economics Practical Magic

A new paper strip and a smartphone camera can detect dangerous fungicides on fruit without needing a laboratory.

April 25, 2026

Original Paper

Lattice-Strained and Electronic Structure-Modulated Pt-Ni Bimetallic Nanozymes for Smartphone-Assisted Paper-Based Colorimetric Sensing of Prochloraz in Fruits

Yunyun Hu, Qian Luo, Yan Liu, Shuqi Zhang, Yinghao Feng, Bei Fan, Fengzhong Wang, Jinhui Zhou

SSRN · 6641860

The Takeaway

Testing produce for chemicals like prochloraz typically requires expensive machinery and days of waiting. This new system uses a bimetallic nanozyme that changes color when it comes into contact with the fungicide. A worker can simply take a photo of the test strip with a smartphone to get an instant reading of the chemical levels. The technology uses strained lattice structures to make the chemical reaction happen quickly and accurately on a piece of paper. This allows for real time safety monitoring on farms and in grocery stores to protect consumers from pesticides. It turns a smartphone into a professional chemical analysis tool.

From the abstract

Effective monitoring of the broad-spectrum postharvest fungicide prochloraz is critical for global food safety. While emerging nanozyme-based sensors offer rapid alternatives to bulky instrumentation, current platforms are frequently hindered by insufficient catalytic activity, poor substrate selectivity, and severe matrix interference, restricting their practical on-site application. To overcome these bottlenecks, we developed lattice-strained Pt-Ni bimetallic nanozymes featuring tunable electr