Highly sensitive sandwich-type immunosensor with enhanced electrocatalytic durian-shaped MoS2/AuPtPd nanoparticles for human growth differentiation factor-15 detection

Growth differentiation factor-15 (GDF-15) expression is a potential biomarker for the diagnosis, risk stratification, and prognosis of various cardiovascular diseases. A sandwich-type electrochemical immunosensor was constructed using amine-modified graphene-supported gold nanorods (NG/AuNPs) as a substrate platform and the durian-shaped MoS2/AuPtPd nanodendrite (NDs) as a label for secondary antibodies (Ab2) for the quantification of GDF-15. NG/AuNPs were used to increase the surface area of electrodes and immobilize primary antibodies (Ab1). The MoS2/AuPtPd NDs have a unique morphology with a high crystal surface index and good stability, ability to load secondary Ab (Ab2), and provide a larger active site for the catalysis of H2O2. In a clinical sample experiment, tissue sections were subjected to immunohistochemical analyses and western blotting. To demonstrate the feasibility of the immunosensor in realistic applications, we compared the performance of the immunosensor and a GDF-15 enzyme-linked immunosorbent assay (ELISA) kit by analyzing clinical human blood samples. As demonstrated by its remarkable performance throughout the study, the devised immunosensor may be a reliable and practical "liquid biopsy" tool for the serological detection of GDF-15. It has the potential to facilitate the early diagnosis and subsequent treatment of patients with cardiovascular disease.