Methods for the fabrication of polyelectrolyte capsules for different biomedical applications

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Polyelectrolyte capsules (PECs) are versatile hollow polymer particles constructed via layer-by-layer (LbL) assembly.
• Their tunable properties and cargo encapsulation capabilities make them highly promising for biomedical applications.
• Standardized fabrication and characterization are crucial for optimizing PECs for specific biomedical tasks.

Purpose of the Study:

• To summarize common protocols for synthesizing and characterizing polyelectrolyte capsules.
• To outline fabrication methods for both biodegradable and non-biodegradable PECs.
• To highlight strategies for cargo loading and essential characterization techniques.

Main Methods:

• Layer-by-layer (LbL) assembly using alternating polyelectrolyte deposition around sacrificial templates (e.g., calcium carbonate).
• Detailed preparation including template synthesis, shell deposition, and core dissolution.
• Characterization using dynamic light scattering (DLS), microscopy (optical, fluorescence, TEM), and spectroscopy (UV-Vis, fluorescence).

Main Results:

• Fabrication of PECs ranging from 800 nm to 5 μm, including biodegradable and non-biodegradable variants.
• Emphasis on calcium carbonate as a biocompatible sacrificial template with high loading capacity.
• Established protocols for cargo loading (co-precipitation, post-loading) and comprehensive characterization of PECs.

Conclusions:

• Review addresses current advantages and limitations in PEC fabrication, including scalability and uniformity.
• Proposes future directions for advanced biomedical applications using microfluidics, automation, and novel template designs.
• Standardized synthesis and characterization are key to unlocking the full potential of PECs in medicine.