Overcoming acidic limitations: an Os–Ru bimetallic polymeric nanozyme at neutral pH for dual-mode detection of acetylcholinesterase activity and its inhibitors

= 0.716 µM and 0.92 µM for the clinical drug rivastigmine tartrate), outperforming most reported neutral-pH AChE assays. Beyond analytical performance, this study establishes a generalizable design principle for decoupling nanozyme catalytic efficiency from pH constraints, establishing a versatile framework for physiologically adaptive, multimodal biosensing with broad implications in neurodegenerative diagnostics and drug discovery.