Source: CHEMICAL ENGINEERING JOURNAL

Published: NOV  2025

DOI: 10.1016/j.cej.2025.168737

IF: 13.2

Abstract: Enhancing catalytic activity of peroxidase-like nanozymes is essential for developing ultrasensitive lateral flow immunoassay (LFIA). The peroxidase-like catalytic process involves spin-dependent electron transfer during radical formation, and boosting single electron transfer (SET) efficiency is therefore critical to enhance catalytic performance. Here, we fabricated a strained-Co3O4 exhibiting significant atomic compressive strain (epsilon xx =-3.34 %, epsilon yy =-6.52 %). The atomic-level displacement direction and distance information determined by atomic displacement analysis (ADA) offer detailed information for density functional theory computational modeling. We discovered that the strain engineering elevated crystal field splitting energy, which promotes the transition of Co3O4 from low-spin states (t2g6eg0) to high-spin states (t2g4 eg2), resulting in efficient SET performance. Spin-state modulation dramatically enhances the peroxidase-like catalytic efficiency, resulting in 28.0-fold and 11.8-fold lower Michaelis constants (Km) for TMB and H2O2, respectively, than those of the pristine-Co3O4. In addition, the strained-Co3O4 was successfully employed in the development of LFIA for Xanthomonas oryzae pv. oryzae (Xoo) monitoring, and the LFIA achieved a detection sensitivity of 5 x 102 CFU mL-1 that was 20-fold higher than Au nanoparticles-based LFIA and was 2-3 orders of magnitude higher than commercial LFIAs. Our findings established a correlation between strain-spin orbit-peroxidase-like activity, offering a promising strategy for the rational design of nanozymes.