Ma Junning, Veltman Boris, Tietel Zipora, Tsror Leah, Liu Yang, Eltzov Evgeni
Department of Postharvest Science, Institute of Postharvest and Food Sciences, The Volcani Center, Agricultural Research Organization, Bet Dagan, 50250, Israel; Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China.
Department of Postharvest Science, Institute of Postharvest and Food Sciences, The Volcani Center, Agricultural Research Organization, Bet Dagan, 50250, Israel; Institute of Biochemistry, Food Science and Nutrition, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel.
Talanta. 2020 Nov 1;219:121333. doi: 10.1016/j.talanta.2020.121333. Epub 2020 Jul 5.
Over the past two decades, whole-cell biosensors (WCBs) have been widely used in the environmental field, with only few applications proposed for use in agricultural. This study describes the development and optimization of a WCB for the detection of volatile organic compounds (VOCs) that is produced specifically by infected potato tubers. First, the effect of calcium-alginate matrix formation (beads vs. tablets) on the membrane uniformity and sensing efficiency was evaluated. Then, important parameters in the immobilization process were examined for their effect on the sensitivity to the presence of VOCs. The highest sensitivity to the target VOC was obtained by 20 min polymerization of bacterial suspension with optical density of 0.2 at 600 nm, dissolved in low-viscosity sodium alginate (1.5% w/v) and exposure to VOC at 4 °C. After optimization, the lowest limit of detection for three infection-sourced VOCs (nonanal, 3-methyl-1-butanol, and 1-octen-3-ol) was 0.17-, 2.03-, and 2.09-mg/L, respectively, and the sensor sensitivity was improved by 8.9-, 3.1- and 2-fold, respectively. Then, the new optimized immobilization protocol was implemented for the CMOS-based application, which increased the sensor sensitivity to VOC by 3-fold during real-time measurement. This is the first step in creating a sensor for real-time monitoring of crop quality by identifying changes in VOC patterns.
在过去二十年中，全细胞生物传感器（WCBs）已在环境领域广泛应用，而在农业领域的应用却很少。本研究描述了一种用于检测受感染马铃薯块茎特异性产生的挥发性有机化合物（VOCs）的全细胞生物传感器的开发与优化。首先，评估了海藻酸钙基质形成（珠子与片剂）对膜均匀性和传感效率的影响。然后，研究了固定化过程中的重要参数对VOCs存在时灵敏度的影响。通过将在600nm处光密度为0.2的细菌悬浮液与低粘度海藻酸钠（1.5% w/v）溶解后聚合20分钟，并在4°C下暴露于VOC，获得了对目标VOC的最高灵敏度。优化后，三种感染源VOCs（壬醛、3-甲基-1-丁醇和1-辛烯-3-醇）的最低检测限分别为0.17mg/L、2.03mg/L和2.09mg/L，传感器灵敏度分别提高了8.9倍、3.1倍和2倍。然后将新的优化固定化方案应用于基于CMOS的应用中，在实时测量期间，这使传感器对VOC的灵敏度提高了3倍。这是通过识别VOC模式变化创建用于实时监测作物质量的传感器的第一步。
