Hybrid Mesoporous Nanoparticles for pH-Actuated Controlled Release

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Chemistry

Background:

• Mesoporous silica nanoparticles (MSNs) are attractive for drug delivery due to their high surface area, tunable pores, and functionalizability.
• Developing stimuli-responsive delivery systems is crucial for targeted and controlled release of therapeutic agents.

Purpose of the Study:

• To develop novel hybrid mesoporous silica nanoparticles (MSNs) with a pH-responsive polymer shell for controlled cargo delivery.
• To investigate the pH-dependent behavior and cargo release characteristics of these hybrid nanoparticles.

Main Methods:

• Synthesis of hybrid MSNs by grafting a pH-responsive polymer shell (poly(2-(diisopropylamino)ethyl methacrylate)) onto a mesoporous silica core using RAFT polymerization.
• Characterization of nanoparticle size changes at different pH values.
• Evaluation of cargo release kinetics based on pH-induced polymer conformational changes and electrostatic interactions.

Main Results:

• The hybrid nanoparticles exhibited a significant size change, from ~100 nm at pH < 6.5 to ~60 nm at pH > 6.5.
• A very low cargo release rate was observed at acidic pH due to electrostatic interactions and extended polymer chains.
• A large cargo release rate was achieved at basic pH, attributed to the polymer shell's coil-to-globule transition and reduced electrostatic attraction.

Conclusions:

• The developed hybrid MSNs demonstrate excellent pH-responsive behavior for controlled cargo release.
• The system effectively modulates cargo release based on pH changes, offering a promising platform for targeted drug delivery applications.
• The combination of silica core properties and polymer shell responsiveness enables tunable release profiles.