The full story
This is the episode's narration, word for word. Headings jump to that point in the video.
The question 0:00
If a burn takes most of your skin, where does the new skin come from? In Perth in the 1990s, a surgeon, Fiona Wood, and a scientist, Marie Stoner, started spraying a patient's own skin cells onto burns. The headlines called it spray-on skin. The real story is cleverer, and more careful, than the headline. It starts with how skin fixes itself.
A wall that rebuilds itself 0:28
Your skin's outer layer, the epidermis, has no blood vessels of its own. At its base sits a row of cells that keep dividing. Their daughters, called keratinocytes, fill up with a tough protein, keratin, and get pushed towards the surface, where they flatten, die and flake away. The whole dead outer layer is replaced about every four weeks. Underneath is the dermis, a mesh of collagen carrying blood vessels, nerves, hair follicles and sweat glands.
Islands of new skin 1:03
So how does a graze heal? New cells crawl in from the edges, but also up out of the hair follicles and glands that reach deep into the dermis. Each follicle is an island of skin-making cells, so a shallow wound closes from many places at once. That's why a second-degree burn can heal in several weeks. But a third-degree burn destroys the epidermis and the dermis. The islands are gone, and new skin can only creep in from the edges.
Why a big burn kills 1:36
Skin keeps water in, and germs out. After a big burn, damaged blood vessels leak fluid into the tissues, and the circulation can collapse into shock. Then the open wound lets bacteria in. In one autopsy study, more than sixty per cent of burn deaths were down to infection. In an adult, a burn over more than twenty per cent of the skin is usually treated as a major burn.
Borrowing skin from yourself 2:04
The standard repair is a skin graft. Surgeons cut away the dead tissue, then shave a thin layer of healthy skin from elsewhere and lay it on. The donor site heals by itself, from its own follicles, and can be shaved again later. Grafts are cut with slits so they stretch, up to about six times their area, but the more they stretch, the more fragile they get. And here's the trap. Burn ninety per cent of someone, and there's only ten per cent left to borrow from.
Racing the clock 2:38
With big burns, surgeons have to cover the wound in stages, using donated cadaver skin as a stopgap while the donor sites regrow. Wounds that take longer than about three weeks to heal are more likely to form thick, raised scars, which affect somewhere between thirty and ninety per cent of burn patients. As Fiona Wood put it: the quicker you close that wound, the less scar you'll get.
Growing skin in a dish 3:05
Could you grow more instead? Human skin cells refused to grow well in the lab until 1975, when James Rheinwald and Howard Green, at MIT, found the trick. They sat the skin cells on a layer of mouse cells that had been irradiated so they couldn't divide. Fed by those helpers, a single skin cell could grow into a whole colony. By 1979, Green's lab was growing sheets of epidermis from small samples, and suggesting surgeons try them.
The first grown skin 3:39
They did. Lab-grown skin was first used on burns patients in 1981. In 1983, two young brothers with burns over more than ninety-five per cent of their bodies were covered with sheets grown from small samples of their own skin; the results were published in 1984. About five months later, their wounds were more than eighty-five per cent healed, roughly half of it by the cultured cells. The method got a name: cultured epithelial autograft.
Why that wasn't enough 4:13
But growing a sheet takes at least three weeks. That's three weeks a badly burned person waits without their own skin on those wounds. The sheets are only a few cells thick, so they're fragile, they blister, and how many survive on the wound varies from sixty to a hundred per cent. In 2006, Wood and colleagues reviewed the evidence for these sheets and found mostly case reports, with no top-level trials.
Perth, 1992 4:43
Fiona Wood trained in London and moved to Perth in 1987. In October 1992, as a young plastic surgeon, she treated a twenty-nine-year-old science teacher burned over more than ninety per cent of his body in an explosion. His skin was grown in a lab in Melbourne, and he survived, but it was a long, hard road. Wood said afterwards that she felt they hadn't done well enough, and could do better.
Wood and Stoner 5:12
In 1993, Wood began working with Marie Stoner, a medical scientist in the skin culture laboratory at Perth's children's hospital. That lab grew the cells. Wood brought the patients and the surgical problem. Their first paper together, with Stoner as lead author, tracked how well each patient's cells grew in the dish.
Don't wait for the sheet 5:36
Why wait for the cells to join into a sheet in the dish, when they could join up on the patient? So they lifted the growing cells off early, suspended them in liquid, and sprayed them on. That aimed to cut the wait from twenty-one days to five. By the mid-1990s, this cultured spray, later sold as CellSpray, was in use in Perth. A pig study with Boston colleagues showed sprayed cells filled the gaps in a meshed graft faster.
Two different sprays 6:08
It's easy to blur two things here. CellSpray still meant days of lab culture. It reached the market in Australia in 2001, and Europe in 2004. Wood and Stoner had founded a company, Clinical Cell Culture, in 1999. Its next device, ReCell, skipped the lab entirely. It went on sale in Europe in 2005, and Australia and Canada in 2006. In 2008 the company became Avita Medical.
