灭多威分子印迹光子晶体传感器的制备及应用

Preparation and Application of Methomyl Molecularly Imprinted Photonic Crystal Sensor

将光子晶体技术和分子印迹技术相结合,制备了分子印迹光子晶体传感器(MIPC),用于检测农药灭多威。以直径320 nm的SiO_2微球制备的光子晶体为制孔模板,灭多威为印迹模板分子,甲基丙烯酸和丙烯酰胺为功能单体,乙二醇二甲基丙烯酸酯为交联剂,经过热聚合后形成凝胶薄膜,将SiO_2微球和灭多威分子洗脱后得到灭多威MIPC。通过扫描电子显微镜对聚合物薄膜的形貌进行了表征,发现薄膜中形成了具有典型面心立方结构的三维互连大孔阵列。通过测试其反射峰的位置变化,研究了此MIPC在灭多威溶液中的响应性能,结果表明,MIPC膜对目标分子灭多威具有良好的特异性响应。当灭多威溶液浓度在0～0.02 g/L变化时,反射峰从533 nm红移至589 nm,表观颜色由绿色变为橙红色,响应时间仅为13 min,而与其分子结构相似的克百威则没有出现明显的反射峰位移。测试了此传感器在实际样品中的实用性。当MIPC浸入灭多威含量为0.002、0.02和0.2 mg/L的白菜样品基质溶液时,MIPC反射峰偏移量分别为28、34和42 nm,表明在复杂基质中此传感器具有良好的选择性和高灵敏度的响应能力。

A novel sensing material with high sensitivity and specificity was developed for the detection of methomyl by combining photonic crystal technique with molecularly imprinting technique which was named molecularly imprinted photonic crystal(MIPC). MIPC was prepared by thermal polymerization with SiO2 microspheres array as pore-forming templates, methomyl as imprinting molecule, methacrylic acid and acrylamide as monomers and ethylene dimethacrylate as cross-linker, followed by chemical removal of SiO2 microspheres and imprinting molecules. The morphology of the polymer films was characterized by scanning electron microscopy(SEM). The results showed that a three-dimensional interconnected macroporous array with a typical face-centered cubic structure was formed in the film. The response of the MIPC to methomyl solution was studied by measuring the change of the position of the reflection peak. The results showed that the MIPC film had good specificity to methomyl. When the concentration of methomyl solution changed from 0 to 0.02 g/L, the reflection peak shifted from 533 nm to 589 nm, the apparent color changed from green to orange-red, and the response time was only 13 min. There is no significant peak shift when measuring the analog of methomyl. The response of the MIPC to methomyl in biological samples was tested. When the MIPC was immersed in the matrix solution of cabbage samples with 0.002, 0.02 and 0.2 mg/L of methomyl, the offsets of MIPC reflection peak were 28, 34 and 42 nm, respectively. The results show that the sensor still maintains high selectivity and high sensitivity in the presence of complex matrix interference.