Abstract
Oral bacteriotherapy is increasingly exploited but faces challenges in simultaneously monitoring treatment process and achieving desirable efficacy. Here, we develop theranostic bacteria by depositing a protective visual therapeutic nanocoating via in situ sequential mineralization. Using two-step metal ion adsorption and nucleation, bacterial surface is successively mineralized with an inner manganese dioxide/ferric oxide nanoparticle layer and an outer calcium carbonate layer. Upon ingestion, the outer layer neutralizes gastric acid through double-decomposition reaction, protecting bacterial viability and the inner layer. During intestinal passage, the inner layer enables T1/T2 dual-mode magnetic resonance imaging for real-time tracking, whereas the lesion-triggered release of manganese ions allows T1 single-mode pathological detection. The inner layer also exhibits superoxide dismutase and catalase activities, synergizing therapeutic effects with bacteria. Further supported by satisfactory performances in two murine models of Salmonella-induced colitis and apolipoprotein E-deficient atherosclerosis, this work provides a platform to generate innovative theranostic agents for advanced bacteriotherapy.