Donor manipulation for constructing a pH sensing thermally activated delayed fluorescent probe to detect alkaliphiles

Area of Science:

• Biotechnology and Biochemistry
• Fluorescence Spectroscopy
• Microbiology

Background:

• Maintaining pH homeostasis is critical for alkaliphilic microorganisms, which are extensively utilized in various biotechnological processes.
• Accurate and quantitative monitoring of alkaline pH within these organisms presents a significant technical challenge.
• Existing methods may lack the sensitivity or applicability for real-time intracellular pH measurements in alkaliphiles.

Purpose of the Study:

• To synthesize and characterize a novel fluorescent probe for quantitative alkaline pH monitoring.
• To evaluate the probe's performance in measuring intracellular pH within living alkaliphilic organisms.
• To demonstrate the probe's utility in assessing factors affecting pH homeostasis, such as sodium ion concentration.

Main Methods:

• Synthesis of a novel thermally activated delayed fluorescent (TADF) pH probe, designated NI-D-OH.
• Characterization of the probe's fluorescence intensity response across a neutral to alkaline pH range (7.0-8.6).
• Application of the probe for intracellular pH monitoring in living organisms and evaluation of Na+ effects.

Main Results:

• The synthesized NI-D-OH probe demonstrated a strong linear correlation between fluorescence intensity and pH in the 7.0-8.6 range.
• The probe exhibited long-lived thermally activated delayed fluorescence (TADF) emission, suitable for time-resolved imaging.
• NI-D-OH successfully monitored intracellular pH in living organisms and revealed the impact of Na+ on pH homeostasis.

Conclusions:

• NI-D-OH is the first TADF pH probe developed for effective alkaline pH monitoring in alkaliphiles.
• The probe offers a promising tool for quantitative, real-time intracellular pH measurements and fluorescence imaging.
• This advancement has significant potential for optimizing biotechnological applications reliant on alkaliphilic microorganisms.