Alternating Current-Driven Silver Needle-Based Electrochemiluminescence Biosensor for Rapid and Low-Damage Diagnosis...

Rapid and efficient electrochemiluminescence (ECL) biosensors are crucial for low-injury in vitro testing in emergencies. This work introduces a silver needle electrode (Ag NE) as a replacement for a glassy carbon electrode to build an ECL platform. The ECL emitter, 2,6-dimethyl-1,7-sulfonyl-8-(3-carboxyphenyl)4,4'-difluorobor diazodiazepine (BETS) is covalently linked on Ag NE (BETS-Ag NE), coupled with K₂S₂O₈ as a coreactant for enhanced ECL efficiency. Alternating current voltammetry-driven ECL (ACV-ECL) applied to the BETS-Ag NE system shortens response time to 0.5 s, and the mechanism is examined. Afterward, 2,4-dinitroaniline (DTE), linked via sulfonamide bond, quenches the ECL signal but allows 66.3% recovery within 1.0 min when selenocysteine (Sec) exists even at ultralow-volume samples without dilution. The biosensor shows a wide linear range (10.0-160.0 μM) with a low detection limit of 5.1 pM. It also achieves 97.5% accuracy for auxiliary diagnosis of cerebral hemorrhage (ICH) using Sec as a biomarker with low-volume blood samples, enabling early prediction of edema severity and timely intervention. This work advances the construction of in vitro diagnostic ECL setups, providing a reliable approach for ICH edema diagnosis and microenvironment research.