A fluorescence aptasensor for high sensitivity detection of Golgi protein 73 based on N, S-GQDs and MoS2@RGO via fluorescence resonance energy transfer mechanism.

Quantitative detection of Golgi protein 73 (GP73), a promising biomarker for hepatocellular carcinoma (HCC), is crucial for early diagnosis. In this study, we developed a fluorescence aptasensor for sensitive and specific detection of GP73 based on fluorescence resonance energy transfer (FRET) between GP73 aptamer-functionalized nitrogen/sulfur co-doped graphene quantum dots (N, S-GQDs-GP73Apt) as the fluorescence donor and molybdenum disulfide@reduced graphene oxide (MoS2@RGO) as the fluorescence acceptor. In the absence of GP73, the fluorescence of N, S-GQDs-GP73Apt was effectively quenched by MoS2@RGO. Upon introduction of GP73, specific binding between GP73 and its aptamer triggered dissociation of the donor-acceptor complex, disrupting FRET and restoring fluorescence. Under optimized conditions, the normalized fluorescence intensity showed a good linear relationship with GP73 concentration ranging from 0.0001 to 100.0 μg/mL, with a low detection limit of 0.019 ng/mL. The aptasensor's performance was further validated using human serum samples with relative error ranging of 0.76%-3.85% and no statistically significant difference via t-test compared with ELISA results, demonstrating its potential as a reliable and cost-effective platform for early HCC diagnosis.