Micro flow photochemical synthesis of Ca-sensitive fluorescent sensor particles

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Materials Science

Background:

• Fluorescence probes are common for detecting calcium ions (Ca²⁺) in cells.
• Quantitative determination of Ca²⁺ concentrations using fluorescence probes is less common.
• A novel approach using hydrogel particles is proposed for quantitative Ca²⁺ detection.

Purpose of the Study:

• To develop and validate hydrogel particles for the quantitative determination of calcium ion concentrations.
• To establish a method for fast optical determination of Ca²⁺ in small sample volumes.

Main Methods:

• Hydrogel particles were synthesized using microfluidic co-flow and photo-curing.
• Particles were loaded with Rhod-5N, a calcium ion-selective fluorescent probe.
• Dried particles were re-hydrated and exposed to varying Ca²⁺ concentrations for fluorescence measurement.

Main Results:

• Fluorescence intensity of the hydrogel particles increased with Ca²⁺ concentration up to 0.50 mM.
• The intensity-concentration relationship was accurately modeled by a 1:1 Ca²⁺:Rhod-5N complex equilibrium.
• The particles allowed for rapid Ca²⁺ determination in sample volumes as low as 10 μL.

Conclusions:

• Novel hydrogel particles offer a viable method for quantitative Ca²⁺ concentration determination.
• This approach enables fast, optical sensing of Ca²⁺ in low-volume biological samples.
• The developed particles have potential applications in various analytical and imaging techniques.