Cross-linked self-assembled micelle based nanosensor for intracellular pH measurements

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Accurate intracellular pH monitoring is crucial for understanding cellular processes.
• Existing pH sensors often face limitations in range, stability, or biocompatibility.
• Development of advanced nanosensors is needed for real-time cellular pH analysis.

Purpose of the Study:

• To synthesize and characterize a novel micelle-based nanosensor for ratiometric pH measurements in living cells.
• To evaluate the nanosensor's performance, including its pH sensing range and uniformity.
• To demonstrate the nanosensor's utility in monitoring intracellular pH distributions using fluorescent microscopy.

Main Methods:

• Synthesis of an amphiphilic triblock copolymer: poly(ethylene glycol)-b-poly(2-aminoethyl methacrylate)-b-poly(styrene) (PEG-b-PAEMA-b-PS).
• Formation of micelles via self-assembly and subsequent chemical cross-linking of the PAEMA shell.
• Functionalization of the cross-linked micelle with pH-sensitive and reference fluorophores.
• Characterization of the nanosensor's size, uniformity, and pH-responsive fluorescence properties.
• In vitro testing using fluorescent microscopy to monitor pH in HeLa cells.

Main Results:

• A uniform, cross-linked micelle-based nanosensor with a diameter of 29 nm was successfully synthesized.
• The nanosensor exhibited ratiometric pH sensing capabilities with a broad measurement range, influenced by its chemical design.
• Cell experiments demonstrated the nanosensor's ability to effectively monitor pH distributions within HeLa cells.

Conclusions:

• The developed micelle-based nanosensor is a promising tool for ratiometric pH sensing in biological applications.
• The sensor's design allows for broad pH measurement ranges and effective intracellular pH monitoring.
• This nanosensor offers a valuable advancement for fluorescent microscopy-based cellular analysis.