Development of a plasma-based 3D printing system for enhancing the biocompatibility of 3D scaffold.

Fused deposition modeling (FDM) is a three-dimensional (3D) printing technology typically used in tissue engineering. However, 3D-printed row scaffolds manufactured using material extrusion techniques have low cell affinity on the surface and an insufficient biocompatible environment for desirable tissue regeneration. Thus, in this study, plasma treatment was used to render surface modification for enhancing the biocompatibility of 3D-printed scaffolds. We designed a plasma-based 3D printing system with dual heads comprising a plasma device and a regular 3D FDM printer head for a layer-by-layer nitrogen plasma treatment. Accordingly, the wettability, roughness, and protein adsorption capability of the 3D-printed scaffold significantly increased with the plasma treatment time. Hence, the layer-by-layer plasma-treated (LBLT) scaffold exhibited significantly enhanced cell adhesion and proliferation in anin vitroassay. Furthermore, the LBLT scaffold demonstrated a higher tissue infiltration and lower collagen encapsulation than those demonstrated by a non-plasma-treated scaffold in anin vivoassay. Our approach has great potential for various tissue-engineering applications via the adjustment of gas or precursor levels. In particular, this system can fabricate scaffolds capable of holding a biocompatible surface on an entire 3D-printed strut. Thus, our one-step 3D printing approach is a promising platform to overcome the limitations of current biocompatible 3D scaffold engineering.

Pharmacy Students' Attitudes Toward Persons With Disabilities and Perceptions of Right to Self-Determination.

Objective. As the number of persons with disabilities increases, pharmacists are responsible for providing optimal pharmaceutical care services to more patients in this population. The purpose of this study was to assess pharmacy students' perceptions of the right of persons with disabilities to self-determination and to identify factors that affect pharmacists' attitudes and perceptions.Methods. A survey of 370 pharmacy students was conducted. The revised Korean versions of the Scale of Attitudes Towards Disabled Persons (SADP) and the Attitudes Toward Disabled Persons Form O (ATDP-O) were used to measure attitudes toward persons with disabilities. Pharmacy students' perception of the right of persons with disabilities to self-determination was measured in 2 subdomains developed by education and ethics experts: absoluteness of right and social support.Results. Responses from 363 pharmacy students were included in the analysis. We found that the more contact students had with persons with disabilities in the past, the more positive attitudes they had toward this patient group. In addition, students' understanding of self-determination and positive attitudes toward persons with disabilities were determined to be statistically significant factors affecting pharmacy students' perceptions of both the absoluteness of right of persons with disabilities and the level of social support that should be given to this patient group.Conclusion. Since experience relating to people with disabilities is associated with pharmacy students' positive perceptions about the right of persons with disabilities to self-determination, education and activities are needed in the pharmacy curriculum to ensure students have experiences with this patient group.

The Effectiveness of Compartmentalized Bone Graft Sponges Made Using Complementary Bone Graft Materials and Succinylated Chitosan Hydrogels.

Bone defects can occur from many causes, including disease or trauma. Bone graft materials (BGMs) have been used to fill damaged areas for the reconstruction of diseased bone tissues since they are cost effective and readily available. However, BGMs quickly disperse around the tissue area, which ultimately leads to it migrating away from the defect after transplantation. We tested chitosan hydrogels as a useful carrier to hold BGMs in the transplantation area. In this study, we synthesized succinylated chitosan (SCS)-based hydrogels with a high decomposition rate and excellent biocompatibility. We confirmed that BGMs were well distributed inside the SCS hydrogel. The SCS-B hydrogel showed a decrease in mechanical properties, such as compressive strength and Young's modulus, as the succinylation rate increased. SCS-B hydrogels also exhibited a high cell growth rate and bone differentiation rate. Moreover, the in vivo results showed that the SCS hydrogel resorbed into the surrounding tissues while maintaining the BGMs in the transplantation area for up to 6 weeks. These data support the idea that SCS hydrogel can be useful as a bioactive drug carrier for a broad range of biomedical applications.

