Incorporating silver nanoparticles into electrospun nanofibers of casein/polyvinyl alcohol to develop scaffolds for tissue engineering.

Developing novel antimicrobial wound dressings that have the potential to address the challenges associated with chronic wounds is highly imperative in providing effective infection control and wound healing support. Biocompatible electrospun nanofibers with their high porosity and surface area enabling efficient drug loading and delivery have been investigated in this regard as viable candidates for chronic wound care. Here, we design Casein/Polyvinyl alcohol (CAN/PVA) nanofibers reinforced with silver nanoparticles (Ag NPs) by the electrospinning technique to develop diabetic wound healing scaffolds. The prepared samples were characterized using spectroscopic and electron microscopic techniques. The biocompatibility of the polymer samples were assessed using 3 T3 fibroblast cell lines and the maximum cell viability was found to 95 % at a concentration of 50 µg/mL for the prepared nanofibers. Scratch assay tests were also performed to analyze the wound healing activity of the nanofibers wherein they demonstrated increased migration and proliferation of fibroblast 3 T3 cells. Moreover, these nanofibers also exhibit antibacterial efficiency against Gram-negative bacteria, Escherichia coli (E.coli). Therefore, the antimicrobial nature of the electrospun nanofibers coupled with their moisture absorption properties and wound healing ability render them as effective materials for wound dressing applications.

Efficacy of Ageratum conyzoides on tissue repair and collagen formation in rats.

BACKGROUND: Wound healing occurs as a fundamental response to tissue injury. Several natural products have been shown to accelerate the healing process. AIM: To observe the efficacy of topical administration of an ethanolic extract of Ageratum conyzoides on cutaneous wound healing in rats. METHODS: An ethanolic extract of A. conyzoides was prepared, and its wound-healing efficacy on rats was studied. An open excision wound was made on the back of each rat, and 200 µL (40 mg/kg body weight) of the A. conyzoides extract was applied topically once daily to the treated wounds. The control wounds were treated with 200 µL of 50% ethanol. The wound tissues formed were removed at 4, 8 and 12 days after wounding, and biochemical parameters such as DNA, total protein, total collagen, hexosamine and uronic acid were estimated. The extent of epithelialization and the tensile strength of the wounded tissues were also measured. RESULTS: The A. conyzoides extract increased cellular proliferation and collagen synthesis. Wounds treated with the extract were found to heal much faster, based on the improved rates of epithelialization and wound contraction, and on the histopathological results. A 40% increase in the tensile strength of the treated tissue was seen. CONCLUSIONS: Topical application of A. conyzoides accelerates the rate of wound healing.

Fibrin as a matrix for grafting 2-hydroxyethyl methacrylate: preparation and characterization of the graft and its in vivo evaluation for wound healing.

In this work, fibrin was used as a substrate to graft 2-hydroxyethyl methacrylate (HEMA) by free radical polymerization using potassium persulfate and sodium metabisulfite as redox initiators. The extent of grafting the synthetic polymer on the biopolymer was studied under various experimental conditions, and the optimum factors for affording maximum grafting were standardized. The graft, fib-g-p[HEMA], was characterized by Fourier transform infrared, scanning electron microscopy, and X-ray diffraction studies. The graft exhibited a higher shelf life than native fibrin. The biocompatibility of the graft has been tested by in vivo studies and the results, in terms of collagen formation and wound size, proved its suitability for wound healing.

Molecular species of collagen in the intramuscular connective tissues of the marine crab, Scylla serrata.

Type V like collagens are widely distributed in marine invertebrates, particularly crustaceans and molluscs. We have been investigating the nature of collagens in the muscular tissues of crustaceans. The presence of type V like homotrimeric collagen in prawn muscle was noted before. We report here a comparative analysis of collagens purified from the pepsin digest of abdominal and pereiopod muscle tissues of the crab, Scylla serrata. The major collagen in either muscle precipitated at 1.2 M NaCl at acid pH, suggestive of a type V like property. The homotrimeric collagen was then purified to near homogeneity by precipitation with 20% ammonium sulphate. Solubility characteristics and biochemical studies indicated the leg muscle collagens to be highly crosslinked and stabilised by more bound carbohydrates, as compared to the abdominal muscle collagen. Analysis of amino acid composition revealed a close similarity to known type V collagens and the leg muscle collagen was characterised by more lysine hydroxylation and slightly reduced glycine content. The leg muscle collagen had a higher denaturation temperature and intrinsic viscosity than the abdominal muscle collagen. Our results confirm the similarity of major crustacean muscle collagens to vertebrate type V collagen. Further, the relative complexity of leg muscle collagen, unlike the abdominal muscle collagen, correlates to the specific functional requirements, where the former is involved in locomotion and preying and the latter in normal growth and development.

Effects of Centella asiatica extract on dermal wound healing in rats.

Effects of oral and topical administration of an alcoholic extract of C. asiatica on rat dermal wound healing was studied. The extract increased cellular proliferation and collagen synthesis at the wound site, as evidenced by increase in DNA, protein and collagen content of granulation tissues. Quicker and better maturation and crosslinking of collagen was observed in the extract-treated rats, as indicated by the high stability of acid-soluble collagen and increase in aldehyde content and tensile strength. The extract treated wounds were found to epithelialise faster and the rate of wound contraction was higher, as compared to control wounds. The results show that C. asiatica produced different actions on the various phases of wound repair.

Differentiation of keloid and hypertrophic scar; correlation of the water proton relaxation times with the duration of the scar.

Spin lattice relaxation times of water protons have been reported to correlate with the water contents of malignant as well as benign tissues. In order to investigate whether such a correlation exists in keloid and hypertrophic scars, T1 values of keloid and hypertrophic scars were measured using Magnetic Resonance Imaging and compared with that of normal skin. A linear correlation of the T1 values of the scars with their age was observed. Even though both the scars exhibited higher T1 values in the early stages of lesion, a faster return to the steady state level was observed in hypertrophic scars compared to keloids. It is suggested that the measurement of T1 values could serve to differentiate the two abnormal wound healing situations.