Fluorescent Aptamer-Polyethylene Glycol Functionalized Graphene Oxide Biosensor for Profenofos Detection in Food
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doi: 10.1007/s40242-019-9257-4
Fluorescent Aptamer-Polyethylene Glycol Functionalized Graphene Oxide Biosensor for Profenofos Detection in Food XIONG Jin’en, LI Shuang, LI Yi*, CHEN Yingli, LIU Yu, GAN Junlan, JU Jiahui, XIAN Yaoling and XIONG Xiaohui* College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, P. R. China Abstract A biosensor based on self-assembled ssDNA(aptamer) and polyethylene glycol functionalized graphene oxide(GO-PEG) has been designed for sensing profenofos in food. The sensor has employed the fluorescence “on/off” switching strategy in a single step in homogeneous solution. Compared to traditional detection methods, the strategy proposed here is simple, convenient, fast and sensitive. Furthermore, compared with the general aptamer-GO structure, this aptamer-GO-PEG structure is in possession of a better detection performance, which is largely attributed to the improvement of the biocompatibility and the adjustment of the adsorption capacity of GO by grafting the blocking agent PEG onto the surface of GO. Additionally, the improved biocompatibility of GO shows better stability in salt solutions and physiological solutions, which is more conducive to its practical application in foods. In this project, profenofos had been detected with the proposed strategy, and the limit of detection has been controlled to be 0.21 ng/mL. This aptasensing assay has been applied to determining profenofos in (spiked)tap water, cabbage and milk with the recovery values ranging from 93.1% to 108.5%, from 90.8% to 113.2% and from 105.9% to 114.2%, respectively. Keywords Aptamer; Graphene oxide; Polyethylene glycol; Profenofos
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Introduction
As an organophosphorus pesticides, profenofos is widely used to control pests on a diversity of crops[1,2]. Since profenofos is highly toxic to fish and macroinvertebrates[3], it is highly effective to inhibit acetylcholinesterase activity[4]. As a result, humans are inevitably exposed to its residues in various ways. However, to date, the detection and the quantification of profenofos are mainly restricted to chromatography and mass spectrometry[5—9]. Despite the fact that these methods are accurate and sensitive, they are not suitable for screening analysis due to expensive instruments, lack of skilled analysts, as well as the need to involve time-consuming sample preparation steps. Therefore, the development of biosensors for profenofos analysis represents a fast, economical, and easy alternative contrary to traditional environmental monitoring techniques[10]. Aptamers are single-stranded nucleic acid sequences that can be used as probes for various molecules, such as peptides, acetamiprid, metal ions, proteins and cancer cells[11,12]. The widespread use of aptamers is mainly attributed to its excellent stability, effortless modification, low cost, high affinity and selectivity towards targets[13—15].
With facile surface modification, large surface area, low background, and a superior quenching efficiency for the fluorescence from fluoresceins
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