Nanobody-enhanced split-luciferase technology for innovative detection of the liver cancer biomarker alpha-fetoprotein

Abstract

Liver cancer is one of the most common cancers and the third leading cause of cancer deaths worldwide. Diagnosis and screening for liver cancer rely on the alpha-fetoprotein (AFP) biomarker. This study aimed to pioneer a novel assay for AFP detection utilizing a tri-part split-luciferase system in conjunction with nanobodies targeting AFP. The strategy involved fusing anti-AFP nanobodies P5 and P15 to the split-nanoluciferase components β9 and β10, respectively. Upon binding to AFP and in the presence of the third nanoluciferase component Δ11S, the proximity-induced reassembly of split-nanoluciferase components triggers luciferase activation and luminescence emission. Following expression in a bacterial system, purification, and assay implementation, the developed assay exhibited high sensitivity in detecting AFP within a linear range of 1–20 ng/ml, with a Limit of Detection (LOD) of 0.5 ng/ml. The assay results were in line with those obtained from ELISA, indicating its efficiency. This study highlights the specificity of the homogenous assay developed with nanobodies for AFP, offering a reliable and user-friendly test for AFP detection. © 2024 Elsevier B.V.