Institute of Advanced Chemistry in Catalonia, Spanish Council for Scientific Research (IQAC-CSIC), CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain.
J Agric Food Chem. 2011 May 11;59(9):5036-43. doi: 10.1021/jf1048035. Epub 2011 Apr 8.
An inexpensive and portable surface plasmon resonance (SPR) sensor, SPReeta Evaluation Kit SPR3, has been used to develop a biosensor for the determination of fluoroquinolone antibiotics (FQs) and to demonstrate its performance analyzing FQ residues in milk samples. The SPReeta three-channel gold chips were activated with a mixed self-assembled monolayer (m-SAM) and functionalized with a FQ haptenized protein. Binding of the antibody produced a concentration-dependent increase of the SPR signal as a result of the change in the refraction index. Similarly, the presence of the FQ produced a dose-dependent decrease of the response, which allowed a good limit of detection (LOD) to be obtained (1.0 ± 0.4 μg L(-1) for enrofloxacin in buffer). The response was reproducible in all three channels, on different injections and days, and also between chips. Milk samples could be analyzed after a simple sample treatment involving fat removal by centrifugation and dilution with water. Under these conditions calibration curves were obtained showing that FQ residues can be analyzed in milk samples with an IC(50) value of 26.4 ± 7.2 μg L(-1) and a LOD of 2.0 ± 0.2 μg L(-1) (for enrofloxacin), far below the European Union regulations for this antibiotic family in this matrix. Finally, the paper also demonstrates that the biosensor is able to selectively detect the presence of FQs in milk samples, even in the presence of other antibiotics. Enrofloxacin, ciprofloxacin, and norfloxacin residues were detected in blind samples supplied by Nestlé Co.
一种廉价且便携的表面等离子体共振（SPR）传感器，SPReeta 评估套件 SPR3，已被用于开发一种用于测定氟喹诺酮类抗生素（FQs）的生物传感器，并展示其分析牛奶样品中 FQ 残留的性能。SPReeta 三通道金芯片通过混合自组装单层（m-SAM）激活，并通过与 FQ 半抗原化蛋白功能化。抗体的结合导致 SPR 信号的浓度依赖性增加，这是由于折射率的变化所致。同样，FQ 的存在导致响应的剂量依赖性降低，从而可以获得良好的检测限（LOD）（缓冲液中恩诺沙星的 LOD 为 1.0 ± 0.4 μg L(-1)）。在不同的注入和不同的日子，在所有三个通道中，响应都是可重复的，而且在芯片之间也是可重复的。在简单的样品处理后，可以分析牛奶样品，该处理包括通过离心去除脂肪和用水稀释。在这些条件下，获得了校准曲线，表明可以在牛奶样品中分析 FQ 残留，IC(50)值为 26.4 ± 7.2 μg L(-1)，LOD 为 2.0 ± 0.2 μg L(-1)（对于恩诺沙星），远低于欧盟对此类抗生素在该基质中的规定。最后，本文还证明了该生物传感器能够选择性地检测牛奶样品中 FQs 的存在，即使存在其他抗生素也是如此。雀巢公司提供的盲样中检测到了恩诺沙星、环丙沙星和诺氟沙星残留。