How ReCell works 6:44
In the operating theatre, a surgeon takes a thin skin sample a few square centimetres in size. It soaks in a warm enzyme solution for fifteen to twenty minutes, which loosens the bond between the epidermis and the dermis. Then the cells are scraped free, filtered and sprayed on. The mix is mostly keratinocytes and fibroblasts, plus a few melanocytes, the cells that make skin colour. One square centimetre of skin can treat up to eighty square centimetres of wound.
Seed, not turf 7:20
Think of a graft as turf, and the spray as seed. Seed goes further, but must grow in place. The spray doesn't rebuild the dermis. It seeds living cells onto a cleaned wound, where they spread like those islands from earlier. That's why, in trials, it was used on burns that still had living dermis, or alongside a widely stretched graft on deeper ones.
Bali, October 2002 7:48
On the twelfth of October 2002, two bombs in Bali killed two hundred and two people. Holidaying health workers gave first care, and the Defence Force flew survivors to burns units across Australia. Royal Perth Hospital took twenty-eight badly burned patients in a week, about fifteen per cent of its usual year. Long delays before treatment probably played a part: in one audit, sixty-eight per cent of the Bali patients developed a burn-wound infection, against eighteen per cent of usual patients.
The response 8:24
The team used conventional grafts, and alongside them, CellSpray. By Wood's account, more than twenty of the twenty-eight were healed within three weeks. Three patients died. In 2005, Wood was named Australian of the Year.
The doubters 8:43
Not everyone was convinced. Most other burns units treating Bali survivors didn't use the spray, and critics said it had never been through formal clinical trials. Peter Maitz, a Sydney burns surgeon, said there was no scientific evidence as yet that it reduced illness or death. Critics also pointed out that Wood was a director and shareholder of the company. Maitz himself said he didn't think she was motivated by money. Wood said that had been disclosed every step of the way, and royalties went to research.
The trials 9:18
So the evidence had to come from trials. In a US trial of a hundred and one patients, each person had two similar burned areas: one got ReCell, the other a standard stretched graft. At four weeks, almost all of both had healed. But the ReCell donor patch was about forty times smaller, and hurt less. On the twentieth of September 2018, the US Food and Drug Administration approved ReCell for burns in adults.
What we know, and don't 9:49
That trial was funded by the company and the US government. An independent review, across many kinds of wound, confirms the big win, far less donor skin. Pooling the burns trials, new skin covered wounds about one point seven days sooner on average. But in burns, reviews found no clear difference in scarring or in infection. One found fewer complications overall when the spray was added to a graft, but only just, and from mixed-quality studies. Both called for bigger, better trials. Whether it suits any particular burn is a question for a burns team; this video is only the science and the history.
Who made it 10:34
So who invented spray-on skin? Growing skin came from Rheinwald and Green at MIT. Perth's spray, and then the step that skipped the lab, came from Fiona Wood and Marie Stoner working together. The Australian of the Year citation doesn't mention Stoner, but the scientific papers put her name right alongside Wood's.
The next question 10:58
Next time, a different kind of surface, one that has to survive being handled, folded and copied. Why would a country print its money on plastic instead of paper, and how could a clear little window stop a forger?
Sources
Every factual claim in the episode is tied to one of these. Spotted an error? Tell us.
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- Australian Academy of Science: "Dr Fiona Wood, plastic surgeon", interview by Norman… — science.org.au
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- OpenStax, Anatomy and Physiology 2e: "5.1 Layers of the Skin" — openstax.org
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- F. M. Wood, M. L. Kolybaba, P. Allen, "The use of cultured epithelial autograft in the… — pubmed.ncbi.nlm.nih.gov
- F. A. Navarro, M. L. Stoner et al., "Sprayed keratinocyte suspensions accelerate… — pubmed.ncbi.nlm.nih.gov
- J. H. Holmes IV, "A Brief History of RECELL and Its Current Indications", J Burn Care… — academic.oup.com
- Clinical Cell Culture (C3): "History", company website, 2003 (archived) — web.archive.org
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- F. M. Wood et al., "Characterisation of the cell suspension harvested from the dermal… — pubmed.ncbi.nlm.nih.gov
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- R. C. Silla et al., "Infection in acute burn wounds following the Bali bombings: a… — pubmed.ncbi.nlm.nih.gov
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- US FDA (CBER): approval order, RECELL Autologous Cell Harvesting Device, BP170122, 20… — fda.gov
- J. Lou et al., "The efficacy and safety of autologous epidermal cell suspensions for… — pmc.ncbi.nlm.nih.gov
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- F. M. Wood, M. L. Stoner, B. V. Fowler, M. W. Fear, "The use of a non-cultured… — pubmed.ncbi.nlm.nih.gov
Image credits
- ReCell kit in use at a U.S. Army burn centre, January 2012 · U.S. Army photo · public domain · via Wikimedia Commons
- Fiona Wood speaking in Sydney, May 2011, at the announcement of Imagine Cup 2012 · photo Life@Microsoft Australia · CC BY 2.0 · via Wikimedia Commons · licence: https://creativecommons.org/licenses/by/2.0/
Researched and scripted with AI assistance, fact-checked claim by claim, with synthetic narration and diagrams drawn in code. How we make episodes.
