Quantitative Detection of ALP Activity via Electrochemiluminescence Signal Switching on a Biomimetic Zirconia Interface

Quantitative detection of alkaline phosphatase (ALP) activity is crucial in clinical diagnosis and bioanalysis. Herein, we have developed a highly sensitive electrochemiluminescence (ECL) biosensor that employs a biomimetic zirconia interface as its core sensing platform. The interface was constructed by immobilizing o-phosphorylethanolamine (PEA) onto zirconium oxide nanofilms (ZrO2NFs), forming a surface rich in Zr-O-P bonds. This design mimics phosphate recognition and enzyme-triggered dephosphorylation processes, where ALP catalyzes the hydrolysis of these bonds, triggering a direct switch in the ECL signal from Ru(bpy)32+-loaded gold nanocage (Ru-AuNCs) emitters. This sensor achieves a wide linear range of 0.100–100 U/L and a low detection limit down to 0.0899 U/L. Its practical utility was validated through the accurate detection of ALP in fetal bovine serum samples, confirming high recovery and reliability. This strategy highlights the potential of biomimetic zirconia interfaces in developing robust biosensors for early disease diagnosis.