Fabrication of poly (aspartic) acid functionalized graphene quantum dots based FRET sensor for selective and sensitive detection of MAGE-A11 antigen

Abstract

In the present work, we investigated a label-free fluorescence resonance energy transfer (FRET) based poly (aspartic) acid (PAsP) functionalized graphene quantum dot (PAsP-GQDs) immunosensor for the selective and sensitive sensing of MAGE-A11 antigen.Synthesis of GQDs was accomplished with hydrothermal carbonization of Onion hull (ONI-GQDs). Synthesized PAsP-GQDs were characterized for fluorescence performance, functional compositions and morphological analysis. To form a typical FRET system, functionalized GQDs conjugated with anti-MAGE-A11 (antibody) using EDC/NHS chemistry served as an energy donor, while graphene nanosheets served as energy acceptors (quenchers). The fabricated PAsP-GQDs@M−A11−Ab immunosensor demonstrated high selectivity to MAGE-A11 with a broader detection range about of 0.05 ng mL−1 – 5 μg mL−1 (R2 = 0.9906) and a detection limit of about of 5.6 pg mL−1, with a rapid response time of 12 min. The performance of the developed immunosensor was established using real sample analysis, which showed an average recovery of 96.8 % with % RSD 0.71 indicating the high precision and reproducibility of the method. Furthermore, to implicate the post-functionalization modifications, cellular bioimaging potential and cytotoxicity studies were conducted as a comparative assessment. The present immunosensing strategies can be utilized as an analytical tool for detecting MAGE-A11 in various cancers.