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Sodium alginate (SA) is a non-toxic, biocompatible and biodegradable natural polymer. It has good printability, which is why it is often used in inks for three-dimensional (3D) printing in tissue engineering fields. However, pure SA hydrogel has unstable mechanical properties. In this study, we fabricated a structurally stable 3D scaffold by blending SA with poly(vinyl alcohol) (PVA) to enhance the mechanical properties of the scaffold. Moreover, we characterized the surface morphology and various mechanical properties of the scaffolds using scanning electron microscopy, Fourier transform-infrared spectroscopy, thermogravimetric analysis and several mechanical tests. The SA/PVA scaffolds were mechanically more stable than the pure SA scaffold and are good candidate as implantable biodegradable scaffolds for tissue engineering and medical applications.

3D printed scaffolds composed of gelatin and β-tri-calcium phosphate (β-TCP) as a biomimetic bone material are fabricated, thereby providing an environment appropriate for bone regeneration. The Ca2+ in β-TCP and COO- in gelatin form a stable electrostatic interaction, and the composite scaffold shows suitable rheological properties for bioprinting. The gelatin/β-TCP scaffold is crosslinked with glutaraldehyde vapor and unreacted aldehyde groups which can cause toxicity to cells is removed by a glycine washing. The stable binding of the hydrogel is revealed as a result of FTIR and degradation rate. It is confirmed that the composite scaffold has compressive strength similar to that of cancellous bone and 60 wt% β-TCP groups containing 40 wt% gelatin have good cellular activity with preosteoblasts. Also, in the animal experiments, the gelatin/β-TCP scaffold confirms to induce bone formation without any inflammatory responses. This study suggests that these fabricated scaffolds can serve as a potential bone substitute for bone regeneration.

To adapt biomaterials for solid freeform fabrication (SFF), methoxy polyethylene glycol (MPEG)-(PLLA-co-PCL) (LxCy) block copolymers were prepared using MPEG as the initiator to precisely control the molecular weight of PLLA and PCL. The LxCy block copolymers were designed such that the PLLA and PCL content varied and their molecular weights were within 200–1000 kDa. The cylindrical LxCy scaffolds were prepared by using LxCy block copolymers in SFF. The feasibility of using LxCy block copolymers was examined in terms of flowability from the micronozzle and solidification at room temperature after scaffold printing. The flowability and solidification of LxCy block copolymers mainly depend on the proportions of PLLA and PCL. Fabrication of the cylindrical LxCy scaffolds by using SFF was rapid and showed high reproducibility. In in vivo implantation, the cylindrical LxCy scaffolds exhibited biocompatibility and gradual biodegradation on a 16 week timescale. Immunohistochemical characterization showed that the in vivo LxCy scaffolds elicit only a modest inflammatory response. Taken together, these results show that LxCy block copolymers may serve as suitable biomaterials for the fabrication of well-defined three-dimensional scaffolds by using SFF.

Three-dimensional (3D) printing is a novel process used to manufacture bone tissue engineered scaffolds. This process allows for easy control of the architecture at the micro structure. However, the scaffold properties are typically limited in terms of cellular activity at the scaffold surface due to the printed materials properties. In this study, we developed a polycaprolactone (PCL) blended with polyethylene glycol (PEG) 3D printed scaffold using a rapid prototyping system. The manufactured scaffolds were then washed out to form small pores on the surface in order to improve the scaffolds hydrophilicity. We analyzed the resultant material by using Scanning Electron Microscopy (SEM), water absorption, water contact angle, in vitro WST-1, and the Bradford assay. Additionally, cells incubated on the fabricated scaffolds were visualized by Confocal Laser Scanning Microscopy (CLSM). The developed scaffolds exhibited small pores on the strand surface which served to increase hydrophilicity as well as improve cellular proliferation and increase total protein content. Our findings suggest that the presence of small pores on the scaffolds can be used as an effective tool for improving implant cellular interaction. This research indicates that these modified scaffolds can be considered useful for bone tissue engineering applications to improve human health.

