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The airway mucosa is the first point of exposure to all inhalant materials. It is possible to produce microenvironments functionally similar to airway by using different types of extracellular matrices around mucosal cells, such as an extracellular matrix decellularized from trachea. In this study, we introduced a novel human respiratory mucosa-on-a-chip model that uses decellularized tracheal extracellular matrix to assess functional similarities. We also evaluated the effects of respiratory toxicant based on changes in cell viability, tight junction function, oxidative stress, expression of cell adhesion proteins in the vascular network, mucous secretion, and inflammatory cytokine secretion after treatment. This novel human respiratory mucosa-on-a-chip model is expected to be useful for assessing respiratory mucosa reactions to external bacteria or viruses and inhaled drugs.

Drug-releasing implantable scaffolds have been used for a variety of biomedical applications. Sustained release of drugs, including antibacterial drug release after operation and/or treatment, is becoming more important in medical fields. We developed a biodegradable scaffold using air-jet spinning and solvent casting. The implantable scaffold consists of a core scaffold, made of alginate, and an outer layer of polycaprolactone (PCL), both of which are biomaterials with good biocompatibility and biodegradability. The morphology of the PCL/alginate scaffolds was analyzed by scanning electron microscopy and atomic force microscopy. Fourier-transform infrared spectroscopy was performed to confirm the characteristics of the PCL/alginate scaffold. NIH/3T3 cells were used to determine the cytotoxicity of the PCL/alginate scaffold and its effect on cell proliferation. The rate of drug release could be easily controlled by adjusting the degree of crosslinking of the alginate scaffold, which was confirmed by high-performance liquid chromatography. Optimal conditions were reached when the alginate scaffold was crosslinked using a 10% CaCl2 solution, with the amount of the released drug maintained above the minimum inhibitory concentration for the longest period of time. In summary, the implantable PCL/alginate scaffold system developed in this study has the potential for biomedical applications.

Curcumin, a hydrophobic polyphenol derived from the Curcuma longa plant, is known to affect various cellular activities such as cell cycle regulation, oncogene expression, apoptosis, and mutagenesis, and is thus considered a promising candidate for an anticancer drug. In this study, we report the development of a platform that is effective to evaluate the anticancer effects of curcumin on one of the most aggressive tumors, glioblastoma. To generate platforms that satisfy both rapid and sensitive detection of curcumin effects, the surface of transparent conductive electrodes was first modified with two different types of electrocatalytic materials, gold and silver nanoparticles, with different densities. Among the four different substrates fabricated, a high-density gold nanostructure film (HDGN) in combination with peptide modification was found to be the best in terms of measuring the electrochemical signals of human glioblastoma cells (U87MG). The electrical signals of U87MG cells (Epc = -0.05 V vs. Ag/AgCl), obtained from cyclic voltammetry, showed excellent linearity (R2 = 0.99) within the range of 20,000–60,000 cells, and were thus demonstrated to be suitable for assessment of curcumin anticancer effects on U87MG cells. A clear curcumin toxicity on human glioblastoma was found with concentrations higher than 30 μM, which was consistent with the results obtained from cell counting kit-8 (CCK-8) assays. Remarkably, unlike the conventional colorimetric methods, the HDGN/peptide-modified platform was completely free from a possible signal interference from curcumin (absorbance: 425 nm). In addition, it enabled rapid (detection time

In this study, we aimed to control the drug release rate from calcium phosphate-alginate (CaP-Alg) core-shell nanoparticle (NPs) using CaP phases (brushite (DCPD) [Bru] and hydroxyapatite [HA]) generated under different pH conditions. Core-shell NPs consisted of an inorganic CaP core and an organic Alg shell and were synthesized by the water-in-oil emulsification and precipitation method. CaP-Alg NPs were synthesized under different pH conditions, resulting in the mineralization of CaP with Bru and HA in the core region of core-shell NPs. Albumin-fluorescein isothiocyanate conjugate (FITC-BSA) was used as a model drug for in-vitro drug release studies. CaP-Alg (Bru-Alg and HA-Alg) NPs exhibited a higher loading capacity and encapsulation efficiency than Ca-Alg NPs. The release behavior of synthesized core-shell NPs showed different patterns due to the pH-sensitivity of Alg and CaP. At physiological pH, Ca-Alg NPs exhibited an initial burst release behavior, while CaP-Alg showed controlled release behavior. Our results demonstrate that HA-Alg NPs are more suitable for controlled intracellular delivery while Bru-Alg NPs are more suitable for extracellular compartment delivery. Therefore, CaP-Alg NPs could be potential candidates for controlled gene and biomolecule delivery into cells for therapeutic purposes.

This study is the first to demonstrate the capability of Cl– to markedly accelerate organic oxidation using thermally activated peroxymonosulfate (PMS) under acidic conditions. The treatment effici...

Iron immobilized on supports such as silica, alumina, titanium oxide, and zeolite can activate hydrogen peroxide (H2O2) into strong oxidants. However, the role of the support and the nature of the ...

