Do-It-Yourself: An Ultralow-Cost Sensing Platform with Integrated High-Entropy Nanozyme for the Rapid Detection of Exhaled H ₂ S

Herein, a noninvasive platform for rapid, low-cost detection of exhaled H₂S was developed using nano-high-entropy Prussian blue frames (nanoPBFs) based on nanozyme poisoning. Synthesized via two-step coprecipitation and ammonia etching, nanoPBFs showed uniform element distribution, 4.1-fold higher catalytic activity than high-entropy Prussian blue nanocubes, and strong substrate affinity (<i>K</i>_m = 0.016 mM for H₂O₂). Molecular dynamics simulations confirmed enhanced H₂O₂ diffusion on nanoPBFs (mean square displacement = 34.56 Ų ps^-1). Integrated into a polyethylene microtube with homemade modules, the sensor achieved 0.05 ppm detection limit, high specificity against interferents, and good stability. It correlates well with gold standard method results (<i>R</i>²= 0.99), enabling 45 min on-site testing at $5.14 per 100 tests, promising for the noninvasive diagnosis of asthma and chronic obstructive pulmonary disease via exhaled H₂S.