In this study, we designed scaffolds coated with gold nanoparticles (GNPs) grown on a polydopamine (PDA) coating of a three-dimensional (3D) printed polycaprolactone (PCL) scaffold. Our results demonstrated that the scaffolds developed here may represent an innovative paradigm in bone tissue engineering by inducing osteogenesis as a means of remodeling and healing bone defects.

β-tricalcium phosphate (β-TCP) and polycaprolactone (PCL) composites were manufactured using the lab-made 3D bioprinting system to produce 50TCP50PCL (50% β-TCP with 50% PCL) and 70TCP30PCL (70% β-TCP with 30% PCL) composite scaffolds for bone tissue engineering. The 70TCP30PCL scaffold containing the highest β-TCP content exhibited rougher morphologies and more porous than the other scaffolds ( i.e. , PCL and 50TCP50PCL). In vitro studies revealed that cell proliferation and alkaline phosphate activity were improved on the β-TCP-based composite scaffolds. Our results suggest that our 3-D printed β-TCP-containing PCL scaffolds would benefit new dental applications or regeneration therapies.

In this study, we designed a hybrid Ti by heparin modifying the Ti surface followed by Growth/differentiation factor-5 (GDF-5) loading. After that, products were characterized by physicochemical analysis. Quantitative analysis of functionalized groups was also confirmed. The release behavior of GDF-5 grafted samples was confirmed for up to 21days. The surface modification process was found to be successful and to effectively immobilize GDF-5 and provide for its sustained release behavior. As an in vitro test, GDF-5 loaded Ti showed significantly enhanced osteogenic differentiation with increased calcium deposition under nontoxic conditions against periodontal ligament stem cells (PDLSc). Furthermore, an in vivo result showed that GDF-5 loaded Ti had a significant influence on new bone formation in a rabbit model. These results clearly confirmed that our strategy may suggest a useful paradigm by inducing osseo-integration as a means to remodeling and healing of bone defects for restorative procedures in dentistry.

Three-dimensional (3D) bioprinting is a free-form fabrication technique enabling fine feature control for tissue engineering applications. Especially, 3D scaffolds capable of supporting cell attachment, proliferation, and osteogenic differentiation are a prerequisite for bone tissue regeneration. Herein, we elaborated this approach to produce a 3D polycaprolactone (PCL) scaffold with long-term osteogenic activity. Specifically, we coated polydopamine (PDA) on 3D PCL scaffolds, subsequently deposited hydroxyapatite (HA) nanoparticles via biomimetic mineralization, and finally immobilized bone morphogenetic protein-2 (BMP-2). Material properties were characterized and compared with various 3D scaffolds, including PCL, PDA-coated PCL (PCL/PDA), and PDA-coated and HA-deposited PCL (PCL/PDA/HA). In vitro cell culture studies with osteoblasts revealed that the PCL/PDA/HA scaffolds immobilized with BMP-2 showed long-term retention of BMP-2 (for up to 21 days) and significantly increased osteoblast proliferation and osteogenic differentiation, as evidenced by metabolic activity, alkaline phosphatase activity, and calcium deposition. We believe that this multifunctional osteogenic 3D scaffold will be useful for bone tissue engineering applications.

This paper demonstrates a simple and cost-effective method to maintain superhydrophilicity of three-dimensional shaped aluminum fins' surface of dehumidifier over long period of time in order to improve water collection and energy efficiency. Wire-metallization, commercially available method in the ...

In the last decade, stent implantation therapy has been widely performed in the clinic. Although the patient's cardiovascular state depends on their age, gender, and health condition, the development of customized individual stents has been limited. Thus, a patient-specific stent manufacturing system should be devised for more successful stent therapy. In this study, we prepared a 3D printed PLA biodegradable polymeric stent using polydopamine (PDA), polyethyleneimine (PEI) and heparin (Hep) chemistry to prevent restenosis and thrombosis with anticoagulation and good blood compatibility. Physico-chemical characterization indicated that pristine PLA substrates were well modified as the amine abundant surface allowed for coating of a large amount of Hep. From in vitro and ex vivo analysis, heparinized 3D PLA stents showed excellent thromboresistance and hemocompatibility functions as well as modulation of smooth muscle cell (SMC) and endothelial cell (EC) proliferation. In an in vivo study, the heparinized 3D PLA stent showed the widest lumen area with the least neointimal hyperplasia and without atherosclerosis or thrombosis. All of these assessments clearly confirmed that our innovative strategy may suggest a useful paradigm as a preparation method for a patient-customized fully biodegradable individual stent for successful implantation therapy. This would find wide utilization for cardiovascular clinical applications.