Osteochondral defects, including damage to both the articular cartilage and the subchondral bone, are challenging to repair. Although many technological advancements have been made in recent years, there are technical difficulties in the engineering of cartilage and bone layers, simultaneously. Moreover, there is a great need for a valuable in vitro platform enabling the assessment of osteochondral tissues to reduce pre-operative risk. Three-dimensional (3D) bioprinting systems may be a promising approach for fabricating human tissues and organs. Here, we aimed to develop a polycaprolactone (PCL)/alginate bipartite hybrid scaffold using a multihead 3D bioprinting system. The hybrid scaffold was composed of PCL, which could improve the mechanical properties of the construct, and alginate, encapsulating progenitor cells that could differentiate into cartilage and bone. To differentiate the bipartite hybrid scaffold into osteochondral tissue, a polydimethylsiloxane coculture system for osteochondral tissue (PCSOT) was designed and developed. Based on evaluation of the biological performance of the novel hybrid scaffold, the PCL/alginate bipartite scaffold was successfully fabricated, importantly, our findings suggest that this PCSOT system may be applicable as an in vitro platform for osteochondral tissue engineering.

Surgery, particularly open surgery, is known to cause tissue/organ adhesion during healing. These adhesions occur through contact between the surgical treatment site and other organ, bone, or abdominal sites. Fibrous bands can form in unnecessary contact areas and cause various complications. Consequently, film- and gel-type anti-adhesion agents have been developed. The development of sustained drug delivery systems is very important for disease treatment and prevention. In this study, the drug release behavior was controlled by crosslinking lidocaine-loaded alginate/carboxymethyl cellulose (CMC)/polyethylene oxide (PEO) nanofiber films prepared by electrospinning. Lidocaine is mainly used as an anesthetic and is known to have anti-adhesion effects. Our results show that drug release is regulated by the crosslinking degree of the lidocaine-loaded alginate/CMC/PEO film. The drug release behavior was confirmed by HPLC, and, as a result, an excellent anti-adhesion barrier was developed that can be applied to treat patients in the medical field.

The materials of the dental barrier membranes (DBM), which is widely used for effective alveolar bone reconstruction, require high biocompatibility and additional functions. In this study, we prepared a chitosan/polyurethane (CSP) nanofibrous membrane incorporated silver nanoparticles (AgNPs) within the membrane. Characterization of CS-AgNP/polyurethane composite (AgCSP) nanofiber membranes showed that AgNPs were well embedded in chitosan membranes. In addition, biocompatibility and antibacterial effect against Porphyromonas gingivalis of the AgCSP was demonstrated by viability analysis and growth inhibition test. Collectively, AgCSP nanofiber membrane with antibacterial activity as well as biocompatibility may be useful in DBM and other tissue engineering applications.

Summary Aim Major hepatic resection of a cirrhotic liver may result in a fatal clinical course. Preoperative erythropoietin (EPO) treatment has been shown to have protective properties and to stimulate liver regeneration. This study aims to investigate the effect of preoperative EPO on survival following major hepatic resection in a cirrhotic rat model. Methods Cirrhotic liver was induced by intraperitoneal injection of thioacetamide (200 mg/kg/mL) in 72 Lewis rats. Each 36 rats received EPO (1 IU/g, every second day, 5 times preoperatively) or saline (control) and major hepatectomy (removal of the left and half of the median lobe) was performed. Biochemical and immunohistochemical parameters, cytokines and overall survival were compared following surgery. Results Rats that received preoperative EPO had decreased hepatic aspartate aminotransferase, alanine aminotransferase and interleukin (IL)-1β expression, 48 hours following surgery. They had increased hepatocyte growth factor and vascular endothelial growth factor expression at 1 hour, increased IL-6 expression at 24, 48 and 120 hours and increased Ki-67, 120 hours following surgery. Overall, survival was significantly improved among EPO-treated rats (P = 0.034). Conclusion Preoperative EPO treatment has a protective effect and stimulates liver regeneration, leading to improved overall survival following major hepatectomy in a cirrhotic rat model.

Poly(lactide-co-glycolide) (PLGA) is a biocompatible and biodegradable polymer that has been widely used in devices for tissue engineering and drug delivery applications. Gold nanoparticles (GNPs) have also been used as biomaterials and have been found to have a positive effect on bone formation. In this study, we synthesized thiol end-capped PLGA (PLGA-SH) and used it for binding GNPs. This PLGA was processed into a sheet form via electrospinning. GNPs with an approximate size of 30 nm were attached onto the PLGA-SH sheet surfaces (PLGA-GNPs). This membrane was characterized by thermogravimetric analysis, ultraviolet/visible spectrophotometry, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and confocal laser scanning microscopy. Characterization results show that the GNPs are well attached on the PLGA-SH sheet and it is possible to control the GNPs load. Additionally, in-vitro results showed that PLGA-GNPs have good biocompatibility. They were also found to enhance osteogenic differentiation of human adipose derived stem cells. From these results, we have determined that the PLGA-GNP fibers can be useful as materials for bone regeneration and can also potentially serve as drug carriers.

