The Effects of Luminescent CdSe Quantum Dot-Functionalized Antimicrobial Peptides Nanoparticles on Antibacterial Activity and Molecular Mechanism

Abstract

Background With the development of bacterial resistance, the range of effective antibiotics is increasingly becoming more limited. The effective use of nanoscale antimicrobial peptides (AP) in therapeutic and diagnostic methods is a strategy for new antibiotics. Methods Combining both AP and cadmium selenide (CdSe) into a composite material may result in a reagent with novel properties, such as enhanced antibacterial activity, fluorescence and favorable stability in aqueous solution. Results AP-loaded CdSe NPs (AP-CdSe NPs) showed strong antibacterial activity against multidrug-resistant (MDR) Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) in vitro and in vivo. Colony-forming unit (CFU) and minimum inhibitory concentration (MIC) assays showed that AP-CdSe NPs have highly effective antibacterial activity. The quantitative analysis of apoptosis by flow cytometry analysis further confirmed that MDR E. coli and S. aureus treated with AP-CdSe NPs had death rates of 98.76% and 99.13%, respectively. Also, AP-CdSe NPs was found to inhibit bacterial activity in an in vivo bacteremia model in mice infected with S. aureus . In addition, the antibacterial mechanism of AP-CdSe NPs was determined by RNA sequencing analysis. Gene ontology (GO) analysis and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis revealed the molecular mechanism of the antibacterial effect of AP-CdSe NPs. Importantly, histopathology analysis, and hematological toxicity analysis indicated that AP-CdSe NPs had few side effects. Conclusion These results demonstrate that AP loaded on CdSe NPs had a higher water solubility, bioavailability and antibacterial effect compared with raw AP. This study reports findings that are helpful for the design and development of antibacterial treatment strategies based on AP.

New Insights into the Cellular Toxicity of Carbon Quantum Dots to Escherichia coli

“…However, the exact mechanism still needs further research. One possible cause of the change in the permeability of E. coli is oxidative stress, where the adhesion of CQDs to the bacterial cell wall leads the superoxide anion and free radicals being produced that rapidly and directly interact with bacteria, destroying the cell membrane and causing leakage of the cytoplasm [ 32 , 33 ].…”

Biofilm Microenvironment-Mediated MoS2 Nanoplatform with Its Photothermal/Photodynamic Synergistic Antibacterial Molecular Mechanism and Wound Healing Study

“…At the end of the incubation, the cells were stained in the dark for 30 min using the Live/Dead live bacteria/dead bacteria double-staining kit [SYTO9 and propidium iodide (PI), Life Technologies]. The excess staining solution was removed by washing three times with PBS at the end of staining . The samples were prepared, and the fluorescence colocalization in the images was observed.…”

“…The excess staining solution was removed by washing three times with PBS at the end of staining. 42 The samples were prepared, and the fluorescence colocalization in the images was observed.…”

Synthesis of a Two-Dimensional Molybdenum Disulfide Nanosheet and Ultrasensitive Trapping of Staphylococcus Aureus for Enhanced Photothermal and Antibacterial Wound-Healing Therapy

“…Log-phase S. aureus cultures were inoculated (1:40) in medium containing MoS 2 -Van-FITC (100 μg/mL), MoS 2 (100 μg/mL), or Van (1 μg/mL) and incubated in a shaking incubator at 37°C for 12 h. The irradiation power density was 1.5 W/cm 2 , and the irradiation time was 300 s. Thereafter, the cells were stained with SYTO9 and propidium iodide for 30 min in the dark, washed twice with PBS, and red and green channels were examined under a fluorescence microscope. The number of non-viable bacterial cells was determined by the CytoFLEX system (Beckman Coulter, Brea, CA, USA) [ 2 , 39 ].…”

“…Bacterial infections are consistently ranked as one of the leading causes of human mortality, with infection rates, mortality rates, and hospitalization costs increasing annually [ 1 , 2 , 3 ]. The high prevalence of bacterial infections has led to the misuse of antibiotics, resulting in the emergence of superbugs as bacteria become resistant to treatment.…”