articles and large retrospective and prospective reviews were included in author’s analysis. The clinical performance and characteristics of 13 bioprosthetic tissue matrices were evaluated.

Results:

The majority of the products evaluated perform well in contaminated fields, where the risk of wound-healing difficulties is high. Clinical outcomes, which included infection, reherniation, and bulge formation, were variable, and the majority of the studies had a mean follow-up of less than 24 months.

Conclusions:

Although bioprosthetic matrix has a multitude of indications within the growing field of abdominal wall reconstruction, the functionality, regenerative capacity, and long-term fate of these products have yet to be fully established. Furthermore, the clinical performance, indications, and contraindications for each type of matrix need to be fully evaluated in long-term outcome studies.