In this study, we prepared a helical, biocompatible, and biodegradable stent by 3D rapid prototyping. The fabricated polycaprolactone (PCL) stent was coated with sirolimus mixed with poly-(lactide-co-glycolide) (PLGA), and polyethylene glycol (PEG), via a spraying method for slow drug release. The engineered, drug-eluting, bio-absorbable vascular stent (BVS) was analyzed and tested in vivo, and proving effective in animal experiments. These findings suggest that our new approach is useful for treating coronary thrombosis, and it may provide a promising scaffold for developing biological stent technology.

Recently, computer-designed three-dimensional (3D) printing techniques have emerged as an active research area with almost unlimited possibilities. In this study, we used a computer-designed 3D scaffold to drive new bone formation in a bone defect. Poly-L-lactide (PLLA) and bioactive β-tricalcium phosphate (TCP) were simply mixed to prepare ink. PLLA + TCP showed good printability from the micronozzle and solidification within few seconds, indicating that it was indeed printable ink for layer-by-layer printing. In the images, TCP on the surface of (and/or inside) PLLA in the printed PLLA + TCP scaffold looked dispersed. MG-63 cells (human osteoblastoma) adhered to and proliferated well on the printed PLLA + TCP scaffold. To assess new bone formation in vivo, the printed PLLA + TCP scaffold was implanted into a full-thickness cranial bone defect in rats. The new bone formation was monitored by microcomputed tomography and histological analysis of the in vivo PLLA + TCP scaffold with or without MG-63 cells. The bone defect was gradually spontaneously replaced with new bone tissues when we used both bioactive TCP and MG-63 cells in the PLLA scaffold. Bone formation driven by the PLLA + TCP30 scaffold with MG-63 cells was significantly greater than that in other experimental groups. Furthermore, the PLLA + TCP scaffold gradually degraded and matched well the extent of the gradual new bone formation on microcomputed tomography. In conclusion, the printed PLLA + TCP scaffold effectively supports new bone formation in a cranial bone defect.

In this paper, a simple and low-cost fabrication method is demonstrated to make superhydrophobic and superoleophobic Aluminum (Al) surfaces. The Al surfaces have hierarchical structures mimicking the lotus leaf. The manufacturing process is easily performed via grinding, acid etching, and low surface tension chemical coating, in sequence. The wettability of the fabricated Al surfaces is characterized with several liquids having different surface tension energy such as water, diiodomethane, and hexadecane. The effects of grinding and acid etching on wettability are also investigated to enhance the superhydrophobicity and superoleophobicity of the Al surface. The grinding process makes the surface rough effectively and improves the wetting behavior. Especially, the ground sample prepared with a sandpaper of P1000 grade shows the highest static contact angle and lowest sliding angle among the fabricated samples. Even though the wetting properties are generally improved by increasing the acid etching time, the repellency of the liquids on the surface is saturated at 10min of acid etching time. The morphology difference of Al surfaces is characterized by measurement of field-emission scanning electron microscope (FE-SEM). The hierarchical micro/nanostructures combined with chemical coating enable the Al surface to be superhydrophobic and superoleophobic.

In tissue engineering, fabrication of 3D scaffolds with well-defined, inter-connected pores followed by culture of mammalian cells is a typical approach. In practice, however, hydrophobicity of scaffold surfaces is not suitable for cells to be adhered because of poor wettability. Especially, infiltration followed by adhesion of cells inside hydrophobic scaffolds remains as a challenge. Thus, hydrophilic conversions of the surfaces regardless of surface location are critical for success. Herein, a method to enhance infiltration and adhesion of preosteoblasts inside hydrophobic poly(ϵ-caprolactone) (PCL) scaffolds by a bio-inspired, hydroxyapatite formation is demonstrated. The approach can be a general method for controlling hydrophilicity of inner surfaces of scaffolds.

