Green-synthesized Tio₂ Nanoparticles for Sunscreen: Eco-Friendly Approach to Spf Enhancement

This study aims to evaluate the potential of green-synthesized titanium dioxide (TiO₂) nanoparticles (NPs) derived from herbal extracts-namely Camellia sinensis (Green Tea), Eclipta prostrata (Bhringraj), Glycyrrhiza glabra (Licorice), and Cinnamomum zeylanicum (Cinnamon)-for enhancing the Sun Protection Factor (SPF) in sunscreen formulations. Addressing the environmental and toxicity concerns associated with conventionally synthesized TiO₂ NPs, this eco-friendly approach offers a sustainable and effective alternative for cosmetic applications without compromising efficacy. The synthesized nanoparticles were characterized using UV-Vis spectroscopy, X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), and then incorporated into oil-in-water emulsions containing 5% homosalate. In vitro SPF was measured using the Labsphere UV-2000S system, while formulation stability was assessed via pH monitoring, rheological behavior, and accelerated centrifugation using the LUMiSizer. Statistical analysis, including one-way ANOVA and effect size metrics (η², Cohen's d), confirmed significant SPF enhancement, particularly in formulations using Green Tea and Cinnamon-derived TiO₂ NPs, which showed 3.12-fold and 3.11-fold improvements, respectively. Notably, smaller crystallite size (30.2 nm in Green Tea-derived TiO₂) correlated with higher SPF (14.97 ± 0.31). All formulations exhibited excellent physical and thermal stability. These findings underscore the promise of plant-mediated TiO₂ NPs as a viable, sustainable solution for next-generation sunscreen products, with further investigation warranted for scale-up and in vivo validation.