Eddy Shan

This study evaluated the structural properties and biological in vitro performance of 3D-printed polycaprolactone (PCL) scaffolds, coated with bioactive glass (BG) and functionalized with epsilon-poly-L-lysine (EPL) when co-cultured with rat bone marrow mesenchymal stem cells. The physicochemical characterization included scanning electron microscopy, energy dispersive spectroscopy, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and degradation kinetics. The biological characterization assessed antibacterial activity using a disk diffusion assay, cell viability of rat bone marrow mesenchymal stem cells with confocal laser scanning microscopy, cell proliferation and cytotoxicity with tetrazolium assay and relative gene and protein expression through reverse transcriptase quantitative polymerase chain reaction and western blot. The physicochemical characterization showed a successful and homogeneous distribution of the ceramic component and confirmed EPL-loading. The PCL-BG-EPL scaffolds demonstrated antibacterial activity against Staphylocccus aureus for up to 7 days. Cell proliferation was significantly higher for PCL-BG and PCL-BG-EPL scaffolds, but cytotoxicity also increased in both groups when comparing day 3 and day 7. The osteogenic potential was enhanced for BG-coated scaffolds, with an upregulation of Alpl, Opn , and Col1a1 genes when compared to controls. However, no significant differences were detected for protein synthesis among the three groups. Composite scaffolds exhibited favorable technical properties and superior biological performance over pure PCL scaffolds.

This study characterized the biological response of MG-63 cells to synthetic, hydroxyapatite scaffolds (HAsint) fabricated via fused filament fabrication. Scaffolds were compared to 2D plate-adherent cultures using six assays: cell morphology and distribution with scanning electron microscopy and confocal laser scanning microscopy; cell proliferation and cytotoxicity via WST-1 tetrazolium assay; relative osteogenic gene expression through reverse-transcription–quantitative polymerase chain reaction, and protein synthesis via multiplex immunoassay. Data were analyzed using one-way ANOVA. Results confirmed high cell viability and uniform distribution on HAsint scaffolds. Proliferation increased significantly over 7 days, though direct cytotoxicity also increased, likely due to the static conditions of the experiment and, subsequently, the high ion reprecipitation from scaffold degradation. Importantly, HAsint scaffolds significantly enhanced osteogenic marker expression of phosphatase alkaline (ALPL), osteopontin (OPN), and osteocalcin (OCN) genes, and elevated concentrations of interleukins (IL)-6, IL-8 and matrix metalloproteinase 1 compared to plate-adherent controls. It can be concluded that 3D-printed HAsint scaffolds support robust osteogenic differentiation and proliferation despite inducing a transient cytotoxic response in vitro. The marked upregulation of key osteogenic genes and proteins confirms the scaffolds’ bioactivity and highlights their potential for bone tissue engineering applications.

This study evaluated the biological performance in vitro of two 3D-printed hydroxyapatite (HA) and polylactic acid (PLA) composite scaffolds with two different infill densities (50% [HA-PLA50] and 70% [HA-PLA70]). Comparative analysis using MG-63 cell cultures evaluated the following: (1) integrity after exposure to various sterilization methods; (2) cell viability; (3) morphological characteristics; (4) cell proliferation; (5) cytotoxicity; (6) gene expression; and (7) protein synthesis. Ultraviolet radiation was the preferred sterilization method. Both scaffolds maintained adequate cell viability and proliferation over 7 days without significant differences in cytotoxicity. Notably, HA-PLA50 scaffolds demonstrated superior osteogenic potential, showing a significantly higher expression of collagen type I (COL1A1) and an increased synthesis of interleukins 6 and 8 (IL-6, IL-8) compared to HA-PLA70 scaffolds. While both scaffold types supported robust cell growth, the HA-PLA50 formulation exhibited enhanced bioactivity, suggesting a potential advantage for bone tissue engineering applications. These findings provide important insights for optimizing 3D-printed bone graft substitutes.