Microbial Toxicity of a Type of Carbon Dots to Escherichia coli
Microbial Toxicity of a Type of Carbon Dots to Escherichia coli
复制标题
一种碳点对大肠杆菌的微生物毒性
DOI：
10.1007/s00244-015-0222-z
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发表时间：
2015-11-01
影响因子：
4
通讯作者：
Masakorala, Kanaji
中科院分区：
文献类型：
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作者：
Liu, Wenjuan;Yao, Jun;Masakorala, Kanaji
碳点作为一类新型的光致发光纳米探针，近年来因其广泛的应用而引起了人们的极大兴趣。因此，化学点在生物系统中的毒性和行为成为需要重视的重要基础问题。在本研究中，采用混合酸处理制备了直径为5nm的Cdots。Cdots在紫外光照射下表现出强烈的黄色荧光，随着激发波长的改变，发射峰发生位移。以革兰氏阴性菌大肠杆菌（E. coli）为实验模型，通过微量热、光谱学和显微观察等方法研究了Cdots对细胞生长的生物学效应。在低浓度（0 ~ 5.00 mg/L）下，Cdots的引入使最大热功率（P峰）和总发热量（Q总）逐渐增加。根据微量热数据计算代谢速率常数(k)和半抑制浓度（IC50）。结果表明，Cdots对大肠杆菌的生长具有浓度依赖性。为了证实这一点，我们研究了不同浓度的Cdots的生长曲线和集落形成单位。用扫描电镜（SEM）测定了Cdots存在和不存在时大肠杆菌的形态。这些研究结果与微量热法的分析结果一致。
Carbon dots (Cdots), as a class of novel photoluminescence nanoprobes, has attracted tremendous interest for its broad application in recent years. Thus, the toxicity and behavior of Cdots in biological systems become important fundamental problems that require significant attention. In this study, Cdots with diameters of 5 nm are produced using mixed-acid treatment. The Cdots exhibit strong yellow fluorescence under UV irradiation and shifted emission peaks as the excitation wavelength is changed. Gram-negative bacteria Escherichia coli (E. coli) are applied as testing model to study the biological effect of Cdots on the cell growth by microcalorimetric, spectroscopic, and microscopic investigation. The introducing of Cdots caused a gradual increase of the maximum heat power (P peak) and the total heat produced (Q total) at low concentrations (0.0-5.00 mg/L). The metabolism rate constant (k) and half inhibitory concentration (IC50) were calculated from the microcalorimetric data. The results indicated that Cdots had a concentration-dependent effect on the growth of E. coli. For confirmation, the growth curves and colony-forming units at different concentration of Cdots were studied. The morphology of E. coli in the absence and presence of Cdots was determined by scanning electron microscopy (SEM). The results of these studies were in agreement well with the analysis explored from microcalorimetry.