A fluorescent chemosensor for sodium based on photoinduced electron transfer

Area of Science:

• Analytical Chemistry
• Biomedical Engineering
• Materials Science

Background:

• Accurate sodium measurement is crucial for clinical diagnostics and patient management.
• Existing methods for sodium analysis may have limitations in speed, sample requirements, or cost.
• Development of novel sensors is needed for rapid, point-of-care sodium determination.

Purpose of the Study:

• To describe a new optical sensor for practical sodium measurement in serum and whole blood.
• To detail the design and performance characteristics of the photoinduced electron transfer (PET) fluoroionophore-based sensor.
• To demonstrate the sensor's applicability in a commercial critical care analyzer.

Main Methods:

• Development of a novel PET fluoroionophore incorporating a sodium-binding ionophore and a suitable fluorophore.
• Immobilization of the fluoroionophore within a hydrophilic polymer layer.
• Integration of the sensor into a disposable cartridge for use with the Roche OPTI CCA analyzer.

Main Results:

• The sensor exhibits a slope of approximately 0.5%/mM in the clinically relevant sodium range (120-160 mM).
• The sensor demonstrated high precision (better than +/- 1 mM, 1 SD) when implemented in the analyzer.
• Excellent stability was observed, with <5% slope change after 9 months of wet storage at 30°C.

Conclusions:

• The developed optical sensor offers a practical and reliable method for sodium determination in biological samples.
• The sensor's design, based on intramolecular PET signal transduction, shows excellent stability and performance.
• The underlying design concept is adaptable for creating sensors for other essential cations like potassium, calcium, and magnesium.