An Ultrasensitive Photoluminescent Immunosensing of Lipovitellin by Using N-doped Graphene Quantum Dots

Abstract

The increasing levels of environmental estrogens (EEs) have caused harmful effects on wildlife and human beings. Constructing a sensitive detection technique for EEs is meaningful. For intrinsic high specificity and sensitivity, immunosensing technique is a good choose for estrogeneous chemicals test in complex environment. As the main cleavage composition of vitellogenin (Vtg), a biomarker of EEs, lipovitellin (Lv) was proved to have same immunogenicity as Vtg, while better thermal stability than Vtg, thus Lv is more suitable than Vtg to be used as a standard matter to establish standard test curve. Upon the fluorescence resonance energy transfer (FRET) between N-doped graphene quantum dots (N-GQDs) coupled with anti-lipovitellin monoclonal antibody (anti-Lv-mAb) and reduced graphene oxide (rGO), a free-labelled photoluminescent immunosensing of Lv was developed and validated to quantify Lv of Paralichthys olivaceus. The assay obtained a large linear measuring range of 1 pg/mL- 2 µg/mL, high sensitivity of 9910.67 CPS/(ng/mL), low limit of detection (LOD) of 9.4 pg/mL and relative standard deviation of 1.19%. For 1 ng/mL Lv dispersed in drink water and sea water, the error of the recovery ratio is 1.65% and 10. 27% respectively. Our results demonstrated that the N-GQDs prepared by ultrasonic-assisted hydrothermal method could be effectively used to construct a nano photoluminescent immunosensor, which possesses the advantages of simplicity, rapidity, high specificity and anti-interference.