Rapid and ultrasensitive detection of ellagic acid by integrating boronate-affinity controllable-oriented imprinted magnetic nanoparticle and boronic acid-modified / polyethylene glycol-coated allochroic-graphene oxide

Abstract

Herein, we integrate boronate-affinity controllable-oriented ellagic acid-imprinted magnetic nanoparticles (BCEMN) and boronic acid-modified / polyethylene glycol-coated allochroic-graphene oxide (BPAO) for specific and ultrasensitive detection of ellagic acid (EA). The novel detection method depends on a dual boronate-affinity sandwich strategy. The symmetric EA is first specifically captured by the BCEMN based on the boronate-affinity-related molecularly imprinted recognition, and then labeled with BPAO due to the boronate-affinity recognition. The BPAO, which is functionalized with 2,6-difluoro-4-formyl-phenylboronic acid, loaded with a large amount of pH-sensitive thymol phthalide and coated with hydrophilic polyethylene glycol, can specifically recognize the cis-diol of EA at physiological condition (pH 7.4) and perform signal amplification and readout through pH-triggered allochroism. Furthermore, the signal readout of allochroism is linear with the logarithm of EA concentration over the range between 0.02 ng mL−1 to 104 ng mL−1 with a good correlation coefficient (R2 = 0.993), and the limit of detection (LOD) is 2.96 pg mL−1. Finally, the BCEMN linked BPAO (BCBP) strategy has also been successfully applied in the detection of EA concentration in spiked strawberry sample with recovery and relative standard deviation in the range of 84.9%–110.2% and 3.9%–6.1%, respectively.