DR WILLY Tan will soon run Singapore’s only silkworm farm – and he is doing it for the good of science.
The Republic Polytechnic researcher is leading a project that coaxes silkworms to spin stronger silk by exposing them to an electric field before they spin.
Defence engineering firm ST Kinetics is interested in turning this tougher silk into stronger ballistic or bullet-proof vests and composite materials.
Before Dr Tan got involved with the silkworm project in 2008, the 37-year-old materials scientist had no experience rearing insects. ‘I’m not a live animal person – but it’s part of the scientific learning curve,’ he admitted.
At the time, Republic Polytechnic’s applied science school was casting about for a project to commercialise.
It approached National University of Singapore (NUS) physics researchers Liu Xiang-Yang and Du Ning, who had filed a patent for the method to make stronger silkworm silk.
Normally, silk proteins are arranged like several bundles of chopsticks, grouped to form a bigger single bundle of chopsticks. The ‘chopsticks’, or protein molecules, are linked with other molecules called beta crystals.
Exposing the silkworm to an electric field before it spins changes the way the crystals are lined up, firming up the ‘chopstick’ links and strengthening the silk strand.
That enhanced strand is 40 per cent stronger than normal silkworm silk and needs two to three times the force before it breaks, putting it on a par with spider silk.
It is also stretchier and lighter than current synthetic fibres such as Kevlar. A Kevlar-reinforced helmet can weigh several kilograms. Enhanced silk helmets could be up to 30 per cent lighter, Dr Tan estimates.
While spider silk is tougher than steel, researchers are trying to find alternatives as it is nearly impossible to mass-produce. For instance, another NUS group is studying the structure of spider silk and trying to replicate it in the laboratory.
Dr Tan’s silkworm project is supported by about half a million dollars from a National Research Foundation translational grant, which helps polytechnics shepherd inventions from universities and research institutes along to commercialisation.
At the moment, the enhanced silkworm silk costs about $140 per kg to produce in the lab, but the cost will drop to about $70 per kg when the silkworm farm begins larger-scale production.
The farm, holding 16,000 cocoons in a facility the size of a large classroom, will be up and running by May.
The worms will be ordered from catalogues, from Canada, China and India, housed and bred in incubators here, and fed on a paste made from mulberry leaves.
Tape strips will be pasted along the breeding room’s doorways to prevent any getaways.
When the fibres are harvested, they will be used in composite materials, and made into fabric with different weaves whose properties will be studied.
Dr Tan expects the enhanced silk to be ready for commercialisation in about three years’ time.
Dr Liu said: ‘People have been weaving silkworm silk for 7,000 years, and nothing has changed. This could revolutionise the silk industry.’
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