The group of Sheila MacNeil has recently developed a 3-dimensional bacterially infected human skin wound model. This has proved invaluable for testing the antimicrobial activity of novel biocompatible wound dressings based on triblock copolymer hydrogels through a collaboration with Professor Steve Armes in the Department of Chemistry. These latter hydrogels are capable of entering both mammalian and bacterial cells and certain combinations of the triblocks have intrinsic antimicrobial activity. The hydrogels are also capable of releasing drugs and we have been exploring their potential both as topical drug delivery vehicles and as inherent antimicrobial dressings.
Above: the ability of a modified hydrogel to bind gram positive bacteria. In this case the hydrogel was modified with vancomycin which specifically interacts with gram positive bacteria. The lower panel shows the ability of a polymer modified with polymixin B to bind gram negative bacteria.
Collaboration between Sheila MacNeil and Dr Steve Rimmer (Department of Chemistry), and Prof Ian Douglas (Oral Health Dental School) is seeing the development of antibiotic modified hydrogels capable of recognising either gram positive or gram negative bacteria. On binding of the bacteria the hydrogels collapse around the bacteria. These responsive hydrogels are being developed to reduce bacterial infection in wounds and they also have the potential to deliver a signal on binding the bacteria. A patent has been filed on this technology and the first paper on the chemistry accepted in the Journal of the American Chemical Society.
We have also developed a surface modified contact lens for the transfer of limbal epithelial cells to the cornea for ocular surface diseases and in another project with Chemistry we developed a biodegradable electrospun scaffold for tissue engineering which is also capable of releasing ibuprofen as it degrades. This is also covered by a patent application as it represents a useful material in treating inflamed skin wounds. Essentially it is being designed to provide an anti-inflammatory to both reduce inflammation and pain for the patient and, as the dressing is biodegradable, it doesn’t need to be removed – yet fibres are in place for providing skin cell guidance and migration.