A macrocyclic fluorescent probe for the detection of citrate

Area of Science:

• Analytical Chemistry
• Biochemistry
• Immunology

Background:

• Citrate plays a crucial role in cellular metabolism and immune responses.
• Accurate detection of citrate in biological systems is essential for understanding cellular function.
• Existing methods for citrate detection can be limited in sensitivity or specificity in complex biological matrices.

Purpose of the Study:

• To develop and characterize a novel macrocyclic fluorescent probe for selective citrate detection.
• To evaluate the probe's performance in aqueous solutions and its specificity against common dicarboxylates.
• To demonstrate the probe's utility in analyzing citrate levels within immune cell subsets.

Main Methods:

• Synthesis and characterization of a macrocyclic fluorescent receptor.
• Spectroscopic analysis (fluorescence spectroscopy) to determine binding interactions and response.
• Application of the probe for staining murine splenocytes and subsequent flow cytometry analysis.

Main Results:

• The macrocyclic probe exhibits a 'turn-on' fluorescence response upon selective binding to citrate via hydrogen-bonding.
• The probe demonstrates high specificity, with minimal interference from biologically relevant dicarboxylate species.
• Flow cytometry analysis revealed distinct basal citrate levels in different murine immune cell subsets.

Conclusions:

• The developed macrocyclic fluorescent probe is a sensitive and selective tool for citrate detection in aqueous media.
• This probe enables the quantitative analysis of intracellular citrate levels in complex biological samples.
• The findings provide a valuable method for investigating the role of citrate in immune cell function and heterogeneity.