Browsing by Author "Chen, San-Yuan"

Now showing 1 - 20 of 192

3D laser-printed porous Ti6Al4V dental implants for compromised bone support
(2020-01-01)
Tu, Che Chang
;
Tsai, Pei-, I
;
Chen, San-Yuan
;
Kuo, Mark Yen-Ping
;
Sun, Jui-Sheng
Background/Purpose: Alveolar bone loss following peri-implantitis remains a clinical challenge. We aimed to design a novel bioactive dental implant to accommodate the large bone defect caused by removal of previously failed implant. Methods: Bio-Active(ITRI) dental implant was manufactured with laser-sintered additive 3D printing technique. A 7.5 mm diameter x 7.0 mm depth osteotomy defect was created at the lateral aspect of distal femur of 20 New Zealand white rabbits to simulate the bony defect after removal of failed dental implant. One side of distal femurs was randomly selected for the commercially pure titanium NobelActive (TM) implant (control group) and the other side with Bio-Active(ITRI) Ti-6 Al4V porous dental implant (ITRI group). Animals were sacrificed at 4, 8 and 12 weeks after the implants' insertion. The samples were processed for gross morphological analysis, radiographic examination, micro-CT evaluation, and mechanical testing. Results: In histomorphometrical evaluation and micro-CT analysis, active new bone formation and good osseointegration within the ITRI implants were observed at the bone gap surrounding the dental implants. The biomechanical parameters in the Bio-Active(ITRI) dental implants were significantly higher than those of the commercially control samples. For the Bio-Active(ITRI) dental implants, the trabecular thickness decreased, while the trabecular separation and total porosity increased from the prescribed 1-month to 3-month time points; reflecting the natural remodeling of surrounding bony tissue in the Bio-Active(ITRI) dental implants. Conclusion: The novel porous structured Bio-Active(ITRI) dental implants may have a great potential for the prosthetic reconstruction where bone support is compromised after removal of a previously failed implant. Copyright (C) 2019, Formosan Medical Association. Published by Elsevier Taiwan LLC.
A flexible drug delivery chip for the magnetically-control led release of anti-epileptic drugs
(2009-11-03)
Huang, Wei-Chen
;
Hu, Shang-Hsiu
;
Liu, Kun-Ho
;
Chen, San-Yuan
;
Liu, Dean-Mo
A flexible drug delivery device was designed and fabricated using electrophoretic deposition of drug-carrying magnetic core-shell Fe(3)O(4) at SiO(2) nanoparticles onto an electrically conductive flexible PET substrate. The PET substrate was first patterned to a desired layout and subjected to deposition. In doing so, a uniform and nanoporous membrane could be produced. After lamination of the patterned membranes, a final chip-like device of thickness less than 0.5 mm is formed that is used for controlled delivery of an anti-epileptic drug, i.e., ethosuximide (ESM). The release of useful drugs can be controlled by directly modulating the magnetic field, and the chip is capable of demonstrating a variety of release profiles (i.e., slow release, sustained release, step-wise release and burst release profiles). These profiles can follow a wide spectrum of patterns ranging from zero to pulsatile release kinetics depending on the mode of magnetic operation. When the magnetic field was removed, the release behavior was instantly ceased, and vice versa. A preliminary in-vivo study using Long-Evans rat model has demonstrated a significant reduction in spike-wave discharge after the ESM was burst released from the chip under the same magnetic induction as in-vitro, indicating the potential application of the drug delivery chip. The flexible and membrane-like drug delivery chip utilizes drug-carrying magnetic nanoparticles as the building blocks that ensure a rapid and precise response to magnetic stimulus. Moreover, the flexible chip may offer advantages over conventional drug delivery devices by improvement of dosing precision, ease of operation, wider versatility of elution pattern, and better compliance. (C) 2009 Elsevier B.V. All rights reserved.
