Polytechnic University researchers have developed a 3D printing material that they claim can kill the coronavirus up to five years after it is used.

It is also cheap and easy to produce and can be used in making door handles and elevator buttons to reduce transmission risks not only from Covid but also from other viruses and bacteria, said Chris Lo Kwan-yu, an associate professor from the university’s Institute of Textiles and Clothing and the research team’s leader.

Lo said 70 percent of the coronavirus and other germs can be eradicated two minutes after they come into contact with the material, 90 percent in 10 minutes and almost 100 percent in 20 minutes.

He added the material can kill over 84 percent of viruses in 10 minutes three years after it had been applied.

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“Using 3D printing technology, the material can be produced in different forms catering to different needs,” Lo said. “It is highly flexible and can be used extensively in public facilities to provide prevention support.”

The material is mostly composed of resin but added with antiviral agents that can destroy the membranes of viruses and bacteria, killing them.

“The antiviral agents carry positive charge, while viruses and bacteria have negative charges on their surfaces. The clash of opposite charges will destroy their surfaces and kill them,” said another team member, Kan Chi-wai.

The team has collaborated with the Home Affairs Department, the Hong Kong Wetland Park and an environmental group to produce recycling bin handles and toilet door knob covers for further testing of the material’s effectiveness and durability.

“No Covid virus and other bacteria are detected on the recycling bin handle’s surface after it had been used for a year. This proves the efficacy rate of the material only diminishes gradually after three years of use and is effective in fighting against viruses and bacteria,” Kan said.

He said the material is effective against mutant viruses as it kills them through physical means.

The material’s disinfection components are embedded in the product rather than coated on the surface, so daily cleaning with disinfectants does not compromise its anti-virus performance, Kan added.

The team has applied for a patent and said the material can be used for commercial purposes, such as phone cases and for housing construction.

“We believe the material can be used in making elevator buttons as we can produce 10 buttons in around 10 minutes at a cost of about HK$10,” Lo said.

He said it can be used to make handle covers, which can be produced through a mould injection method, costing some tens of Hong Kong dollars each.

The team will also work with the Sham Shui Po District Office to produce door knob protective covers for over 100 unmanaged “Three-Nil” buildings in the district and has plans to apply the material to schools, health-care facilities and public transport.