Developing multifunctional wound dressings capable of inducing rapid angiogenesis and with antibacterial activity would be attractive for diabetic and superficial wound healing. Hydrogels delivered from tubes have several desirable features -they are easy to apply, keep the wound moist, reduce the entry of microorganisms and avoid the need for painful dressing removal. Previously we reported that 2 deoxy-D-ribose (2dDR) delivered from a variety of dressings is capable of promoting wound healing by stimulating angiogenesis. Alginate hydrogels are an ideal vehicle to deliver a bioactive agent capable of promoting wound healing. In this study we developed and evaluated a tube hydrogel capable of delivering 2dDR with the aim of achieving a stable, convenient to administer and biologically effective wound treatment. Further, we included the stabilizer 2-phenoxy ethanol which provided antimicrobial activity. We synthesized hydrogels by the Green method, using simple mixing of sodium alginate, propylene glycol, 2-phenoxy ethanol and 2dDR in water. FTIR (Fourier transformation infrared spectroscopy) analysis confirmed an absence of undesirable chemical changes in the gel components, and SEM images of the freeze-dried gels showed porous structures. When 2dDR alginate gel (2dDR-SA hydrogel) was placed in PBS at 37°C, almost 92% of 2dDR was released within 7 days. When tested on cultured cells, 2dDR-SA hydrogels did not inhibit metabolic activity or proliferation, achieving up to 90 and 98% of control respectively over 7 days. 2dDR-SA hydrogel also showed anti-bacterial activity against E. coli, Pseudomonas aeruginosa, Staphylococcus aureus, and MRSA which was attributable to the stabilizer 2-phenoxy ethanol in the hydrogel. Stimulation of angiogenesis in the chorioallantoic membrane assay by 2dDR-SA hydrogel was found to be significant compared to the blank-SA. Wound healing potential was studied in full-thickness wounds in rats where acceleration of wound healing was seen. H&E staining of the wound tissue showed an enhanced number of blood vessels and re-epithelization, and a reduced number of inflammatory cells in 2dDR-SA treated animals compared to blank-hydrogels while Masson's trichrome staining showed increased collagen deposition. In summary we describe a convenient to apply hydrogel which has promise for use in a range of superficial skin wounds including applications in chronic wound care.
Keywords: 2dDR-SA hydrogel; Cell metabolic activity; chorio-allantoic membrane assay; collagen deposition; inflammatory cells; proliferation; re-epithelization.