Polydopamine-Functionalized Bacterial Cellulose as Hydrogel Scaffolds for Skin Tissue Engineering.

Bacterial cellulose (BC) is a natural polysaccharide polymer hydrogel produced sustainably by the strain Gluconacetobacter hansenii under static conditions. Due to their biocompatibility, easy functionalization, and necessary physicochemical and mechanical properties, BC nanocomposites are attracting interest in therapeutic applications. In this study, we functionalized BC hydrogel with polydopamine (PDA) without toxic crosslinkers and used it in skin tissue engineering. The BC nanofibers in the hydrogel had a thickness of 77.8 ± 20.3 nm, and they could be used to produce hydrophilic, adhesive, and cytocompatible composite biomaterials for skin tissue engineering applications using PDA. Characterization techniques, namely Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Raman spectroscopy, were performed to investigate the formation of polydopamine on the BC nanofibers. The XRD peaks for BC occur at 2θ = 14.65°, 16.69°, and 22.39°, which correspond to the planes of (100), (010), and (110) of cellulose type Iα. Raman spectroscopy confirmed the formation of PDA, as indicated by the presence of bands corresponding to the vibration of aromatic rings and aliphatic C-C and C-O stretching at 1336 and 1567 cm-1, respectively. FTIR confirmed the presence of peaks corresponding to PDA and BC in the BC/PDA hydrogel scaffolds at 3673, 3348, 2900, and 1052 cm-1, indicating the successful interaction of PDA with BC nanofibers, which was further corroborated by the SEM images. The tensile strength, swelling ratio, degradation, and surface wettability characteristics of the composite BC biomaterials were also investigated. The BC/PDA hydrogels with PDA-functionalized BC nanofibers demonstrated excellent tensile strength and water-wetting ability while maintaining the stability of the BC fibers. The enhanced cytocompatibility of the BC/PDA hydrogels was studied using the PrestoBlue assay. Culturing murine NIH/3T3 fibroblasts on BC/PDA hydrogels showed higher metabolic activity and enhanced proliferation. Additionally, it improved cell viability when using BC/PDA hydrogels. Thus, these BC/PDA composite biomaterials can be used as biocompatible natural alternatives to synthetic substitutes for skin tissue engineering and wound-dressing applications.

Recent Progress on Hyaluronan-Based Products for Wound Healing Applications.

Hyaluronic acid (HA) based nanocomposites are considered excellent for improving wound healing. HA is biocompatible, biodegradable, non-toxic, biologically active, has hemostatic ability, and resists bacterial adhesion. HA-based nanocomposites promote wound healing in four different sequential phases hemostasis, inflammation, proliferation, and maturation. The unique biological characteristics of HA enable it to serve as a drug, an antibacterial agent, and a growth factor, which combine to accelerate the healing process. In this review, we focus on the use of HA-based nanocomposites for wound healing applications and we describe the importance of HA for the wound healing process in each sequential phase, such as hemostasis, inflammation, proliferation, and maturation. Metal nanoparticles (MNPs) or metal oxide nanoparticles (MO-NPs) loaded with HA nanocomposite are used for wound healing applications. Insights into important antibacterial mechanisms are described in HA nanocomposites. Furthermore, we explain antibiotics loaded with HA nanocomposite and its combination with the MNPs/MO-NPs used for wound healing applications. In addition, HA derivatives are discussed and used in combination with the other polymers of the composite for the wound healing process, as is the role of the polymer in wound healing applications. Finally, HA-based nanocomposites used for clinical trials in animal models are presented for wound healing applications.

Fungal-derived carboxymethyl chitosan blended with polyvinyl alcohol as membranes for wound dressings.

Multifunctional blend membranes composed of poly (vinyl alcohol) (PVA) and fungal mushroom-derived carboxymethyl chitosan (F-CMCS) were produced using a simple solution casting technique for wound dressing applications. The structural interactions between PVA and F-CMCS were confirmed by Fourier infrared spectroscopy. The crystallinity of the membranes was examined by X-ray diffraction. Field emission scanning electron microscopy confirmed the homogeneity and coarser texture with a porous-like network in the internal structure of the membranes. The hydrophilicity, swelling, and degradation of the fabricated membranes were examined according to the F-CMCS content. The PVA/F-CMCS membrane displayed potential antibacterial activity against Escherichia coli (gram-negative) and Staphylococcus (gram-positive) bacteria. An in vitro cell study of skin fibroblasts and keratinocytes on the PVA/F-CMCS membranes confirmed the biocompatibility. The hemolysis assay demonstrated the hemocompatibility of the developed membranes. The antibacterial, biocompatibility, and good hemolysis in the PVA membrane were influenced by the F-CMCS composition ratio up to 40%. The all-inclusive properties of the PVA/F-CMCS membranes highlight its potential use in wound dressing applications.