Title : Smart hydrogel films for wound monitoring and healing
Abstract:
It is estimated that up to 2% of the population in developed countries will suffer from a chronic wound in their lifetime. This number will most likely increase due to the fact that the life expectancy increases and the world population with chronic diseases, such as diabetes and vasculopathy, prone to chronic wounds, will age in the following decades. Modern, smart, wound dressings not only provide an optimal healing environment but can also provide critical information about the wound healing process.
The scope of this work is to design and develop a “smart” hydrogel film wound dressing that can monitor and enhance the healing process of chronic dermo-epidermal wounds. In the process of product design, it is critical to take into account the following: 1) choosing the best polymer for matrix formation of the hydrogel film 2) choosing the proper components to be incorporated in the hydrogel film and their concentrations 3) choosing the best methods to evaluate the properties of the hydrogel film 4) optimisation of production and working strategy.
The hydrogel film can be made of natural and/or synthetic polymers that incorporate numerous compounds with different effects such as antimicrobial, wound healing enhancement and wound healing monitoring. One can use different polymers for product design, such as alginate, chitosan, polyvinyl alcohol, polyvinylpyrrolidone. The polymer used in this work was alginate since it has the unique property of gel-formation in the presence of multivalent cations (especially divalent cations) in aqueous media. In our experiments we used sodium alginate, a commonly used natural polysaccharide obtained from the condensation of β-D-mannuronic acid and 1-4 linked α-L-glucuronic residues. Curcuma longa extract, also known as curcumin, is a polyphenolic compound with antioxidant, anti-inflammatory, antibacterial and anticancer properties and also it can be used as a great pH indicator. In our experiments we used Curcuma longa extract as a pH indicator comparatively with phenolphthalein (pH 8.2-10) and brilliant yellow (pH 7.4-8.6). Chronic wounds are characterised by an enhanced protease activity so a dressing that modulates protease levels can help the wound healing process. It has been reported that doxycycline, beside the antimicrobial properties, can also non-selectively inhibit matrix metalloproteinases (MMPs) in skin keratinocytes by binding to zinc and calcium atoms and cause conformational changes and loss of enzymatic activity. It has been reported that silver nanoparticles have antibacterial activity against gram negative and gram positive bacteria. For antimicrobial activity doxycycline and silver nanoparticles were incorporated. Collagen, elastin and hyaluronic acid were incorporated to enhance the wound healing process. Preliminary results show that these hydrogels films can be used to monitor wound healing activity due to the presence of the pH indicator, have suitable mechanical and swelling properties and have good cytocompatibility.