Facile Preparation of ß-Cyclodextrin-grafted Chitosan Electrospun Nanofibrous Scaffolds as a Hydrophobic Drug Delivery Vehicle for Tissue Engineering Applications.

Despite advances in the bio-tissue engineering area, the technical basis to directly load hydrophobic drugs on chitosan (CTS) electrospun nanofibers (ENs) has not yet been fully established. In this study, we fabricated CTS ENs by using an electrospinning (ELSP) system, followed by surface modification using succinyl-beta-cyclodextrin (ß-CD) under mild conditions. The ß-CD-modified CTS (ßCTS) ENs had slightly increased hydrophobicity compared to pristine CTS ENs as well as decreased residual amine content on the surface. Through FTIR spectroscopy and thermogravimetric analysis (TGA), we characterized the surface treatment physiochemically. In the drug release test, we demonstrated the stable and sustained release of a hydrophobic drug (e.g., dexamethasone) loaded on ß-CD ENs. During in vitro biocompatibility assessments, the grafting of ß-CD was shown to not reduce cell viability compared to pristine CTS ENs. Additionally, cells proliferated well on ß-CD ENs, and this was confirmed by F-actin fluorescence staining. Overall, the material and strategies developed in this study have the potential to load a wide array of hydrophobic drugs. This could be applied as a drug carrier for a broad range of tissue engineering applications.

Simple and facile preparation of recombinant human bone morphogenetic protein-2 immobilized titanium implant via initiated chemical vapor deposition technique to promote osteogenesis for bone tissue engineering application.

Over the past few decades, titanium (Ti) implants have been widely used to repair fractured bones. To promote osteogenesis, immobilization of osteoinductive agents, such as recombinant human bone morphogenic protein-2 (rhBMP2), onto the Ti surface is required. In this study, we prepared rhBMP2 immobilized on glycidyl methacrylate (GMA) deposited Ti surface through initiated chemical vapor deposition (iCVD) technique. After preparation, the bio-functionalized Ti surface was characterized by physicochemical analysis. For in vitro analysis, the developed Ti was evaluated by cell proliferation, alkaline phosphatase activity, calcium deposition, and real-time polymerase chain reaction to verify their osteogenic activity against human adipose-derived stem cells (hASCs). The GMA deposited Ti surface was found to effectively immobilize a large dose of rhBMP2 as compared to untreated Ti. Additionally, rhBMP2 immobilized on Ti showed significantly enhanced osteogenic differentiation and increased calcium deposition with nontoxic cell viability. These results clearly confirm that our strategy may provide a simple, solvent-free strategy to prepare an osteoinductive Ti surface for bone tissue engineering applications.

Injectable hydrogel composite containing modified gold nanoparticles: implication in bone tissue regeneration.

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 osteodifferentiation. 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 osteodifferentiation 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.

Inhibition of Osteoclast Differentiation and Bone Resorption by Bisphosphonate-conjugated Gold Nanoparticles.

In recent years, gold nanoparticles (GNPs) have been reported to affect the regeneration of bone tissue. The goal of this study was to improve bone tissue regeneration by using targeted GNPs. We fabricated a functionalized GNPs conjugated with alendronate (ALD), of the bisphosphonate group. Subsequently, the ALD, GNPs, and ALD conjugated GNPs (GNPs-ALD) were analyzed by ultraviolet-visible absorbance (UV-vis) spectrophotometer, Attenuated total reflectance Fourier transform infrared spectrometer (ATR-FTIR), and thermo gravimetric analysis (TGA). The prepared GNPs-ALD were used to investigate their inhibitory effects on the receptor activator of nuclear factor- κb ligand (RANKL)-induced osteoclastogenesis in bone marrow-derived macrophages (BMMs). Additionally, the GNPs-ALD were applied to ovariectomy (OVX)-induced osteoporotic mice and the experiments were evaluated. ALD was found to be successfully conjugated to the GNPs surface, and it displayed significant adhesion onto the bone surface. The in-vitro study indicated that the GNPs, ALD and GNPs-ALD suppressed osteoclast formation in a dose-dependent manner. Furthermore, in the OVX mouse model, the mice treated GNPs-ALD had higher bone density as compared to other OVX mice groups. The results from these tests indicated that GNPs-ALD can be useful agents for preventing and treating osteoporosis.

