A facile and efficient strategy to encapsulate the model basic protein lysozyme into porous CaCO₃

Area of Science:

• Biomaterials Science
• Nanotechnology
• Drug Delivery

Background:

• Basic proteins are crucial for biological functions and therapies but are limited by instability and short half-lives.
• Protein encapsulation in carriers enhances stability and controls release, but achieving high loading under mild conditions remains challenging.
• Layer-by-layer (LBL) assembly with sacrificial templates is used for protein encapsulation, though porous CaCO3 struggles with basic proteins.

Purpose of the Study:

• To develop a highly efficient and simple method for encapsulating basic proteins, specifically lysozyme, into porous calcium carbonate (CaCO3) carriers.
• To overcome the poor loading ability of porous CaCO3 for basic proteins by incorporating a doping agent.
• To ensure the retention of the encapsulated protein's biological activity and control its release during subsequent processing.

Main Methods:

• Development of a method involving doping porous CaCO3 with heparin to enhance lysozyme encapsulation.
• Utilizing the layer-by-layer (LBL) technique with sacrificial CaCO3 templates for protein carrier fabrication.
• Investigating the encapsulation efficiency and protein activity retention post-encapsulation and during LBL wrapping.

Main Results:

• Achieved a 99.5% encapsulation efficiency and a capacity of 91.6 mg g-1 for lysozyme under mild conditions.
• Demonstrated near 100% retention of lysozyme activity after encapsulation.
• Showed that lysozyme loss during LBL wrapping is controllable by selecting appropriate polyelectrolyte pairs.

Conclusions:

• Heparin doping significantly enhances the efficiency and capacity of basic protein (lysozyme) encapsulation in porous CaCO3.
• The developed method preserves the biological activity of encapsulated proteins, crucial for therapeutic applications.
• This approach offers a versatile platform for encapsulating various functional proteins for applications in catalysis, disease treatment, and tissue engineering.