Sunscreen testing ethics could be solved with a sensor

New technology developed by researchers at RMIT, Australia, could be used to reduce reliance on human testers in sunscreen effectiveness trials.

Current international practice is to use ultraviolet (UV) light to test a product’s effectiveness. Of course, it is precisely this UV radiation that causes the cancer that sunscreens are designed to protect against.

Human sunscreen testing therefore grapples with this ethical question. This is especially difficult for countries like Australia which have a high incidence of skin cancers due to UV exposure.

Explainer: how sunscreen is tested.

As Dr Stuart Henderson, Deputy Director of the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) for UV exposure assessment points out, this is something that needs to change.

“It’s not the only way to test sunscreens, but it’s how they’re integrated into international standards,” says Henderson. “The difficulty is in the way [sunscreen] interacts with the skin and the way it’s applied – it’s very hard to fake.

“That’s why human testing is considered the ‘gold standard’ and has made it [as the] international standards.

“Even though human volunteers are used to test sunscreen, every little UV exposure increases their chances of developing skin cancer, which is a big health concern for the country.”

That’s why a project being developed at RMIT shows promise: Within a decade, the use of human subjects in sunscreen testing could be minimized, at least in Australia.

People are surprised to learn how sunscreens are tested

When Professor Vipul Bansal first heard about the international standard for sunscreen testing, he was too. But a new type of sensor technology developed by his team at RMIT’s Sir Ian Potter NanoBioSensing facility (Bansal is the facility’s director), could offer a chance to get humans out of the lab.

“What we’re trying to do is replace that skin with a skin-mimicking sensor that can provide a unique response,” says Bansal.

A prototype sensor developed by Bansal’s team changes color when exposed to UV light. If they can modify the sensor to mimic human skin, real skin may no longer be needed.

Although it’s still a long way off – a decade is the timeframe Bansal is working on – it could solve the problem of exposing willing sunscreen testers to the very thing the products are supposed to protect against.

RMIT researchers (LR) Dr Rajesh Ramanthan, Dr Wenyue Zou and Professor Vipul Bansal Credit: RMIT University

First Australia, then the world?

If sensor technology can be successfully adapted to replace human skin with simulated skin, it will likely be tested locally first.

From there, its expansion to the rest of the world would depend on the results: that means having proof that not only is the sensor an adequate replacement for human skin, but that the technology actually demonstrates the effectiveness of sun protection.

This is an opportunity that largely depends on the outcome, which is why the project is being implemented without the participation of product manufacturers.

This level of independent rigor, Bansal says, will help build support for the technology. “The Australian government wants to develop this technique in collaboration with us,” he says. “It is therefore an independent method validated by the regulations.

“He has no potential influence on the [sunscreen product] manufacturer, so once it comes out, it will reduce the barrier to market adoption.

“Once there is scientific evidence that the new method is as good or better than the existing one, then other countries will start adopting it.”

Five arms with sensors that could be used to test sunscreens
Sensors developed by RMIT. Credit: RMIT University

Is the simulated skin enough to replace the real thing?

It’s unclear at this point to what extent sensor technology could replace a human subject in sunscreen testing processes. After all, a textured, skin-like layer designed to react like the real thing, still isn’t the real thing. And the sensor isn’t designed to test the safety of the materials used to make this keeper mush – they would still need to be assessed.

But what Henderson hopes is that at least the sensor technology will help regulators avoid the current ethical problem of exposing people to UV.

“What we’re hoping for is that we’ll eliminate the human testing element that involves exposing people to ultraviolet light – it’s a known carcinogen, that’s what we want to get away from,” Henderson says.

“On the UV side only, that’s the goal.”

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