Bone related-bacterial diseases including wound infections and osteomyelitis (OM) still remain a serious problem. In this study, a hybrid co-electrospun membrane consisting of gelatin (GE) and Poly( d , l -lactide-co-glycolide) (PLGA) fibrous sheets containing different concentrations (0, 0.1, 0.5, and 1 wt%) of silver sulfadiazine (AgSD) was designed to provide for improved antimicrobial effect and biocompatibility. Well-defined products were characterized by physicochemical analyses. For biological in vitro assessments, mouse osteoblastic MC3T3-E1 cells were cultured on the scaffolds. This test was done in order to assay for cytotoxicity by measuring cell proliferation. Antibacterial activity against gram-negative Pseudomonas aeruginosa (P. aeruginosa), gram-positive Staphylococcus aureus (S. aureus), and Methicillin-resistant Staphylococcus aureus (MRSA) was also tested. These biological tests showed that GE/PLGA-AgSD scaffolds had good cell viability, as well as effective antimicrobial activity. These remarkable results suggest that GE/PLGA-AgSD scaffolds possess great potential for the treatment of OM and can find many uses in the field of bone tissue engineering.

In this study, we developed a hybrid dental resin containing silver nanoparticle (AgNPs) to eliminate periodontal disease causing bacteria such as streptococcus mutans (S. mutans) and streptococcus sobrinus (S. sobrinus). The silver nanoparticles enables the resin to prevent oral pathogen growth during orthodontic therapy. First, AgNPs were directly synthesized in dimethylformamide (DMF) solvent with a capping agent. Second, pure orthodontic primer was mixed with the synthesized AgNPs solvent-slurry followed by photocuring. The resultant material was characterized by physicochemical characterization. Finally, an in vitro antimicrobial test was carried out. The results showed that the AgNPs were fully synthesized and clearly embedded in dental resin. In the bacterial test, the dental resin containing AgNPs showed potent antimicrobial activity against two kinds of bacteria. In conclusion, our methodology may allow for the generation of a wide range of dental resin and composite products which inhibit periodontitis causing bacteria.

Peroxymonosulfate (PMS) activated by Hematite (α-Fe2O3) was capable of degrading different organic compounds. Several lines of experimental evidence are presented which argue against the generation of radical species as well as singlet oxygen (1O2). Tests using radical scavengers and probes, and electron paramagnetic resonance (EPR) spectroscopy suggested that the PMS-activation by α-Fe2O3 does not involve the generation of SO4•−, •OH, and O2•−. The possibility of 1O2 generation was also excluded by EPR spectroscopy and kinetic experiments performed in deuterium oxide. The ternary reactive complex that mediates the electron-transfer between target organic compounds and PMS (frequently proposed as a nonradical mechanism in previous studies) was not likely formed in this system. Based on the electrochemical analyses as well as other experiments, a high-valent iron species (most likely ferryl species, Fe(IV)) is believed to be responsible for the oxidation of organic compounds by the α-Fe2O3/PMS system.

In this study, we designed highly-aligned thermoplastic polycarbonate urethane (PCU) fibrous scaffolds coated with bioactive compounds, such as Poly- l -Lysine (PLL) and Poly- l -Ornithine (PLO), to enhance cellular adhesion and directivity. These products were characterized by scanning electron microscope (SEM) analysis which demonstrated that highly aligned fiber strands were formed without beads when coated onto a mandrel rotating at 1800 rpm. During in vitro cell test, PLO-coated, aligned PCU scaffolds were found to have significantly higher proliferation rates than PLL coated and bare PCU scaffolds. Interestingly, dental pulp stem cells (DPSCs) were observed to stretch along the longitudinal axis parallel to the cell direction on highly aligned scaffolds. These results clearly confirm that our strategy may suggest a useful paradigm by inducing neural tissue repair as a means to remodeling and healing of tissue for restorative procedures in neural tissue engineering.

Hydrogel-based integral nerve electrodes have been studied as an effective implant strategy for recovery after a spinal cord injury (SCI). However, a weak physical connection between the hydrogel and nerve electrode can lead to implant failure. In this study, we introduce poly(L-lactic acid) (PLA) nanorods (PLANRs) as a new approach to improve the physical property, i.e. stability of agarose hydrogel-based integrated neuro-electrodes. The hydrogels were characterized by scanning electron microscope (SEM), rheometry, and tensile test machine. Thus, the hydrogels containing PLANRs displayed high mechanical properties. These interesting findings suggest that PLANRs enhance the mechanical properties of integral nerve electrode hydrogels making them useful materials in neural tissue engineering.

