To successfully treat a severe burn, doctors must manage pain, restore skin integrity, and close the wound as quickly as possible, while avoiding secondary issues such as scarring, wound contracture, infection, muscle wasting, and bone loss.1 Cultured epithelial autograft (CEA), a method in which a small section of the patient’s own skin is harvested and expanded into sheets of epidermis, was a mainstay in burn treatment for decades.2 But surgeons weren’t entirely satisfied with it.
“It took three weeks to grow, and when you use it, it's fragile, it blisters, and it's difficult [to work with],” said plastic surgeon and burns specialist Fiona Wood, who started working in burns injury recovery in the early 1990s. “…I thought, well, we've got to be able to do this better.”
So Wood, along with Marie Stoner, her colleague at the Royal Perth Hospital, developed spray-on skin, which heals burns with minimal scarring and improves patient outcomes. The duo later co-founded Avita Medical to commercialize their spray-on skin technique, which is currently also being investigated for treating other skin diseases.
A Lab Under the Stairs, an Interesting Lead, and a Soup of Cells
Wood and Stoner did not set out to create spray-on skin. In fact, they were originally looking to simply reduce the time it took to grow CEAs to improve the protocol. “We looked at everything that had been written about growing skin, and we worked out that we could do it in 10 days,” Wood recalled. “That was that was our first step.”
In 1993, after receiving a grant, the duo converted a storeroom under the stairs of the hospital fire escape into a tiny lab where they could grow the grafts. During this time, they noticed something rather interesting: Contrary to what they expected, the sheets of skin that were slightly fragile actually fared better when they were transplanted onto patients. The discovery launched a raft of follow-up experiments. “We worked out that if we put the cells on as individual cells, like in a soup, in a suspension, they would stick to the wound better, and then grow across the wounds,” Wood explained. Applying the cells as a suspension meant they could harvest them within just five days.
Fiona Wood was determined to improve outcomes for burn patients by cutting down the time it took to grow skin grafts from the standard three weeks. Instead, she invented a technique of applying cells in a spray-on suspension, leaving patients with minimal, and in some cases, no scarring.
Submitted by Fiona Wood
Wood and Stoner jumped to the next question: Could they apply the suspension of cells as a spray? They developed a method of aerosolizing the cultured skin cells without damaging them, using a trypsin-based enzyme. They started using their spray-on skin treatment on pediatric patients in 1995, and they immediately knew they were onto something big. “80 percent of our pediatric cases have no visible scar,” Wood remarked.
Trigger Warning: The following section includes a graphic photo showing a patient with a burn injury before and after treatment.
Determination Drives Incremental Improvements
Despite their initial success, Wood and Stoner saw plenty of room for improvement. They noticed that patients who had larger burns but were treated with spray-on skin had minimal scarring compared to patients with smaller but more severe burns, for whom they couldn’t justify waiting the five days. The latter group of patients received traditional skin grafts and ended up with significant scarring. “Over 90 percent of the time, a skin graft will take, but it will leave a scar every time,” said Wood. The duo took a step back and considered their approach, paring it down to the bare essentials.
For traditional skin grafts, doctors use scalpels or irrigation with high-pressure jets of sterile saline solution to remove large amounts of tissue to reveal enough blood vessels to support the new skin layer. Wood and Stoner found that they could accelerate timeframes for their spray-on skin by treating the wound itself as the tissue culture environment, allowing them to harvest and apply the cells in as little as 20 minutes.
“Our surgery [to prepare the wound] changed into a meticulous attention to detail and a salvage [operation], because we can salvage frameworks that, if we used a skin graft, we'd have to remove,” Wood said. “…Then we don't need the blood vessels in the same kind of way, and they come in secondarily.” The benefits to patients were clear, Wood said, including reduced pain, minimal scarring, and quick turnaround times. “We'd made a very complex situation very simple… We were doing this work routinely by 1997-1998,” she added.
To turn their approach into a kit that could be readily deployed and used by other doctors, Wood and Stoner leveraged multidisciplinary collaborations. “Marie and I actually designed and built the kit, so we got help from people who did electronics, from people who did enzymes, people who did plastic molding, and people who did sterilization and packaging,” Wood commented. The spray-on skin method was approved by Australia’s regulator, the Therapeutic Goods Administration, in 2002; further trials funded by the US military led to its approval by the FDA in 2018.
A patient with second degree facial burn injuries showing progressively improving outcome over a year post spray-on skin treatment.
Photos courtesy of Dr. Holmes, Wake Forest
Beyond Burns: Treating Disease with Spray-On Skin
While approvals and widespread adoption of the spray-on skin system took time, research has confirmed the benefits to patients and hospitals. A 2022 analysis showed that patients who received spray-on skin therapy spent less time in hospital compared to those who were treated with traditional skin grafts, which was associated with increased bed capacity and significant cost savings for the hospitals that used the technique.3
When it became evident that spray-on skin was going to change the face of burn treatment, Wood assigned her intellectual property to a not-for-profit in her name, the Fiona Wood Foundation, with a goal of making the technology widely available and using the royalties to fund further research. A large focus of that research is to develop spray-on skin applications for conditions other than burns, including traumatic injuries, chronic wounds, and skin cancer.
The approach can also be used in scar revision for old wounds. “If you've got a poor scar, you can actually modulate that by reintroducing a higher load of skin cells that are programmed for regeneration,” Wood explained. Other, more complex skin diseases can also potentially be treated with spray-on skin, including vitiligo, epidermolysis bullosa, and toxic epidermal necrolysis. “The exciting thing, as we go forward, is the co-delivery of the cells with a framework that will facilitate a more complete reconstruction of the skin, and that's in the research space,” said Wood. “We can manipulate the genetics [of the cells] and then use the skin cells [to] deliver the novel genetic makeup in complex diseases.”
- Markiewicz-Gospodarek A, et al. Burn wound healing: clinical complications, medical care, treatment, and dressing types. Int J Environ Res Public Health. 2022;19(3):1338.
- Atiyeh BS, Costagliola M. Cultured epithelial autograft (CEA) in burn treatment: Three decades later. Burns. 2007;33(4):405-413.
- Carter JE, et al. Length of stay and costs with autologous skin cell suspension versus split-thickness skin grafts: burn care data from US centers. Adv Ther. 2022;39(11):5191-5202.
