Synthesis Of FeSe₂ Nanoparticles And Study On Their Anti-bacterial Mechanism

The microbiological contamination is among the major factors that cause high death rates of infectious diseases and pose a major threat to human health.Antibiotics are the widely-used treatment for these microbiological infections,but the abuse of antibiotics has increased the resistance of pathogenic bacteria and aggravated the medical burden.Therefore,it is critical to find emerging antibacterial materials replace conventional antibiotic agents.Although traditional antibacterial Fe nanoparticles（NPs）have exhibited advantages such as Fe Se₂ nanoparticles,they still face challenges in invariability and biotoxicity toward clinical applications.Recently,the combination of non-metallic elements and Fe-based materials can enhance the stability of single-element metal NPs and improve their biocompatibility simultaneously.Here,the main research of this paper is listed as follows:（1）One-step synthesis and characterization of Fe Se₂ NPs.Fe Se₂ NPs were synthesized by one-step synthesis with the average particle sizes of（5.17±0.05）nm,（80.61±0.05）nm,and（1.06±2.19）μm,respectively,and they were characterized by X-ray diffraction（XRD）and energy spectrometry（EDS）.The results indicate that Fe Se₂ nanoparticles are rhomboidal crystalline.（2）Comparison of the antibacterial activity of iron diselenide nanoparticles against different pathogenic bacteria.The effects of Fe Se₂ NPs with three particle sizes of（5.17±0.05）nm,（80.61±0.05）nm and（1.06±2.19）μm on the minimum inhibitory concentration（MIC）and survival rate of pathogenic micro-organisms,S.aureus,E.coli,L.monocytogenes and C.albicans,were compared.The results showed that the larger the particle size of Fe Se₂ NPs,the stronger the inhibition activity;the larger the concentration of Fe Se₂NPs,the more significant the inhibition effect;Fe Se₂ NPs with different particle sizes showed differences in the inhibition ability of different micro-organisms,（5.17±0.05）nm Fe Se₂ NPs showed stronger inhibition effect on L.monocytogenes,（80.61±0.05）nm Fe Se₂ NPs showed stronger inhibition effect on S.aureus and C.albicans,and（80.61±0.05）nm Fe Se₂NPs showed stronger inhibition effect on L.monocytogenes.Saureus and C.albicans,and（1.06±2.19）μm Fe Se₂ particles showed stronger inhibition effect on S.aureus.（3）Exploration of the inhibition mechanism of Fe Se₂ nanoparticles against C.albicans.Content changes of malondialdehyde（MDA）,reactive oxygen species（ROS）and glutathione（GSH）demonstrated that antibacterial rates of Fe Se₂ NPs were positively related with MDA and ROS values,while negatively related with GSH content in the experimental group of C.albicans.Thus,the mechanism of inhibition was initially determined as ROS-mediated oxidative stress inhibition mechanism.The results of transcriptomic analysis showed that Fe Se₂ NPs mainly inhibited C.albicans in terms of porin transport capacity,modulation of mutant feedback oxidative stress response,and reduction of recombinant enzyme activity.Additionally,anti-inflammatory and binding protein genes of C.albicans exhibited upregulation.These genes and pathways are related to the antioxidant process of the organism,suggesting that Fe Se₂ NPs inhibit the growth and reproduction of C.albicans mainly through the mechanism of oxidative stress.