Researchers at Chengdu University and Hefei University of Technology have developed a novel optical detection system for hydrogen peroxide (H₂O₂) using a persistent luminescence nanoparticle (PLNP) probe coated with a manganese dioxide (MnO₂) shell, as published in Food Quality and Safety on August 28, 2025. The study addresses the need for simple, sensitive, and autofluorescence-free detection of H₂O₂, which is widely used as a disinfectant and oxidizing agent in food processing, pharmaceuticals, and consumer products but poses health risks when residues exceed safe levels.
Conventional methods for H₂O₂ detection, such as electrochemical sensing, fluorescence probing, and enzyme-based assays, often require specialized equipment, continuous excitation, or complex sample preparation. Background autofluorescence in food or biological samples can further reduce signal clarity and accuracy. The new approach leverages persistent luminescence, which emits light for an extended period after excitation ceases, eliminating autofluorescence interference and enabling clean, high-contrast signals without continuous excitation.
The nanoprobe, designated PLNPs@MnO₂, consists of near-infrared ZnGa₂O₄:Cr persistent luminescence nanoparticles uniformly coated with a MnO₂ shell. In its initial state, the MnO₂ layer quenches the luminescence through interfacial electron transfer, resulting in a 'turned-off' signal. When H₂O₂ is present in a mildly acidic environment, MnO₂ is rapidly reduced to Mn²⁺, interrupting the quenching pathway and immediately restoring persistent luminescence. The detection limit reaches 0.079 μmol/L, significantly more sensitive than many conventional sensors. The restored red luminescence can also be visually recognized under UV illumination, allowing detection on flat plates or paper substrates without instruments.
The probe demonstrates strong anti-interference performance in the presence of common ions, sugars, amino acids, and proteins, and exhibits excellent reproducibility and batch stability. Applications in bottled water, milk, and contact lens solutions yielded recovery rates ranging from 90.56% to 109.73%, confirming reliability in real samples. 'The key innovation of this work lies in overcoming autofluorescence interference, which has long limited optical sensing in real-world food and biological matrices,' said the study's corresponding author. 'By using persistent luminescence instead of conventional fluorescence, our method produces clean, high-contrast signals without requiring continuous excitation. This makes the technology highly suitable for rapid, portable detection, even outside laboratory environments.'
This autofluorescence-free detection strategy offers practical advantages for food safety monitoring, environmental inspection, and biomedical assays. Its capability for naked-eye detection is particularly valuable in remote or resource-limited settings. Future development may enable integration into smart packaging, wearable chemical sensors, and real-time contamination alert systems. The study was supported by the Natural Science Foundation of Sichuan Province and the Sichuan Innovation Team Project of National Modern Agricultural Industry Technology System. For more details, the full study is available at https://doi.org/10.1093/fqsafe/fyaf040.
