Evaluating the Effects of Poly(ε-Caprolactone)-Nanohydroxyapatite Composition on 3D-Printed Scaffold Structural...

Current bone tissue engineering scaffolds struggle to balance biocompatibility, mechanical strength, and degradation rates. Most existing scaffolds perform well in one or two areas but fail to meet all requirements simultaneously. Prior research has shown that polymer-based scaffolds often lack sufficient mechanical strength, while ceramic additions can improve rigidity but may hinder degradation. The challenge remains in creating a scaffold that maintains mechanical integrity during tissue regeneration while degrading at a controlled pace. This gap motivated the need for a new approach that combines polymer and ceramic properties. Researchers have explored various polymer blends and ceramic loadings, but the effects of molecular weight variation and high ceramic content on fiber structure and performance remain unclear. No prior work had resolved how these variables interact to influence scaffold behavior. The field requires a systematic method to tailor scaffold properties for specific clinical applications. This study addresses those limitations by investigating the effects of polymer molecular weight and ceramic content on 3D-printed scaffold performance.

This study aimed to evaluate how varying polymer molecular weight blends and ceramic content affect the structural and mechanical properties of 3D-printed bone scaffolds. The researchers focused on poly(ε-caprolactone) (PCL) with different molecular weights and nanohydroxyapatite (nHA) concentrations. Their goal was to identify optimal composition ratios that balance mechanical strength and degradation rates. By adjusting PCL molecular weight from 25 kDa to 14 kDa and nHA content from 0 to 40 wt%, the team sought to create scaffolds with tunable properties. The motivation stemmed from the need for scaffolds that can support tissue growth while degrading at a controlled rate. Traditional approaches often sacrifice one property for another, so this study aimed to find a balanced solution. The researchers also wanted to quantify how ceramic distribution within printed fibers affects scaffold performance. Their work provides a framework for designing scaffolds with application-specific characteristics.

The study used 3D printing to fabricate scaffolds from nine different inks. Each ink combined PCL with varying molecular weights (25 kDa and 14 kDa) and nHA content (0, 30, or 40 wt%). The researchers prepared three PCL blend ratios: 100:0, 70:30, and 50:50. They then printed scaffolds and analyzed their thermal, mechanical, and structural properties. Micro-computed tomography was used to assess nHA distribution in individual fibers. Compressive testing measured moduli, yield stress, and peak stress. An accelerated degradation study tracked PCL mass loss over time. The team compared mechanical performance across all groups to determine how composition affected scaffold behavior. They also evaluated how nHA content influenced fiber homogeneity and degradation rates. By systematically varying molecular weight and ceramic content, the researchers identified how these factors interact to shape scaffold properties.

The 40 wt% nHA group showed the most homogeneous nHA distribution within fibers, as observed through micro-computed tomography. In contrast, the 30 wt% nHA group exhibited significant radial distribution differences. PCL blends with both molecular weights achieved the highest compressive moduli. The 0 and 30 wt% nHA groups had the highest yield and peak stresses before becoming brittle. The 40 wt% nHA group showed similar brittleness to the 30 wt% group. The accelerated degradation study revealed increased PCL mass loss when nHA was present. This suggests that nHA promotes faster PCL degradation. The highest mechanical performance was observed in scaffolds with blended PCL molecular weights. These findings indicate that combining different PCL weights and high nHA content can tailor scaffold properties. The study also showed that nHA content significantly affects fiber structure and degradation rates. The results highlight the potential for using these composition strategies to design scaffolds for specific clinical needs.

The study demonstrated that blending PCL molecular weights and incorporating high nHA content can effectively tailor scaffold properties. The researchers found that 40 wt% nHA provided the most uniform fiber structure, while 30 wt% nHA showed uneven distribution. Blended PCL achieved the highest compressive moduli, and the 0 and 30 wt% nHA groups had the highest stress values before failure. The presence of nHA accelerated PCL degradation, as shown by the accelerated study. These findings suggest that nHA content and polymer composition can be adjusted to meet specific mechanical and degradation requirements. The team also quantified how nHA distribution affects fiber performance, which is a novel contribution to the field. The study supports the use of these composition strategies to design scaffolds for bone tissue engineering. The authors propose that these methods offer a practical way to balance mechanical strength and degradation rates in 3D-printed scaffolds.