A fully-aqueous red-fluorescent probe for selective optical sensing of Hg2+ and its application in living cells
(2016-07)
Pola, Murali Krishna
;
Raju, Mandapati V. Ramakrishnam
;
Lin, Chein-Ming
;
Putikam, Raghunath
;
Lin, Ming-Chang
A new red-fluorescent mercury ion sensor material is designed and synthesized, which is composed of at weezer-shaped hydrophilic probe containing bifurcated soft-base atoms N and S coupled with 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF) unit. By virtue of the strong electron-accepting nature of TCF unit (as a push pull chromophore), this designed sensor material can selectively detect Hg2+ over various tested metal ions in a 100% aqueous medium via naked-eye and photoluminescence (PL) observations. Theoretical and time-resolved photoluminescence measurements further confirmed the selectivity and reversibility of the probe towards Hg2+ via intramolocular charge transfer mechanism in this sensor material. Moreover, the living cell tests by confocal fluorescence images of this sensor material towards Hg2+ were also investigated. Finally, distinguished absorption changes and fluorescence quenching spectral appearances allowed us to present the selective optical indicator of Hg2+ via TCF moiety for the first time. (C) 2016 Elsevier Ltd. All rights reserved.
A High-Sensitivity and Low-Power Theranostic Nanosystem for Cell SERS Imaging and Selectively Photothermal Therapy Using Anti-EGFR-Conjugated Reduced Graphene Oxide/Mesoporous Silica/AuNPs Nanosheets
(2016-03-16)
Chen, Yu-Wei
;
Liu, Ting-Yu
;
Chen, Po-Jung
;
Chang, Po-Hsueh
;
Chen, San-Yuan
A high-sensitivity and low-power theranostic nanosystem that combines with synergistic photothermal therapy and surface-enhanced Raman scattering (SERS) mapping is constructed by mesoporous silica self-assembly on the reduced graphene oxide (rGO) nanosheets with nanogap-aligned gold nanoparticles (AuNPs) encapsulated and arranged inside the nanochannels of the mesoporous silica layer. Rhodamine 6G (R6G) as a Raman reporter is then encapsulated into the nanochannels and anti-epidermal growth factor receptor (EGFR) is conjugated on the nanocomposite surface, defined as anti-EGFR-PEG-rGO@CPSS-Au-R6G, where PEG is polyethylene glycol and CPSS is carbon porous silica nanosheets. SERS spectra results show that rGO@CPSS-Au-R6G enhances 5 x 10(6) magnification of the Raman signals and thus can be applied in the noninvasive cell tracking. Furthermore, it displays high sensitivity (detection limits: 10(-8) M R6G solution) due to the "hot spots" effects by the arrangements of AuNPs in the nanochannels of mesoporous silica. The highly selective targeting of overexpressing EGFR lung cancer cells (A549) is observed in the anti-EGFR-PEG-rGO@CPSS-Au-R6G, in contrast to normal cells (MRC-5). High photothermal therapy efficiency with a low power density (0.5 W cm(-2)) of near-infrared laser can be achieved because of the synergistic effect by conjugated AuNPs and rGO nanosheets. These results demonstrate that the anti-EGFR-PEG-rGO@CPSS-Au-R6G is an excellent new theranostic nanosystem with cell targeting, cell tracking, and photothermal therapy capabilities.
A Multifunctional Nanodevice Capable of Imaging, Magnetically Controlling, and In Situ Monitoring Drug Release
(2009-11-09)
Hu, Shang-Hsiu
;
Kuo, Kuan-Ting
;
Tung, Wei-Lin
;
Liu, Dean-Mo
;
Chen, San-Yuan
The multifunctional nanodevice described here integrates nanoscaled imaging, targeting, and controlled drug delivery, as well as the capability to monitor, in situ, the amount of drug released from the nanodevice with single-cell resolution. The nanodevice is composed of a polymer core/single-crystal iron oxide shell nanostructure bonded to a quantum dot. It shows outstanding release and retention characteristics via an external on/off manipulation of a high-frequency magnetic field. Upon magnetic stimulation, the single-crystal iron oxide shell demonstrates formation of nanometer-sized polycrystal domains of varying orientation. This allows a variation between retention and slow release of the drug. Further stimulation causes permanent rupturing of the shell, causing release of the drug in a burst-like manner. The quantum dot bonded to the nanodevice provides optical information for in situ monitoring of the drug release through use of a magnetic field. Remote control drug release from the nanodevice in a cancerous cell line (HeLa) was successfully accomplished using the same induction scenario. When nanodevices equipped with quantum dots are taken into cancerous cells, they are able to provide real-time drug dose information through a corresponding variation in emission spectrum. The nanodevice designed in this study has achieved its potential as a cell-based drug-delivery system for therapeutic applications.
