Spermidine-capped carbon dots as potent antimicrobial nanomaterials against Escherichia coli
Tianqi Cui, Yue Wu, Zeyu Peng, Qingfeng Ban, Mingyang Wang, Jianjun Cheng, Yunqing Jiang
Abstract
The food industry must prevent food contamination caused by pathogenic Escherichia coli, as they pose a severe public health threat globally, hence the need to explore new antimicrobial materials. In this paper, spermidine capped carbon dots (S-PCDs) were synthesized by hydrothermal reaction, and the antibacterial effects against E. coli and multi-drug resistant E. coli (MREC) was determined, so as to explore their potential application as antibacterial nanomaterials. The minimum inhibitory concentration values of S-PCDs against E. coli and MREC were 64 μg/mL and 128 μg/mL, respectively, showing strong antibacterial activity. The antibacterial zone was increased significantly with the increasing content of S-PCDs (p < 0.05). The results of bacteriostatic curve and bactericidal curve of S-PCDs on E. coli and MREC also showed that S-PCDs had a concentration-dependent inhibition on bacteria. In addition, the intrinsic antibacterial mechanism indicated that the antibacterial action of S-PCDs may involve cell membrane damage and reactive oxygen species production. During 30 days of exposure, S-PCDs showed persistent antibacterial effect against both E. coli and MREC without detectable resistance, especially without triggering secondary resistance in MREC. S-PCDs has potential application value in foodborne diseases caused by complex bacteria and even drug-resistant bacteria.