Electrochemiluminescence sensor for point-of-care detection of pyrrolizidine alkaloids

Pyrrolizidine alkaloids (PAs) and PA N-oxides are hepatotoxic natural products, produced by over 6000 plant species worldwide. However, an unmet need remains for confirmative measurement of PAs in routine clinical tests. Here, we develop a visual, easy-to-use, and economic mesoporous silica-electrochemiluminescence (MPS-ECL) sensor for point-of-care (POC) testing of PAs, utilizing MPS's amplification effect on positive ions. The relationship between PAs' different structures and corresponding Ru(bpy)₃²⁺ ECL activity shows that reaction mechanism, stability of intermediate, molecular geometry and alternative anodic reactivity significantly affect the ECL activity. The ECL intensity varies among different PAs: monocrotaline _˃ senecionine N-oxide _˃ retrorsine _˃ senkirkine. The POC sensors possess excellent linearity (0.9993 > R² > 0.9944), low detection limits (0.02 μM-0.07 μM), and good recoveries (90.12%-105.93%), indicating good accuracy and practicability. The portable and low-cost sensor is user-friendly, which holds promise to be applied to POC testing of PAs in drugs, food products, and clinical samples, which is promising for initial assessments of PA-induced health risk.