A Multitheragnostic Nanobubble System to Induce Blood-Brain Barrier Disruption with Magnetically Guided Focused Ultrasound
(2015-01-27)
Huang, Hsin-Yang
;
Liu, Hao-Li
;
Hsu, Po-Hung
;
Chiang, Chih-Sheng
;
Tsai, Chih-Hung
A nanoporous optically transparent CdS-pHEMA hybrid with high optical sensing capability to dielectric liquids
(2009-03-04)
Liao, Hung-Chou
;
Liu, Yen-Yu
;
Chen, San-Yuan
;
Liu, Dean-Mo
;
材料科學與工程學系
A hydrogel-based functional hybrid with highly uniformly dispersed nanoparticulate CdS semiconductors is proposed. The hybrid is synthesized using an in situ polymerization following an in situ chemical reduction, where the resulting particle size and the distribution of CdS nanocrystals (NCs) can be narrowly manipulated. The hybrids, containing a relatively small amount of the CdS NCs, exhibit a pronounced photoluminescence spectrum shift when in contact with a number of dielectric liquids and such a pronounced dielectric-confinement effect has been experimentally verified and modeled in this study. The sensing capability of the hybrids with respect to dielectric liquids or molecules can be optically characterized and varied depending upon the intensity of the dielectric environment surrounding the hybrids. This work suggests that the transparent, nanoporous CdS-pHEMA hybrids can be used as highly efficient optical sensing materials.
A novel multifunctional nano-platform with enhanced anti-cancer and photoacoustic imaging modalities using gold-nanorod-filled silica nanobeads
(2013)
Chen, Po-Jung
;
Hu, Shang-Hsiu
;
Fan, Chih-Tai
;
Li, Meng-Lin
;
Chen, You-Yin
The novel nano-seaurchin structure is characteristic of high-density and well-dispersed gold nanorods in one mesoporous silica nanobead. This nanoplatform provided increased photothermal stability, stable photoacoustic signal and highly efficient hyperthermia effect both in vitro and in vivo, indicating a powerful theranostic modality.
A PLGA hollow microsphere system with an magnetically-activated molecular switch that can sequentially co-deliver a chemopreventive agent and a chemotherapy drug to enhance therapeutic efficacy
(2016-02)
Pan, Wen-Yu
;
Chiang, Wei-Lun
;
Chuang, Er-Yuan
;
Hsiao, Hsu-Chan
;
Liu, Hung-Yi
A potential peptide derived from cytokine receptors can bind proinflammatory cytokines as a therapeutic strategy for anti-inflammation
(2019-02-19)
Jiang, Shinn-Jong
;
Tsai, Pei-I
;
Peng, Shih-Yi
;
Chang, Chun-Chun
;
Chung, Yi
Chronic inflammation is a pivotal event in the pathogenesis of cardiovascular diseases, including atherosclerosis, restenosis, and coronary artery disease. The efficacy of current treatment or preventive strategies for such inflammation is still inadequate. Thus, new anti-inflammatory strategies are needed. In this study, based on molecular docking and structural analysis, a potential peptide KCF18 with amphiphilic properties (positively charged and hydrophobic residues) derived from the receptors of proinflammatory cytokines was designed to inhibit cytokine-induced inflammatory response. Simulations suggested that KCF18 could bind to cytokines simultaneously, and electrostatic interactions were dominant. Surface plasmon resonance detection showed that KCF18 bound to both tumor necrosis factor-alpha (TNF-alpha) and interleukin-6, which is consistent with MM/PBSA binding free energy calculations. The cell experiments showed that KCF18 significantly reduced the binding of proinflammatory cytokines to their cognate receptors, suppressed TNF-alpha mRNA expression and monocyte binding and transmigration, and alleviated the infiltration of white blood cells in a peritonitis mouse model. The designed peptide KCF18 could remarkably diminish the risk of vascular inflammation by decreasing plasma cytokines release and by directly acting on the vascular endothelium. This study demonstrated that a combination of structure-based in silico design calculations, together with experimental measurements can be used to develop potential anti-inflammatory agents.
