Scaffold surgery

A breakthrough in understanding cell behaviour and a newly-developed, dissolvable scaffold for growing new areas of skin could provide a safer, more effective way of treating burns, diabetic ulcers and other severe skin injuries.

The ultra-fine, 3D scaffold, which is made from specially-developed polymers derived from polylactic acid, resembles tissue paper but has fibres 100 times finer.

Before being placed on the wound, via a biopsy, the patient's skin cells are introduced and attach themselves to the scaffold, multiplying until they eventually grow over it. This is then placed over the wound and after six to eight weeks the scaffold dissolves, leaving the skin cells behind.

Fibre mats

The process used to make the scaffold is based on a technique called electrospinning, which produces polymer fibres down to nano-scale by applying an electric field. However, the team has developed a new method of making aligned-fibre 'mats' from the same biodegradable polymers. These promote the growth of nerves, tendons and cartilage.

Prof Tony Ryan, who leads the research at Sheffield University, said: 'Normal electrospinning leaves the fibres running in random directions. We have developed a method to control the orientation of the fibres by controlling the electric field. This is now being patented.'

Ryan said the breakthrough was as much about understanding cell behaviour as the scaffold. 'What we have shown is that cells know the order in which they need to build, so you get the same strata in the new skin as you had in your own. '

Funded by the EPSRC, the skin- reconstruction project is designed primarily for cases where extensive burns leave surgeons unable to obtain enough skin grafts from elsewhere on the body to cover the damaged tissue.

Existing methods raise numerous medical and moral objections; bovine collagen or decellularised pig skin are two common alternatives, but both have an associated risk of infection.

Ryan said that the key to this technology is its simplicity. Previous attempts to encourage skin cell growth involved chemical additives and complicated scaffolds and had limited success.

As the cells are 'smart', they need a comparatively uncomplicated scaffold. By this Ryan means the polymers to make the scaffold can be simple and are derived from the same polymer as goes into plastic bottles or polyester for shirts.

However, it is biodegradable. 'The polymers are broken down into lactic acid, which the body can dispose of easily as it is used to dealing with it,' Ryan said.

Medical implants

Clinical trials are the next step, but Ryan admitted that, due to the ethical difficulties concerned with human testing, this is at least another couple of years off.

The technology also offers possibilities for testing the toxicity of cosmetic and dermatological products, using materials grown in the laboratory that resemble human skin. 'It is not something that has been done yet, but it is on the agenda. The polymers are already approved for use in medical implants,' said Ryan.

Ultimately, he hopes the process will allow the treatment of burns victims and reconstructive surgery as well as producing bespoke skin.

One of the research team is already involved in a skin graft company called

. Ryan is confident that this will help bring the technology to market following the completion of trials.