Hierarchical structured Mn2O3 nanomaterials with excellent electrochemical properties for lithium ion batteries

Short-term effects of Mn2O3 nanoparticles on physiological activities and gene expression of nitrifying bacteria under low and high dissolved oxygen conditions

The short-term effects of Mn₂O₃ nanoparticles (NPs) were examined for nitrifying bacterial enrichments exposed under low and high dissolved oxygen (DO) conditions using substrate (ammonia) specific oxygen uptake rates (sOUR), reverse transcriptase - quantitative polymerase chain reaction (RT-qPCR) assays, and by analysis of 16S rRNA sequences. Samples from nitrifying bioreactor were exposed in batch vessels to Mn₂O₃ NPs (1, 5 and 10 mg/L) for either 1 or 3 h under no additional aeration or 0.25 L/min aeration. There was increase in nitrification inhibition as determined by sOUR with increasing dosages of Mn₂O₃ NPs for both low and high DO. At 10 mg/L Mn₂O₃ NPs, the inhibition was about 7-10% for 1 and 3 h exposure in both cases. There was notable reduction in the transcript levels of amoA, hao and nirK for 10 mg/L of Mn₂O₃ NPs under 3 h, high DO exposure, which corresponded well with sOUR. The 16S rRNA sequencing showed that there was an inhibitory effect on ammonia oxidizers activity upon exposure to 10 mg/L of Mn₂O₃ NPs. Collectively, the findings in this study advanced understanding of the different effects of Mn₂O₃ NPs on nitrifying bacteria.

Dimanganese trioxide (Mn2O3) based label-free electrochemical biosensor for detection of Aflatoxin-B1

This work presents, a manganese oxide nanoparticles (Mn₂O₃nps) based electrochemical immunosensor for the detection of Aflatoxin-B1 (AFB1). X-ray diffrraction spectroscopy study confirms the purely synthesized Mn₂O₃nps with an average crystallite size of 31.5 nm. Transmission electron microscopy study confirms average particle size of 45 nm. To fabricate an electrochemical biosensor, a thin film of Mn₂O₃nps was fabricated onto indium tin oxide (ITO) surface using electrophoretic technique. Such fabricated thin film was utilized to immobilize antibodies (Anti-AFB1) for the selective detection of AFB1 using differential pulse voltammetry technique. Prior to perform sensing, bovine serum albumin (BSA) was utilized to block the uncovered sites on the Anti-AFB1/Mn₂O₃/ITO immunoelectrode surface. The response of BSA/Anti-AFB1/Mn₂O₃/ITO immunoelectrode was measured as a function of AFB1 in a linear detection range of 1 pg mL^-1 to 10 µg mL^-1 and sensor showed highest sensitivity of 2.044 μA mL ng^-1cm^-2 with lower detection limit of 0.54 pg mL^-1. A spiked sample response of corn extract was studied in the linear range of 1 pg mL^-1 to 10 µg mL^-1 and immunoelectrode (BSA/Anti-AFB1/Mn₂O₃/ITO) showed recovery rate of 98.6 %.