Combination of chiral selenium and manganese nanoparticles for alleviating aging through antioxidation and antiinflammation

Skin aging, marked by alterations in external appearance, internal function, and structure, is predominantly driven by oxidative stress and inflammatory responses. Chiral selenium (L-Se) and manganese dioxide (D-MnO₂) nanoparticles (NPs), modified by L-cysteine and D-gluconic acid, respectively, were developed for anti-aging. Circular dichroism (CD) spectra of L-Se and D-MnO₂ NPs showed the highest CD intensity of 145.3 ± 5.5 mdeg at 646 nm and 94.3 ± 4.9 mdeg at 552 nm, respectively. In vitro experiments showed that chiral L-Se NPs were oxidized to Se⁴⁺ in the presence of hydrogen peroxide, wherein Mn²⁺ and Mn⁴⁺ were in a dynamic state because a disproportionation reaction occurred between chiral D-MnO₂ NPs and hydrogen peroxide. Importantly, chiral L-Se and D-MnO₂ NPs showed scavenging reactive oxygen species (ROS) and multienzyme-like antioxidative activity. Living cell experiments demonstrated that the ROS level decreased 2.45-fold and the inflammatory factors level reduced about 2-fold after cotreatment with D-MnO₂ and L-Se NPs. The mechanism demonstrated that chiral NPs resisted aging by scavenging ROS and reducing inflammation, L-Se and D-MnO₂ NPs were mediated by the extracellular CD44 and CD147 transmembrane proteins, respectively, while L-Se NPs showed superior anti-inflammatory capability whereas D-MnO₂ NPs had stronger anti-oxidative property. Notably, the boosted ability of antioxidation and antiinflammation was successfully confirmed by experiments in vivo. These findings suggest that multiple chiral NPs highly enhance the anti-aging efficiency.