Editorial and opinion


Guest editorial


A synthetic skin scaffold to treat full-thickness wounds


Dr Julian Dye discusses the development of an artificial skin product that shows rapid blood vessel formation.


A


involved grafting skin from other parts of the body to treat the burn or wound. However, in the case of burns there might not be enough healthy skin left to provide grafting material due to the large size of the burn. This can be a limiting factor in some cases. 'For some patients, conventional


grafts risk simply creating a new wound site elsewhere on the body, which cannot heal completely,' explains Dr Dye. 'This is most problematic in elderly patients with pressure sores and people with diabetic or other chronic ulcers.'


n independent UK-based charity has spent several years developing a synthetic ‘off-the-


shelf’ skin scaffold which could prove effective at wound healing. The charity, known as RAFT (the Restoration of Appearance and Function Trust), is unique among many medical charities in the sense that it raises money for its own research institute and team of researchers.


Regeneration of full-thickness skin The basic concept of Smart Matrix™ is to encourage rapid in-growth of blood vessels and has been designed to be used in the treatment of a variety of full- thickness skin wounds. These include combat injuries, burns, and chronic wounds, ranging from diabetic ulcers to pressure sores. Working in the dermal layer of skin, RAFT also claims that Smart Matrix would reduce scarring and the need for further surgery. 'When a burn or chronic wound


severely damages skin, the body can never regenerate full-thickness skin,' says Dr Julian Dye, Smart Matrix project leader.


Skin graft limitations Traditionally, surgical intervention


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A new artificial skin product Work on the Smart Matrix has been ongoing at RAFT’s laboratory for nearly eight years. 'I joined RAFT in 2001 as a post-


doctoral research scientist and was appointed Group Leader in 2004,' says Dr Dye, who has a background in endothelial biology — biology of the skin cells that form blood vessels. 'The initial motivation to pursue the


idea of a "Smart Matrix" was hearing from plastic surgeons about the clinical limitations and failures of existing artificial skin products. 'However, witnessing the reality of


what patients needing surgical skin reconstruction undergo, and talking with patients who had survived and endured prolonged suffering from wound infections, made me appreciate the urgency of this need and it continues to spur us forward.' In drawing up criteria for what they had in mind, RAFT came up with the


following list: n A synthetic material that reliably ‘integrates’ with the body


n Rapid growth of blood capillaries into the material


n Possibility for rapid wound closure n Ability to minimise scar formation


Wounds International Vol 3 | Issue 2 | ©Wounds International 2012


n A product that is easy to store and available to surgeons off-the-shelf. 'We looked at existing artificial skin


products, the use of donor skin and tissue engineering of new skin; although each has its own advantages, there are disadvantages as well,' says Dr Dye. One form of biomaterial used for


treating large wound areas is donor skin, harvested post-mortem and processed for safety and preservation. It does provide a biocompatible wound cover, but will be rejected in two-to- three weeks. In itself, donor skin is too dense to provide an effective structure for capillary growth and integration. Also, despite thorough processing procedures and screening measures, there are concerns about the possibility of transmitting diseases. Epidermal cells (keratinocytes) can be


cultured from a small skin biopsy and expanded into sheets of cells suitable for autografting. However, this method entails a delay of 3–6 weeks before these cells will be ready for grafting. 'The hypothesis that drove the


development of the synthetic skin scaffold was the idea that a biomaterial, which supported the rapid growth of blood capillaries [angiogenesis], would show an improved rate of integration and cellularisation compared with available scaffolds,' says Dr Dye.


Fibrin as a biomaterial In screening a variety of possible ways to stimulate capillary formation, RAFT identified fibrin as a potent extracellular matrix material when compared with collagen. Understanding the difference in cellular responses to fibrin and collagen was important in helping to develop a more effective biomaterial. 'We went on to devise a porous


composite material based on fibrin and developed a manufacturing process to


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