Here, we propose a new combinational method supplemented with melt-plotting and in situ plasma treatment to improve the coating ability of chitosan solution. Using the proposed method, the hydrophobic surface of poly(3-caprolactone) (PCL) was altered to a hydrophilic surface to facilitate homogeneous coating of the micro-structured PCL scaffold with chitosan of various molecular weights.The fabricated chitosan-coated PCL scaffolds were assessed in terms of not only physical properties, including tensile strength and water uptake ability, but also biological capabilities by culturing osteoblast-like cells (MG63) in the presence of coatings of chitosan of various molecular weights (1-5, 5-10, and >10 kDa). The chitosan-based scaffolds showed complete water absorption ability and significantly increased mechanical properties (13-36% increase in Young's modulus) compared to the untreated PCL scaffold. A number of assays (fluorescence analysis, alkaline phosphatase (ALP) activity, and calcium deposition) indicated that the scaffold coated with high-molecular-weight chitosan induced highly active cellular responses that would be of interest for bone-tissue regeneration.

Three-dimensional (3D) biomedical scaffolds that are physically and mechanically similar to regenerated tissues and provide bioactive sites for cultured cell adhesion, growth, and even differentiation have been used widely in various tissue regenerative materials. In this work, we propose new composite scaffolds consisting of poly(3-caprolactone) (PCL), alginate, and phenamil methanesulfonate (PM), manufactured by a combined process involving 3D plotting together with a low-temperature working plate and a versatile coating process. The composite scaffolds consist of microsized struts with a core (PCL)-shell (alginate/PM) structure. The PCL in the micro-sized struts has the function of providing mechanical support to the scaffold, and the shell region (alginate/phenamil) is used as a biologically active material.PM is known to stimulate osteoblastic differentiation and mineralization. However, phenamil cannot be used easily as a biomedical scaffold material because of its low molecular weight and low processability.We first introduced the bioactive component, PM, in a solid-freeform fabricated multi-layered pore structure. To assess the effects of PM, the biocompatibility of the composite scaffolds for bone tissue regeneration was characterized in vitro using preosteoblasts (MC3T3-E1 cells). Cells were distributed more extensively and proliferated to a greater degree on the PCL/alginate-PM scaffold in a limited PM concentration range versus the PCL/alginate scaffold. Specifically, cell viability and ALP activity were high in a composite scaffold containing PM at 3.5 mg, but not higher PM levels (PM: 5.6 mg per scaffold), compared with PCL/alginate scaffolds. These results suggest that the multi-layered PCL/alginate-PM scaffold may be a promising bioactive material for enhancing bone tissue growth, but over a limited range of PM levels.

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Three-dimensional (3D) scaffolds composed of various biomaterials, including metals, ceramics, and synthetic polymers, have been widely used to regenerate bone defects. However, these materials possess clear downsides, which prevent bone regeneration. Therefore, composite scaffolds have been developed to compensate these disadvantages and achieve synergetic effects. In this study, a naturally occurring biomineral, FeS2, was incorporated in PCL scaffolds to enhance the mechanical properties, which would in turn influence the biological characteristics. The composite scaffolds consisting of different weight fractions of FeS2 were 3D printed and compared to pure PCL scaffold. The surface roughness (5.77-fold) and the compressive strength (3.38-fold) of the PCL scaffold was remarkably enhanced in a dose-dependent manner. The in vivo results showed that the group with PCL/FeS2 scaffold implanted had increased neovascularization and bone formation (2.9-fold). These results demonstrated that the FeS2 incorporated PCL scaffold might be an effective bioimplant for bone tissue regeneration.