A fluorometric aptasensor for patulin based on the use of magnetized graphene oxide and DNase I-assisted target recycling amplification.

Abstract

A fluorometric patulin (PAT)assayis presented that is based on theuse of magnetic reducedgrapheneoxide (rGO) and DNase I. The fluorescence of the PAT aptamer labelled with6-carboxyfluorescein (FAM) is quenched by magnetized reduced graphene oxide (rGO-Fe3O4) due to fluorescence resonance energy transfer (FRET). However, in the presence of PAT, the labelled aptamer is stripped offfrom rGO-Fe3O4. The rGO-Fe3O4 is then magnetically separated so that the fluorescence of freelabelled PAT aptameris restored. DNase I cannot hydrolyze the aptamer on rGO-Fe3O4, but it can cleave the free aptamer-PAT complex. This will release FAM and PAT which can undergo a number of additional cycles to trigger the cleavage of abundant aptamer. Recycling of DNase I-assisted target therefore leads to a strong amplification of fluorescence and consequently to an assay with low limit of detection. The detection limit for PAT is as low as 0.28μgL-1 which is about 13 times lower than that without using DNase I. The method offers a new approach towards rapid, sensitive and selective detection based on anaptamer. Conceivably, it has a wide scope in that it may be applied to numerous other analytes if appropriate aptamers are available. Abstract Schematic of a fluorometric assay based on theuse of magnetic grapheneoxide and DNase I. It was applied to the determination of patulin. DNase I was introduced for recycling amplification. The detection limit is about 13 times lower than that without usingDNase I. Figure a contains poor quality of text in image. Otherwise, please provide replacement figure file.Thank you. I will provide the figure file.