It is of great importance to develop multifunctional bioactive scaffolds, which combine angiogenesis capacity, osteostimulation, and antibacterial properties for regenerating lost bone tissues. In order to achieve this aim, we prepared copper (Cu)-containing mesoporous bioactive glass (Cu-MBG) scaffolds with interconnective large pores (several hundred micrometer) and well-ordered mesopore channels (around 5 nm). Both Cu-MBG scaffolds and their ionic extracts could stimulate hypoxia-inducible factor (HIF)-1a and vascular endothelial growth factor(VEGF) expression in human bone marrow stromal cells(hBMSCs). In addition, both Cu-MBG scaffolds and their ionic extracts significantly promoted the osteogenic differentiation of hBMSCs by improving their bone-related gene expression (alkaline phosphatase (ALP), osteopontin(OPN) and osteocalcin (OCN)). Furthermore, Cu-MBG scaffolds could maintain a sustained release of ibuprofen and significantly inhibited the viability of bacteria. This study indicates that the incorporation of Cu2þ ions into MBG scaffolds significantly enhances hypoxia-like tissue reaction leading to the coupling of angiogenesis and osteogenesis. Cu2þ ions play an important role to offer the multifunctional properties of MBG scaffold system. This study has demonstrated that it is possible to develop multifunctional scaffolds by combining enhanced angiogenesis potential, osteostimulation, and antibacterial properties for the treatment of large bone defects.

Copper-containing mesoporous bioactive glass scaffolds with multifunctional properties of angiogenesis capacity, osteostimulation and antibacterial activity

Piezoelectric andferroelectric ceramicmaterialsarematureand ubiquitous materials for advanced technology. Theseceramics are the active elements in a range of piezoelectricdevices and perform functions such as sensing and actuation.The performance of these materials is closely related to theirmicrostructures and, for this reason, to the ways they havebeen processed. The ﬁrst step in obtaining high-performanceceramics with a homogeneous microstructure and controlledgrain size that meet the requirements of industry isto preparepowderswithcontrolledstoichiometryandsmallparticlesize.However, even if a small-size powder is used, conventionalsintering is often unable to provide dense, very ﬁne-grainedceramics, due to the high temperatures still required fordensiﬁcation,andthefactthatthelowestgrainsizeachievableby classical techniques remains about 0.5mm or even higher,depending on the system. To solve this problem, the masstransport during the sintering step must be enhanced, sincethe temperature and time needed for consolidation must bereduced in order to achieve smaller grain sizes. Among themethods reported for activation of the mass transportduring the sintering process, the application of an electricalcurrent through the sample during heating represents apromising technique for rapid densiﬁcation of ceramics atrelatively low temperatures. The most novel and increas-ingly used method is spark plasma sintering, which hasclear advantages over conventional sintering methods,making it possible to sinter nanometric powders to nearfull densiﬁcation with little grain growth. This has becomeincreasingly important recently, with the miniaturization ofelectronic devices and the need to investigate size effects onthe properties in the sub-micrometer range and approach-ing the nanometer scale ( 100nm).In many material applications there is a need for densematerials, often being very close to their theoretical density.Unfortunately, taking account the fragility and refractoryproperties of ceramic materials and several difﬁcultiesinherent in the sintering process, the compaction withoutany additives becomes a real challenge from both practicaland theoretical aspects.The ﬁnal electromechanical properties of piezoelectricceramic components greatly depend upon the history of theceramic. Each step in the preparation of the material has to becarefully monitored and controlled toobtain the best product.The primary steps of the preparation of the ceramic materialaresynthesisoftheprecursor,fabricationofgreenbodiesand,last but not least, sintering of the pellet to achieve properdensiﬁcation. This third step, which follows powder prepara-tion, consists of thermal treatment with the aim of strengthen-ing the desired piece. It occurs via bonding of the compactgrains without melting. Such ‘‘welding’’ may be followed

https://www.icmm.csic.es/ac/publications/publication10.pdf

Spark Plasma Sintering as a Useful Technique to the Nanostructuration of Piezo-Ferroelectric Materials**

