Bioactive Cellulose Nanocrystal-Poly(ε-Caprolactone) Nanocomposites for Bone Tissue Engineering Applications

Area of Science:

• Biomaterials Science
• Nanotechnology
• Regenerative Medicine

Background:

• 3D-printed poly(ε-caprolactone) (PCL) scaffolds show promise for bone defect treatment.
• PCL's low stiffness and lack of bioactivity limit its use in load-bearing applications.
• Surface modification of additives is crucial for enhancing scaffold performance.

Purpose of the Study:

• To investigate surface-oxidized cellulose nanocrystals (SO-CNCs) as multi-functional additives for PCL bone scaffolds.
• To evaluate the impact of SO-CNCs on PCL's mechanical properties and biomineralization capacity.
• To assess the cytotoxicity of SO-CNCs and their influence on PCL's material characteristics.

Main Methods:

• Prepared PCL nanocomposites with varying SO-CNC concentrations (1-10 wt%) via melt compounding.
• Assessed in vitro biomineralization in simulated body fluid to evaluate calcium phosphate formation.
• Characterized mechanical properties (Young's modulus, tensile strength), crystallinity, thermal transitions, and water contact angle.
• Performed cytotoxicity assays using MC3T3 preosteoblasts.

Main Results:

• SO-CNCs effectively induced calcium phosphate mineral formation in simulated body fluid.
• 10 wt% SO-CNCs significantly increased PCL's Young's modulus (over 2-fold) and ultimate tensile strength (over 60%).
• SO-CNCs did not exhibit cytotoxicity to preosteoblasts and slightly decreased PCL's crystallinity and water contact angle while increasing crystallization temperature.

Conclusions:

• SO-CNCs act as effective multi-functional additives for PCL bone scaffolds.
• The enhanced mechanical properties and biomineralization capability of SO-CNC/PCL composites are promising for bone regeneration.
• SO-CNCs offer a viable strategy to improve PCL-based materials for load-bearing bone scaffold applications.