Facile, Green and Scalable Synthesis of Single-Layer Manganese Dioxide Nanosheets and its Applications for GSH and cTnl Colorimetric Detection

Abstract

Manganese dioxide (MnO2) nanosheets possess unique physical and chemical properties, making them widely applicable in various fields such as chemicals and biomedicine. Although MnO2 nanosheets have been produced by bottom-up wet chemistry synthesis methods, their scale is below the gram level an requires a long processing time, restricting their effective application from laboratory to market. We report a facile, green method and scalable synthesis of MnO2 nanosheets by mixing Shiranui mandarin orange juice and KMnO4 for 30 minutes. We produced more than a grams (1.095) of MnO2 nanosheets with 0.65 nm mean thickness, 50 nm mean lateral size. Furthermore, we established a visual colorimetric biosensing strategy based on MnO2 nanosheets for assay of glutathione (GSH) and Cardiac troponin I (cTnI), emerging high sensitivity and feasibility in clinical sample. GSH with a limit of detection of 0.08 nM and cTnI with a limit of detection of 0.70 pg mL-1. Meanwhile, it can be real-time monitored by smartphone-enabled biosensing strategy, which can provide a realize point-of-care testing in remote areas.