An anionic shell shields a cationic core allowing for uptake and release of polyelectrolytes within core-shell...

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Cationic carriers are essential for delivering anionic drugs but often exhibit toxicity.
• Developing safe and effective drug delivery systems requires overcoming carrier toxicity limitations.

Purpose of the Study:

• Investigate core-shell microgels with cationic cores and anionic shells as potential drug delivery vehicles.
• Determine if an anionic shell can shield a cationic core while facilitating anionic guest uptake and release.
• Assess the influence of anionic guest polyelectrolyte size on loading and release dynamics.

Main Methods:

• Synthesis of N-isopropylacrylamide (NIPAM)-based core-shell microgels.
• Loading microgels with polystyrene sulfonate (PSS) of varying molecular weights.
• Utilizing small-angle neutron scattering (SANS) to analyze PSS spatial distribution.
• Employing UV-vis spectroscopy, electrophoretic mobility, and potentiometric titrations for uptake/release studies.
• Performing Brownian molecular dynamics simulations for theoretical validation.

Main Results:

• Anionic shells effectively shield cationic cores, mitigating potential toxicity.
• Core-shell microgels demonstrate efficient uptake of anionic guest polyelectrolytes.
• Anionic guest molecules can be released from the microgel system.
• The size of anionic guest molecules influences their location within the core-shell structure.
• Shell presence enhances the stability of microgel-polyelectrolyte complexes compared to cationic microgels alone.

Conclusions:

• NIPAM-based core-shell microgels offer a promising strategy for safe and effective drug delivery.
• The core-shell architecture balances carrier functionality with reduced toxicity.
• These microgels provide a tunable platform for controlling the loading and release of anionic therapeutic agents.