Silk Protein-Based Nanoporous Microsphere for Controllable Drug Delivery through Self-Assembly in Ionic Liquid System

Area of Science:

• Biomaterials Science
• Nanotechnology
• Drug Delivery Systems

Background:

• Ionic liquids (ILs) offer unique properties for biomedical applications.
• Silk protein (SP) and its composites are explored for drug delivery vehicles.
• Self-assembly methods are crucial for fabricating advanced biomaterials.

Purpose of the Study:

• To fabricate and characterize silk protein and silk protein/poly(d,l-lactic acid) nanoporous microspheres using an IL-induced self-assembly method.
• To investigate the effect of material composition on drug loading, release kinetics, and anticancer efficacy.
• To elucidate the interaction mechanisms and structural changes influencing drug delivery.

Main Methods:

• Fabrication of silk protein and silk protein/poly(d,l-lactic acid) microspheres via IL-induced self-assembly.
• Morphological and structural characterization using SEM, TEM, FTIR, XPS, DSC, XRD, and TGA.
• Drug loading and in vitro release studies.
• Assessment of anticancer efficacy and thermal stability.

Main Results:

• Silk protein microspheres exhibited larger nanopores and higher drug loading (88.7%) compared to composites.
• The composite showed faster initial drug release (53.5% in 4 h) than pure silk protein.
• Both formulations demonstrated sustained release after 24 h, anticancer efficacy, and improved thermal stability.
• IL-induced self-assembly involved electrostatic and hydrophobic interactions, leading to reversible protein structural transitions.

Conclusions:

• Silk protein-based nanoporous microspheres fabricated via IL self-assembly are promising drug delivery vehicles.
• Tuning the silk protein structure, e.g., by blending with poly(d,l-lactic acid), allows for control over drug release kinetics.
• These microspheres offer potential for incorporation into various biomaterials for enhanced therapeutic applications.