Characteristics of Mesiodens and Its Related Complications.

PURPOSE: The purpose of this study was to evaluate the effect of mesiodens on adjacent permanent anterior teeth according to mesiodens characteristics. METHODS: To evaluate complications associated with mesiodens, according to its characteristics, a total of 107 children were studied who had a chief complaint of mesiodens. The number, morphology, direction of eruption, position of mesiodens, root developmental stage and complications related to adjacent permanent maxillary central incisors (APMCIs) were evaluated by radiographic imaging. RESULTS: The final sample was 107 children and total number of mesiodens was 153. Among these patients, 67 percent showed clinical complications. The primary morphologic type was conical (96.1 percent) and the most common direction of eruption was inverted (56.2 percent). Most mesiodens (80.4 percent) were located on the palatal side of the APMCIs. CONCLUSIONS: The direction of mesiodens and the eruption period of adjacent permanent incisors affected the complication rate. The positional relationship between mesiodens and adjacent permanent central incisors had the strongest influence on both eruption disturbance and displacement of permanent central incisors.

Inhibition of osteoclast differentiation by gold nanoparticles functionalized with cyclodextrin curcumin complexes.

Gold nanoparticles (GNPs) have been previously reported to inhibit osteoclast (OC) formation. However, previous research only confirmed the osteoclastogenesis inhibitory effect under in vitro conditions. The aim of this study was to develop a therapeutic agent for osteoporosis based on the utilization of GNPs and confirm their effect both in vitro and in vivo. We prepared ß-cyclodextrin (CD) conjugated GNPs (CGNPs), which can form inclusion complexes with curcumin (CUR-CGNPs), and used these to investigate their inhibitory effects on receptor activator of nuclear factor-κb ligand (RANKL)-induced osteoclastogenesis in bone marrow-derived macrophages (BMMs). The CUR-CGNPs significantly inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells in BMMs without inducing cytotoxicity. The mRNA expressions of genetic markers of OC differentiation including c-Fos, nuclear factor of activated T cells 1 (NFATc1), TRAP, and osteoclast associated receptor (OSCAR) were significantly decreased in the presence of CUR-CGNPs. In addition, the CUR-CGNPs inhibited OC differentiation of BMMs through suppression of the RANKL-induced signaling pathway. Additionally, CUR-CGNPs caused a decrease in RANKL-induced actin ring formation, which is an essential morphological characteristic of OC formation allowing them to carry out bone resorption activity. Furthermore, the in vivo results of an ovariectomy (OVX)-induced osteoporosis model showed that CUR-CGNPs significantly improved bone density and prevented bone loss. Therefore, CUR-CGNPs may prove to be useful as therapeutic agents for preventing and treating osteoporosis.

[Team dynamics and clinical performance of medical students in web-based and high-fidelity simulations].

PURPOSE: The importance of team dynamics with regard to clinical performance is being emphasized to improve patient safety and the quality of health care. The aim of this study was to examine the correlation and differences in team dynamics and team clinical performance in a web-based simulation (WS) and high-fidelity simulation (HS) in the medical students. METHODS: The simulations were held for 15 teams of fourth year medical students (n=52). They were given two clinical cases, dyspnea (case 1) and chest pain (case 2) by WS and then HS. The scores on the team dynamics and the team's clinical performance were analyzed by paired t-test and multiple regression using SPSS version 21.0 (IBM Corp.). RESULTS: The teamwork scores on case 2 (22.67 ± 6.58) were higher than for case 1 in the HS (20.47 ± 7.22). Team clinical performance scores were the same the WS and HS. Team clinical performances were significantly associated with team dynamics in both cases by HS. Teamwork scores of team dynamics were each explanation on case 1 (74.9%), case 2 (63.4%) in the HS. CONCLUSION: The team dynamics and clinical performance can improve if undergraduate medical students have more opportunities. They should be trained in these endeavors to become future doctors for which scenario-based simulations could be valuable.

