Ultrasensitive label-free sandwich immunoassay of cardiac biomarker myoglobin using meso-SiO2@ploydapamine@PtPd nanocrystals and PtNi nanodendrites for effective signal amplification

Acute myocardial infarction (AMI) is one of main causes in human death, whose early diagnostics and prevention are challenging yet imperative for their efficient treatment. In this work, a new sandwich-typed electrochemical immunosensor was constructed for ultrasensitive detection of cardiac biomarker myoglobin (Myo) based on mesoporous SiO2@polydopamine@PtPd nanocrystals (m-SiO2@PDA@PtPd NCs) and PtNi nanodendrites (NDs). In such analysis, m-SiO2@PDA@PtPd NCs effectively accelerated interfacial electron transport and increased loading capacity of the biomolecules. The prepared Ab2-PtNi NDs can further decrease the access of redox marker to the glassy carbon electrode (GCE), ultimately contributing to the sensitivity. This established biosensor had a linear dynamic range from 0.001 to 1000 ng mL−1 in the optimal surroundings, with a low detection limit of 0.21 pg mL−1 (S/N = 3), combined with reliable and applicable results for Myo detection in human serum samples. This research shows a potent prospect for clinical prevention and monitoring during the AMI treatment process.