The application possibility of acellular dermal matrix decorated with nano-silver in the reconstruction of contaminated abdominal wall

Balanced chemical reactivity, antimicrobial properties and biocompatibility of decellularized dermal matrices for wound healing

The prevention of bacterial infection and prompt wound repair are crucial considerations when local skin tissue is compromised by burns, cuts, or similar injuries. Porcine acellular dermal matrix (pADM) is a commonly employed biological material in wound repair due to its inherent natural properties. Nonetheless, the pADM's primary constituent, collagen fibers, lacks antimicrobial properties and is vulnerable to bacterial infection when used in the treatment of incompletely debrided wounds. Meanwhile, conventional antimicrobial agents primarily consist of chemical compounds that exhibit inadequate biocompatibility and biological hazards. This research endeavors to create an antimicrobial collagen scaffold dressing utilizing the Schiff base reaction through the incorporation of oxidized chitosan diquaternary (ODHTCC) salt into the pADM. Compared with the unmodified pADM, ODHTCC-pADM (OD-pA) still retained the three-stranded helical structure of natural collagen. At an ODHTCC cross-linker concentration of 4%, the thermal denaturation temperature of OD-pA was 85 °C. According to the enzymatic degradation resistance test in vitro, the degradation resistance of OD-pA to type I collagenase was significantly improved compared with that of the uncross-linked pADM. In addition, OD-pA exhibited good antibacterial properties, with inhibition rates of 95.6% and 99.9% for E. coli and Staphylococcus aureus, respectively, and a cytotoxicity level 1, meeting the in vitro requirements of national biomedical materials. In vivo experiments showed that the OD-pA scaffold could better promote wound healing and more effectively promote the positive expression of bFGF, PDGF and VEGF. In conclusion, OD-pA has struck a balance between antibacterial properties, chemical reaction properties and biocompatibility, ultimately achieving controllability, and has broad application prospects in the field of antibacterial biomedical materials.

In Situ Cross-Linked Collagen-Based Biological Patch Integrating Anti-Infection and Anti-Calcification Properties

Acellular dermal matrix (ADM) can be used as collagen-based biological patches for regeneration and repair of soft tissues in vivo. However, the problems of calcification and infection during treatment with patches can lead to premature patch failure and even to a severely increased risk of recurrence. In this study, first, porcine ADM (pADM) grafted with vinyl underwent an in situ cross-linking reaction in the presence of an initiator, while quaternary ammonium groups were introduced into the pADM during the cross-linking process to obtain MA-DMC-pADM, which is a biological patch with anti-infection and anti-calcification properties. The results of physicochemical property tests of the material showed that the pADM after cross-linking had better physical and mechanical properties. Importantly, antibacterial and anti-calcification experiments showed that MA-DMC-pADM had a good antibacterial and anti-calcification effect. Therefore, the MA-DMC-pADM biological patch facilitates their longer-lasting effectiveness, allowing pADM to be used in a wider range of applications.

Polydopamine-modified decellularized intestinal scaffolds loaded with adipose-derived stem cells promote intestinal regeneration

Regeneration of gastrointestinal tissues remains a great challenge due to their unique microenvironment. Functional composite decellularized scaffolds have shown great potential in gastrointestinal repair and inducing gastrointestinal tissue-specific proliferation. In this study, polydopamine (PDA)-mediated surface modification of decellularized intestinal scaffolds (DIS), combined with adipose tissue-derived stem cells (ADSC), was used to promote intestinal wound healing while avoiding intestinal resection. The results showed that DIS had good biocompatibility and could maintain the growth and proliferation of ADSC. Moreover, PDA-coated DIS not only had anti-infection ability but could also further promote the secretory activity for the paracrine effects of ADSC. ADSC cultured on PDA-DIS produced significantly higher levels of anti-inflammatory and proangiogenic cytokines than those cultured on plastic plates or DIS. In vivo, ADSC-PDA-DIS significantly promoted intestinal wound closure in rat intestinal defect models. Moreover, ADSC-PDA-DIS was able to induce more neovascularization at 4 weeks postoperatively and promoted macrophage recruitment to accelerate wound healing. Taken together, the results showed that PDA-modified DIS could significantly improve the efficacy of stem cell therapy, and ADSC-PDA-DIS could improve the wound healing process with anti-infection effects, enhancing neovascularization and immunoregulation, which may be of great clinical significance for gastrointestinal regeneration.

Acellular dermal matrix decorated with collagen-affinity peptide accelerate diabetic wound healing through sustained releasing Histatin-1 mediated promotion of angiogenesis

Treating diabetic ulcers is a major challenge in clinical practice, persecuting millions of patients with diabetes and increasing the medical burden. Recombinant growth factor application can accelerate diabetic wound healing via angiogenesis. The local administration of recombinant growth factors has no robust clinical efficiency because of the degradation of append short duration of the molecules in the hostile inflammatoryenvironment.The present study focused on the pathophysiology of impaired neovascularization and growth factor short duration in the diabetic wound. We prepared a collagen-binding domain (CBD)-fused recombinant peptide (C-Histatin-1) that had both pro-angiogenesis capacity and collagen-affinity properties. Next, we created a biocompatible acellular dermal matrix (ADM) as a drug delivery carrier that featured collagen-richness, high porosity, and non-cytotoxicity. C-Histatin-1 was then tethered on ADM to obtain a sustained-release effect. Finally, a functional scaffold (C-Hst1/ADM) was developed. C-Hst1/ADM can sustain-release Histatin-1 to promote the adhesion, migration, and angiogenesisof vascular endothelial cells in vitro. Using a diabetic wound model, we showed that C-Hst1/ADM could significantly promote angiogenesis, reduce scar widths, and improve extracellular collagen accumulation. Therefore, the results of this study provide a foundation for the clinical application of C-Hst1/ADM covering scaffold in the treatment of diabetic wounds.

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.

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