Graphical abstractDisplay Omitted Highlights? Single conducting polymer nanowire is fabricated directly on the device platform. ? Facile method provids the controlled position, width, and length of nanowire. ? Nanowire is electrochemically deposited on the nanopatterned area of electrode. ? Polypyrrole nanowire based field effect transistor is successfully established. In this paper, a facile method by which conducting polymer nanowire can be fabricated directly on the device platform in controlled position, width, and length is proposed. Conducting polymer was electrochemically deposited on the nanopatterned area of a working electrode. The shape and position of the nanowire, in particular the length of the nanowire can be easily controlled by modulation of the nanopatterned area via lithography method. Through the proposed fabrication method, a polypyrrole nanowire based field effect transistor was successfully established. This fabrication design provides an easy way to manufacture the conducting polymer nanowire based devices in controlled manner, and the devices are suitable for application in chemical and biological sensors as well as organic electronics.

For tissue engineering, a bio-porous scaffold which is applied to bone-tissue regeneration should provide the hydrophilicity for cell attachment as well as provide for the capability to bind a bioactive molecule such as a growth factor in order to improve cell differentiation. In this work, we prepared a three-dimensional (3D) printed polycaprolactone scaffold (PCLS) grafted with recombinant human bone morphogenic protein-2 (rhBMP2) attached via polydopamine (DOPA) chemistry. The DOPA coated PCL scaffold was characterized by contact angle, water uptake, and X-ray photoelectron spectroscopy (XPS) in order to certify that the surface was successfully coated with DOPA. In order to test the loading and release of rhBMP2, we examined the release rate for 28 days. For the In vitro cell study, pre-osteoblast MC3T3-E1 cells were seeded onto PCL scaffolds (PCLSs), DOPA coated PCL scaffold (PCLSD), and scaffolds with varying concentrations of rhBMP2 grafted onto the PCLSD 100 and PCLSD 500 (100 and 500 ng/ml loaded), respectively. These scaffolds were evaluated by cell proliferation, alkaline phosphatase activity, and real time polymerase chain reaction with immunochemistry in order to verify their osteogenic activity. Through these studies, we demonstrated that our fabricated scaffolds were well coated with DOPA as well as grafted with rhBMP2 at a quantity of 22.7 ± 5 ng when treatment with 100 ng/ml rhBMP2 and 153.3 ± 2.4 ng when treated with 500 ng/ml rhBMP2. This grafting enables rhBMP2 to be released in a sustained pattern. In the in vitro results, the cell proliferation and an osteoconductivity of PCLSD 500 groups was greater than any other group. All of these results suggest that our manufactured 3D printed porous scaffold would be a useful construct for application to the bone tissue engineering field. Statement of Significance Tissue-engineered scaffolds are not only extremely complex and cumbersome, but also use organic solvents which can negatively influence cellular function. Thus, a rapid, solvent-free method is necessary to improve scaffold generation. Recently, 3D printing such as a rapid prototyping technique has several benefits in that manufacturing is a simple process using computer aided design and scaffolds can be generated without using solvents. In this study, we designed a bio-active scaffold using a very simple and direct method to manufacture DOPA coated 3D PCL porous scaffold grafted with rhBMP2 as a means to create bone-tissue regenerative scaffolds. To our knowledge, our approach can allow for the generation of scaffolds which possessed good properties for use as bone-tissue scaffolds.

For tissue engineering and regeneration, a porous scaffold with interconnected networks is needed to guide cell attachment and growth/ingrowth in three-dimensional (3D) structure. Using a rapid prototyping (RP) technique, we designed and fabricated 3D plotting system and three types of scaffolds: those from polycaprolactone (PCL), those from PCL and hydroxyapatite (HA), and those from PCL/HA and with a shifted pattern structure (PCL/HA/SP scaffold). Shifted pattern structure was fabricated to increase the cell attachment/adhesion. The PCL/HA/SP scaffold had a lower compressive modulus than PCL and PCL/HA scaffold. However, it has a better cell attachment than the scaffolds without a shifted pattern. MTT assay and alkaline phosphatase activity results for the PCL/HA/SP scaffolds were significantly enhanced compared to the results for the PCL and PCL/HA scaffolds. According to their degree of cell proliferation/differentiation, the scaffolds were in the following order: PCL/HA/SP > PCL/HA > PCL. These 3D scaffolds will be applicable for tissue engineering based on unique plotting system.

