Microalgae-Based Dosimetry for Monitoring Blue Light Exposure

Blue light therapy is increasingly used to treat various skin conditions like acne, psoriasis, and neonatal hyperbilirubinemia. Yet, excessive blue light exposure can also negatively impact human health by disrupting circadian rhythms, generating free radicals, and damaging skin barrier function. Quantifying personal blue light exposure is therefore essential for optimizing therapeutic efficacy while preventing side effects. However, current blue light dosimetry techniques require complex, expensive instrumentation, making routine monitoring impractical. In this feasibility study, we explored the potential for developing a blue-light dosimeter that uses the color changes of photodegraded microalgae to measure blue light doses relevant for phototherapy. Two fiber-coupled light-emitting diodes (LEDs), one emitting at 415 nm and the other at 455 nm, were used. A Schizochlamys sp. strain of microalgae exhibited a photobleaching response upon blue light irradiation, with color changes quantitatively linked to exposure dose. This approach enables real-time monitoring and assessment of blue light exposure in a variety of contexts, including the workplace, the home, and healthcare facilities, in a cost-effective and user-friendly way.