Peng_2025_Analyst__

Afterglow electrochemiluminescence (ECL), persistent luminescence observed after the cessation of electrical excitation, has attracted great attention but remains unexplored in sensing applications. Here, we present a solid-state afterglow ECL biosensor leveraging enzyme-responsive polymer nanoarchitectonics for lipase quantification. The sensor is constructed by covalently grafting an amphiphilic block copolymer (PCL-PEG) onto nitrogen-deficient carbon nitride nanosheets (CN(x)NS) deposited on electrodes. Hydrophobic PCL segments self-assemble into a compact barrier under aqueous conditions, blocking S(2)O(8)(2-) diffusion and suppressing CN(x)NS's afterglow ECL. Lipase-triggered hydrolysis of PCL dynamically increases the film's permeability, enabling the recovery of afterglow ECL proportional to enzyme activity. The sensor achieves a detection limit (3sigma) of 1 microU mL(-1) with a broad linear range of 1 microU mL(-1) to 10 mU mL(-1), and shows high specificity against interferents (e.g. alpha-amylase, trypsin). Real-sample validation in toners demonstrates its practical applicability. This work establishes a paradigm for afterglow ECL-based biosensing.