Surface Roughness and Biocompatibility of Polycaprolactone Bone Scaffolds: An Energy-Density-Guided Parameter...

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Additive Manufacturing

Background:

• Three-dimensional porous polycaprolactone (PCL) bone scaffolds fabricated via selective laser sintering (SLS) show promise for non-load-bearing bone defect repair.
• The influence of SLS parameters on PCL scaffold surface roughness and its subsequent effect on biocompatibility requires systematic investigation.
• Microgeometry and surface characteristics are critical factors affecting scaffold performance in bone regeneration.

Purpose of the Study:

• To investigate the impact of selective laser sintering (SLS) process parameters on the surface roughness of polycaprolactone (PCL) bone scaffolds.
• To establish the relationship between scaffold surface roughness and biocompatibility, specifically cell attachment and proliferation.
• To determine an optimal energy density range for SLS fabrication of PCL scaffolds balancing structural integrity and biological performance.

Main Methods:

• Utilized an energy density model (EDM) incorporating PCL powder thermodynamics to define a suitable sintering energy density range (Ed1-Ed3).
• Fabricated five PCL scaffolds by varying laser power and scanning speed within the defined energy density range.
• Evaluated dimensional accuracy, mechanical strength, surface properties (roughness), and in vitro bioactivity via MC3T3-E1 cell attachment and proliferation assays.

Main Results:

• High energy density (Ed3) led to reduced dimensional accuracy (pore size, porosity) and a dense, smooth surface, resulting in poor cytocompatibility.
• Low energy density (Ed1) yielded weak mechanical properties due to incomplete sintering but promoted cell adhesion and proliferation via a rough surface.
• Intermediate energy densities likely offer a balance between structural integrity and enhanced surface properties for improved bioactivity.

Conclusions:

• SLS energy density significantly influences PCL bone scaffold surface roughness and, consequently, biocompatibility.
• Scaffold surface roughness plays a critical role in facilitating cell adhesion and proliferation, impacting overall bioactivity.
• Energy-density-guided SLS parameter optimization for PCL bone scaffolds must consider surface roughness and biocompatibility alongside mechanical properties and structural accuracy.