This paper reports on a web of superamphiphobic fluoro-compound fibers that forms as a result of a typical electrospinning method without any additional treatment. An electrospun web of poly(2,2,2-trifluoroethyl methacrylate) fibers exhibits superamphiphobicity when the water and hexadecane contact angles both exceed 150°. The morphology of a web is modulated by changing the polymer solution concentration from 24 to 30 wt.-% with other fixed processing conditions. The fiber diameter length depends mainly on the polymer concentration. A web formed from a 26 wt.-% solution has the smallest and most uniform fiber diameter; it also has the highest robustness parameter on wetting, thus the highest water and hexadecane contact angles. This result offers the possibility of simple industrial production of an amphiphobic surface.

Nanoscale patterning of gold layers on GaAs substrate is demonstrated using a combination of soft lithographic molding and galvanic displacement deposition. First, an electroless deposition method has been developed to plate gold on GaAs with ease and cost-effectiveness. The electroless metallization process is performed by dipping the GaAs substrates into a gold salt solution without any reducing agents or additives. The deposition proceeds via galvanic displacement in which gold ions in the aqueous solution are reduced by electrons arising from the GaAs substrate itself. The deposition rate, surface morphology and adhesion property can be modulated by the plating parameters such as the choice of acids and the immersion time. Second, soft lithographic patterning of nanodots, nanorings, and nanolines are demonstrated on GaAs substrates with hard-polydimethylsiloxane (h-PDMS) mold and plasma etching. This method can be easily applied to the metallization and nanopatterning of gold on GaAs surfaces.

In this paper, we design and fabricate a 3D scaffold using rapid prototyping (RP) technology for tissue engineering. The scaffold should have a three-dimensional interconnected pore network. We fabricate a polycaprolactone (PCL) scaffold with interconnecting pores and uniform porosity for cell ingrowth using a 3D plotting system. In order to keep the three dimensional shape under mechanical loading while implanted, we design an oscillating nozzle system to increase elastic modulus and yield strength of PCL strand. We characterize the influence of pore geometry, compressive modulus of the scaffold, elastic modulus and yield strength of the strand using SEM, dynamical mechanical analysis (DMA) and Nano-UTM. Finally the cell responses on scaffolds are observed.

This paper describes a simple fabrication method for creating superhydrophobic and transparent glass surfaces that mimic natural surfaces such as lotus leaves, moth eyes or cicada wings. Nanostructured glass surfaces were created by a combination of colloidal lithography and plasma etching. A colloidal mask was formed simply by the spin coating of the polystyrene beads and with modification of the interparticle distance between the beads. The etching of the glasses was conducted by CF4 plasma. Tower-shaped nanostructures at an aspect ratio of 1:4 were treated using fluoroalkylsilane self-assembled monolayers (SAMs) to obtain the hydrophobic surfaces. The treated glass surfaces showed superhydrophobicity with a water contact angle of around 150° and a hexadecane contact angle of around 110°. Furthermore, the nanostructured glass was transparent to visible light.

We have developed a novel atomic force microscope (AFM) probe as a highly sensitive sensor and an application of the probe into various mechanical tests for characterizing micro/nanostructures. Using MEMS fabrication technique, we have designed and fabricated rhombus-shaped symmetric AFM probe. Adhesion forces between silicon tip and artificial nano-hair structures of cyclic olefin copolymer (COC) and polypropylene (PP) were measured using the probe with a flat tip. The results exhibited the usual characteristics of force-displacement curves of COC and PP nano-hair structures, in which a pull-off force was detected at the point of unloading. The average adhesion forces of the COC and PP hair structures are about 9.48 μN and 10.67 μN, respectively.

