pH-Sensitive polymeric micelle-based pH probe for detecting and imaging acidic biological environments

Area of Science:

• Biomedical Engineering
• Materials Science
• Nanotechnology

Background:

• Monomeric pH probes face limitations in acidic tumor environments.
• Polyethylene glycol (PEG)-b-poly(L-histidine) (PHis) and PEG-b-poly(L-lactic acid) (PLLA) are effective drug carriers.
• Developing advanced pH sensing systems is crucial for cancer research.

Purpose of the Study:

• To design and evaluate a mixed micelle pH probe for acidic tumor environments.
• To enhance pH detection and mapping using nuclear magnetic resonance (NMR).
• To assess the impact of doxorubicin loading on pH-sensing capabilities.

Main Methods:

• Fabrication of mixed micelles from PEG-b-PHis and PEG-b-PLLA.
• Utilizing pH-induced structural destabilization for sensing.
• Employing NMR and magnetic resonance spectroscopy for pH detection and mapping.
• Testing probes in various biological and nonbiological buffers.

Main Results:

• Mixed micelles exhibit pH-dependent structural transformation for sensing.
• Achieved pH detection and mapping with 0.2-0.3 pH unit resolution.
• Demonstrated successful pH sensing in phosphate buffer, cell culture medium, and rat whole blood.
• Doxorubicin loading did not impair the pH-sensing ability of the micelles.

Conclusions:

• PHis-based mixed micelle pH probes offer a promising approach for tumor microenvironment analysis.
• These probes can simultaneously detect and map pH variations in vivo.
• Potential application in combined cancer therapy and diagnostics.