Translational Research Platform for Veterinary Biologicals, Department of Animal Biotechnology, Madras Veterinary College, Tamil Nadu Veterinary and Animal Sciences University (TANUVAS), Chennai 600007, India.
Biosens Bioelectron. 2014 Jan 15;51:47-54. doi: 10.1016/j.bios.2013.07.009. Epub 2013 Jul 24.
Glycine functionalized (Gly/Fe3O4) and non-functionalized (Fe3O4) magnetic particles were synthesized in an autoclave and characterized by transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), energy-dispersive X-ray spectroscopy (EDX), differential scanning calorimetry (DSC), X-ray diffraction patterns (XRD) and zeta potential. The size of the both these particles were in the range of 220-230 nm but the shape of the Gly/Fe3O4 particles was hexagonal in contrast to the spherical shape of Fe3O4 particles. The particle characterization tests confirmed that glycine was functionalized on the Gly/Fe3O4 particles, they were positively charged and possessed strong magnetic property. These particles possessed the ability to bind to bacteria such as Escherichia coli, Streptococcus and Staphylococcus in the range of 72-90%. They were used to entrap bacteria from clinical mastitic milk samples from cows. The entrapped bacteria of the above species from these samples were isolated and used individually in the conventional disc-diffusion method of antibiotic susceptibility determination. The results were compared with that of the bacterial species isolated directly from the mastitic milk samples and were found to be 100% concordant (n=25). The developed portable antibiotic selection kit was tested with twenty five samples of mastitic milk. The results indicated that, antibiotic resistant bacteria turned the methylene blue in to white color while the bacteria that were killed (sensitive) retained the blue color of the dye. Thus the right choice of the antibiotic to treat cows with mastitis could be determined based on the naked eye. In conclusion, the kit gave quicker results, was easy to assay and read and can be 'farm-gate' applicable than the presently available conventional method.
甘氨酸功能化（Gly/Fe3O4）和非功能化（Fe3O4）磁性粒子在高压釜中合成，并通过透射电子显微镜（TEM）、傅里叶变换红外光谱（FTIR）、振动样品磁强计（VSM）、能谱（EDX）、差示扫描量热法（DSC）、X 射线衍射图谱（XRD）和zeta 电位进行了表征。这两种粒子的尺寸都在 220-230nm 范围内，但 Gly/Fe3O4 粒子的形状是六角形，而 Fe3O4 粒子的形状是球形。粒子特性测试证实，甘氨酸已在 Gly/Fe3O4 粒子上功能化，它们带正电荷且具有很强的磁性。这些粒子具有与大肠杆菌、链球菌和葡萄球菌等细菌结合的能力，范围在 72-90%之间。它们被用于从奶牛的临床乳腺炎牛奶样本中捕获细菌。从这些样本中捕获的上述细菌种属，被单独用于常规的药敏纸片扩散法抗生素药敏性测定。将结果与直接从乳腺炎牛奶样本中分离出的细菌种属进行比较，发现完全一致（n=25）。开发的便携式抗生素选择试剂盒在 25 份乳腺炎牛奶样本中进行了测试。结果表明，抗生素耐药菌会将亚甲基蓝变为白色，而被杀死的细菌（敏感菌）则保留染料的蓝色。因此，可以根据肉眼来确定治疗乳腺炎奶牛的正确抗生素选择。总之，该试剂盒的检测结果更快、更易于检测和读取，并且比目前可用的常规方法更适用于农场现场。
