Smartphone integrated portable oxidase-like hydrogel kit for UO₂²⁺ colorimetric analysis

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Uranyl ion (UO2^2+) pollution in marine environments presents significant risks to human health and ecosystems.
• Traditional detection methods often rely on large, complex instrumentation, limiting on-site analysis.

Purpose of the Study:

• To develop a portable, field-deployable kit for the on-site quantitative detection of uranyl ions (UO2^2+).
• To utilize nanozyme technology integrated with a smartphone for uranium detection, overcoming limitations of conventional methods.

Main Methods:

• Fabrication of spindle-shaped FeOOH/MnO2 nanozymes within an agarose hydrogel matrix.
• Utilizing the nanozymes' intrinsic oxidase-like activity to catalyze TMB oxidation, with UO2^2+ inducing a color change.
• Quantification via microplate reader or smartphone analysis of RGB values from the hydrogel wells.

Main Results:

• The developed hydrogel kit successfully detected UO2^2+ with a detection limit of 5.53 ppb.
• This detection limit is well below the WHO safety standard of 30 ppb for drinking water.
• The system demonstrated a distinct color transition upon UO2^2+ complexation, enabling visual or instrumental quantification.

Conclusions:

• The study presents the first portable oxidase-like hydrogel kit for UO2^2+ detection.
• The integrated platform offers a reliable, high-throughput, and field-deployable strategy for monitoring uranium contamination.
• This approach may serve as a model for developing detection strategies for other marine pollutants.