A novel strategy to precisely detect or monitor various biomaterials in living cells poses paramount importance in understanding cellular processes. Graphene, a newly emerged two-dimensional carbon material, has been widely utilized for biosensors owing to its multifarious characteristics including mechanical, electrical, and optical properties (e.g. stability, conductivity, fluorescence quenching and photoluminescence). In addition, graphene derivatives and their innate characteristics, such as biocompatibility low cytotoxicity and water solubility have facilitated the use of graphene-based materials for live cell biosensing, wherein graphene is utilized as a core material by itself or in combination with other functional nanomaterials to load target-specific probes, fluorescent dyes, and other signaling molecules. Such graphene-based hybrid nanomaterials have been employed to detect various cellular entities in living cells, including ions, biomolecules, genetic molecules, proteins, enzymes, and even whole cells. The following review will discuss a number of previous studies in which graphene-based hybrid constructs were used for live cell biosensing, and their potential applications in cancer research and stem cell therapy.

Several challenges remained to fabricate a molecular-level nucleic acid biosensor such as surface immobilization control, single mismatch detection and low current response. To overcome those issues, for the first time, authors presented a novel parallel structural dsDNA/recombinant azurin (PSD/rAzu) hybrid structure for the general nucleic acid detection. The PSD was designed and introduced by the optimized 8 Ag+ ions to have greater conductivity than the canonical dsDNA, and conjugated with rAzu to develop a general platform for electrochemical detection of miRNAs and viral DNAs with high reproducibility and ultra-sensitivity towards single base pair mutation. Thanks to the bifunctional rAzu as the selective spacer and electrochemical signal mediator, in the presence of the target strand, the imperfect PSD switched rapidly to the upright position where the Ag+ ions intercalated between C-C mismatches of dsDNAs at the top of each structure brought further from the electrode surface resulting in a significant electrochemical signal drop of the Ag+ ions. The charge transfer (CT) mechanism across the hybrid structure was simply clarified on the basis of the redox potential location of the species. The electrical conductivity of DNAs were measured using scanning tunneling spectroscopy (STS) at the molecular scale and cyclic voltammetry (CV) technique based on the reduction of Ag+ ion. The proposed PSD/rAzu hybrid structure with a great capability of single mutation recognition and miRNA expression level profiling in cancer cells holds a very promising platform to be studied for further development of various kinds of nanoscale biosensors, bioelectronic devices., Highlights • We fabricated a novel parallel structural dsDNA/recombinant azurin (PSD/rAzu) hybrid structure for nucleic acid detection. • The PSD was designed and introduced by the optimized 8 Ag+ ions to have higher conductivity than the canonical dsDNA. • The PSD/rAzu functioned as a general platform for electrochemical detection of miRNAs and viral DNAs with high sensitivity. • The charge transfer mechanism across the hybrid structure was clarified based on the redox potential location of the species.

In this study, we describe a new approach of antibacterial water-filter generation which utilized inkjet printing to deposit silver nanoparticles onto an electrospun polyurethane fibrous membrane. It was found that the polyurethane fiber was uniformly fabricated and silver nanoparticles were evenly deposited onto the fibrous strands. As an in vitro test, our developed silver-nanoparticle modified polyurethane fibrous membrane showed significant inhibition against four kinds of pathogens that lead to fatal water borne diseases. These results indicate that our approach, which allows for simple, low-cost, mass production of filters, may be useful in the field of water environmental science.

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.

The nanocomposite of metallic nickel and nickel oxide (denoted as Ni–NiO), synthesized by a simple sol–gel method, was found to activate peroxydisulfate (PDS), resulting in the effective oxidation of phenolic compounds and selected pharmaceuticals. A nonradical mechanism was proposed to explain the activation of PDS by Ni–NiO, in which organic contaminants are believed to be oxidized through an electron abstraction pathway mediated by the reactive complexes formed between PDS and the Ni–NiO surface. This mechanism was supported by multiple lines of evidence including radical scavenger experiments, the oxidation products, linear sweep voltammetry, and electron paramagnetic resonance spectroscopy. The Ni–NiO/PDS system exhibited a PDS utilization efficiency (expressed by the ratio of degraded organic contaminant to decomposed PDS) that was over 80%, and Ni–NiO showed a greater activity for PDS activation than a commercial nanoparticulate nickel oxide. This improved performance of Ni‒NiO was attributed to the disproportioned incorporation of the metallic Ni into the NiO matrix, creating more sites with oxygen vacancy. Also owing to the metallic Ni, Ni–NiO possessed magnetic properties and therefore could be easily separated and reused.

