An Analyte-Derived Turn-On Fluorescent Nanozyme Sensor Enabled by a Programmable Light-Driven Cascade for...

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Conventional fluorescence sensing methods for o-nitroaniline (o-NA) suffer from unstable fluorophores and unreliable "turn-off" signals.
• Existing techniques are prone to interference from similar compounds, limiting their accuracy in complex samples.

Purpose of the Study:

• To develop a probe-free, analyte-derived "turn-on" fluorescence sensing platform for o-nitroaniline.
• To establish a novel "self-luminescence" mechanism for enhanced detection accuracy and reduced false positives.
• To enable sensitive and selective monitoring of o-NA in real water matrices.

Main Methods:

• Utilized commercial nano-titanium dioxide (nano-TiO2) with programmable charge migration.
• Implemented a light-triggered reduction-oxidation cascade involving oxalic acid and Cu2+.
• Leveraged the conversion of o-NA to 2,3-diaminophenazine for fluorescence generation.

Main Results:

• Achieved a "turn-on" fluorescence signal directly derived from the target analyte.
• Demonstrated a new "self-luminescence" mechanism minimizing batch effects and interferences.
• Reported a linear detection range of 2.0–40 μM and a detection limit of 0.23 μM for o-NA.
• Validated the platform's effectiveness in real water samples.

Conclusions:

• The developed platform offers a robust and sensitive method for o-nitroaniline detection.
• The probe-free, analyte-derived "turn-on" approach overcomes limitations of conventional sensing.
• This technology supports compliance-oriented environmental monitoring with improved accuracy and reliability.