A graphene oxide based biosensor for microcystins detection by fluorescence resonance energy transfer.
Water safety is one of the most pervasive problems afflicting people throughout the world. Microcystin, a hepatotoxin produced by cyanobacteria, poses a growing and serious threat of water safety. According to World Health Organization (WHO), the limit of content of microcystin-LR (MC-LR) in drinking water is as low as 1 μg/L; it is thus necessary to explore a sensitive method for the trace detection of microcystins (MCs). Based on the observation of gold nanoparticles (Au NPs) induced graphene oxide (GO) fluorescence quenching, a reliable biosensor was developed here for microcystins detection. MCs could be attached on Au NPs through the interaction with single strand-DNA (ss-DNA) modified on Au NPs, which formed Au-DNA-MCs complexes. These MCs in the complexes could be immunologically recognized by the antibodies adsorbed on GO sheets, as a result, Au NPs were close enough to quench the photoluminescence of GO by the fluorescence resonance energy transfer (FRET). The fluorescence intensity decreased with the increase of MCs as more Au NPs linked onto GO surface. The limit of detection was 0.5 and 0.3 μg/L for microcystin-LR and microcystin-RR (MC-RR), respectively, which satisfies the strictest standard of WHO. Well defined results were also obtained in natural lake water and the specificity experiment. The antibody used here could recognize Adda group, the conservative part of MCs, which allowed the biosensor to detect both single toxin and the total content of MCs existing in the water sample.
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, Jilin, PR China.
Yan
Y
Shi
Jiazhen
J
Wu
Yujing
Y
Sun
Yue
Y
Zhang
Zhiwei
Z
Wen
Haichao
H
Dai
Hongda
H
Wang
Zhuang
Z
Li
D001427:Bacterial Toxins / Q000032:analysis*; D015374:Biosensing Techniques / Q000379:methods; D000458:Cyanobacteria / Q000302:isolation & purification; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D052998:Microcystins / Q000032:analysis*; D053758:Nanoparticles / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D012680:Sensitivity and Specificity; D014871:Water Microbiology
D001427:Bacterial Toxins; D052998:Microcystins; D010087:Oxides; D006046:Gold; D006108:Graphite