Titanium implants (Ti) have been widely used in several medical fields. In clinical practice, Ti can become contaminated with bacteria through a variety of mechanisms. This contamination can lead to implant failure and serious infections. In this study, we aimed to develop a new, hybrid Ti with good biocompatibility and antibacterial properties by immobilizing ceftazidime (CFT) onto the Ti surface through polydopamine (PDA) and polyethyleneimine (PEI) chemistry. Hybrid Ti was confirmed by assessing the cell proliferation of human adipose-derived stem cells using a cell counting. The biofilm formation across the Ti surface of two bacterial strains associated with nosocomial infections, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus, was evaluated by scanning electron microscopy. The viability of the bacteria exposed to Ti surface was evaluated by cell counting. Our results clearly demonstrate that the bacterial biofilm formation as well as bacterial viability was significantly reduced on the hybrid Ti as compared to the control, Ti alone. Collectively, the Ti surface was successfully modified to form the hybrid Ti exhibiting good biocompatibility and antibacterial properties through PDA, PEI, and CFT grafting. Within the limitations of this in vitro study, we conclude that the hybrid Ti may be useful for successful implant treatment., This research was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) funded by the Korean government (MSIT) (No. 2017M3A9E4048170).

Articular cartilage exhibits reduced self-healing following degeneration. This research evaluated the effects of hydrogels derived from various polysaccharides-gellan gum (GG), alginate, and agarose-on cartilage regeneration compared with that of hyaluronic acid (HA), which is commonly used in cartilage tissue engineering. Chondrocytes were isolated from the articular cartilage of New Zealand White (NZW) rabbits and stimulated with IL-1β followed by incubation with polysaccharides. The expressions of NF-κB and Cox-2 were decreased and those of IκBα, Sox-9, aggrecan, and type II collagen were increased in HA, GG, and Alginate groups. Osteochondral defects in NZW rabbits were treated with intra-articular polysaccharide injections; all except alginate resulted in tissue regeneration. Significant improvements were observed in cartilage regeneration in the GG and agarose groups. These results show that GG and agarose improve cartilage regeneration by suppressing inflammatory mediators and inducing cartilage formation and autophagy-related gene expression, indicating their potential for cartilage tissue engineering.

In this study, we manufactured various ratios of polycaprolactone (PCL)/gelatin (GE) highly aligned electrospun nanofibrous scaffolds (ENs) to investigate the effects of polymer ratio on tenogenic differentiation activity. For biological assessments, the cell proliferation rate was optimal in the PCL/GE (9:1) group. Interestingly, however, the tenogenic differentiation rate was best for the PCL/GE (7:3) group. From our outcomes, we established that a poly-blending mix of PCL/GE (7:3) is a promising ratio for tenogenic differentiation. Thus, our findings may provide for an effective mesh to promote tenogenic differentiation of ENs in future tendon tissue engineering applications., This work was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) & funded by the Korean government (MSIP&MOHW) (No. 2017M3A9E4048170).

The 3D multi-cellular tumoroid (MCT) model is an in vivo-like, avascular tumor model that has received much attention as a refined screening platform for drug therapies. Several types of research have been efforted to improve the physiological characteristics of the tumor microenvironment (TME) of the in vivo-like MCTs. Size-controlled MCTs have received much attention for obtaining highly reproducible results in drug screening assays and achieving a homogeneous and meaningful level of biological activities. Here, we describe an effective method for fabricating the size-controlled in vivo-like MCTs using a cell-loss-free (CLF) microwell arrays. The CLF microwell arrays was fabricated by using the simple operation of laser carving of a poly (methyl methacrylate) (PMMA) master mold. We also demonstrated the biophysicochemical effect of tumor microenvironment (TME) resident fibroblasts through the expression of TGFβ, αSMA, Type I-, IV collagen, angiogenesis related markers on tumorigenesis, and confirmed the drug response of MCTs with anti-cancer agents. This technology for the fabrication of CLF microwell arrays could be used as an effective method to produce an in vitro tumor model for cancer research and drug discovery.

In the dental medical field, an infection of opened oral tissues by bacteria give rise to serious periodontal disease (PD) after trauma or various oral surgery such as third molar extraction, oral implant, and unexpected trauma. However, progress for bioactive improvement, a prevention of oral tissue contamination, has been currently limitation. Therefore, an innovative research is extremely important and needed for immediately inhibition of bacteria. In this study, we designed a biocompatible oral wound dressing as co-electrospun nanofiber to combine gelatin (GE) and polyurethane (PU) containing silver nanoparticle (AgNPs) to enhance antibacterial activity targeting to periodontal bacteria. Prior to an electrospinning (ELSP), AgNPs was directly synthesized by silver nitrate with capping agent within dimethylformamide (DMF) for use as an ELSP solvent. The fabricated products were cross-linked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) followed by characterized via theoretical analysis. In results, AgNPs were not only perfectly synthesized without a reduction agent, but also electrospun nanofiber (EN) containing AgNPs was well fabricated with the modulation of AgNPs levels. Additionally, the presence of AgNPs within the fiber strand was clearly shown. In the antibacterial test, the developed oral wound dressing showed excellent antibacterial activity as increasing content of the AgNPs. All of tests clearly confirmed that our strategy may suggest a useful paradigm as oral wound dressing to prevent of a bacterial infection as means to oral wound dressing of gingiva and periodontal tissues for obviation of periodontitis.

