Nanoalgosomes from Tetraselmis chuii: Microalgal Extracellular Vesicles for UV Protection, Anti-Aging, and Skin Depigmentation

The search for effective dermocosmetic treatments has recently been accompanied by the growing demand for ingredients that are both naturally derived and sustainable. In this context, microalgae have emerged as a promising biofactory, producing bioactive compounds for skin health, widely recognized for their antioxidant, anti-inflammatory, and anti-aging activities. To leverage these properties, besides the conventional use of microalgal mass or extracts, the isolation and application of their secretome including in particular the extracellular vesicles named nanoalgosomes emerged as a novel, increasingly studied approach. EVs are membranous nanoparticles released by all cells and naturally efficient in the transport of both endogenous and exogenous bioactive molecules. Their unique biological properties make them ideal candidates for therapeutic and cosmetic applications. Here, we propose nanoalgosomes, as a sustainable and effective solution for innovative dermocosmetic treatments. In this study we exemplify the use of the microalgae Tetraselmis chuii, an edible, green and renewable EV bio-source. We demonstrated the nanoalgosomes skin-health promoting potential, by employing the human skin cells as a model to evidence the nanoalgosome ability to protect the cells from ultraviolet B (UVB) radiation-related damages. Treatment with nanoalgosomes reduced the oxidative stress, enhancing cell viability in a dose dependent manner. Nanoalgosomes also led to a marked decrease in senescence-associated (SA)-beta-galactosidase activity, indicating a reduction in senescence-associated phenotype in UVB-exposed skin cells. Furthermore, we observed that nanoalgosomes effectively modulate melanogenesis in UVB-stimulated melanocytes by downregulating tyrosinase expression, resulting in a significant decrease in melanin content. These findings validate nanoalgosomes not only as photoprotective agents but also as potential modulators of pigmentation processes. Altogether, our results provide a solid foundation for the development of nanoalgosome-based formulations in dermocosmetic applications aimed at UV protection, anti-aging, and depigmentation, supporting the transition toward natural and sustainable skincare solutions.