In situ O2-releasing quantum dot composites with enhanced radical scavenging behaviour, biosafety, and broadband UV shielding applications

Abstract

Understanding the defect-driven photophysics-surface chemistry interplay at the nanoscale further augments new design considerations for active ingredients used in sun-protection, emphasizing affordability, safety, and multi-functionality. Accelerating it, our study unravelled broad-spectrum UV attenuation (250 nm–400 nm) and long-lasting photostability (>5 h) exhibited by in-house fabricated β-cyclodextrin functionalized, oxygen vacancy (VO●) engineered-CeO2(x)/ZnO(1-x) quantum dot composites (Em-C(x)Z(1-x)). A conceptually different strategy was pursued, involving artificially engineering surface VO● defects to modulate the band structure and enhance the molar absorptivity through photogenerated electron-hole separation. Unlike conventional inorganic UV blockers, these QD composites harnessed surface VO● for a self-cascading antioxidant effect, scavenging 62.8 % ●OH radicals. Results indicated that autocatalytic endogenous O2 generation from H2O2 scavenging, accelerated by Ce3+/Ce4+ couple, begets anti-photoaging and sunburn alleviation. Em-C(x)Z(1-x) demonstrated synergistic suppression of oxidative stress development and remarkable cell viability (≥90 %) even under UV irradiation. These underlying principles can be extended to prevent and treat other ROS-induced skin ailments. Incorporating Em-C0.3Z0.7 in commercial sunscreens unveiled a substantial enhancement in overall sun protection and antioxidative efficacy. Thus, it is envisioned that Em-C(x)Z(1-x) holds promise for developing safe, efficacious, and economical sunscreens.