a – Center for Molecular Recognition and Biosensing, School of Life Sciences, Shanghai University,
Shanghai 200444, P.R. China
b – Shanghai Key Laboratory of Bio-Energy Crop, School of Life Sciences, Shanghai University, Shanghai 200444, P.R. China
c – School of Medicine, Shanghai University, Shanghai 200444, P.R. China
d – School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, P.R. China
e – Department of Chemistry, Chungnam National University, Daejeon 301-747, Republic of Korea
f – Institute of General Education, Pusan National University, Busan 609-735, Republic of Korea
Leukocyte cell-derived chemotaxin 2 (LECT2) has been proved to be a potential biomarker for the diagnosis of liver fibrosis. In this work, a sensitive surface plasmon resonance (SPR) assay for LECT2 analysis was developed. Tyrosine kinase with immune globulin-like and epidermal growth factor-like domains 1 (Tie1) is an orphan receptor of LECT2 with a C-terminal Fc tag, which is far away from the LECT2 binding sites. The Fc aptamer was intentionally used to capture the Tie1 through its Fc tag, connecting with Fe3O4-coated silver magnetic nanoparticles (Ag@MNPs) and ensuring the LECT2 binding site to be outward. Attributed to the orientation nature of the captured protein, Ag@MNPs were able to enhance the SPR signal. A sensitive LECT2 sensor was successfully fabricated with a detection limit of 10.93 pg/mL. The results showed that the immobilization method improved the binding efficiency of Tie1 protein. This strategy could be extended to attach antibodies or recombinant Fc label proteins to Fc aptamer-based nanoparticles.