Aerogels made from waste cotton-based fabric waste can be used to control haemorrhaging, claim researchers from the National University of Singapore (NUS) Faculty of Engineering.

Aerogels are among the lightest materials in the world and are highly porous with strong absorption capacity and low thermal conductivity. They are also costly to produce, hindering widespread utilisation.

Now, Associate Professor Hai Minh Duong and Professor Nhan Phan-Thien from NUS’ Department of Mechanical Engineering have led a research team in the development of novel cotton aerogels that are easily compressed and quickly recover up to 97 per cent of their original size when placed in water.

Assoc Prof Duong said: “This new eco-friendly cotton aerogel is a major improvement from the aerogel that our team had previously developed using paper waste. It is highly compressible, hence storage and transportation costs could be greatly reduced.

“Furthermore, these cotton aerogels can be fabricated within eight hours – this is nine times faster than our earlier invention and about 20 times faster than current commercial fabrication processes. They are also stronger, making them more suitable for mass production.

“While we have demonstrated novel application of the cotton aerogels for effective haemorrhage control and heat insulation, we will continue to explore new functions for this advanced material.”

Current haemorrhage control devices comprise a syringe filled with small capsules of cellulose-based sponge, coated with chitosan, a natural agent derived from crustacean shells that promotes blood clotting. The syringe is inserted into the wound to release the capsule, which expands and applies pressure on the wound to stop the blood flow. According to NUS, the expansion and absorption rates of cellulose-based sponges are still relatively slow.

https://www.youtube.com/watch?v=cZBlh8-0VsA

To address these limitations, NUS researchers developed highly compressible hybrid cotton aerogel pellets that are said to be more effective than cellulose-based sponges for treatment of deep haemorrhagic wounds.

NUS further claimed that the pellets – comprising cotton and cellulose aerogels coated with chitosan – are simple and cost-effective to produce, and they can be easily integrated into a clinical syringe to be used as a haemorrhage control device.

“Each cotton aerogel pellet can expand to 16 times its size in 4.5 seconds – larger and more than three times faster than existing cellulose-based sponges – while retaining their structural integrity,” said Assoc Prof Duong. “The unique morphology of the cotton aerogels allows for a larger absorption capacity, while the compressible nature enables the material to expand faster to exert pressure on the wound.”

The findings for this novel application were published in Colloids and Surfaces A in January 2018.

The NUS team has filed a patent for the novel cotton aerogels – that also provide heat insulation – and is exploring opportunities to work with companies to commercialise the technology.