Recently, implantable neural electrodes have been developed for recording and stimulation of the nervous system. However, when the electrode is implanted onto the nerve trunk, the rigid polyimide has a risk of damaging the nerve and can also cause inflammation due to a mechanical mismatch between the stiff polyimide and the soft biological tissue. These processes can interrupt the transmission of nerve signaling. In this paper, we have developed a nerve electrode coated with PEG hydrogel that contains poly(lactic-co-glycolic) acid (PLGA) microspheres (MS) loaded with anti-inflammatory cyclosporin A (CsA). Micro-wells were introduced onto the electrode in order to increase their surface area. This allows for loading a high-dose of the drug. Additionally, chemically treating the surface with aminopropylmethacrylamide can improve the adhesive interface between the electrode and the hydrogel. The surface of the micro-well cuff electrode (MCE) coated with polyethylene glycol (PEG) hydrogel and drug loaded PLGA microspheres (MS) were characterized by SEM and optical microscopy. Additionally, the conductive polymers, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT/PSS), were formed on the hydrogel layer for improving the nerve signal quality, and then characterized for their electrochemical properties. The loading efficiencies and release profiles were investigated by High Performance Liquid Chromatography (HPLC). The drug loaded electrode resulted in a sustained release of CsA. Moreover, the surface coated electrode with PEG hydrogel and CsA loaded MP showed a significantly decreased fibrous tissue deposition and increased axonal density in animal tests. We expect that the developed nerve electrode will minimize the tissue damage during regeneration of the nervous system. Statement of Significance The nerve electrodes are used for interfacing with the central nervous system (CNS) or with the peripheral nervous system (PNS). The interface electrodes should facilitate a closed interconnection with the nerve tissue and provide for selective stimulation and recording from multiple, independent, neurons of the neural system. In this case, an extraneural electrodes such as cuff and perineural electrodes are widely investigated because they can completely cover the nerve trunk and provide for a wide interface area. In this study, we have designed and prepared a functionalized nerve cuff electrode coated with PEG hydrogel containing Poly lactic-co-glycol acid (PLGA) microspheres (MS) loaded with cyclosporine A (CsA). To our knowledge, our findings suggest that surface coating a soft-hydrogel along with an anti-inflammatory drug loaded MS can be a useful strategy for improving the long-term biocompatibility of electrodes.

Osteoporosis, a major skeletal disorder, is an increasing worldwide social burden among the aging society, which develops when the ratio of bone resorption regulated by osteoclasts reverses the bone formation in the bone remodeling cycle. Basically, osteoporosis is commonly treated using bone resorption inhibitors such as bisphosphonates. However, long-term intake of bisphosphonates exposes patients to traumatic side effects such as digestive disorders and medication-related osteonecrosis of the jaw (MRONJ). Therefore, an alternative solution is required in the area of bone tissue engineering. Hence, to solve this issue, in this study, we designed GNPs and functionalized GNPs’ surface through conjugation with SH-PEG-vitamin D (SPVD) via the Au-S binding system. Vitamin D-conjugated GNPs (VGNPs) were successfully synthesized and confirmed by various physicochemical analyses. These conjugated nanoparticles significantly increased cell viability and decreased tartrate-resistant acid phosphatase (TRAP) activity and actin ring formation. In addition, VGNPs suppressed the expression of genes associated with osteoclast differentiation. Finally, VGNPs also significantly inhibited the expression of reactive oxygen species (ROS). These results demonstrate the inhibitory effect of VGNPs on osteoclast differentiation and suggest that the developed nanocarriers could play a key role as a bone resorption inhibitor in the field of bone tissue engineering.

Air-jet spinning has been used to fabricate fibers with nano-micro diameters and is widely applied in medical products such as wound treatment patches, gauze, and graft scaffolds. In particular, wounds vary from light to deep, and basically the wound is vulnerable to infection by external harmful factors. Therefore, blocking harmful factors from entering the wound area is very important. In addition, the wound site has high levels of oxidative stress, and thus the use of antioxidants is suggested as a good solution for wound treatment. We developed wound healing agents using gelatin, which shows excellent biocompatibility, catechin, which has high antioxidant activity, and polycaprolactone, which was spun on catechin and gelatin films, to produce a double layered structure using air-jet spinning. This structure blocked harmful external factors and is a candidate for efficient wound treatment.

