Fluorescent aptamer-functionalized graphene oxide biosensor for rapidly detection of chloramphenicol
Lu Jinghe, TAN Suzhen, ZHU Yuqing, LI Wei, CHEN Tianxiao
School of Chemical and Biological Engineering, Changsha University of Science and Technology, Changsha, Hunan, China No. 960, Section 2, Wanjiali South Road, Yuhua District, Changsha City, Hunan Province 410114
A label free and rapidly fluorescent method for quantitative detection of chloramphenicol (CAP) based on graphene oxide (GO) fluorescence switch-based functional G-quadruplex probe (FGP) was developed. The FGP consisted of a choramphenicol aptamer and a G-rich sequence. The aptamer was used to bind CAP and the G-quadruplex formed by G-rich sequence was employed as a signal reporter after binding to Thioflavin T (ThT). In the absence of CAP, the FGP was absorbed onto the surface of GO through π-π stacking interactions, which restrained the G-rich sequence to form a G-quadruplex structure. Thus, the fluorescent intensity of background was low. In the addition of the CAP, the aptamer part of FGP could recognize and bind CAP to form a target-FGP complex, which led to the desorption of the complex from GO. Therefore, the free G-rich sequence could form G-quadruplex structure and bind to ThT, resulting a increase in the fluorescence intensity of the solution. We observed that the fluorescence increasement of the sensing platform had a linear relationship with the concentrations of CAP in the range of 2-20 nM, and the limit of detection was 1.45 nM. Besides, this detection system was applied for detecting CAP in the spiked milk, the recovery rate was between 93.2-103.3%. These results indicated that this developed method can be used to efficiently recognize CAP in real samples.