Most consumers prefer to buy fish from supermarkets or order skinned fish in restaurants, but research from Nanyang Technological University in Singapore (NTU) has revealed that fish scales have a number of biomedical applications. Instead of wasting fish scales, the collagen they contain could be repurposed to provide both biomedical and sustainable benefits.
Collagen is the main structural protein found in skin and other connective tissues, and scientists found that collagen from fish scales promoted blood and lymphatic vessel formation when modified and applied to mice.
Associate Professor Andrew Tan from the NTU School of Biological Sciences explained, “Collagen is commonly used for wound dressing material due to its favourable biological properties. Applying collagen dressings to a wound to stimulate tissue growth can provide relief for a wide variety of injuries. Collagen dressings come in all shapes and sizes — gels, pastes, powders and pads. It can potentially treat wounds of all dimensions.”
Collagen itself is known to promote wound healing, but it also offers promise as a carrier of drugs that can enhance wound healing, such as growth factors.
In its natural, unmodified form, collagen is only soluble in acidic conditions which damage the drugs, but NTU scientists created water-soluble collagen from the fish scales using chemical modification. This means it could be successfully used to fabricate wound dressings to enhance healing.
Partnering with a local Singaporean fish farm that supplied the team with fish scales from sea bass, snakehead and tilapia, the researchers found that sourcing these fish scales should not be a difficult task going forward.
Owner of Singapore’s KhaiSeng Trading & Fish Farm Teo Khai Seng said, “We descale and sell over 200 fish a day to wholesalers, restaurants and walk-in customers. If these discarded fish scales can lead to successful biomedical applications in future, it would be a good use of these waste materials.”
The 2016 State of World Fisheries and Aquaculture report published by the United Nations’ Food and Agriculture Organisation stated aquaculture production is expected to reach 102 million tonnes by 2025. This would mean the amount of aquaculture waste would be substantial, but scientists found that several other fisheries were open to discussing how to convert aquaculture waste material and scale up the collagen extraction process.
Currently, collagen used in biomedical products tends to come from mammals such as pigs, cows and sheep, which raises a number of cultural and health issues. As a result, this research has prompted interest from manufacturers looking to find alternatives.
“Clinical application of these materials has been limited due to cultural and religious restrictions associated with these mammalian tissue-derived materials. 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,” said Assistant Professor Cleo Choong from the NTU School of Materials Science and Engineering.
Another benefit of using fish as a source of collagen is the reduced costs compared to cowhide. Fish scales are readily available since they are regarded as waste products, and about 200 mg of collagen can be derived from 10 g of fish scales, which can be obtained from one or two fish.
The results were published in the journal Acta Biomaterialia.