Effect of ethyl alcohol aging on the apatite formation of a low-modulus Ti-7.5Mo alloy treated with aqueous NaOH

Ho, Wen-Fu,Tsou, Hsi-Kai,Wu, Shih-Ching,Hsu, Shih-Kuang,Chuang, Shao-Hsuan,Hsu, Hsueh-Chuan Techno-Press 2014 Biomaterials and biomedical engineering Vol.1 No.1

The purpose of this experiment was to evaluate the apatite-formation abilities of low-modulus Ti-7.5Mo substrates treated with NaOH aqueous solutions and subsequent ethyl alcohol aging before soaking them in simulated body fluid. Specimens of Ti-7.5Mo were initially treated with 5 M NaOH at $60^{\circ}C$ for 24 h, resulting in the formation of a porous network structure composed of sodium hydrogen titanate. Afterwards, the specimens were aged in ethyl alcohol at $60^{\circ}C$ for 5 or 10 min, and subsequently immersed in simulated body fluid at $37^{\circ}C$ for 3, 7 and 14 days. Ethyl alcohol aging significantly increased the apatite-forming abilities of Ti-7.5Mo. The amount of apatite deposited on the Ti-7.5Mo after NaOH treatment and subsequent ethyl alcohol aging was much greater, especially after the Ti-7.5Mo specimens were aged for 5 min. Due to its excellent combination of bioactivity, low elastic modulus and low processing costs, the Ti-7.5Mo treated with NaOH aqueous solutions and subsequently aged in ethyl alcohol has promising heavy load-bearing applications.

Effect of ethyl alcohol aging on the apatite formation of a low-modulus Ti-7.5Mo alloy treated with aqueous NaOH

Ho, Wen-Fu,Tsou, Hsi-Kai,Wu, Shih-Ching,Hsu, Shih-Kuang,Chuang, Shao-Hsuan,Hsu, Hsueh-Chuan Techno-Press 2014 Biomaterials and Biomechanics in Bioengineering Vol.1 No.1

The purpose of this experiment was to evaluate the apatite-formation abilities of low-modulus Ti-7.5Mo substrates treated with NaOH aqueous solutions and subsequent ethyl alcohol aging before soaking them in simulated body fluid. Specimens of Ti-7.5Mo were initially treated with 5 M NaOH at $60^{\circ}C$ for 24 h, resulting in the formation of a porous network structure composed of sodium hydrogen titanate. Afterwards, the specimens were aged in ethyl alcohol at $60^{\circ}C$ for 5 or 10 min, and subsequently immersed in simulated body fluid at $37^{\circ}C$ for 3, 7 and 14 days. Ethyl alcohol aging significantly increased the apatite-forming abilities of Ti-7.5Mo. The amount of apatite deposited on the Ti-7.5Mo after NaOH treatment and subsequent ethyl alcohol aging was much greater, especially after the Ti-7.5Mo specimens were aged for 5 min. Due to its excellent combination of bioactivity, low elastic modulus and low processing costs, the Ti-7.5Mo treated with NaOH aqueous solutions and subsequently aged in ethyl alcohol has promising heavy load-bearing applications.

Establishment of the Model Widely Valid for the Melting and Vaporization Zones in Selective Laser Melting Printings Via Experimental Verifications

Chang-Shuo Chang,Kuan-Ta Wu,Chang-Fu Han,Tsung-Wen Tsai,Sung-Ho Liu,Jen-Fin Lin 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.1

