细菌数与细菌中三磷酸腺苷(ATP)含量成比例,可通过生物荧光法检测细菌中ATP含量,间接获得细菌总数。研制了一种便携式生物荧光传感器,可依次进行细菌ATP的提取和检测,最终实现对细菌总数的快速检测。以十六烷基三甲基溴化铵(CTMAB)作为细菌ATP提取剂,当CTMAB浓度为5mmol/L、提取时间2min、中和剂浓度为5mmol/L时,ATP提取效率最高。在优化的实验条件下,传感器响应光强与细菌总数线性相关,线性范围58~5.89×10’cfu/mL,相关系数达0.979。传感器检测结果与传统方法吻合,线性相关系数为0.873,满足现场使用要求。从加样到ATP提取到最后获得检测结果所需总时间小于5min。所研制的传感器具有操作简单、易于携带、成本低,适用于食品卫生质量控制、环境检测等领域的细菌总数现场检测。
The method of fluorimetric determination of adenosine 5'-triphosphate (ATP), which is approxi- mately in the same level in every living bacterial cells, was used to detect the microbial count. A portable biosensor was developed to detect microbial count, which integrated ATP extracting and detecting together. The ATP can be extracted absolutely under the optimal conditions: CTMAB was chosen as extractant, extraction time was 2 min, and concentrations of the extractant and relevant neutralizing reagent were 5 and 7.5 mmol/L, respectively. Under the optimized experimental conditions, a linear response of luminescence intensity to microbial count was obtained from 58 to 5.89 × 107 cfu/mL with a correlation coefficient of 0. 979. Moreover, the results correlated well with those from the conventional plate count method with a correlation coefficient of 0. 873. The results proved that the biosensor can be applied in scene. The whole time from sampling to the ATP extraction to obtain the results was less than 5 min. The proposed biosensor with characters of low cost, easy operation and fast response provided potential application for rapid evaluation of bacterial contamination in food industry, environment monitoring and other fields.