Stimuli-responsive microgels with cationic moieties: characterization and interaction with E. coli cells.

Area of Science:

• Polymer Chemistry
• Materials Science
• Biotechnology

Background:

• Stimuli-responsive microgels with ionizable groups are crucial for drug delivery and cell encapsulation.
• Understanding their volume phase transitions and monomer distribution is key for rational design.

Purpose of the Study:

• To synthesize and characterize poly(N-vinylcaprolactam-co-1-vinyl-3-methylimidazolium) (poly(VCL-VIM+)) microgels.
• To investigate the behavior of neutral and charged functional groups within the microgel network.
• To evaluate the antibacterial efficacy of these positively charged microgels.

Main Methods:

• Synthesis of poly(VCL-VIM+) microgels.
• 1H high-resolution NMR spectroscopy.
• Transverse (T2) magnetization relaxometry.
• Electrophoretic mobility measurements.

Main Results:

• Characterization of comonomer transition temperatures, transition width, and transition entropy.
• Correlation of these properties with charged group concentration and electrophoretic mobility.
• Detection of a core-corona architecture with charged VIM+ groups concentrated in the corona.
• Demonstration of antibacterial activity against Gram-negative E. coli.

Conclusions:

• Poly(VCL-VIM+) microgels exhibit distinct behaviors for neutral and charged segments during volume phase transitions.
• The charged VIM+ groups are primarily located in the microgel corona.
• These biocompatible, positively charged microgels are effective antibacterial agents against E. coli.