基于DNA桥连氧化石墨烯的Fpg荧光检测

Fluorescence detection of Fpg based on DNA bridging graphene oxide

甲酰胺嘧啶DNA糖基化酶(Fpg)可特异性识别并切除由鸟嘌呤损伤产生的8-oxoG碱基以修复DNA序列,因此对Fpg进行定量检测可以反映鸟嘌呤受损程度,为污染物毒性效应评价提供技术手段.基于不同长度的DNA桥连氧化石墨烯(GO)强度不同的原理,以及GO优异的荧光淬灭能力,构建了DNA桥连GO基荧光传感器.该传感器在不同浓度Fpg下,特异性识别和切除8-oxoG碱基,产生短链DNA,其上修饰的荧光基团不能被GO有效淬灭,因而产生荧光信号.该荧光信号与Fpg浓度在一定范围内呈线性关系,可实现Fpg的定量检测,检测的线性范围为0~0.4 U/mL,检出限为0.014 U/mL,并表现出良好的特异性识别能力.采用加标回收法对稀释后胎牛血清中的Fpg进行了检测,回收率为93.5%~111%.其为Fpg快速检测提供了可行的方法,为DNA鸟嘌呤损伤评价提供了一种有效的技术手段.

Formamidopyrimidine DNA glycosylase(Fpg)can specifically identify and excise the 8-oxoG nucleobases produced by guanine damage to repair the DNA sequence,so quantitative detection for Fpg can reflect the degree of impairment of guanine and provide technical means for contaminant toxic effects evaluation.Based on the principle that DNA with different lengths has different bridging strengths to graphene oxide(GO)and the excellent fluorescence quenching ability of GO,a DNA bridging GO-based fluorescence sensor is constructed.In the presence of different concentrations of Fpg,the 8-oxoG nucleobases are specifically recognized by this sensor and excised to generate short-chain DNA,and the fluorophore modified on short-chain DNA can not be effectively quenched by GO,thus generating a fluorescent signal.The fluorescent signal has a linear relationship with the Fpg concentration within a certain range,which can realize the quantitative detection of Fpg.The linear range of detection is 0-0.4 U/mL.The limit of detection is 0.014 U/mL.The sensor shows good specific recognition ability.Fpg in diluted fetal bovine serum is detected by standard addition recovery method,and the recovery rate is 93.5%-111%.This work can provide a feasible method for rapidly detecting Fpg and an effective technical means for evaluating DNA guanine damage.