Dual mode detection of amifostine based on gold nanoparticles and sulfanilic acid functionalized graphene quantum dots

Abstract

In this work, we developed a versatile dual-readout (colorimetric and fluorometric) amifostine (WR2721) sensor based on the inner filter effect (IFE) of gold nanoparticles (AuNPs) on sulfanilic acid functionalized graphene quantum dots (SGQDs). The fluorescence of SGQDs can be adequately suppressed by AuNPs via the IFE. Besides, alkaline phosphatase (ALP) can catalyze the hydrolysis of amifostine to generate WR1065, which combined with AuNPs by S–Au conjunction and induced the aggregation of the AuNPs with a color change from red to blue. Thus, the IFE of the AuNPs on the SGQDs was weakened and the switched off fluorescence of the SGQDs was switched on accordingly. Therefore, amifostine can be detected through the color changes of solutions and the fluorescence recovery of SGQDs. This IFE-based sensing platform showed a good linear relationship from 1 to 175 nmol L⁻¹, with a detection limit of 0.4 nmol L⁻¹. Moreover, the proposed method was successfully used for the detection of amifostine in serum samples.