A thiol-selective fluorogenic probe based on the cleavage of 4-methylumbelliferyl-2',4',6'-trinitropheyl ether

Area of Science:

• Analytical Chemistry
• Biochemistry
• Organic Synthesis

Background:

• Biothiols play crucial roles in various biological processes.
• Sensitive and selective detection methods for biothiols are essential for biomedical research and diagnostics.
• Existing detection methods may suffer from limitations in sensitivity, selectivity, or operational simplicity.

Purpose of the Study:

• To design and synthesize a new fluorescent probe for sensitive and selective detection of biothiols.
• To evaluate the probe's performance in terms of linear range, detection limits, and selectivity.
• To demonstrate the probe's applicability in analyzing real biological samples.

Main Methods:

• Synthesis of 1,4-methylumbelliferyl-2',4',6'-trinitropheyl ether (Probe 1) via a one-step reaction.
• Investigation of the probe's response to biothiols (cysteine, homocysteine, glutathione) under neutral aqueous conditions.
• Spectrofluorometric analysis to determine linear relationships and detection limits.
• Assessment of probe selectivity against biologically relevant analytes.
• Application of the probe for biothiol detection in human serum samples.

Main Results:

• Probe 1 was successfully synthesized as a nonfluorescent compound.
• Upon reaction with biothiols, Probe 1 released the fluorescent 4-methylumbelliferone (4-MU), causing a significant increase in fluorescence.
• Good linear relationships were observed for cysteine (0.1–4.0 µmol L⁻¹), homocysteine (0.1–3.0 µmol L⁻¹), and glutathione (0.2–3.0 µmol L⁻¹).
• Low detection limits were achieved: 24.3 nmol L⁻¹ for Cys, 35.6 nmol L⁻¹ for Hcy, and 26.8 nmol L⁻¹ for GSH.
• Probe 1 exhibited high selectivity for biothiols and was successfully applied to detect biothiols in human serum.

Conclusions:

• The developed fluorescent probe (Probe 1) is effective for sensitive and selective detection of key biothiols.
• The probe's ability to function under neutral aqueous conditions and its application in human serum highlight its potential for biological and clinical analysis.
• This new probe offers a valuable tool for biochemical research and diagnostic applications requiring biothiol quantification.