In this study, an electrochemical anodizing method was applied as surface modification of the 316L biomedical stainless steel (BSS). The surface properties, microstructural characteristics, and biocompatibility responses of the anodized 316L BSS specimens were elucidated through scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractometry, transmission electron microscopy, and in vitro cell culture assay. Analytical results revealed that the oxide layer of dichromium trioxide (Cr2O3) was formed on the modified 316L BSS specimens after the different anodization modifications. Moreover, a dual porous (micro/nanoporous) topography can also be discovered on the surface of the modified 316L BSS specimens. The microstructure of the anodized oxide layer was composed of amorphous austenite phase and nano-Cr2O3. Furthermore, in vitro cell culture assay also demonstrated that the osteoblast-like cells (MG-63) on the anodized 316L BSS specimens were completely adhered and covered as compared with the unmodified 316L BSS specimen. As a result, the anodized 316L BSS with a dual porous (micro/nanoporous) oxide layer has great potential to induce cell adhesion and promote bone formation.

The ability of Pluronic F127 (PF127) conjugated with tetrapeptide Gly-Arg-Gly-Asp (GRGD) as a sequence of Arg-Gly-Asp (RGD) peptide to form the investigated potential hydrogel (hereafter referred to as 3DG bioformer (3BE)) to produce spheroid, biocompatibility, and cell invasion ability, was assessed in this study. The fibroblast cell line (NIH 3T3), osteoblast cell line (MG-63), and human breast cancer cell line (MCF-7) were cultured in the 3BE hydrogel and commercial product (Matrigel) for comparison. The morphology of spheroid formation was evaluated via optical microscopy. The cell viability was observed through cell counting Kit-8 assay, and cell invasion was investigated via Boyden chamber assay. Analytical results indicated that 3BE exhibited lower spheroid formation than Matrigel. However, the 3BE appeared biocompatible to NIH 3T3, MG-63, and MCF-7 cells. Moreover, cell invasion ability and cell survival rate after invasion through the 3BE was displayed to be comparable to Matrigel. Thus, these findings demonstrate that the 3BE hydrogel has a great potential as an alternative to a three-dimensional cell culture for drug screening applications.

The present study was to investigate the rheological property, printability, and cell viability of alginate–gelatin composed hydrogels as a potential cell-laden bioink for three-dimensional (3D) bioprinting applications. The 2 g of sodium alginate dissolved in 50 mL of phosphate buffered saline solution was mixed with different concentrations (1% (0.5 g), 2% (1 g), 3% (1.5 g), and 4% (2 g)) of gelatin, denoted as GBH-1, GBH-2, GBH-3, and GBH-4, respectively. The properties of the investigated hydrogels were characterized by contact angle goniometer, rheometer, and bioprinter. In addition, the hydrogel with a proper concentration was adopted as a cell-laden bioink to conduct cell viability testing (before and after bioprinting) using Live/Dead assay and immunofluorescence staining with a human corneal fibroblast cell line. The analytical results indicated that the GBH-2 hydrogel exhibited the lowest loss rate of contact angle (28%) and similar rheological performance as compared with other investigated hydrogels and the control group. Printability results also showed that the average wire diameter of the GBH-2 bioink (0.84 ± 0.02 mm (*** p < 0.001)) post-printing was similar to that of the control group (0.79 ± 0.05 mm). Moreover, a cell scaffold could be fabricated from the GBH-2 bioink and retained its shape integrity for 24 h post-printing. For bioprinting evaluation, it demonstrated that the GBH-2 bioink possessed well viability (>70%) of the human corneal fibroblast cell after seven days of printing under an ideal printing parameter combination (0.4 mm of inner diameter needle, 0.8 bar of printing pressure, and 25 °C of printing temperature). Therefore, the present study suggests that the GBH-2 hydrogel could be developed as a potential cell-laden bioink to print a cell scaffold with biocompatibility and structural integrity for soft tissues such as skin, cornea, nerve, and blood vessel regeneration applications.

In this study, we proposed a three-dimensional (3D) printed porous (termed as 3DPP) scaffold composed of bioceramic (beta-tricalcium phosphate (β-TCP)) and thermoreversible biopolymer (pluronic F-127 (PF127)) that may provide bone tissue ingrowth and loading support for bone defect treatment. The investigated scaffolds were printed in three different ranges of pore sizes for comparison (3DPP-1: 150–200 μm, 3DPP-2: 250–300 μm, and 3DPP-3: 300–350 μm). The material properties and biocompatibility of the 3DPP scaffolds were characterized using scanning electron microscopy, X-ray diffractometry, contact angle goniometry, compression testing, and cell viability assay. In addition, micro-computed tomography was applied to investigate bone regeneration behavior of the 3DPP scaffolds in the mini-pig model. Analytical results showed that the 3DPP scaffolds exhibited well-defined porosity, excellent microstructural interconnectivity, and acceptable wettability (θ < 90°). Among all groups, the 3DPP-1 possessed a significantly highest compressive force 273 ± 20.8 Kgf (* p < 0.05). In vitro experiment results also revealed good cell viability and cell attachment behavior in all 3DPP scaffolds. Furthermore, the 3DPP-3 scaffold showed a significantly higher percentage of bone formation volume than the 3DPP-1 scaffold at week 8 (* p < 0.05) and week 12 (* p < 0.05). Hence, the 3DPP scaffold composed of β-TCP and F-127 is a promising candidate to promote bone tissue ingrowth into the porous scaffold with decent biocompatibility. This scaffold particularly fabricated with a pore size of around 350 μm (i.e., 3DPP-3 scaffold) can provide proper loading support and promote bone regeneration in bone defects when applied in dental and orthopedic fields.

In the present study, the piezoelectric aluminum nitride (AlN)/tantalum (Ta) (PAT) thin film was investigated as a biocompatible film and osseointegrated with biomedical devices such as implants. The stress variation on the interaction of cells with the PAT surface was investigated using osteoblast-like cells (MG-63) and fibroblast cells (NIH3T3). A singular behavior was observed on the PAT film with a (002) texture, in which the MG-63 cells were more dispersed and displayed longer and more filopodia than the NIH3T3 cells. Moreover, the MG-63 cells showed ingrowth, adherence, and proliferation on the PAT film surface. The MG-63 cells had more obvious stress variation than the NIH3T3 cells in the differentiation and proliferation. The mechanobiological reaction to cell differentiation and proliferation not only caused osseointegration, but also reduced the surface activation energy, thus enhancing bone remodeling. The formation of a nanopolycrystalline PAT film is believed to enhance the mechanobiological effect, promoting osseointegration.