▎ 摘　　要

In this study, aptamers targeting angiopoietin-like 4 (ANGPTL4) with high affinity and specificity were first obtained by SELEX technology. Subsequently, through the optimization strategy of mutation and truncation, a core sequence was generated, with the binding affinity increased by 4-5 times. The improvement after optimization is attributed to the reduction in steric hindrance of targeted binding and the conversion of the aptamer's folding structure, which results in sufficient exposure of the binding site. Finally, a graphene oxide-based aptasensor was developed using the fluorescence on/off switching mechanism, with the detection limit of ANGPTL4 determined as 0.12 nM. The aptasensor showed good reproducibility and stability in the analysis of ANGPTL4 in serum samples. The developed aptasensor may come to be a robust, convenient, and cost-effective approach for practical detection of ANGPTL4 in the future.