The thermally affected material properties operating in the three phases and porosity variations in the SS316L steel powder have been introduced to the numerical analyses for the transient volumetric heat source (Q) models developed for the solid powder, melting, and vaporization regions in the selective laser melting (SLM). The bulk Q is thus a function of these heat sources and their ratio defined for the liquid and vapor phases. The heat conduction developed for the solid powders with porosity strings the heat convection with Q as the moving heat source to solve two-dimensional temperature distributions efficiently without the confinement of operating conditions and phase presumption. The specimens with single- and multiple-track printings are prepared to investigate the effects of incident energy density (E) and power intensity (I o) on the geometries of single-track printings and the areal surface roughness (Sa) values of the multiple-track printings with 0 and 50% overlap ratios. Laser power and scanning velocity are the controlling factors for the melting pool depth D and width W . D and W become the governing factors for the keyhole with evaporations, which affects the height H of single track after solidification. The W and D results predicted by the theoretical models developed in this study have an error range, 5–20%, compared to the experimental ones, which is much lower than those reported in the literatures (Gusarov et al. in J Heat Transf 131(7):072101, 2009. https ://doi.org/10.1115/1.31092 45 ; Hussein et al. in Mater Des 52:638–647, 2013. https ://doi.org/10.1016/j.matde s.2013.05.070 ; Yin et al. Int J Adv Manuf Technol 83(9–12): 1847–1859, 2016. https ://doi.org/10.1007/s0017 0-015-7609-x ; Andreotta et al. in Finite Elem Anal Des 135: 36–43, 2017. https ://doi.org/10.1016/j.finel .2017.07.002 ). The contact angle ( ϕ * ) is defined as a function of single-track width ( W ) and solidification height ( H ). ϕ * and Sa are significantly reduced as an E is applied beyond its critical value (47.62–57.14 J/mm 3 ). Significant change in Sa is ascribed to the big difference in the morphology and its surface pattern when E or I o reaches its critical value.

Hydroxyapatite prepared from eggshell and mulberry leaf extract by precipitation method

Wu, Shih-Ching,Hsu, Hsueh-Chuan,Hsu, Shih-Kuang,Liu, Mei-Yi,Ho, Wen-Fu Techno-Press 2019 Biomaterials and Biomechanics in Bioengineering Vol.4 No.1

Eggshell is a waste material after the usage of egg. In this work, biowaste chicken eggshells were used for preparing carbonated hydroxyapatite (HA) nanoparticles of high purity through aqueous precipitation method at room temperature. The eggshell-derived HA will be a cost-effective bioceramics for biomedical applications and an effective material-recycling technology. Additionally, mulberry leaf extract was used as a template to regulate the morphology, size and crystallinity of HA, and the effects of pH value were also examined. Characterization of the samples was performed by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. Scanning electron microscopy (SEM) was used to determine the size, shape and morphology of HA. The results indicate that only one phase of HA were synthesized in the both absence and presence of mulberry leaf extract at pH of 7 and above, while DCPD or DCPA/DCPD phase was observed at pH 4 condition. The crystallite sizes of the HA samples obviously decreased when adding mulberry leaf extract as a template, while they decreased gradually as the solution pH levels increased. With increasing pH level from 7 to 14, the rod-like HA nanoparticles gradually changed to spherical shape at pH 14. Note that, the obtained product is Mg and Sr containing A- and B-type carbonate HA at alkaline pH and it can be a potential material for biomedical applications.

Novel Metastable Nonequiatomic Ti-Zr-Nb-Mo Medium-Entropy Alloys with High Yield-Strength-to-Elastic-Modulus Ratios

Ka‑Kin Wong,Hsueh‑Chuan Hsu,Shih‑Ching Wu,Wen‑Fu Ho 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.10

In this study, novel nonequiatomic Ti-rich Ti-Zr-Nb-Mo medium-entropy alloys (Ti-MEAs) with a metastable body-centeredcubic structure were designed using Mo equivalent theory ([Mo]eq) for biomedical applications. The Ti65-Zr20-Nb14-Mo1(at%; Ti65-M1) and Ti65-Zr18-Nb16-Mo1 (at%; Ti65-M2) exhibited high yield strength of 1188 and 1118 MPa, respectively. Notably, the moduli of Ti65-M1 and Ti65-M2 were as low as 67.4 and 61 GPa, respectively, which were considerably lowerthan those of commercial biomedical alloys and several biomedical HEAs/MEAs. Transmission electron microscopy imagesindicated that Ti65-M2 reached a metastable state, resulting in a low elastic modulus. Furthermore, the yield-strength-to-elastic-modulus ratios (× 1000) of Ti65-M1 and Ti65-M2 were as high as 17.6 and 18.3, respectively, which were approximatelythree times greater than that of a commercial Ti-6Al-4V ELI implant. This study applied metastable theory for developingtwo metastable Ti-MEAs with low elastic moduli.

