Characterization of the structural, optical, photocatalytic and in vitro and in vivo anti-inflammatory properties of Mn2+ doped Zn2GeO4 nanorods

The effect of Mn incorporation on the structural, optical, and photocatalytic properties of Zn2GeO4 (ZGO) host matrices was investigated. Moreover, the ability to modulate in vitro inflammatory mediators and in vivo acute inflammation of Mn-doped ZGO (ZGO:Mn) was evaluated for the first time. We used a one-pot hydrothermal approach for preparing shape-controlled ZGO nanorods with 0, 1, 2, and 4% Mn2+ (ZGO:Mn). Both the ZGO and ZGO:Mn nanorods showed a rhombohedral structure and excellent optical properties with photoluminescence (PL) emission in the visible region at 543 nm attributed to the electronic transitions (T-4(1) -> (6)A(1)) among the 3d(5) orbitals of the incorporated Mn2+ ions in [MnO4] clusters. The nanorods were found to be efficient photocatalysts for the ultraviolet degradation of methylene blue in the presence of H2O2. The ZGO:Mn nanorod catalyst with 2% Mn showed the best methylene blue degradation (complete degradation within 10 min). The surface acidity of the ZGO:Mn nanorods also contributed to their photocatalytic ability. Meanwhile, the ZGO:Mn nanorods significantly reduced the tumor necrosis factor and nitric oxide content. Hence, the 4%-doped nanorods were found to be highly effective in the reduction of carrageenan-induced paw edema. The acute inflammation (on macrophages) results revealed that the nanorods with 4% Mn2+ exhibited promising anti-inflammatory properties.