A Strategy to Synthesize Ultrahigh-N-Doped Hierarchical Carbons via Induced beta-Sheet from Silk Fibroin by In Situ Electrogelation/Electropolymerization
(2020-04-27)
Liu, Ta-Chung
;
Li, Tsung-Yu
;
Hung, Pei-Sung
;
Liang, Chun-Wei
;
Wu, Szu-Chen
Silk fibroin (SF) is recognized for its rich nitrogen content and has been explored for its promising potential in energy storage because of its hexagonal pseudographitic structure from the direct transformation of the unique secondary protein beta-sheet peptides of carbonized SF. In this work, we proposed a novel strategy that combined with in situ electrophoresis and electrogelation of SF as well as the electropolymerization of 3,4-ethylenedioxythiophene (EDOT) for producing high-level nitrogen-doped (N-doped) carbons. A high beta-sheet content of SF can be synthesized in a three-dimensional (3D) inverse opaline skeleton via double-network microstructure (physical beta-sheet cross-linking and chemical PEDOT cross-linking) induced by the hydrophobic EDOTs. This synergistic effect regulating SF distribution and balancing the intra/intermoleeular hydrogen bonding among SF results in boosting beta-sheet contents. Herein, this 3D SF/PEDOT composite inverse opal (SPIO) exhibits a much ultrahigh-coneentrated beta-sheets (46.4%) compared to pure electrogelated SFIO with 16.4% of beta-sheets. After subsequent pyrolysis, a high-level (14.7%) N-doped pseudographitic carbon inverse opal is realized. For evaluation as a pseudocapacitor, this high-level N-doped pseudographitic carbon inverse opal shows a capacitance of 342 F g(-1) at 0.5 A g(-1) and a commendable energy density of 31.7 Wh kg(-1) at an ultrahigh power density of 25009 W kg(-1) (at 50 A g(-1)). After galvanostatic charging/discharging at 15 A g(-1) for 10000 cycles, the sample maintains an impressive capacitance retention of 89.8%.
A theranostic nrGO@MSN-ION nanocarrier developed to enhance the combination effect of sonodynamic therapy and ultrasound hyperthermia for treating tumor
(2016)
Chen, Yu-Wei
;
Liu, Tse-Ying
;
Chang, Po-Hsueh
;
Hsu, Po-Hung
;
Liu, Hao-Li
Sonodynamic therapy (SDT), which induces activation of sonosensitizers in cancer cells through ultrasound irradiation, has emerged as an alternative and promising noninvasive therapeutic approach to kill both superficial and deep parts of tumors. In this study, mesoporous silica (MSN) grown on reduced graphene oxide nanosheet (nrGO) capped with Rose Bengal (RB)-PEG-conjugated iron-oxide nanoparticles (IONs), nrGO@MSN-ION-PEG-RB, was strategically designed to have targeted functionality and therapeutic efficacy under magnetic guiding and focused ultrasound (FUS) irradiation, respectively. The singlet oxygen produced by ultrasound-activated RB and the ultrasound-induced heating effect was enhanced by rGO and IONs, which improved the cytotoxic effect in cancer cells. In an animal experiment, we demonstrated that the combination of sonodynamic/hyperthermia therapy with magnetic guidance using this nanocomposite therapeutic agent can produce remarkable efficacious therapy in tumor growth inhibition. Furthermore, the combination effect induced by FUS irradiation produces significant damage to both superficial and deep parts of the targeted tumor.