Characterization of nanosized hydroxyapatite prepared by an aqueous precipitation method using eggshells and mulberry leaf extract

Wu Shih-Ching,Hsu Hsueh-Chuan,Liu Mei-Yi,Ho Wen-Fu 한국세라믹학회 2021 한국세라믹학회지 Vol.58 No.1

Hydroxyapatite (HA) has been vigorously studied for orthopedic and dental applications due to its excellent bioactivity, osteoconductivity, and osteoinductivity. This study aims to present a simple room-temperature aqueous precipitation method for obtaining carbonated HA nanoparticles of high purity from biowaste chicken eggshells. Biowaste chicken eggshells were used for preparing HA through aqueous precipitation method. Moreover, mulberry leaf extract was used as a template to regulate the morphology, size, and crystallinity of HA. All produced nanocrystalline HA powders exhibited rod-like particle agglomerates of a size below 100 nm. The HA particles synthesized with the mulberry leaf extract showed higher crystallinity and slightly decreased crystallite sizes compared to the samples prepared without adding the extract. Carbonate peaks observed for the specimens closely matched those of A- and B-type carbonates, which can contribute to the low crystallinity. Notably, the HA synthesized from the eggshell powders contains several important trace elements such as Mg and Sr, which are benefi cial to the overall biological performance as biomaterials. The morphology, size, structure, and composition of the obtained HA products are similar to those of natural bones, and consequently, the products show potential as a material for biomedical applications.

Comparative global immune-related gene profiling of somatic cells, human pluripotent stem cells and their derivatives: implication for human lymphocyte proliferation

Chia-Eng Wu,Chen-Wei Yu,Kai-Wei Chang,Wen-Hsi Chou,Chen-Yu Lu,Elisa Ghelfi,Fang-Chun Wu,Pey-Shynan Jan,Mei-Chi Huang,Patrick Allard,Shau-Ping Lin,Hong-Nerng Ho,Hsin-Fu Chen 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Human pluripotent stem cells (hPSCs), including embryonic stem cells (ESCs) and induced PSCs (iPSCs), represent potentially unlimited cell sources for clinical applications. Previous studies have suggested that hPSCs may benefit from immune privilege and limited immunogenicity, as reflected by the reduced expression of major histocompatibility complex class-related molecules. Here we investigated the global immune-related gene expression profiles of human ESCs, hiPSCs and somatic cells and identified candidate immune-related genes that may alter their immunogenicity. The expression levels of global immune-related genes were determined by comparing undifferentiated and differentiated stem cells and three types of human somatic cells: dermal papilla cells, ovarian granulosa cells and foreskin fibroblast cells. We identified the differentially expressed genes CD24, GATA3, PROM1, THBS2, LY96, IFIT3, CXCR4, IL1R1, FGFR3, IDO1 and KDR, which overlapped with selected immune-related gene lists. In further analyses, mammalian target of rapamycin complex (mTOR) signaling was investigated in the differentiated stem cells following treatment with rapamycin and lentiviral transduction with specific short-hairpin RNAs. We found that the inhibition of mTOR signal pathways significantly downregulated the immunogenicity of differentiated stem cells. We also tested the immune responses induced in differentiated stem cells by mixed lymphocyte reactions. We found that CD24- and GATA3-deficient differentiated stem cells including neural lineage cells had limited abilities to activate human lymphocytes. By analyzing the transcriptome signature of immune-related genes, we observed a tendency of the hPSCs to differentiate toward an immune cell phenotype. Taken together, these data identify candidate immune-related genes that might constitute valuable targets for clinical applications.