Cooperative antimicrobial activity of CdTe quantum dots with rocephin and fluorescence monitoring for Escherichia coli

• Published in: Journal of colloid and interface science 2011-10, Vol.362 (1), p.100-106
• Main Authors: Luo, Zhihui, Wu, Qingsheng, Zhang, Meng, Li, Ping, Ding, Yaping
• Format: Article
• Language: English
• Subjects: absorbance; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; anti-infective properties; Antibiotics; Cadmium Compounds - chemistry; Cadmium Compounds - pharmacology; Ceftriaxone - chemistry; Ceftriaxone - pharmacology; Chemistry; Cooperative antimicrobial effects; electrostatic interactions; Escherichia coli; Escherichia coli - drug effects; Escherichia coli Infections - drug therapy; Exact sciences and technology; fluorescence; General and physical chemistry; Humans; hydrogen bonding; Microbial Sensitivity Tests; monitoring; photoluminescence; Quantum Dots; reactive oxygen species; spectroscopy; Synchronous monitoring; Tellurium - chemistry; Tellurium - pharmacology
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2011.06.039

CdTe QDs are used to increase the efficacy of rocephin, and they collaborate to realize “1+1>2” cooperative antimicrobial effects against Escherichia coli. Fluorescent enhancement effect of CdTe QDs with E. coli is firstly adopted to synchronously monitor the concentration changes in E. coli. [Display omitted] ► CdTe QDs are used to greatly enhance efficacy of rocephin for the first time. ► Rocephin with CdTe QDs can achieve cooperative antimicrobial effects to Escherichia coli. ► CdTe QDs are inventively adopted to monitor the concentration changes in E. coli synchronously. In this study, the cooperative antibacterial efficiency of CdTe quantum dots (QDs) and rocephin against Escherichia coli (E. coli) was investigated. Colony-forming capability assay and diameter of inhibition zone (DIZ) measurement showed the antibiotic action of CdTe QDs-rocephin complex was better than the superposition of pure CdTe QDs and rocephin. The fractional inhibitory concentration index (FICI) indicated that CdTe QDs-rocephin complex could achieve great cooperative antimicrobial effects. The infrared ray (IR) spectrum, photoluminescence (PL) spectrophotometry, and detection of reactive oxygen species (ROS) indicated that CdTe QDs and rocephin formed a stable antimicrobial group through electrostatic attraction and hydrogen bonds and then killed the E. coli together. Meanwhile, the fluorescence intensity of CdTe QDs and the optical density (OD) value of E. coli showed a good linear relationship. Thus, dynamic monitoring to total bacterial concentration in the antibacterial process was realized by the CdTe QDs.