Dual-state dual emission from precise chemically engineered bi-ligand MOF free from encapsulation and...

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Dual-state dual emitting metal-organic frameworks (DSDE-MOFs) are challenging to synthesize but offer stability and self-reference for on-site detection.
• Existing methods for detecting non-analyte variables often lack the required sensitivity or on-site applicability.

Purpose of the Study:

• To design and synthesize a novel intrinsic DSDE-MOF for sensitive and selective on-site detection of folic acid.
• To develop a ratiometric sensing platform for quantitative analysis of folic acid.
• To enable visual-based detection of folic acid using smartphone technology.

Main Methods:

• Synthesis of a chemically engineered bi-ligand Europium-based MOF (UoZ-1) with intrinsic dual-state dual emission.
• Characterization of UoZ-1 nanoparticles (10-12 nm) exhibiting blue (425 nm) and red (620 nm) fluorescence.
• Development of a ratiometric platform exploiting the selective quenching of red emission by folic acid.
• Implementation of fluorometric ratiometric detection and smartphone-assisted visual detection using RGB analysis.

Main Results:

• UoZ-1 demonstrated stable blue and red fluorescence in both liquid and solid states upon excitation at 250 nm.
• The ratiometric platform achieved a dynamic linear range of 10–200 µM for folic acid with a limit of detection (LOD) of 0.4 µM.
• Smartphone-assisted visual detection yielded an LOD as low as 2.3 µM.
• The UoZ-1 based sensor exhibited high stability, recyclability, sensitivity, and selectivity for folic acid detection.

Conclusions:

• The intrinsic DSDE-MOF, UoZ-1, provides a robust platform for on-site, visual detection of folic acid without encapsulation or functionalization.
• This approach offers a sensitive, selective, and user-friendly method for folic acid quantification with potential for diverse applications.
• The developed ratiometric sensing strategy highlights the utility of DSDE-MOFs in analytical chemistry and point-of-care diagnostics.