Aligned PLGA/HA nanofibrous nanocomposite scaffolds for bone tissue engineering

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Nanotechnology

Background:

• Bone tissue engineering requires scaffolds that mimic native bone structure and mechanical properties.
• Poly(d,l-lactide-co-glycolide) (PLGA) is a biocompatible polymer, but its mechanical properties may need enhancement for bone regeneration.
• Nano-hydroxyapatite (nano-HA) is a key component of bone, offering potential for improving scaffold osteoconductivity and mechanical strength.

Purpose of the Study:

• To synthesize and characterize aligned nanofibrous scaffolds composed of PLGA and varying concentrations of nano-HA for bone tissue engineering applications.
• To investigate the effect of nano-HA incorporation on the morphology, thermal properties, mechanical behavior, and degradation of PLGA-based scaffolds.
• To determine the optimal concentration of nano-HA for enhancing the performance of these scaffolds.

Main Methods:

• Aligned nanofibrous scaffolds were fabricated using electrospinning with different weight percentages (1%, 5%, 10%, 20%) of nano-HA incorporated into a PLGA matrix.
• Scanning electron microscopy (SEM) was employed for morphological analysis, assessing fiber diameter and HA distribution.
• Thermal properties were evaluated using differential scanning calorimetry (DSC) to determine glass transition temperatures.
• Dynamic mechanical analysis (DMA) was performed to assess the storage modulus and understand the mechanical reinforcement or defect effects of nano-HA.
• In vitro degradation studies were conducted in phosphate-buffered saline (PBS) to evaluate mass loss and water uptake.

Main Results:

• SEM revealed an increase in average fiber diameter with increasing nano-HA content, from 300nm (neat PLGA) to 700nm (20% nano-HA).
• Higher nano-HA concentrations (≥10%) led to agglomeration and fiber breakage, particularly at 20%.
• Thermal analysis indicated that electrospinning resulted in an amorphous PLGA structure with a decreased glass transition temperature, which increased with nano-HA concentration.
• Dynamic mechanical testing showed that nano-HA acted as a reinforcement at 1% and 5% (storage modulus increased from 441MPa to 724MPa), but as defects at higher concentrations (371MPa at 20%).
• Degradation studies demonstrated that nano-HA influenced PBS uptake and mass loss, with mechanical properties showing a complex trend over 6 weeks.

Conclusions:

• Aligned PLGA/nano-HA nanofibrous scaffolds can be successfully fabricated via electrospinning for bone tissue engineering.
• Nano-HA incorporation significantly impacts scaffold morphology, thermal stability, and mechanical properties.
• Lower concentrations of nano-HA (e.g., 5%) enhance mechanical reinforcement, while higher concentrations compromise scaffold integrity.
• These findings highlight the critical role of optimizing nano-HA content for developing effective bone tissue engineering scaffolds.