Amifostine-conjugated pH-sensitive calcium phosphate-covered magnetic-amphiphilic gelatin nanoparticles for controlled intracellular dual drug release for dual-targeting in HER-2-overexpressing breast cancer
(2015-12-28)
Li, Wei-Ming
;
Chiang, Chih-Sheng
;
Huang, Wei-Chen
;
Su, Chia-Wei
;
Chiang, Min-Yu
We developed a surfactant-free method utilizing amifostine to stably link a targeting ligand (Herceptin) to amphiphilic gelatin (AG)-iron oxide@calcium phosphate (CaP) nanoparticles with hydrophobic curcumin (CUR) and hydrophilic doxorubicin (DOX) encapsulated in the AG core and CaP shell (AGIO@CaP-CD), respectively. This multi-functional nanoparticle system has a pH-sensitive CaP shell and degradable amphiphilic gelatin (AG) core, which enables controllable sequential release of the two drugs. The dual-targeting system of AGIO@CaP-CD (HER-AGIO@CaP-CD) with a bioligand and magnetic targeting resulted in significantly elevated cellular uptake in HER2-overexpressing SKBr3 cells and more efficacious therapy than delivery of targeting ligand alone due to the synergistic cell multi-drug resistance/apoptosis-inducing effect of the CUR and DOX combination. This nanoparticle combined with Herceptin and iron oxide nanoparticles not only provided a dual-targeting functionality, but also encapsulated CUR and DOX as a dual-drug delivery system for the combination therapy. This study further demonstrated that the therapeutic efficacy of this dual-targeting co-delivery system can be improved by modifying the application duration of magnetic targeting, which makes this combination therapy system a powerful new tool for in vitro/in vivo cancer therapy, especially for HER2-positive cancers. (C) 2015 Elsevier B.V. All rights reserved.
Amphiphilically-modified gelatin nanoparticles: Self-assembly behavior, controlled biodegradability, and rapid cellular uptake for intracellular drug delivery
(2011)
Li, Wei-Ming
;
Liu, Dean-Mo
;
Chen, San-Yuan
;
材料科學與工程學系
;
Department of Materials Science and Engineering
An amphiphilic gelatin macromolecule capable of self-assembling to form micelle-like nanospheres for entrapping hydrophobic therapeutic molecules was successfully synthesized by grafting hydrophobic hexanoyl anhydrides to the amino groups of primitive gelatin. The substitution and grafting efficiency of the modified gelatin displayed a concentration-dependent manner toward the hexanoyl anhydride. The particle size and stability of the resulting self-assembled nanoparticles strongly depend on the degree of substitution of the gelatin. These gelatin nanoparticles exhibited an outstanding cytocompatibility and highly efficient drug encapsulation efficiency. The drug release profile of the anticancer agent (camptothecin) from the amphiphilic gelatin nanoparticles shows that the drug release mechanism is dominated by a combined effect of diffusion and degradation. Furthermore, a tunable sustained release and degradation behavior can be controlled by changing the degree of substitution of the gelatin. This new type of amphiphilic gelatin nanoparticles with controlled biodegradability and rapid cellular internalization may serve in the intracellular delivery of specific proteins or genes, permitting a novel design for intracellularly-based nanotherapy.
