液晶传感竞争免疫法检测天蚕素B

Label-free liquid crystal immunosensor for detection of cecropin B

制备了一种基于液晶取向变化的非标记液晶型免疫传感器,并结合竞争免疫反应原理,将其用于天蚕素B检测.首先采用硅烷化试剂3-氨丙基三乙氧基硅烷/二甲基十八烷基[3-(三甲氧基硅基)丙基]氯化铵(APTES/DMOAP)混合自组装构建可诱导液晶分子呈均一垂直排列的基底敏感膜,再通过戊二醛交联法将天蚕素B固定到基底表面,当天蚕素B抗体与天蚕素B特异性结合后扰乱了液晶分子的取向,使液晶膜的颜色和亮度发生变化,并通过计算偏光显微镜成像灰度强度,可在0.01~0.1ng/mL范围内定量化分析天蚕素B浓度.结果表明,固定化天蚕素B浓度为150ng/mL,天蚕素B抗体浓度为500ng/mL时,天蚕素B检测限可达0.01ng/mL.本方法具有灵敏度高、特异性好、非标记和操作简单等优点.

A label-free liquid crystal immunosensor based on orientation changes of liquid crystals was prepared for the detection of cecropin B through competitive immunization assay.The mixed APTES/DMOAP self-assembled monolayers formed by both long and short alkyls could cause uniform vertical alignment of liquid crystals.The homeotropic-to-tilted transition of liquid crystals induced by the specific binding event between anti-cecropin B antibody and cecropin B immobilized via a cross-linker glutaradehyde could result in the corresponding changes of the color and brightness of liquid crystal film.The gray-scale intensities of optical images of liquid crystal cells were measured to quantitatively analyse cecropin B concentrations at the range of 0.01~0.1 ng/mL and as a result,the limit of detection is as low as 0.01 ng/mL with immobilized cecropin B concentration of 150 ng/mL and anti-cecropin B antibody concentration of 500 ng/mL.This study offers a simple,highly sensitive and specific,lable-free method for cecropin B detection.