Optical Supramolecular Sensing of Creatinine

Area of Science:

• Supramolecular chemistry
• Analytical chemistry
• Chemical sensing

Background:

• Calix[4]pyrrole phosphonate-cavitands serve as versatile receptors in supramolecular chemistry.
• Creatinine is a key biomarker for kidney function, necessitating accurate detection methods.

Purpose of the Study:

• To design and characterize supramolecular sensors for creatinine and its lipophilic derivative, hexylcreatinine.
• To explore the use of indicator displacement assays for sensitive analyte detection.

Main Methods:

• Utilized calix[4]pyrrole phosphonate-cavitands as receptors.
• Employed indicator displacement assays with fluorescent dyes or black-hole quenchers.
• Characterized binding properties using NMR spectroscopy, isothermal titration calorimetry, and optical spectroscopies.

Main Results:

• Developed supramolecular fluorescence turn-on sensors for creatinine detection.
• Achieved 1:1 binding constants for indicator dyes in the range of 10^7 M^-1.
• Demonstrated a limit of detection as low as 110 nM for hexylcreatinine, suitable for clinical applications.

Conclusions:

• Calix[4]pyrrole-based sensors offer a promising approach for sensitive creatinine detection.
• The indicator displacement assay mechanism enables efficient supramolecular sensing.
• The developed sensors are compatible with creatinine concentrations found in both healthy and diseased patients.