Flexible printed circuit board (PCB), which is used for folder and slide type cellular phones, consists of flexible copper clad laminate (FCCL) and cover layer. Through it an electric current is applied to liquid crystal display (LCD) from the main board of cellular phone. In thin Cu foils of flexible PCB fatigue cracks due to repeated bending motion generate and propagate, and they cause a short circuit. Fatigue behavior of thin Cu foils being used for flexible PCB must be evaluated and confirmed to resolve this problem. It is based on findings by several researches that the mechanical properties of thin film materials differ from those of their bulk counterparts. Thin film properties have been investigated over the last years; however fatigue behavior of thin films has not yet been studied as thoroughly as monotonic behavior. In this study fatigue properties of thin Cu foils for the application in flexible PCB are obtained. Fatigue testing was performed for two kinds of Cu foils that were made by rolling and electrochemical procedures respectively. Differences of fabrications in fatigue behavior of thin foils were distinguished. Especially for rolled Cu foils, effects of rolling directions in fatigue properties were evaluated.

A computer-designed, solvent-free scaffold offer several potential advantages such as ease of customized manufacture and in vivo safety. In this work, we firstly used a computer-designed, solvent-free scaffold and human dental pulp stem cells (hDPSCs) to regenerate neo-bone within cranial bone defects. The hDPSCs expressed mesenchymal stem cell markers and served as an abundant source of stem cells with a high proliferation rate. In addition, hDPSCs showed a phenotype of differentiated osteoblasts in the presence of osteogenic factors (OF). We used solid freeform fabrication (SFF) with biodegradable polyesters (MPEG-(PLLA-co-PGA-co-PCL) (PLGC)) to fabricate a computer-designed scaffold. The SFF technology gave quick and reproducible results. To assess bone tissue engineering in vivo, the computer-designed, circular PLGC scaffold was implanted into a full-thickness cranial bone defect and monitored by micro-computed tomography (CT) and histology of the in vivo tissue-engineered bone. Neo-bone formation of more than 50% in both micro-CT and histology tests was observed at only PLGC scaffold with hDPSCs/OF. Furthermore, the PLGC scaffold gradually degraded, as evidenced by the fluorescent-labeled PLGC scaffold, which provides information to tract biodegradation of implanted PLGC scaffold. In conclusion, we confirmed neo-bone formation within a cranial bone defect using hDPSCs and a computer-designed PLGC scaffold.

The last decade has seen artificial blood vessels composed of natural polymer nanofibers grafted into human bodies to facilitate the recovery of damaged blood vessels. However, electrospun nanofibers (ENs) of biocompatible materials such as chitosan (CTS) suffer from poor mechanical properties. This study describes the design and fabrication of artificial blood vessels composed of a blend of CTS and PCL ENs and coated with PCL strands using rapid prototyping technology. The resulting tubular vessels exhibited excellent mechanical properties and showed that this process may be useful for vascular reconstruction.

The structure and morphology of the electrospun nanofiber depend on the parameters such as the physical properties of polymer, the applied voltages, tip to collector distance and ambient condition. Until now, most of studies have been focused on the effects of the above mentioned parameters for electrospinning process. But the study on vacuum conditions in electrospinning process almost not exists. The goal of this study is to investigate the effects of vacuum conditions in electrospinning process. The setup of electrospinning device is installed within homemade vacuum chamber. The polymer jets are ejected from a multi-spinneret connected with a microsyringe pump towards the collector located at fixed distance from the needle tip under a vacuum condition. The nanofiber mats are fabricated using a rotating collector. The visualization and imaging system of electrospinning process are consisted of a green laser devices, microscope, CCD camera and image recording device. During the electrospinning process, the behaviors of nanofiber are visualized and analyzed by this system. The morphologies and dimensions of electrospun fiber mat are measured with SEM. As a final result, the vacuum conditions of electrospinning process influence the behaviors of nanofiber.

The resistance to air permeation was investigated for ­an intercalated clay/acrylonitrile-butadiene copolymer ­nanocomposite. The nanocomposite is prepared by melt mixing the organo-treated montmorillonite into a rubber matrix, together with peroxide curative, and crosslinked by conventional compression molding for typical rubbers. In the case of intercalated nanocomposite, the air permeability decreases considerably with increasing clay content, and the decreasing trend agrees reasonably with the Neilson's tortuous model. No considerable improvement is found when the pure montmorillonite is added. Copyright © 2002 John Wiley & Sons, Ltd.

