Highly sensitive protein kinase activity assay based on electrochemiluminescence nanoprobes

► ECL nanoprobe based on cysteamine is used for the first time to enzyme activity. ► The sensor is simple and rapid based on Zr4+ linkage without chemical activation. ► Coupling ECL with magnetic beads results in simplicity and low background signal. ► Based on the ingenious design, we achieved high sensitivity of 0.005 U/mL.