快速检测奶粉中阪崎肠杆菌新型酶免疫传感器

A new enzyme immunosensor for repaid detection of E.sakazakii in milk powder

为探求奶粉中阪崎肠杆菌(Enterobacter sakazakii,E.sakazakii)更好的快速检测技术,将硫堇和辣根过氧化物酶标记阪崎肠杆菌抗体依次自组装到多壁碳纳米管/羧甲基壳聚糖-海藻酸钠修饰的丝网印刷碳电极上,制得一种阪崎肠杆菌酶免疫传感器。采用交流阻抗法和循环伏安法对不同修饰电极进行电化学特性表征测试,根据免疫电极CV还原峰电流在孵育前后的变化差值(ΔI)对阪崎肠杆菌进行检测。优化试验条件下,该方法对阪崎肠杆菌检测线性范围为103～109 CFU/mL,检出限为6.6×101 CFU/mL;且具有良好的特异性(非目标菌ΔI<0.5μA)、准确性(与GB/T 4789.40-2010符合率为100%)、稳定性(免疫电极在4℃无菌环境下保存30d,响应电流仍能达到初始值的92.3%)和重现性(RSD=6.3%)。

In order to explore a new rapid detection technology for Enterobacter sakazakii, thionine and HRP-anti-E. Sakazakii were self-assembled on a multi-walled carbon nanotube/carboxymeth- yl chitosan-sodium alginate modified screen-printed carbon electrode, to propose a enzyme immu- nosensor. The assemble procedure was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. E. sakazakii was detected by the change of cyclic voltammetry current before and after the immunoreaction. Under optimal conditions,it showed a good liner in the concentration range of 103-109 CFU/mL E. sakazakii with a detection limit 6. 6 ×10^1 CFU/mL （S/N= 3）. The proposed immunosensor presented a high sensitivity, selectivity（the current change of non-target antigen ΔI〈0. 5） ,accuracy （100% of the results obtained by the immunosensor were in agreement with those obtained by GB/T 4789.40-2010）, stability （the current response was 92.3% of the initial response after being stored at 4 ℃ for one month） ,and reproducibility （RSD〈 6.3%）.