Graft of 3D bioprinted autologous minimally manipulated homologous adipose tissue for the treatment of diabetic foot ulcer.

INTRODUCTION: Adipose-derived stem cells are multipotent precursor cells with the ability to differentiate into cell lineages associated with the regeneration of tissues. OBJECTIVE: The authors investigated the efficacy of AMHAT with 3D bioprinting technology in DFU. MATERIALS AND METHODS: Twenty patients were enrolled in a clinical prospective interventional pilot study. The primary endpoint was a reduction in the size of DFU, and the secondary endpoints were the epithelialization rate and amount of granulation of wound bed at weekly assessments. A bioprinter was used to produce AMHAT in the customized shape of DFU. The data were obtained using photography and computerized digital surface calculation. RESULTS: The mean wound size at the time of hospitalization was 7.529 cm2. All but one of the wounds were completely epithelialized at the ninth week. The mean wound areas decreased at weekly assessments for the first 7 weeks of treatment compared to the pre-application. When the mean decrease in the wound size was compared between consecutive weeks, there were decreases at each of the first 7 weeks. The mean time to the complete closure was 32.20±23.862 days. CONCLUSION: These data indicate that AMHAT is beneficial in terms of ease of application, significant decrease in the wound surface area, no scarring compared to grafting, and full healing times.

Collagen/gold nanoparticle nanocomposites: A potential skin wound healing biomaterial.

In this study, nanocomposite collagen scaffolds incorporating gold nanoparticles (AuNPs) were prepared for wound healing applications. Initially, dose (<20 ppm) and size (>20 nm) of AuNPs that were not cytotoxic on HaCat keratinocytes and 3T3 fibroblasts were determined. Both collagen sponges and AuNP-incorporated nanocomposites (CS-Au) were cross-linked with glutaraldehyde (CS-X and CS-AuX). Incorporation of AuNPs into cross-linked scaffolds enhanced their stability against enzymatic degradation and increased the tensile strength. Hydrolytic degradation of CS-Au group was also less than CS after seven days. Upon confirming in vitro biocompatibility of the scaffolds with cytotoxicity assays, cell attachment and proliferation tests and the in vivo efficacy for healing of full-thickness skin wounds were investigated by applying CS-X, CS-AuX or a commercial product (Matriderm®) onto defect sites and covering with Ioban® drapes. Defects were covered only with drapes for untreated control group. The wound areas were examined with histopathological and biomechanical tests after 14 days of operation. CS-AuX group was superior to untreated control and Matriderm®; it suppressed the inflammation while significantly promoting granulation tissue formation. Inflammatory reaction against CS-AuX was milder than CS-X. Neovascularization was also higher in CS-AuX than other groups, though the result was not significant. Wound closure in CS-X (76%), CS-AuX (69%), and Matriderm® (65%) were better than untreated control (45%). CS-AuX group had the highest tensile strength (significantly higher than Matriderm®) and modulus (significantly higher than Matriderm® and CS-X), indicating a faster course of dermal healing. Further studies are also needed to investigate whether higher loading of AuNPs affects these results positively in a statistically meaningful manner. Overall, their contribution to the enhancement of degradation profiles and mechanical properties, their excellent in vitro biocompatibility, and tendency to accelerate wound healing are encouraging the use of AuNPs in collagen sponges as potent skin substitutes in the future.