One-step preparation of MnO2 nanozyme by PS-CDs for antibacterial, inhibition of S. aureus biofilm growth and colorimetric assay of tiopronin

Abstract

The novel nanozyme has been used in the detection field as biosensor, but has also been employed in new fields like antibacterial and inhibiting of biofilm growth applications. This paper reports the rapid preparation of the nanozyme PS-CDs-MnO2 with oxidase activity by using PS-CDs as reducing agent to reduce KMnO4. The mechanisms of positive electrical property of PS-CDs-MnO2 and the single linear oxygen (1O2) have promised the broad-spectrum antibacterial ability and high efficiency in eliminating bacteria, with 48 h long-term antibacterial effect. The minimum inhibitory concentration (MIC) against Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) at 7.50 μg/mL, 60 μg/mL, 15 μg/mL and 60 μg/mL, respectively. The prepared PS-CDs-MnO2 could effectively inhibit the formation of S. aureus biofilm at the concentration of 10 μg/mL. The visually sensitive and selective sensing platform based on PS-CDs-MnO2-TMB was established, and realized the colorimetric detection of tiopronin (TPN) with a detection range at 285.71 nM–14.28 μM and detection limit at 6.30 nM. This research provides a good theoretical and practical basis for the preparation of oxidase nanozyme and its application in detection, antibacterial and inhibition of biofilm formation fields.