Biocompatible WSe@BSA Dots with Merged Catalyst and Coreactant for Efficient Electrochemiluminescence.

Electrochemiluminescence (ECL) is a powerful tool for clinical diagnosis due to its exceptional sensitivity. However, the standard tripropylamine (TPrA) coreactant for Ru(bpy)Cl, the most widely studied and used ECL system, is highly toxic. Despite extensive research on alternative coreactants, they often fall short in poor efficiency. From a reaction kinetics perspective, accelerating electrooxidation rate of Ru(bpy)Cl is an essential way to compensate the efficiency limitation of coreactants, but is rarely reported. Here, a hybrid electrocatalyst@coreactant dots for the ECL of Ru(bpy)Cl is reported. The as-prepared WSe@bovine serum albumin (WSe@BSA) dots is biocompatible, and demonstrate dual functions, i.e., the BSA shell works as a coreactant, meanwhile, the WSe core effectively catalyzes Ru(bpy)Cl oxidation. As a result, WSe@BSA dots exhibit an exceptionally high efficiency comparable to TPrA for the ECL of Ru(bpy)Cl. In addition, the procedure for synthesizing WSe@BSA dots is facile (room temperature, atmospheric conditions), rapid (5 min), and scalable (for millions of bioassays). A biosensor utilizing WSe@BSA dots shows promise for highly sensitive detecting glypican-3 in clinical liver cancer serum samples, especially for alpha-fetoprotein-negative patients. This work opens a new avenue for developing a highly efficient ECL system for biosensing and clinical diagnosis.