In vitro and in vivo studies of biaxially electrospun poly(caprolactone)/gelatin nanofibers, reinforced with cellulose nanocrystals, for wound healing applications

Abstract: Nanofiber scaffolds have been used widely for wound healing applications. These scaffolds are commonly produced from different biopolymers, but usually a combination of synthetic and natural biopolymers is preferred because they exhibit both physio-mechanical stability and an improved environment for cell growth. In this article, polycaprolactone�gelatin (PCL�gel) hybrid nanofibers were produced by two nozzle electrospinning. Cellulose nanocrystals (CNC) were synthesized and incorporated into the gel and PCL nanofibers to improve their properties. SEM images of nanofibers showed two diameter distributions with diameter averages of 140 nm and 215 nm, corresponding to gel and PCL, respectively. Although XRD patterns showed a decrease in crystallinity, the crystal sizes increased from 16.1 and 11.1 to 19.4 and 12.4 nm respectively for the (110) and (200) crystalline planes when CNC was present in the nanofibers. Mechanical studies revealed an 80 and 60 increase in modulus and tensile strength, respectively, when CNC was incorporated. In vitro studies showed that the CNC-incorporated scaffold degraded 25 more rapidly. However, the MTT assay, cell morphology, and fluorescence staining experiments showed that CNC did not affect nanofiber biocompatibility, and cells could grow, differentiate and cover the scaffold surface. Scaffolds with and without CNC both promoted robust wound healing in Balb/c mice. Graphic abstract: Figure not available: see fulltext.. © 2020, Springer Nature B.V

Enhanced antimicrobial and full-thickness wound healing efficiency of hydrogels loaded with heparinized ZnO nanoparticles: In vitro and in vivo evaluation

Nanotechnology-based fabricated wound dressings are known as appropriate substrates to enhance healing in both acute and chronic wounds. These types of materials have the ability to deliver therapeutic agents. In this study, a wound dressing including heparinized zinc oxide nanoparticles in combination with chitosan and poly(vinyl alcohol) was developed to investigate its antibacterial and regenerative properties in a rat model of full thickness skin wounds. By adding nanoparticles, the mechanical strength increased up to twice as compared to the sample without nanoparticles. In addition, heparin release profile follows the Hixson-Crowell release kinetic. Protein adsorption enhanced by adding nanoparticles in hydrogels and the prepared wound dressings were completely biocompatible. In terms of antibacterial activity, the minimum inhibitory concentration decreased by conjugation of heparin on the surface of zinc oxide nanoparticles compared to the non-functionalized nanoparticles, and, this shows the increased antibacterial synergistic effect by adding heparin to nanoparticles. Furthermore, it was found that the heparinized zinc oxide nanoparticles effectively accelerate wound closure, re-epithelialization and decrease collagen deposition compared to other groups after implantation. Hence, the prepared wound dressings have the capacity to significantly enhance healing of acute wounds. © 2020 Elsevier B.V

Decellularized human amniotic membrane: From animal models to clinical trials

The efficacy of decellularized products for healing of acute and chronic wounds mostly relies on physical and chemical properties, processing methods and host response. Human Amniotic Membrane (HAM) is considered as an effective and highly used wound dressing in clinic. According to the proposed decellularization protocols for developing of HAM, we have compared different protocols to introduce the most efficient methods, which can be used as a functional dermal matrix. In this study, different methods of HAM decellularization were used to achieve an optimal process. After achievement of appropriate decellularized method in vitro the amniotic membrane were examined in term of animal in vivo study and human clinical trial. The results of in vitro and in vivo assay indicate that the HAMs which were prepared with peracetic acid (2 M) had a significantly different in term of GAGs quantification, DNA isolation and quantification, histological assessment, collagen analysis, Cell�Tissue Interaction Study and cytotoxicity (P < 0/05). Tissue samples treated with peracetic acid (2 M) were more acceptable than that of samples prepared with other protocols in terms of preserving natural components and structure and removing of cell fragments. The peracetic acid-processed HAM was further functionally evaluated through in vivo assessments that can further lead to tissue reconstruction within the human host. © 2019 Elsevier Inc

Decellularization and preservation of human skin: A platform for tissue engineering and reconstructive surgery

A matrix derived from natural tissue functions as a highly biocompatible and versatile scaffold for tissue engineering applications. It can act as a supportive construct that provides a niche for colonization by host cells. In this work, we describe a cost-effective, reliable and reproducible protocol for decellularization and preservation of human skin as a potential soft tissue replacement. The decellularized human skin is achieved using purely chemical agents without any enzymatic steps. The suitability of the proposed method for the preservation of the extracellular matrix (ECM) structure and its main components and integrity were evaluated using histological and immunohistochemical analysis. Cryopreservation and final sterility were conducted using programmable freeze-drying and gamma irradiation. The architecture, basement membrane and 3D structure of ECM can be successfully preserved after decellularization. Our protocol was found to be appropriate to maintain key proteins such as collagen type I, III, IV and laminin in the structure of final scaffold. This protocol offers a novel platform for the preparation of a dermal substitute for potential clinical applications. Statement of Significance: Clinical application of naturally-based scaffolds for verity of health problems obliges development of a reproducible and effective technology that does not change structural and compositional material properties during scaffold preparation and preservation. Lack of an effective protocol for the production of biological products using decellularization method is still remaining. This effort is directing to solve this challenge in order to accomplish the off-the �shelf availability of decellularized dermal scaffold in market for clinical application. © 2019 Elsevier Inc

Synthesis and characterization of exopolysaccharide encapsulated PCL/gelatin skin substitute for full-thickness wound regeneration.

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