The state-of-the-art of biocomposites and hybrid biomaterials based on calcium orthophosphates that are suitable for biomedical applications is presented in this review. Since these types of biomaterials offer many significant and exciting possibilities for hard tissue regeneration, this subject belongs to a rapidly expanding area of biomedical research. Through successful combinations of the desired properties of matrix materials with those of fillers (in such systems, calcium orthophosphates might play either role), innovative bone graft biomaterials can be designed. Various types of biocomposites and hybrid biomaterials based on calcium orthophosphates, either those already in use or being investigated for biomedical applications, are extensively discussed. Many different formulations, in terms of the material constituents, fabrication technologies, structural and bioactive properties as well as both in vitro and in vivo characteristics, have already been proposed. Among the others, the nanostructurally controlled biocomposites, those containing nanodimensional compounds, biomimetically fabricated formulations with collagen, chitin and/or gelatin as well as various functionally graded structures seem to be the most promising candidates for clinical applications. The specific advantages of using biocomposites and hybrid biomaterials based on calcium orthophosphates in the selected applications are highlighted. As the way from the laboratory to the hospital is a long one, and the prospective biomedical candidates have to meet many different necessities, this review also examines the critical issues and scientific challenges that require further research and development.

https://www.tandfonline.com/doi/pdf/10.4161/biom.1.1.16782

Biocomposites and hybrid biomaterials based on calcium orthophosphates

In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are bioactive and biodegradable grafting bioceramics in the form of a powder and a liquid. After mixing, both phases form pastes, which set and harden forming either a non-stoichiometric calcium deficient hydroxyapatite or brushite. Since both of them are remarkably biocompartible, bioresorbable and osteoconductive, self-setting calcium orthophosphate formulations appear to be promising bioceramics for bone grafting. Furthermore, such formulations possess excellent molding capabilities, easy manipulation and nearly perfect adaptation to the complex shapes of bone defects, followed by gradual bioresorption and new bone formation. In addition, reinforced formulations have been introduced, which might be described as calcium orthophosphate concretes. The discovery of self-setting properties opened up a new era in the medical application of calcium orthophosphates and many commercial trademarks have been introduced as a result. Currently such formulations are widely used as synthetic bone grafts, with several advantages, such as pourability and injectability. Moreover, their low-temperature setting reactions and intrinsic porosity allow loading by drugs, biomolecules and even cells for tissue engineering purposes. In this review, an insight into the self-setting calcium orthophosphate formulations, as excellent bioceramics suitable for both dental and bone grafting applications, has been provided.

/pdf/self-setting-calcium-orthophosphate-formulations-ro4ppkfnin.pdf

Self-Setting Calcium Orthophosphate Formulations

Mesoporous silica-based bioactive glasses for antibiotic-free antibacterial applications.

In this study, the antibacterial property of silver-incorporated mesoporous bioactive glass microspheres (Ag-MBGMs) was investigated. The samples belonging to the 80SiO2·(15 − x)CaO·5P2O5·xAg2O system where 0 ≤ x ≤ 5 mol% were successfully prepared for bone regeneration and drug carrier applications. The obtained samples were evaluated by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope, Fourier transform infrared spectroscopy, and N2 adsorption/desorption measurements. All Ag-MBGMs had spherical particles with particle size 6–10 µm. TEM images showed mesopore structure. The textural properties showed a decrease in surface area and pore volume with an increase in silver content. XRD patterns exhibited the presence of pseudowollastonite and hydroxyapatite phase for silver-incorporating MBGMs, which might increase its bioactivity and bone bonding ability. Finally, all Ag-MBMGs had an antibacterial effect against both Escherichia coli and Staphylococcus aureus. Therefore, Ag-MBGMs may provide more potential for use as injectable, anticancer and drug-loading biomaterials for bone tissue engineering applications. In this study, the mesoporous bioactive glass microspheres (MBGMs) belonging to the system 80SiO2·(15 − x)CaO·5P2O5·xAg2O (x = 1, 3, and 5) were successfully prepared by the sol–gel process with surfactant-assisted mesoporous template. Effects of silver addition in MBGMs system were investigated for the first time such as particle shape and size, textural analysis, phase composition, in vitro bioactivity, and antibacterial effect. All prepared MBGMs have uniform microspherical particle (2–5 µm) with hierarchically structure. The textural analysis revealed that all prepared MBGMs had high porosity and relatively high surface area. The incorporation of apatite, pseudowollastonite, and metallic silver crystals were found for adding silver content more than 1 mol%. All prepared MBGMs can induce the crystalline hydroxyl carbonate apatite layer on the surface after soaking in simulated body fluid solution for 7 days. All silver-containing MBGMs had a very good antibacterial effect against Staphylococcus aureus and Escherichia coli. In addition, silver-incorporated MBGMs exhibited anticancer property against HepG2 cells.