An amphiphilic silicone-modified polysaccharide molecular hybrid with in situ forming of hierarchical superporous architecture upon swelling
(2012)
Huang, Wei-Chen
;
Chen, San-Yuan
;
Liu, Dean-Mo
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Most hydrogels face the challenge that extensive water uptake deteriorates their mechanical integrity, which restricts potential uses and, in some cases, reduces therapeutic performance in biomedical applications. Motivated by the concept that structural optimization was able to improve the mechanical properties whilst maintaining a high water uptake, in this work we designed a new type of strong network, i.e. PDMS-crosslinked-NOCC polymer networks (PMSC CAPNs), by esterification between cross-linked PDMS diol (bis(hydroxyalkyl) terminated polydimethylsiloxane, silicone) and NOCC (N,O-carboxymethyl chitosan). By manipulating the cross-linked density with PDMS, a hierarchical structure in which PDMS-rich microgels were randomly distributed within the underlying PMSC hydrogel could be tailored through the control of polymer-polymer and polymer-solvent interactions. Besides, the resulting hybrid hydrogel displayed an efficient self-foaming capability to create in situ a hierarchical superporous microarchitecture upon swelling. The swelling behavior accounted for by Flory-Rehner theory indicated that the PDMS macromonomeric crosslinker not only caused the development of a superporous microarchitecture under solvation effects but also escalated both strength and elasticity to the final hydrogel. A new swelling model based on spectroscopic examination of the PMSC CAPNs was successfully proposed, which nicely defined the unique structural transition of the hydrogel upon swelling. We also envision the potential development of such a hybrid hydrogel for advanced biomedical applications.
An electronic silicon-based memristor with a high switching uniformity
(2019-02-01)
Lu, Yang
;
Alvarez, Ana
;
Kao, Chung-Ho
;
Bow, Jong-Shing
;
Chen, San-Yuan
Metal-insulator-metal devices known as memristors offer voltage-regulated nanoscale conductivity and are of interest in the development of non-volatile random access memory. Typically, however, their tunable conductivity is the result of migrating ions within a stochastically formed filament, and as such their combined resistor-memory performance suffers. Here we show that amorphous silicon compositions, which are doped with oxygen or nitrogen and sandwiched between metal electrodes, can be used to create purely electronic memristors. The devices have coherent electron wave functions that extend to the full device thickness (more than 15 nm) and, despite the thinness and very high aspect ratio of the devices, electrons still follow an isotropic, three-dimensional pathway, thus providing uniform conductivity at the nanoscale. Such pathways in amorphous insulators are derived from overlapping gap states and regulated by trapped charge, which is stabilized by electron-lattice interaction. As a result, the nanometallic memristors also exhibit pressure-triggered insulator-to-metal transitions. Our silicon-based memristors, which could be readily integrated into silicon technology, are purely electronic and offer switching capabilities that are fast, uniform, durable, multi-state and low power.
Annealing Effect on Photovoltaic Performance of Hybrid P3HT/In-Situ Grown CdS Nanocrystal Solar Cells
(2011)
Liao, Hung-Chou
;
Chantarat, Naratip
;
Chen, San-Yuan
;
Peng, Cheng-Hsiung
;
材料科學與工程學系
The CdS nanocrystals with different aspect ratios (ARs) can be synthesized directly in the presence of conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3HT). The UV-vis spectra of the composite films show a blue shift of the pi-pi* transition band with an increasing aspect ratio (AR) of the CdS nanocrystals, which was attributed to the destruction of the ordered structure of polymer chains as supported by PL measurements. Atomic force microscope measurements on P3HT/CdS film also demonstrate the aggregation of CdS nanocrystal in the P3HT matrix is more apparent for the CdS nanocrystals of AR 4 than that of AR 16, indicating a stronger interaction between P3HT and CdS for a larger AR (16), which is favorable for the network structure and formation of percolation paths to increase the transport properties of the P3HT/CdS solar cells. Therefore, a higher power conversion efficiencies (PCE) up to 2.95% can be obtained for the in-situ-grown P3HT/CdS with AR 16 upon annealing treatment at 160 degrees C for 60 min. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3585668] All rights reserved.
