The process of wound-healing is a complex cascade of events, which can be extremely problematic when disrupted. In older people and diabetics, for example, slow or incomplete wound healing can be painful, limit mobility and raise the risks of infection. But because of the complexity of the wound-healing cascade, and our incomplete understanding of it, it has been difficult to promote wound healing and this is a common cause of extended hospital stays.
Researchers at EMPA, the Swiss Federal Laboratories for Materials Science and Technology, are addressing this issue in a project called “Scaravoid”. Led by Markus Rottmar of the Biointerfaces laboratory, a team has developed a healing foam which is designed to be packed into an open wound where it promotes rapid and scar-free healing.
"Traditional treatments target individual factors of wound healing, such as oxygen supply or moisture regulation, and only produce an inadequate tissue response," Rottmar explained. The foam works by creating a scaffold into which the body’s self-repair systems can deposit cells that help clean the wound, followed by encouraging the growth of new tissue. The foam is made from a polymer called poly-4-hydroxybutyrate (P4HB), which in nature act as an energy storage material that organisms break down within the tissues when needed. Produced synthetically by a fermentation process, P4HB has a fibrous structure which is attracting attention because of its strength, elasticity and ability to break down in the human body.
The EMPA team expands P4HB in a high-pressure reactor using supercritical carbon dioxide, varying the temperature and pressure of the CO2 to fine-tune the pore size of the resulting foam. The polymer is impregnated by curcumin, a bright yellow compound found in the root turmeric, which when dried and powdered is a common ingredient in curries, but is also known to have anti-inflammatory properties. In Scaravoid foam, curcumin controls the behaviour and function of fibroblast cells that migrate into the P4HB scaffold.
Rottmar’s team is currently studying the behaviour of foam in the form of small discs and is soon to embark on clinical trials using larger membranes that can be cut to size by a doctor and packed into wounds. The team is targeting healing of burns and large wounds such as those caused by traffic accidents.