Addition of MgO nanoparticles and plasma surface treatment of three-dimensional printed polycaprolactone/hydroxyapatite scaffolds for improving bone regeneration.

Magnesium (Mg) plays an important role in the body in mediating cell-extracellular matrix interactions and controlling bone apatite structure and density. Hydroxyapatite (HAp) has been used for osteoconductive bone replacement because of its good compressive strength and biocompatibility. The object of this study is to investigate the effects of adding Magnesium oxide (MgO) nanoparticles to polycaprolactone (PCL)/HAp composites and treating PCL/HAp/MgO scaffolds with oxygen and nitrogen plasma. The 3D PCL/HAp/MgO scaffolds were fabricated using a 3D bioextruder. PCL was mixed with 1-15wt% of MgO and HAp. The scaffolds were treated with oxygen and nitrogen plasma under anisotropic etching conditions to improve the bioactivity. The plasma-treated surfaces were analyzed by X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. In addition, the proliferation and differentiation of pre-osteoblast (MC3T3-E1) cells were examined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and alkaline phosphatase activity. Cell mineralization within the produced scaffolds was analyzed by the quantification of alizarin stainings. The addition of MgO/HAp nanoparticles and plasma treatment enhanced the adhesion, proliferation, and differentiation of MC3T3-E1 cells in the PCL scaffolds. Hence, changes in physical surface morphology and surface chemical properties of the 3D scaffold by plasma treatment can affect the behavior of MC3T3-E1 cells.

660 nm Red LED Induces Secretory Leukocyte Protease Inhibitor (SLPI) in Lipopolysaccharide-Stimulated RAW264.7 Cell.

SLPI acts as a modulator of the innate immune responses of macrophages, neutrophils and odontoblasts, and LPS-inducible anti-inflammatory cytokine to suppress the production of pro-inflammatory products by macrophages. Many studies have revealed the effects of light emitting diodes (LEDs) on the tissue repair and inflammatory responses. Although the anti-inflammatory mechanisms of irradiation with LEDs in gingival fibroblasts are known, the effects of 660 nm red LEDs on the inflammation remain unclear. Moreover, there is no report regarding the molecular mechanism for the relationship between SLPI and biological effects of LEDs. The effects of 660 nm red LEDs on inflammation with SLPI were investigated by examining the effects of 660 nm LED on the SLPI expression of RAW264.7 cells after LPS stimulation. This paper reports that the 660 nm red LED induced SLPI expression or reduced the LPS response, and inhibited NF-κB activation directly, leading to the suppression of pro-inflammatory cytokines, such as TNF-α and IL-1ß, suggesting that it might be a useful wavelength LED for inflammation therapy.

Plasma Polymerization of 1,2-Diaminocyclohexane for Covalent Bonding of Bone Morphogenic Protein-2 on Titanium Surface.

Among the bone morphogenic protein (BMP) family members, BMP-2 is a potent osteoinductive factor that plays key roles during bone formation. In this study, plasma polymerization of 1,2-diaminocyclohexane (DACH) was performed to immobilize the BMP-2 on Ti surface. The plasma polymerization of DACH was carried out at a discharge power of 60 W and 100 W under a pressure of 10 mTorr for 90 sec. The BMP-2 was successfully immobilized on the DACH plasma treated Ti surface. The BMP-2 immobilized Ti surface showed the excellent cell differentiation. The results indicate that the DACH plasma polymerized Ti surface has a potential for immobilization of biomolecules in bone tissue engineering.

Preparation of O2 Plasma Treated Polycaprolactone/Nano TiO2 Composites and In Vitro Bioactivity.

Polycaprolactone (PCL)/TiO2 composite films (PTCFs) were prepared by a solvent casting method at various concentrations of TiO2 (1, 3, 5, and 10 wt%) and then treated using oxygen plasma. The hydrophilicity of the oxygen plasma treated PTCFs increased as the treatment time was increased, due to the oxygen induced production of polar species at the surface of the PTCFs. In vitro bioactivities of the composite films were examined by immersion in simulated body fluid for up to 7 days. It was found that the oxygen plasma treatment significantly influenced the in vitro bioactivity of the PTCFs.