Australia’s harsh sun is infamous for damaging our skin. But what if you could track your skin’s health at home using something smaller than a credit card?

Researchers at RMIT University from TMOS, the ARC Centre of Excellence for Transformative Meta-Optical Systems, have developed a miniature device that monitors skin health across all skin tones. Led by postgraduate student Ying Zhi Cheong, the team has engineered a tiny device which uses four micro-LED lights and a miniature detector to assess skin conditions related to UV-induced damage.

Scientists have long known that exposure to ultraviolet (UV) light over time can result in skin cancers. The device can cleverly map the acute effects UV exposure has on skin.

UV exposure triggers the skin to respond in two key ways: it reddens quickly as blood rushes to the surface, and over hours or days, it produces melanin – the pigment that protects us against UV rays. These responses can be measured accurately, across various skin tones.

“Sensitivity to sunburn varies greatly from person to person,” says Professor Madhu Bhaskaran, co-lead author from RMIT University. “While general guidelines exist based on skin tone, this device offers a personalised way to detect early and cumulative UV-related skin damage.”  

The RMIT device emits light at wavelengths specifically absorbed by melanin and haemoglobin. The detector captures the unabsorbed light reflected from the skin and uses it to measure the presence and concentration of these compounds, effectively providing a snapshot of UV exposure and skin response.

Study first author and PhD student Ying Zhi Cheong adds “By targeting specific wavelengths absorbed by melanin and haemoglobin, we’re able to non-invasively detect how skin responds to UV. This compact device translates complex biology into simple, accessible insights.”

Remarkably, the researchers built and tested this technology without exposing any participants to sunburn. Instead, they turned to an unlikely stand-in: caffeine. When dissolved in water, coffee mimics the light absorption characteristics of melanin under visible and UV light, allowing the team to simulate sun exposure safely in the lab.

“Most of us apply sunscreen once and forget about it. This device helps reveal how well your sunscreen is working before any sun damage becomes visible.” adds co-lead author, Blanca del Rosal.

Looking ahead, the team plans to integrate machine learning to further refine the device’s accuracy. This advancement could pave the way for affordable, accessible tools to manage skin health.

The research has been published in Advanced Science Research and is available online:
Advanced Science Research