February 2014

‘Celtic knot’ polymer research for skin applications

Wed, 12 February 14 12:30

UCD Charles Institute welcomes the arrival of Dr Wenxin Wang and his research group as they establish their research laboratory that will investigate how new synthetic materials can be used in the effort to treat diseases such as diabetic ulcers and Epidermolysis Bullosa (EB).

Dr Wang has been working on the design and preparation of functional polymeric materials for applied applications since pioneering a completely new route to synthesising dendritic structures in 2007.

Polymers are natural and synthetic compounds made from singular ‘monomer’ blocks that link together in fast-growing chains. Until recent years, it has been a time-consuming and labour intensive process to create branched or ‘dendritic’ polymers.

The breakthrough from the Wang group in this novel synthetic approach centred on precisely controlling polymer chain growth so that polymers grow slowly and effectively while branching is introduced in a controlled fashion and the cross linking reaction is delayed.

This slow-motion method of controlling the synthesis of polymers creates chains linking only to themselves and produces a 3D material reminiscent of ancient ‘Celtic knot’ artwork. The technique can also create hyper-branching polymers that spread outwards like trees.

The Wang group have developed a ‘one-pot’ procedure that is easily scalable and will produce high-quality polymers cheaply. This synthesis method can produce a wide range of materials for biomedical applications such as skin adhesives, drug or gene delivery and smart hydrogel materials.

Smart wound healing

Skin substitutes are thought to help the process of wound healing in a number of ways such as maintaining a biologically balanced moist wound environment, supplying beneficial cytokines and growth factors to the wound and providing structural support for tissue regeneration.

Recent studies have reported that adipose tissue derived stem cells (ADSCs) greatly accelerate the wound healing process by regulating immune cells such as growth factors and cytokines. The Wang group are developing a smart wound dressing consisting of polymer and stem cells. This dressing will be liquid at room temperature but, after application to the wound, will turn into a hydrogel to form a dressing as well as a reservoir system to secrete essential immune cells for accelerated wound healing in chronic diabetic ulcers.

Topical gene therapy

The Wang group are also applying their polymer research to a non-viral gene therapy approach for the treatment of severe wounds in recessive dystrophic epidermolysis bullosa (RDEB).
This particular form of the EB blistering disorder is caused by a variety of mutations in the COL7A1 gene, which codes for type VII collagen. This structural protein is crucial to the integrity of the dermal-epidermal junction so mutations in the gene lead to blisters forming easily. Some blisters may only damage the top layer of skin but others form chronic wounds comparable to third degree burns.

The research team are working to develop a topical application that will deliver the genetic information needed to make this vital protein directly to the cells found in the epidermal-dermal junction. They are using a non-viral, polymer-based vector carrying the COL7A1 pcDNA to collagen type VII null-RDEB keratinocytes and dermal fibroblasts. The team aim to optimise the polymer to achieve sufficient collagen type VII expression with reduced cytotoxicity.

Dr Wenxin Wang transferred to UCD Charles Institute from the Network of Excellence for Functional Biomaterials in the National University of Ireland, Galway. There are currently three postdoctoral researchers and twelve graduate students (PhD, MSc) in the Wang team. Their research is funded through awards to Dr Wang from Science Foundation Ireland, Health Research Board, Irish Research Council, EU FP7 programmes and Debra Ireland.

Professor Martin Steinhoff, Director of UCD Charles Institute said, “I am delighted to welcome Dr Wenxin Wang and his research team to University College Dublin and am confident that they will make valuable contributions towards our Institute vision of becoming a world leader in dermatology research and improving patient outcomes with novel therapies”.