Three-Dimensional Printed Porous PLA Scaffolds with Dual Functionality: Cell Proliferation Enhancement and Antibacterial Properties

Scaffold architecture plays a significant role in regulating cellular and microbial interactions in tissue engineering applications. This study evaluates the performance of 3D-printed poly (lactic acid) (PLA) scaffolds with varying porosity levels (20%, 40%, 60%, 80%, and 100%) in mechanical strength, supporting human skin fibroblast (HSF) viability and reducing bacterial colonization of Gram-positive bacteria (<i>Staphylococcus epidermidis, Staphylococcus aureus</i>), and Gram-negative bacteria (<i>Pseudomonas aeruginosa, Escherichia coli</i>). The maximum tensile strength (28 MPa) was achieved in the 100% dense scaffold. Increasing porosity drastically decreased tensile strength, where 80% PLA scaffold possessed 16 MPa strength. At greater levels of porosity (60% and 40%), tensile strengths greatly decrease (8 MPa and 4 MPa), while ductility increases, especially at high porosity levels. HSF viability, assessed using the AlamarBlue assay, showed a time-dependent increase in cell proliferation, with the highest viability observed on scaffolds with 60% and 80% porosity. SEM imaging confirmed strong cell adhesion on the 80% porous scaffold, indicating that intermediate-to-high porosity enhances cell attachment and metabolic activity. In contrast, bacterial adhesion showed species-specific responses to scaffold porosity. <i>S. epidermidis</i> and <i>E. coli</i> exhibited a progressive increase in adherence with porosity, peaking at 100%. <i>P. aeruginosa</i> showed maximum adhesion at 80%, suggesting a porosity "sweet spot" that favors its colonization. <i>S. aureus</i> adhered most strongly to scaffolds with intermediate porosities (40-60%) and significantly less at 100% porosity. The current study provides insights into scaffold design considerations, emphasizing the need for optimized scaffold architecture that balances regenerative potential with infection control in tissue engineering applications.