Graphene oxide as a radon barrier in living environments was introduced by intercalating the polymer resin-coated layer inside a multilayer membrane with an area of 1 × 10 m and a thickness of 2.5 mm, prepared by the roll-to-roll method. A 5 μm-thick graphene oxide polymer resin (GOPR) layer was coated on polyethylene terephthalate (PET) film (100 μm) between the two styrene-butadiene-styrene (SBS)-modified bitumen asphalt layers fitted for construction sites. The inserted graphene oxide materials were characterized by means of infrared, Raman, and X-ray photoelectron spectroscopy (XPS). Dispersion-corrected density functional theory (DFT) calculations suggested weaker binding energies on the oxide surfaces and higher penetration energy barriers of graphene nanopores for radon (222Rn) than in the cases of the atmospheric gas molecules Ar, H2O, CO2, H2, O2, and N2. Theoretical calculations of the graphene nanopores supported the higher barrier energies of 222Rn than most ambient gases. The roll-to-roll prepared graphene materials exhibited good barrier properties for 222Rn as well as for the ambient gases. The purpose of our experimental and theoretical study is to provide a better understanding of using graphene-based materials to reduce the risk of carcinogenic radon gas in construction sites and residential buildings for practical applications.

Donghyun Lee,1 Dong Nyoung Heo,2 Ha Ram Nah,3 Sang Jin Lee,1 Wan-Kyu Ko,4 Jae Seo Lee,3 Ho-Jin Moon,1 Jae Beum Bang,5 Yu-Shik Hwang,6 Rui L Reis,1,7 Il Keun Kwon1 1Department of Dental Materials, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea; 2Department of Engineering Science and Mechanics, Pennsylvania State University, Pennsylvania 16802, USA; 3Department of Detistry, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea; 4Department of Neurosurgery, CHA Bundang Medical Center, CHA University, Seongnam-si, Gyeonggi-do 13496, Republic of Korea; 5Department of Dental Education, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea; 6Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea; 7The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, Barco, Guimarães, Portugal Background: For effective bone regeneration, it is necessary to implant a biocompatible scaffold that is capable of inducing cell growth and continuous osteogenic stimulation at the defected site. Here, we suggest an injectable hydrogel system using enzymatic cross-linkable gelatin (Gel) and functionalized gold nanoparticles (GNPs). Methods: In this work, tyramine (Ty) was synthesized on the gelatin backbone (Gel-Ty) to enable a phenol crosslinking reaction with horseradish peroxidase (HRP). N-acetyl cysteine (NAC) was attached to the GNPs surface (G-NAC) for promoting osteo-differentiation. Results: The Gel-Ty hydrogels containing G-NAC (Gel-Ty/G-NAC) had suitable mechanical strength and biocompatibility to embed and support the growth of human adipose derived stem cells (hASCs) during a proliferation test for three days. In addition, G-NAC promoted osteo-differentiation both when it was included in Gel-Ty and when it was used directly in hASCs. The osteogenic effects were demonstrated by the alkaline phosphatase (ALP) activity test. Conclusion: These findings indicate that the phenol crosslinking reaction is suitable for injectable hydrogels for tissue regeneration and G-NAC stimulate bone regeneration. Based on our results, we suggest that Gel-Ty/G-NAC hydrogels can serve both as a biodegradable graft material for bone defect treatment and as a good template for tissue engineering applications such as drug delivery, cell delivery, and various tissue regeneration uses. Keywords: nanomaterial, gelatin, enzymatic cross-linking, osteogenesis, N-acetyl cysteine

Nucleic acid preparation (concentration and purification of various nucleic acid targets) from biological samples is essential for personalized and precision medicine. The adsorption of short-length DNA on graphene oxide (GO) layers was investigated and compared with that on silica surfaces. GO was efficiently coated on glass beads to be used more easily and spatially. Surface of the GO bead was confirmed by field-emission scanning electron microscopy. GO-coated beads were packed and the adsorption conditions of short-length DNA were optimized under various pH and flow rate conditions. The amount of adsorbed DNA was confirmed by real-time polymerase chain reaction and visualized using fluorescence microscopy.

Dopamine is a key molecule in neurotransmission and has been known to be responsible for several neurological diseases. Hence, its sensitive and selective detection is important for the early diagnosis of diseases related to abnormal levels of dopamine. In this study, we reported a new cylindrical gold nanoelectrode (CAuNE) platform fabricated via sequential laser interference lithography and electrochemical deposition. Among the fabricated electrodes, CAuNEs with a diameter of 700 nm, 150 s deposited, was found to be the best for electrochemical dopamine detection. According to cyclic voltammetry results, the linear range of the CAuNE-700 nm was 1–100 µM of dopamine with a limit of detection (LOD) of 5.83 µM. Moreover, owing to the homogeneous periodic features of CAuNEs, human neural cells were successfully cultured and maintained for more than 5 days in vitro without the use of any extracellular matrix proteins and dopamine was detectable in the presence of these cells on the electrode. Therefore, we concluded that the developed dopamine sensing platform CAuNE can be used for many applications including early diagnosis of neurological diseases; function tests of dopaminergic neurons derived from various stem cell sources; and toxicity assessments of drugs, chemicals, and nanomaterials on human neuronal cells.

