Core-shell silk hydrogels with spatially tuned conformations as drug-delivery system

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Drug Delivery Systems

Background:

• Hydrogels with controlled physicochemical properties are crucial for tissue engineering and drug delivery.
• Silk fibroin (SF) is a promising natural polymer for biomaterial development.

Purpose of the Study:

• To develop core-shell silk fibroin hydrogels with spatially controlled conformation and tunable properties.
• To investigate the structural, mechanical, and degradation characteristics of these core-shell SF hydrogels.
• To evaluate their potential in controlled drug release and as a cartilage substitute.

Main Methods:

• Fabrication of core-shell SF hydrogels via methanol treatment of preformed hydrogels.
• Characterization using scanning electron microscopy (SEM) for morphology.
• Fourier transform infrared spectroscopy (FTIR) for conformational analysis.
• Enzymatic degradation studies and mechanical testing (compressive modulus).
• In vitro drug release studies using albumin.

Main Results:

• Methanol treatment time controlled shell thickness (200-850 μm) and core-shell morphology (compact shell, porous core).
• Shell layer exhibited dominant β-sheet conformation, while the core retained random coil conformation.
• Shell layers showed superior enzymatic stability compared to the core.
• Compressive modulus ranged from 25 kPa to 1.1 MPa, tunable with methanol treatment time.
• Core-shell SF hydrogels demonstrated slower and more controlled albumin release compared to non-treated hydrogels.

Conclusions:

• Core-shell SF hydrogels offer tunable physicochemical properties through controlled methanol treatment.
• These hydrogels possess enhanced stability and mechanical properties suitable for tissue engineering applications.
• The developed hydrogels show significant potential as advanced drug delivery systems and cartilage substitutes.