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

Abstract

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 (⁴T₁ → ⁶A₁) among the 3d⁵ 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.