In this study, poly(ε-caprolactone)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PCL/PHBV) blended porous scaffolds were fabricated by fused deposition modeling (FDM). PCL/PHBV filaments, initially prepared at different weight ratios, that is, 100/0, 75/25, 50/50, and 25/75, were fabricated by the lay-down pattern of 0/90/45/135° to obtain scaffolds with dimension of 6.0 × 6.0 × 2.5 mm and average filament diameters and channel sizes in the ranges of 370-390 µm and 190-210 µm, respectively. To enhance the surface hydrophilicity of the materials, the scaffolds were subsequently subjected to a low pressure oxygen plasma treatment. The untreated and plasma-treated scaffolds were comparatively characterized, in terms of surface properties, mechanical strength, and biological properties. From SEM, AFM, water contact angle, and XPS results, the surface roughness, wettability, and hydrophilicity of the blended scaffolds were found to be enhanced after plasma treatment, while the compressive strength of the scaffolds was scarcely changed. It was, however, found to increase with an increasing content of PHBV incorporated. The porcine chondrocytes exhibited higher proliferative capacity and chondrogenic potential when being cultured on the scaffolds with greater PHBV contents, especially when they were plasma-treated. The PCL/PHBV scaffolds were proven to possess good physical, mechanical, and biological properties that could be appropriately used in articular cartilage regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1141-1150, 2017.

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Enhancement of porcine chondrocyte growth, distribution and functions within polycaprolactone (PCL) scaffolds was attempted using alkaline hydrolysis and oxygen plasma treatment. The hydrolysis of PCL was performed either before or after scaffold fabrication in the preparations of pre-hydrolyzed PCL (pre-HPCL) or post-HPCL scaffolds, respectively. The PCL, pre-HPCL, and post-HPCL scaffolds were subsequently plasma-treated to yield plasma-treated PCL, plasma-treated pre-HPCL, and plasma-treated post-HPCL scaffolds, respectively. All scaffolds were comparatively characterized, in terms of surface morphology, hydrophilicity, and atomic composition using scanning electron microscopy, contact angle measurement and X-ray photoelectron spectroscopy, respectively. The interactions of chondrocytes with individual scaffolds were assessed, in terms of cartilage-gene expression and cartilaginous matrix production using reverse transcription polymerase chain reaction analysis and glycosaminoglycans (GAGs) assay, respectively. The cell infiltration and cartilaginous matrix distribution were investigated by histological and immunofluorescence analysis. The results revealed that the plasma treatment exhibited a more prominent effect on the enhancement of surface roughness and hydrophilicity of the scaffolds than the alkaline hydrolysis. The scaffolds subjected to both surface treatments stimulated the cells to secret more GAGs and type II collagen. The sequence of hydrolysis of PCL also evidently played a crucial role in the hydrophilicity of the materials and the cartilage-gene expression and cartilaginous matrix production of the cultured chondrocytes. The hydrolysis of PCL prior to the fabrication, followed by the oxygen plasma treatment of the resulting fabricated scaffold, yielded plasma-treated pre-HPCL scaffold with homogeneous hydrophilic characteristics all over the material. Consequently, the cells could proliferate well, infiltrate most deeply and ultimately produce the highest amounts of the cartilage-specific substances throughout this scaffold.

Novel three‐dimensional (3D) printing antibacterial thermoplastic polyurethane/green tea/tannic acid (TPU/GT/TA) composite filaments were successfully developed. The antimicrobial property of the filaments was evaluated against three Gram‐positive bacterial strains, that is, Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis, using an agar diffusion assay. It was noted that the enhanced inhibitory potency of the filaments was derived from the synergistic antibacterial activity of GT and TA, also confirmed by the antibacterial potency of the crude extract of GT/TA mixture which was used as a synergism study model. Not only the weight ratio of GT and TA incorporated in the filaments, but also the uniform mixing of the polymer compounds played a crucial role in the antibacterial efficiency of the resulting filaments. Both GT and TA were uniformly distributed in the matrices of filaments composed of total contents of GT and TA ≤ 30 wt%, proven by scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDX), and micro‐computer tomography (μCT) analysis. Furthermore, a number of voids existed in the filament matrix were found to increase with a rising content of fillers. Among the composite filaments prepared, TPU/GT25/TA:70/10/20 filament demonstrated the best tensile property, whereas TPU/GT25/TA:70/15/15 filament possessed the greatest inhibitory potency. The antibacterial stability of the developed composite filaments after 3D printing and storage was eventually assessed. The novel composite filaments had a promising potential use as an effectively antibacterial FDM feedstock for such applications as 3D printed antimicrobial insoles.