Preparation and antibacterial property on silver incorporated mesoporous bioactive glass microspheres

Problem statement: Currently, in order to suppress intermetallic react ion layer formation during dissimilar metals welding between steel/alum inum alloy, only laser beam welding as self- brazing technique has been applied. However, TIG welding process might be one of welding process candidate for joining dissimilar metals welding bet ween steel/aluminum alloys due to its capability in joining thin section. In the present study, the fea sibility of application of TIG welding process in joining dissimilar metals between steel/aluminum al loy was evaluated. Approach: In order to realize the feasibility of TIG welding process, bead on the steel sheet experiment and dissimilar metals welding experiment was carried out. Results: From bead on the steel sheet experimental results, TIG welding could produce the partial penetration weldi ng in 1 mm thickness steel sheet. In dissimilar metals welding experiment, TIG welding process as a self-brazing technique could successfully join dissimilar metal between steel and aluminum alloy. Moreover, the load resistance of bonded zone of dissimilar metals joints was higher than the load r esistance of A1100 aluminum alloy after welding. Conclusion: These results indicated that TIG welding process i s feasible to be dissimilar metals welding candidate for joining steel/aluminum alloy.

Feasibility of Using TIG Welding in Dissimilar Metals between Steel/Aluminum Alloy

The influence of sintering conditions on phase formation, density, microstructure and electrical properties of BCZT ceramics wer investigated. The BCZT (Ba0.85Ca0.075Zr0.1Ti0.9O3) ceramics were fab...

Investigation on electrical properties of BCZT ferroelectric ceramics prepared at various sintering conditions

http://sutir.sut.ac.th:8080/jspui/bitstream/123456789/2441/2/BIB1030_F.pdf

Fabrication of piezoelectric laminate for smart material and crack sensing capability

Zinc Oxide (ZnO) nanostructure thin films doped with bismuth atoms were initially achieved by spin coating preparation from zinc acetate gel on the fused quartz substrate. The optical and structural properties have been preliminary studied in order to obtain more understanding the optimized factors for transparent conductive oxides (TCOs) of thin film solar cell. The optical transmittance was higher than 90% in the visible range for all films. In addition, the optical band gap of the prepared films calculated by Tauc plot showed the change of lightly blue shift with a decrease in annealing temperature. The glancing incident X-ray diffraction result showed that the Bi doped in ZnO nanostructure thin films after annealing have polycrystalline hexagonal wurtzite structure and good preferential orientation along c-axis. This chemical characterization indicated that in-phase behavior occurred in low Bi dopant content between 0.2 – 1.0 atomic percentage Bi content, hence 1 atomic percentage of Bi content was uppermost to obtain preferential orientation in this study. However, the quality of the films surface was better due to the larger number of layers but the optical transmittance will be poorer. The tentative study in term of electrical behavior was investigated for application in TCO film of solar cell. The electrical property showed that more multi ZnO layers affected on an increase in the electrical conductivity of the films.

/pdf/zno-doped-with-bismuth-in-case-of-in-phase-behavior-for-57ca30g5yn.pdf

Sirirat Rattanachan

Papers

Preparation and antibacterial property on silver incorporated mesoporous bioactive glass microspheres

Feasibility of Using TIG Welding in Dissimilar Metals between Steel/Aluminum Alloy

Investigation on electrical properties of BCZT ferroelectric ceramics prepared at various sintering conditions

Fabrication of piezoelectric laminate for smart material and crack sensing capability

ZnO Doped with Bismuth in Case of In-Phase Behavior for Solar Cell Application