Correlation between clinical clerkship achievement and objective structured clinical examination (OSCE) scores of graduating dental students on conservative dentistry.

OBJECTIVES: This study aimed to investigate the effect of clinical clerkship-associated achievements, such as performance of procedures at the student clinic, observation, and attitude towards a clerkship, on the objective structured clinical examination (OSCE) scores of dental students graduating in restorative dentistry. MATERIALS AND METHODS: The OSCEs consisted of two stations designed to assess students' clinical skills regarding cavity preparation for a class II gold inlay and a class IV composite restoration. The clerkship achievements, consisting of the number of student clinical procedures performed, observation-related OSCE, and scores of their attitudes towards a conservative dentistry clerkship, were assessed. Correlation and multiple regression analyses were conducted. RESULTS: The correlation coefficient between the OSCE scores for cavity preparation for a class II gold restoration and clerkship attitude scores was 0.241 (p < 0.05). Regarding a class IV composite restoration, OSCE scores showed statistically significant correlations with the observation (r = 0.344, p < 0.01) and attitude (r = 0.303, p < 0.01) scores. In a multiple regression analysis, attitudes towards a clerkship (p = 0.033) was associated with the cavity preparation for a class II gold inlay OSCE scores, while the number of procedure observations (p = 0.002) was associated with the class IV composite restoration OSCE scores. CONCLUSIONS: The number of clinical procedures performed by students, which is an important requirement for graduation, showed no correlation with either of the OSCEs scores.

Coenzyme q10 regulates osteoclast and osteoblast differentiation.

Coenzyme Q10 (CoQ10), a powerful antioxidant, is a key component in mitochondrial bioenergy transfer, generating energy in the form of ATP. Many studies suggest that antioxidants act as inhibitors of osteoclastogenesis and we also have previously demonstrated the inhibitory effect of CoQ10 on osteoclast differentiation. Despite the significance of this effect, the molecular mechanism when CoQ10 is present at high concentrations in bone remodeling still remains to be elucidated. In this study, we investigated the inhibitory effect of CoQ10 on osteoclastogenesis and its impact on osteoblastogenesis at concentrations ranging from 10 to 100 µM. We found that nontoxic CoQ10 markedly attenuated the formation of receptor activator of nuclear factor κB ligand (RANKL)-induced tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells in both bone-marrow-derived monocytes (BMMs) and RAW 264.7 cells. Osteoclastogenesis with CoQ10 was significantly suppressed the gene expression of NFATc1, TRAP, and osteoclast-associated immunoglobulin-like receptor, which are genetic markers of osteoclast differentiation and scavenged intracellular reactive oxygen species, an osteoclast precursor, in a dose-dependent manner. Furthermore, CoQ10 strongly suppressed H2 O2 -induced IκBα, p38 signaling pathways for osteoclastogenesis. In bone formation study, CoQ10 acted to enhance the induction of osteoblastogenic biomarkers including alkaline phosphatase, type 1 collagen, bone sialoprotein, osteoblast-specific transcription factor Osterix, and Runt-related transcription factor 2 and, also promoted matrix mineralization by enhancing bone nodule formation in a dose-dependent manner. Together, CoQ10 acts as an inhibitor of RANKL-induced osteoclast differentiation and an enhancer of bone-forming osteoblast differentiation. These findings highlight the potential therapeutic applications of CoQ10 for the treatment of bone disease.

Short-term response of mitomycin C on the human rectus muscle following strabismus surgery: histological, ultrastructural, and biomechanical evaluation.

