Protein-Containing Multilayer Capsules by Templating on Mesoporous CaCO3 Particles: POST- and PRE-Loading Approaches

Area of Science:

• Biomaterials Science
• Nanotechnology
• Drug Delivery

Background:

• Developing effective methods for encapsulating fragile biomacromolecules like proteins is crucial for therapeutic applications.
• Multilayer capsules offer a promising platform for controlled release and protection of sensitive cargo.
• Calcium carbonate (CaCO3) microparticles serve as versatile templates for microcapsule fabrication.

Purpose of the Study:

• To investigate the encapsulation efficiency of model proteins (catalase, insulin, aprotinin) into dextran sulphate/protamine multilayer capsules.
• To compare the efficacy of pre-loading versus post-loading strategies for protein encapsulation.
• To assess the impact of protein properties and encapsulation methods on final yield and bioactivity.

Main Methods:

• Utilizing calcium carbonate (CaCO3) microparticles as templates for multilayer capsule formation.
• Employing both pre-loading (adsorption or co-synthesis) and post-loading techniques for protein incorporation.
• Analyzing protein encapsulation efficiency using model proteins of varying sizes and electrostatic properties.

Main Results:

• Pre-loading proteins into CaCO3 templates resulted in significantly higher encapsulation efficiencies (e.g., 630 mg/g for catalase) compared to post-loading (70 mg/g).
• Protein encapsulation is influenced by molecular size and electrostatic interactions with both the CaCO3 template and the multilayer shell.
• Encapsulated protein bioactivity remained largely unaffected by the multilayer shell, though alkaline pH from CaCO3 hydrolysis could cause minor reductions.

Conclusions:

• Pre-loading is a superior strategy for achieving high-efficiency protein encapsulation in multilayer capsules templated on CaCO3.
• The developed method shows potential for the successful encapsulation of fragile biomacromolecules, preserving their bioactivity.
• This research provides valuable insights for optimizing multilayer capsule design for advanced biomacromolecule delivery systems.