Carboxylated Cy5-Labeled Comb Polymers Passively Diffuse the Cell Membrane and Target Mitochondria

Area of Science:

• Polymer Chemistry
• Nanomaterials Science
• Cell Biology

Background:

• Understanding nanomaterial cellular uptake is key for designing targeted drug delivery systems.
• Material properties like charge and targeting groups influence cellular interactions.
• Poly(amino ester)-based comb polymers offer tunable properties for biomedical applications.

Purpose of the Study:

• To synthesize and characterize novel carboxylated comb polymers.
• To investigate the cellular uptake mechanisms and intracellular trafficking of these polymers.
• To evaluate their potential as mitochondria-targeted drug delivery and imaging platforms.

Main Methods:

• Synthesis of carboxylated N-acylated poly(amino ester)-based comb polymers using zwitterionic and RAFT polymerization.
• Characterization by 1H NMR spectroscopy and size exclusion chromatography.
• Cellular uptake and localization studies using flow cytometry and confocal laser scanning microscopy (CLSM) in NIH/3T3 and N27 cell lines.

Main Results:

• Synthesized comb polymers exhibited no cytotoxicity or hemolysis.
• Carboxylated polymers demonstrated passive cell membrane diffusion and targeted mitochondria.
• Modification of carboxylic acids or dye labels shifted uptake mechanism to endocytosis.

Conclusions:

• The interplay between carboxylic acids and dye labels drives passive mitochondrial targeting.
• Comb polymer modifications allow tuning of cellular uptake pathways.
• These polymers represent a versatile platform for mitochondria-targeted drug delivery and imaging.