Seo K H, Brackett R E, Hartman N F, Campbell D P
Center for Food Safety and Quality Enhancement, Food Science and Technology, University of Georgia, Experiment Station, Griffin 30223-1797, USA.
J Food Prot. 1999 May;62(5):431-7. doi: 10.4315/0362-028x-62.5.431.
An integrated optic interferometer for detecting foodborne pathogens was developed. The interferometer is a planar waveguide with two thin antibody-coated channels of immunochemically selective agents that interact with antigen molecules. One channel is coated with antibody to Salmonella as a sample, and the other is coated with human immunoglobulin G as a reference channel by using reductive amination. Salmonella was introduced onto the sensing channels through the flow cell on the channels. Phase shift (pi) generated by refractive index variation, as determined by interfering the perturbed sample channel with an unperturbed reference channel and observing the fringe shift, was used for detection. Salmonella Typhimurium (heat-treated or boiled) was detected by binding to antibody against Salmonella common structural antigen immobilized on a silane-derived sensor surface at concentrations in the range of 1x10(5) to 1x10(7) CFU/ml. Salmonella (1x10(7) CFU/ml) mixed with Escherichia coli (1x10(7) CFU/ml) were readily detected without any decrease in sensitivity by the direct assay. Application of a sandwich assay with a second antibody or a gold-conjugated antibody increased the detection limit to 1x10(5) CFU/ml within a 10-min reaction time. Various methods for the immobilization of the capture antibody to the biosensor channels were compared. The greatest binding response was observed in a direct reductive amination method with a long reaction period and increased the detection limit of direct binding of Salmonella antigen to 1x10(4) CFU/ml. The biosensor was able to detect Salmonella Typhimurium in chicken carcass wash fluid originally inoculated at a level of 20 CFU/ml after 12 h of nonselective enrichment. The planar optic biosensor shows promise as a fast, sensitive, reliable, and economical means of detecting food pathogens in the future.
开发了一种用于检测食源性病原体的集成光学干涉仪。该干涉仪是一种平面波导，具有两个涂有薄抗体的免疫化学选择剂通道，这些选择剂与抗原分子相互作用。一个通道涂有针对沙门氏菌的抗体作为样品，另一个通道通过还原胺化涂有人免疫球蛋白G作为参考通道。沙门氏菌通过通道上的流通池引入传感通道。通过将受干扰的样品通道与未受干扰的参考通道进行干涉并观察条纹移动来确定由折射率变化产生的相移（π），用于检测。鼠伤寒沙门氏菌（热处理或煮沸）通过与固定在硅烷衍生传感器表面的抗沙门氏菌共同结构抗原的抗体结合进行检测，浓度范围为1×10⁵至1×10⁷CFU/ml。直接检测法能够轻松检测出与大肠杆菌（1×10⁷CFU/ml）混合的沙门氏菌（1×10⁷CFU/ml），且灵敏度没有任何降低。使用二抗或金偶联抗体的夹心检测法在10分钟的反应时间内将检测限提高到1×10⁵CFU/ml。比较了将捕获抗体固定到生物传感器通道的各种方法。在反应时间较长的直接还原胺化方法中观察到最大的结合响应，并将沙门氏菌抗原直接结合的检测限提高到1×10⁴CFU/ml。该生物传感器能够在非选择性富集12小时后检测出最初接种水平为20CFU/ml的鸡胴体清洗液中的鼠伤寒沙门氏菌。这种平面光学生物传感器有望在未来成为一种快速、灵敏、可靠且经济的检测食品病原体的方法。