Arrayed rGOSH/PMASH Microcapsule Platform Integrating Surface Topography, Chemical Cues, and Electrical Stimulation for Three-Dimensional Neuron-Like Cell Growth and Neurite Sprouting
(2014-06-01)
Liu, Heng-Wen
;
Huang, Wei-Chen
;
Chiang, Chih-Sheng
;
Hu, Shang-Hsiu
;
Liao, Chia-Hsin
The biocompatible thiol-functionalized rGOSH/PMASH microcapsules encapsulating nerve growth factor (NGF) are arrayed onto a transparent and conductive substrate, i.e., indium tin oxide (ITO), to integrate electrically stimulated cellular differentiation, electrically controlled NGF release, and topographically rough nano-surfaces into a 3-D platform for nerve regeneration. The rGOSH/PMASH microcapsules with microscale topography function not only as an adhesive coating to promote the adhesion of PC12 cells but also as electroactive NGF-releasing electrodes that stimulate NGF release and accelerate the differentiation of PC12 cells during electrical stimulation. Once electrical treatment is applied, NGF release and electrically enhanced cellular differentiation lead to an obvious increase both in the percentage of cells with neurites and in the neurite length. This length can reach nearly 90 m within 2 days of cell culture. The average neurite length is significantly increased (four-fold) after culture on the rGOSH/PMASH microcapsule substrate for 2 days compared with culture on a substrate without an rGOSH/PMASH coating. These multifunctional rGOSH/PMASH microcapsules may be used as potential 3-D patterned substrates for neural regeneration and neural prosthetics in tissue engineering applications.
Augmentation of DMLS Biomimetic Dental Implants with Weight-Bearing Strut to Balance of Biologic and Mechanical Demands: From Bench to Animal
(2019-01-01)
Chang, Jenny Zwei-Chieng
;
Tsai, Pei-I
;
Kuo, Mark Yen-Ping
;
Sun, Jui-Sheng
;
Chen, San-Yuan
A mismatch of elastic modulus values could result in undesirable bone resorption around the dental implant. The objective of this study was to optimize direct metal laser sintering (DMLS)-manufactured Ti6Al4V dental implants' design, minimize elastic mismatch, allow for maximal bone ingrowth, and improve long-term fixation of the implant. In this study, DMLS dental implants with different morphological characteristics were fabricated. Three-point bending, torsional, and stability tests were performed to compare the mechanical properties of different designs. Improvement of the weaker design was attempted by augmentation with a longitudinal 3D-printed strut. The osseointegrative properties were evaluated. The results showed that the increase in porosity decreased the mechanical properties, while augmentation with a longitudinal weight-bearing strut can improve mechanical strength. Maximal alkaline phosphatase gene expression of MG63 cells attained on 60% porosity Ti6Al4V discs. In vivo experiments showed good incorporation of bone into the porous scaffolds of the DMLS dental implant, resulting in a higher pull-out strength. In summary, we introduced a new design concept by augmenting the implant with a longitudinal weight-bearing strut to achieve the ideal combination of high strength and low elastic modulus; our results showed that there is a chance to reach the balance of both biologic and mechanical demands.
BaMgAl10O17 : Eu blue phosphors with MgO coating and microwave irradiation
(2008-02-01)
Kuo, Kuan-Ting
;
Lee, Shu-Ping
;
Chen, San-Yuan
;
Cheng, Bing-Ming
;
Lu, Hsiao-Chi
Europium-activated barium magnesium aluminate (BaMgAl10O17:Eu (BAM)) phosphor particles were modified by surface coating with MgO using a polyol method. The photoluminescence (PL) properties of the MgO-coated BAM phosphors showed slightly improved blue-emission intensity compared to the unmodified ones, and reached a stronger peak intensity with 5.25% MgO coating, under vacuum ultraviolet (VUV) 147 nm excitation. Upon microwave irradiation on the MgO-coated BAM phosphors, the PL properties of the MgO-coated phosphors exhibited a much enhanced relative PL ratio, and a maximum relative PL ratio can be achieved when as high as 10.5% MgO was deposited on the phosphor surface. However, for mechanically ground phosphor powder, it was found that although the intensity of the MgO-coated BAM turned stronger with increasing MgO concentration under microwave irradiation, the purity of the resulting luminescence was slightly disrupted by the presence of a new peak near 470 nm, corresponding to BaMg3Al14O25 compound. (C) 2007 Elsevier Ltd. All rights reserved.