Harvesting water from humid air via dewing can provide a viable solution to a water shortage problem where liquid-phase water is not available. Here we experimentally quantify the effects of wettability and geometry of the condensation substrate on the water harvest efficiency. Uniformly hydrophilic surfaces are found to exhibit higher rates of water condensation and collection than surfaces with lower wettability. This is in contrast to a fog basking method where the most efficient surface consists of hydrophilic islands surrounded by hydrophobic background. A thin drainage path in the lower portion of the condensation substrate is revealed to greatly enhance the water collection efficiency. The optimal surface conditions found in this work can be used to design a practical device that harvests water as its biological counterpart, a green tree frog, Litoria caerulea , does during the dry season in tropical northern Australia.

The three-dimensional (3D) plotting system is a rapidly-developing scaffold fabrication method for bone tissue engineering. It yields a highly porous and inter-connective structure without the use of cytotoxic solvents. However, the therapeutic effects of a scaffold fabricated using the 3D plotting system in a large segmental defect model have not yet been demonstrated. We have tested two hypotheses: whether the bone healing efficacy of scaffold fabricated using the 3D plotting system would be enhanced by bone marrow-derived mesenchymal stem cell (BMSC) transplantation; and whether the combination of bone morphogenetic protein-2 (BMP-2) administration and BMSC transplantation onto the scaffold would act synergistically to enhance bone regeneration in a large segmental defect model. The use of the combined therapy did increase bone regeneration further as compared to that with monotherapy in large segmental bone defects.

ZnO nanowires can convert mechanical energy into electrical energy and we investigated energy conversion of ZnO nanowires grown on a silicon substrate. First, we numerically studied the output voltages of ZnO nanowires while varying diameters and lengths of ZnO nanowires. Second, we measured the currents of ZnO nanowires grown at low temperature using a solution method. The currents were measured using a Current Atomic Force Microscope (I-AFM). ZnO nanowires produced output current pulses when scanned by I-AFM in contact mode because of the piezoelectric effect of ZnO nanowires when the I-AFM tip applied a lateral force to ZnO nanowires.

Eggshell membrane (ESM) has potential as a natural scaffold because of its highly porous structure and good biocompatibility. To mimic its structure and surface properties, soluble eggshell membrane protein (SEP) was extracted from ESM and electrospun with a biodegradable polymer, poly(epsilon-caprolactone) (PCL). SEP/PCL micro/nanofibers were fabricated using a coaxial electrospinning process with a dual nozzle and an auxiliary cylindrical electrode. The fiber web was characterized using the water contact angle, pore-size distribution, mechanical properties and cellular behavior. The SEP/PCL web, which demonstrated the feasibility of producing a scaffold with adequate hydrophilicity, suitable pore size and good mechanical properties compared to a pure PCL micro/nanofiber web, exhibits the ability to mimic a natural biomaterial.

We report on the out-of-plane thermal conductivities of epitaxial Fe3O4 thin films with thicknesses of 100, 300, and 400 nm, prepared using pulsed laser deposition (PLD) on SiO2/Si substrates. The four-point probe three-omega (3-ω) method was used for thermal conductivity measurements of the Fe3O4 thin films in the temperature range of 20 to 300 K. By measuring the temperature-dependent thermal characteristics of the Fe3O4 thin films, we realized that their thermal conductivities significantly decreased with decreasing grain size and thickness of the films. The out-of-plane thermal conductivities of the Fe3O4 films were found to be in the range of 0.52 to 3.51 W/m · K at 300 K. For 100-nm film, we found that the thermal conductivity was as low as approximately 0.52 W/m · K, which was 1.7 to 11.5 order of magnitude lower than the thermal conductivity of bulk material at 300 K. Furthermore, we calculated the temperature dependence of the thermal conductivity of these Fe3O4 films using a simple theoretical Callaway model for comparison with the experimental data. We found that the Callaway model predictions agree reasonably with the experimental data. We then noticed that the thin film-based oxide materials could be efficient thermoelectric materials to achieve high performance in thermoelectric devices.