Second skin

A silicone dressing designed to mimic conditions in the womb is expected to drastically reduce healing time and scarring, and could be used as an alternative to skin grafts. It could save the NHS thousands of pounds, researchers claimed this week.

The special dressing will benefit those with severe, extensive burns, and could speed up the treatment of patients with chronic leg ulcers that take months to heal.The dressing consists of a thin outer layer of silicone containing epidermal cells taken from the patient and an inner layer of sponge-like hyaluronic acid (HA) derivative called Hyaff 11 containing dermal cells, which absorbs any secretions from the burn to form a bioactive gel.

Severe injuries from heat, electricity, chemicals and radiation are usually treated with tissue grafts. But these involve applying skin taken from other people or healthy areas of the victim’s body, making the technique difficult for use on patients with severe or extensive skin damage. The grafts are very fragile and hard to handle, and if a donor’s cells are used the body often rejects the graft.

Both types also tend to produce large scars. These cause problems for the movement, function and cosmetic appearance of the area, requiring further operations.

Instead Italian firm Fidia Advanced Biopolymers has developed a dual-layer wound covering that promotes healing by mimicking conditions experienced by foetal skin in the womb. It also promotes formation of new blood vessels in the area, essential to healing.

The product was developed in an EU-funded programme involving researchers from Italy, Germany and the UK, including Queen Mary School of Medicine, London.The system is designed to promote the growth and joining of the two skin layers, with the scaffold of acid and silicone bio-degrading as the healing process progresses. HA occurs naturally in the skin and is produced to help healing when wounds occur.

Researchers observed that in the womb damage to the skin of a foetus (from an operation, for example) does not result in a scar. They also found that levels of HA surrounding the foetal skin is very high over a prolonged period. But in adults HA near the wound is high at first, but quickly drops.

They therefore developed a system that applies HA to the wound, but protects the site by covering it with a silicone layer made semi-permeable by minute perforations from a laser. This provides protection against infection while allowing the wound to ‘breathe’ by exchanging oxygen and carbon dioxide with the surrounding air. It also prevents skin dehydration.

‘There is a big market for leg ulcer treatments in the UK owing to the large cost to the NHS,’ said Dr Harshad Navsaria, deputy head of the department for wound healing and tissue engineering at the Centre for Cutaneous Research at Queen Mary’s School of Medicine.

‘Patients can be hospitalised and their treatment can last for months. Now we have proved in clinical trials that we can get them out of hospital within four to six weeks, with the rest of their treatment taking place at home.’

Although US-made healing-promoting dressings exist, this is the first to use naturally occurring molecules. It has proved more effective than existing products in trials, and is soon to be used on patients in Italy. Hopes are it will be approved in the UK soon afterwards.