摘要
目的：为增强响应信号,改善生物相容性,研制可以快速检测福氏志贺氏菌（Shigella flexneri,S.flexneri）的电化学免疫传感器。方法：将辣根过氧化物酶标记福氏志贺氏菌抗体（HRP-anti-S.flexneri）吸附在多壁碳纳米管（MWCNT）/海藻酸钠（SA）复合物修饰的四通道丝网印刷电极表面,制得一次性酶免疫传感器。采用原子力显微镜（AFM）表征免疫电极和孵育抗原后的电极表面形态以及循环伏安法（CV）考察不同修饰电极的电化学特性;采用一步法检测福氏志贺氏菌,CV监测酶促反应;根据免疫反应前、后还原峰峰电流的降低值来检测样品中的福氏志贺氏菌。结果：在优化的试验条件下,酶免疫传感器与福氏志贺氏菌浓度的对数在104~1011cfu/mL范围保持良好的线性关系,检出限为3.1×103cfu/mL（S/N=3）。结论：该酶免疫传感器放大了电化学反应信号,保持了生物物质的活性,具有较好的特异性、重现性（RSD=7.8%）、稳定性（4℃放置两周后电流响应为初始值的95.16%）和准确性（与GB/T 4789.5-2003符合率为97.5%）,有望用于福氏志贺氏菌的快速筛检。
Object：For the purpose of amplifying the response signal and improving the biocompatibility,a novel immunosensor for rapid detection of Shigella flexneri（S.flexneri） was successfully fabricated.Methods：Horseradish peroxidase labeled antibodies to S.flexneri（HRP-anti-S.flexneri） was immobilized by physical adsorption on the multi-wall carbon nanotubes（MWCNT）/sodium alginate（SA） composite modified screen-printed electrode surface.In this strategy,MWCNT/SA biocomposite acted as the matrix to adsorb and immobilize HRP-anti-S.flexneri.The preparation process of modified electrodes was characterized with atomic force microscope and cyclic voltammetry（CV）.The analytical performance of proposed immunosensor toward S.flexneri was investigated by CV.Results：Under optimal conditions,the concentration of S.flexneri from 104 to 1011 cfu/mL could be detected,with a detection limit of 3.1×103 cfu/mL（S/N=3）.Conclusions：The MWCNT/SA composite can significantly amplify the response signal and minimize the potential to denature bioactivity of biomolecules.Furthermore,the immunosensor exhibited satisfactory specificity,reproducibility（RSD=7.8%）,stability（the current response was 95.16% of the initial response after being stored at 4 ℃ for two weeks） and accuracy（97.5% of the results obtained by the immunosensor were in agreement with those obtained by GB/T 4789.5-2003）.The proposed immunosensor showed simply fabricative,economical,efficient and potential application for rapid detection and early assessment of S.flexneri.
出处
《中国食品学报》
EI
CAS
CSCD
北大核心
2010年第4期60-66,共7页
Journal of Chinese Institute Of Food Science and Technology
基金
国家自然科学基金资助项目(No.30571623)
"十一五"国家863计划重点项目(No.2007AA091806)
浙江省重中之重项目(No.Z05-178)
