In this study, an optimal selective laser melting (SLM) process for manufacturing dense NiTi alloy with pseudoelasticity and shape-memory capability was proposed. The microstructure, phase-transformation temperature, shape memory capability, and pseudoelasticity were investigated by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and bending and tensile tests. NiTi powder with a particle size > 45 μm was selected for the subsequent SLM process, because it exhibited a Ni/Ti ratio of ~1 and a lower oxygen content than powders with smaller particle sizes. A thin-walled disk (0.48 mm thick) and cuboid samples (5 mm thick) were prepared for investigating the variation in the homogeneity of the microstructure. The thin-walled SLM-NiTi sample exhibited a marginally inhomogeneous microstructure between layers, and defects existed in the previously formed side. The cuboid SLM-NiTi sample was fabricated without undesirable secondary phases, and it exhibited a 100% shape-recovery rate under 2% bending strain and completely pseudoelastic under 3% strain. Also, the SLM-NiTi exhibited lower phase-transformation temperatures and a broader phase-transformation range than the original NiTi. The phase-transformation range can be reduced by annealing.

NSC 95397, a quinone-based small molecule compound, has been identified as an inhibitor for dual-specificity phosphatases, including mitogen-activated protein kinase phosphatase-1 (MKP-1). MKP-1 is known to inactivate mitogen-activated protein kinases by dephosphorylating both of their threonine and tyrosine residues. Moreover, owing to their participation in tumorigenesis and drug resistance in colon cancer cells, MKP-1 is an attractive therapeutic target for colon cancer treatment. We therefore investigated the inhibitory activity of NSC 95397 against three colon cancer cell lines including SW480, SW620, and DLD-1, and their underlying mechanisms. The results demonstrated that NSC 95397 reduced cell viability and anchorage-independent growth of all the three colon cancer cell lines through inhibited proliferation and induced apoptosis via regulating cell-cycle-related proteins, including p21, cyclin-dependent kinases, and caspases. Besides, by using mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor U0126, we provided mechanistic evidence that the antineoplastic effects of NSC 95397 were achieved via inhibiting MKP-1 activity followed by ERK1/2 phosphorylation. Conclusively, our results indicated that NSC 95397 might serve as an effective therapeutic intervention for colon cancer through regulating MKP-1 and ERK1/2 pathway.

Cancer is a leading cause of mortality and a major public health problem worldwide. For biological therapy against cancer, we previously developed a unique immunotherapeutic platform by combining mesenchymal stem cells with an antigen-specific protein vaccine. However, this system possesses a few limitations, such as improperly immortalized mesenchymal stem cells (MSCs) along with transfected oncogenic antigens in them. To overcome the limitations of this platform for future clinical application, we freshly prepared primary adipose-derived stem cells (ADSCs) and modified the E7’ antigen (E7’) as a non-oncogenic protein. Either subcutaneously co-inoculated with cancer cells or systemically administered after tumor growth, ADSC labeled with enhanced green fluorescent protein (eGFP) and combined with modified E7’ (ADSC-E7’-eGFP) cells showed significant antitumor activity when combined with the protein vaccine in both colon and lung cancer in mice. Specifically, this combined therapy inhibited tumor through inducing cell apoptosis. The significantly reduced endothelial cell markers, CD31 and vascular endothelial growth factor (VEGF), indicated strongly inhibited tumor angiogenesis. The activated immune system was demonstrated through the response of CD4+ T and natural killer (NK) cells, and a notable antitumor activity might be contributed by CD8+ T cells. Conclusively, these evidences imply that this promising immunotherapeutic platform might be a potential candidate for the future clinical application against cancer.

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.

The present study established a maximum standard for printing quality and developed a preliminary ideal index to print three-dimensional (3D) construct using the Gly-Arg-Gly-Asp (GRGD) peptide modified Pluronic-F127 hydrogel (hereafter defined as 3DG bioformer (3BE)) as bioink. In addition, the biocompatibility of 3BE for 3D printing applications was carefully investigated. For biocompatibility study and ideal printing parameter, we used the formulation of 3BE in three different concentrations (3BE-1: 25%, 3BE-2: 30%, and 3BE-3: 35%). The 3BE hydrogels were printed layer by layer as a cube-like construct with all diameters of the needle head under the same feed (100 mm/s). The printing parameters were determined using combinations of 3BE-1, 3BE-2, and 3BE-3 with three different standard needle sizes (Φ 0.13 mm, Φ 0.33 mm, and Φ 0.9 mm). The printed constructs were photographed and observed using optical microscopy. The cell viability and proliferation were evaluated using Live/Dead assay and immunofluorescence staining. Results showed that a stable of printed line and construct could be generated from the 3BE-3 combinations. Cytotoxicity assay indicated that the 3BE hydrogels possessed well biocompatibility. Bioprinting results also demonstrated that significant cell proliferation in the 3BE-3 combinations was found within three days of printing. Therefore, the study discovered the potential printing parameters of 3BE as bioink to print a stable construct that may also have high biocompatibility for cell encapsulation. This finding could serve as valuable information in creating a functional scaffold for tissue engineering applications.