Cadmium telluride (CdTe) and silver-doped CdTe (CdTe/Ag) nanocrystals have been used to study the antibacterial activity against gram-positive bacteria (Streptococcus pneumoniae and Staphylococcus aureus) and gram-negative bacteria (Klebsiella pneumoniae and Escherichia coli) by disc diffusion method. Here, CdTe and CdTe/Ag nanocrystals have been prepared by chemical method and characterized by transmission electron microscope (TEM) and X-ray diffraction (XRD). TEM images show that both the nanocrystals are spherical in shape with an average diameter of 6 nm and 5 nm respectively, whereas XRD pattern indicates that these nanocrystals are cubic in structure. Further, nuclear magnetic resonance study as well as FTIR spectral study confirm that prepared nanocrystals are well capped by 3-marcaptopropionic acid. For antibacterial test, different concentrations from 1 to 10 μg ml⁻¹ of CdTe and CdTe/Ag nanocrystals are placed in the agar broth against all the gram-positive and gram-negative bacterial strains. Here, Ampicillin and water have been used as a standard reference and a control respectively. It is found that both the nanocrystals are effective against all the bacterial strains and the zone of inhibition (ZOI) is measured after 24 h of incubation. But, CdTe/Ag nanocrystals show much more ZOI than CdTe nanocrystals. Among the gram-positive bacteria, these nanocrystals are more effective against S. pneumonia (ZOI-9 mm for 1 µg ml⁻¹), compared to S. aureus (ZOI-8 mm for 1 µg ml⁻¹). Whereas, among the gram-negative bacteria, activity is more against the E. Coli (ZOI-8 mm for 1 µg ml⁻¹) than that in K. pneumonia (ZOI-6.5 mm for 1 µg ml⁻¹).

中文翻译：

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MPA封盖的CdTe和Ag掺杂的CdTe纳米晶体的抗菌活性：对革兰氏阳性和革兰氏阴性细菌表现出不同的活性

碲化镉（CdTe）和银掺杂的CdTe（CdTe / Ag）纳米晶体已用于研究对革兰氏阳性菌（肺炎链球菌和金黄色葡萄球菌）和革兰氏阴性菌（肺炎克雷伯菌和大肠杆菌）的抗菌活性。）通过光盘扩散方法。在这里，CdTe和CdTe / Ag纳米晶体已经通过化学方法制备，并通过透射电子显微镜（TEM）和X射线衍射（XRD）进行了表征。TEM图像显示两个纳米晶体均为球形，平均直径分别为6nm和5nm，而XRD图表明这些纳米晶体为立方结构。此外，核磁共振研究和FTIR光谱研究证实，制备的纳米晶体被3-巯基丙酸很好地覆盖。对于抗菌测试，浓度范围为1至10μgml ^-1将CdTe和CdTe / Ag纳米晶体分别置于琼脂肉汤中，以对抗所有革兰氏阳性和革兰氏阴性细菌菌株。在这里，氨苄青霉素和水已分别用作标准参考和对照。发现两种纳米晶体均对所有细菌菌株均有效，并且在孵育24小时后测量抑制区（ZOI）。但是，CdTe / Ag纳米晶体比CdTe纳米晶体显示出更多的ZOI。在革兰氏阳性细菌中，与金黄色葡萄球菌（ZOI-8 mm，1 µg ml ^-1）相比，这些纳米晶体对肺炎链球菌（ZOI-9 mm，1 µg ml ^-1）更有效。而在革兰氏阴性细菌中，对大肠杆菌的活性更大（ZOI-8 mm，1 µg ml ^-1）比肺炎克雷伯菌（ZOI-6.5 mm，1 µg ml ^-1）。