SINGAPORE - Beneath the hard exterior of fish scales is a trove of collagen that can be used to accelerate wound healing. And all from a product that would normally be discarded.
Collagen is the main protein found in skin and other connective tissue. Collagen from fish scales is especially good at tissue repair and regeneration, and it is cheaper to produce than other sources of collagen such as cow or pig skin, say a group of Singapore researchers.
It does so by promoting the formation of blood vessels and lymphatic vessels, which transport fluid containing white blood cells from tissues to the bloodstream.
While fish scale-derived collagen in its natural form can already promote wound healing, the researchers took it a step further.
They found a way to modify the collagen chemically to make it water soluble, potentially allowing it to hold drugs.
The collagen in its natural form dissolves only in acidic conditions, which could damage a drug mixed with it.
But with the modified collagen, scientists can, for instance, use it to package growth factors - such as vitamins or hormones, which stimulate the growth of living cells.
This paves the way for wound dressings with "superior healing potential", the team said on Monday (March 12).
The findings were published recently in scientific journal Acta Biomaterialia.
Associate Professor Andrew Tan, who is from the Nanyang Technological University (NTU) School of Biological Sciences, was one of two people who led the research.
"Collagen dressings come in all shapes and sizes - gels, pastes, powders and pads. It can potentially treat wounds of all dimensions," he said.
Collagen from fish scales will overcome the cultural and religious restrictions associated with most commercial collagen today, which are mostly derived from pigs, cows and sheep, noted Assistant Professor Cleo Choong from NTU's School of Materials Science and Engineering, who led the research with Prof Tan.
"Clinical application of these materials has been limited due to cultural and religious restrictions associated with these mammalian tissue-derived materials," she said.
"In addition, more checks and processing have to be in place due to the risk of diseases that can be transmitted from mammals to humans."
Collagen from fish scales is cheaper too.
About 200mg of collagen can be obtained from 10g of fish scales - supplied from one or two fish, and will cost just over $8 to make in the lab, excluding labour costs. In comparison, 200mg of cow-derived collagen costs about $80 on the market.
There is also little cost in getting the fish scales as they are usually discarded, unlike other sources, such as cowhide, which have a wide range of other uses, the team, which collaborated with Associate Professor Veronique Angeli from the National University of Singapore, said.
It is in talks with a few local fisheries to explore ways of converting aquaculture waste material into useful materials, and to scale up the collagen extraction process.
Mr Teo Khai Seng, who owns KhaiSeng Trading & Fish Farm, which descales more than 200 fish a day, said: "If these discarded fish scales can lead to successful biomedical applications in future, it would be a good use of these waste materials."