Silk protein plastics for sustained and controlled drug release

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Materials Engineering

Background:

• Thermomechanical processing allows solid-state molding of silk into tunable biomaterials.
• Silk-based materials offer potential for controlled drug release applications.

Purpose of the Study:

• To develop enzyme-embedded, drug-loaded silk reservoirs using thermoplastic molding.
• To evaluate the in vitro drug release, degradation, and therapeutic efficacy of these silk reservoirs.
• To demonstrate the stabilization of therapeutics within silk matrices under thermal stress.

Main Methods:

• Silk thermoplastic molding at varying temperatures (95°C, 125°C, 145°C).
• Encapsulation of proteolytic enzymes and therapeutics (doxorubicin, temozolomide, L-asparaginase).
• In vitro drug release and degradation studies over 70 days.
• Cytotoxicity assays against U87 glioblastoma cells.

Main Results:

• Processing temperature influenced silk crystallinity, affecting drug release rates and degradation.
• Embedded enzymes enabled tunable, sustained drug release.
• Encapsulated drugs retained bioactivity and outperformed unprotected drugs.
• Silk matrices stabilized both small-molecule and protein-based therapeutics under thermal stress.

Conclusions:

• Silk reservoirs provide a modular platform for long-acting drug delivery with tunable properties.
• The developed system offers structural tunability, enzymatic responsiveness, and thermal stability for labile compounds.
• This approach shows promise for localized oncology treatments and other sustained drug delivery applications.