Novel pyrazoline-based fluorescent probe for detecting thiols and its application in cells

Area of Science:

• Analytical Chemistry
• Biochemistry
• Organic Chemistry

Background:

• Amino acids play crucial roles in biological systems.
• Selective detection of specific amino acids like thiol is essential for biological research and diagnostics.
• Existing detection methods may lack sensitivity, selectivity, or applicability in biological environments.

Purpose of the Study:

• To design and synthesize a novel fluorescent probe for the sensitive and selective detection of thiol.
• To evaluate the probe's performance in detecting thiol among other amino acids.
• To assess the probe's utility in biological samples, including living cells.

Main Methods:

• Synthesis of N-(4-(1,5-diphenyl-4,5-dihydro-1H-pyrazol-3-yl)phenyl)-acrylamide (probe L).
• Spectroscopic characterization of the probe (IR, NMR, HRMS).
• Fluorescence spectroscopy to determine probe response to thiol in buffered solutions (DMSO:HEPES, pH 7.4).
• Cell imaging studies using HeLa cells to assess cell permeability and in-cell thiol detection.

Main Results:

• The synthesized probe L exhibited blue fluorescence emission at 474 nm upon reaction with thiol.
• The probe demonstrated a highly sensitive and linear "off-on" fluorescence response to thiol.
• Fluorescence emission was found to be independent of pH within the physiological range.
• Living cell imaging confirmed probe L's cell permeability and selective detection of thiol in HeLa cells.

Conclusions:

• Probe L is a sensitive and selective fluorescent tool for thiol detection.
• The probe's pH independence and cell permeability make it suitable for biological applications.
• This development offers a valuable method for studying thiol-related biological processes.