The aim of this study was to investigate the anti-inflammatory effects by ursodeoxycholic acid (UDCA) in rats with a spinal cord injury (SCI). A moderate mechanical compression injury was imposed on adult Sprague-Dawley (SD) rats. The post-injury locomotor functions were assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale and the tissue volume of the injured region was analyzed using hematoxylin and eosin staining. The pro-inflammatory factors were evaluated by immunofluorescence (IF) staining, a quantitative real-time polymerase chain reaction (qRT-PCR), and enzyme-linked immunosorbent assay (ELISA). The phosphorylation of the extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 in mitogen-activated protein kinase (MAPK) signaling pathways related to inflammatory responses were measured by Western blot assays. UDCA improved the BBB scores and promoted the recovery of the spinal cord lesions. UDCA inhibited the expression of glial fibrillary acidic protein (GFAP), tumor necrosis factor-α (TNF-α), ionized calcium-binding adapter molecule 1 (iba1), and inducible nitric oxide synthase (iNOS). UDCA decreased the pro-inflammatory cytokines of TNF-α, interleukin 1-β (IL-1β), and interleukin 6 (IL-6) in the mRNA and protein levels. UDCA increased the anti-inflammatory cytokine interleukin 10 (IL-10) in the mRNA and protein levels. UDCA suppressed the phosphorylation of ERK, JNK, and the p38 signals. UDCA reduces pro-inflammatory responses and promotes functional recovery in SCI in rats. These results suggest that UDCA is a potential therapeutic drug for SCI.

Radon exhalation rates have been determined for samples of concrete, gypsum board, marble, and tile among building materials that are used in domestic construction environment. Radon emanation was measured using the closed chamber method based on CR-39 nuclear track detectors. The radon concentrations in apartments of 100 households in Seoul, Busan and Gyeonggi Provinces were measured to verify the prediction model of indoor radon concentration. The results obtained by the four samples showed the largest radon exhalation rate of 0.34314 Bq/m 2 ·h for sample concrete. The radon concentration contribution to indoor radon in the house due to exhalation from the concrete was 31.006 ± 7.529 Bq/m 3 . The difference between the prediction concentration and actual measured concentration was believed to be due to the uncertainty resulting from the model implementation. Key words : Radon emanation, Radon exhalation rates, Building materials, Nuclear track detector(NTD), Prediction model

A new method of growing a semi-insulating GaN layer for high electron mobility transistor (HEMT) structure by eliminating a degenerate layer located at the GaN/sapphire interface is proposed. In the process, during the temperature ramp-up after the growth of a low temperature GaN buffer layer, trimethylgallium (TMGa) was flowed into the reactor together with ammonia, leading to the growth of an additional GaN layer of high carbon concentration. We confirmed that the introduction of TMGa induced high carbon concentration in the degenerate layer. The incorporated carbon formed deep acceptors, CN, compensating donors such as ON, resulting in the elimination of the degenerate layer. A HEMT device made on the sample grown by the new growth process shows a good pinch-off characteristic and high off-state breakdown voltage over 800 V at a gate voltage of −4 V, indicating the new scheme is effective to grow a high quality semi-insulating GaN layer.

Initiated chemical vapor deposition (iCVD) was utilized to generate a 200nm thick, uniform, functionalized polymer nanolayer comprised of glycidyl methacrylate (GMA) on the surface of titanium implants as a means to improve cellular attachment. Dot-patterned GMA-coated specimens were prepared as well as fully coated specimens. In vitro cellular responses, including cell morphology, protein adsorption, cell proliferation assays, alkaline phosphate activity (ALP) assays, and calcium deposition assays were studied using adipose derived stem cells. The mechanical stability of the thin film was investigated by XPS and FE-SEM analysis of the GMA-coated implant after implantation to an extracted bone from a pig. The GMA-coated specimens displayed increased protein adsorption, higher alkaline phosphatase activities, and higher calcium deposition as compared to control sample with no cytotoxicity. Additionally, no defect was observed in the test of mechanical stability. Notably, dot-patterned GMA-coated samples displayed higher alkaline phosphatase activities than others. Functionalized polymer nanolayer deposition via iCVD is a flexible and robust technique capable of mass production of biocompatible layers. These properties make this technique very suitable for implant applications in a variety of ways.

In the last decade, titanium has been effectively used in the dental field for oral surgery as an implant material. However, disinfected Ti can be easily re-infected by the surrounding environment. Thus, a novel anti-fouling treatment for Ti implants is currently necessary. In this study, we designed an anti-fouling surface comprised of poly N-isopropylacylamide (PIPAAM) grafted Ti by introducing poly glycidyl methacrylate (pGMA) coating via an initiated chemical vapor deposition (iCVD) system to prevent bacterial infection. The results indicate that pristine Ti was well coated with pGMA with a film thickness of approximately 60 nm and uniformly grafted with PIPAAM. The bacteria were effectively detached after rinsing with a buffer solution at room temperature, while hADSCs were well attached on the surface treated Ti surface at oral temperature. All tests clearly confirm that our strategy may be a useful means of imparting anti-fouling characteristics to Ti in order to prevent bacterial adhesion and resultant peri-implantitis.