This study investigated the inflammatory effect of intraoperative mitomycin C (MMC) on adhesion reformation in human rectus muscles. Ten consecutive patients who underwent medial rectus resection had their postoperative rectus muscles divided into two groups: control group (n = 10) and MMC group (n = 10). In the MMC group, the muscle was soaked for 2 min with MMC, prepared as a 0.2 mg/mL (0.02%) solution. The 0.02% MMC reactions were examined using histological analysis with hematoxylin-eosin (inflammatory response) and Masson's trichrome (collagen fibrils), immunoreactivities of cyclooxygenase-II (inflammatory response), and collagen type I and III, scanning electron microscopy analysis to quantify the diameter and D-periodicity of collagen fibrils, and atomic force microscopy analysis to quantify the diameter, D-periodicity, and adhesion force of collagen fibrils. The rectus muscles treated with 0.02% MMC showed a significantly increased inflammatory response (p < 0.05), increased collagen density (p < 0.0001), increased fibril diameter (p < 0.001 or p < 0.05), and decreased fibril adhesion force (p < 0.005) compared to the rectus muscles in the control group. MMC simultaneously caused an inflammatory response as well as nanostructural and biomechanical property changes in the collagen fibril network.

ZrO2 surface chemically coated with hyaluronic acid hydrogel loading GDF-5 for osteogenesis in dentistry.

The objective of this study was to modify zirconium dioxide (ZrO(2)) with photo-cured hyaluronic acid hydrogel (pcHAgel), and to subsequently evaluate the bone regeneration potential of the modified ZrO(2). In the present study, HA grafted onto a ZrO(2) substrate was investigated for its biocompatibility and other properties. We describe the positive influences of ZrO(2) surface-modified with pcHAgel (Zr-3) containing two different loads of growth and differentiation factor-5 (GDF-5) to aid new bone formation as compared to the same amount of BMP-2 (Zr-4-7). We characterized the Zr-3 for their surface morphology and chemical properties. Atomic force microscopy (AFM), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) showed that the pcHAgel was successfully grafted onto the ZrO(2) surface. The sustained release of GDF-5 and BMP-2 were observed to occur in the Zr-4-7. In vitro cell tests showed a higher level of MG63 cell proliferation and differentiation on Zr-4-7 than on Zr-3. The Zr-3 is a good biomaterial to deliver osteogenic differentiation factors such as BMP-2 and GDF-5, and GDF-5 can be useful as an effective alternative to aid new bone formation as compared to BMP-2.

Current progress in Reactive Oxygen Species (ROS)-Responsive materials for biomedical applications.

Recently, significant progress has been made in developing "stimuli-sensitive" biomaterials as a new therapeutic approach to interact with dynamic physiological conditions. Reactive oxygen species (ROS) production has been implicated in important pathophysiological events, such as atherosclerosis,aging, and cancer. ROS are often overproduced locally in diseased cells and tissues, and they individually and synchronously contribute to many of the abnormalities associated with local pathogenesis. Therefore, the advantages of developing ROS-responsive materials extend beyond site-specific targeting of therapeutic delivery, and potentially include navigating,sensing, and repairing the cellular damages via programmed changes in material properties. Here we review the mechanism and development of biomaterials with ROS-induced solubility switch or degradation, as well as their performance and potential for future biomedical applications.

Porphyromonas gingivalis lipopolysaccharide regulates interleukin (IL)-17 and IL-23 expression via SIRT1 modulation in human periodontal ligament cells.

Increased interleukin (IL)-17 and IL-23 levels exist in the gingival tissue of periodontitis patients, but the precise molecular mechanisms that regulate IL-17 and IL-23 production remain unknown. The aim of this study was to explore the role of SIRT1 signaling on Porphyromonas gingivalis lipopolysaccharide (LPS)-induced IL-17 and IL-23 production in human periodontal ligament cells (hPDLCs). IL-17 and IL-23 production was significantly increased in LPS-treated cells. LPS treatment also led to the upregulation of SIRT1 mRNA and protein expression. LPS-induced IL-17 and IL-23 upregulation was attenuated by pretreatment with inhibitors of phosphoinositide 3-kinase (PI3K), p38, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), mitogen-activated protein kinase (MAPK), and NF-κB, as well as neutralizing antibodies against Toll-like receptors (TLRs) 2 and 4. Sirtinol treatment (a known SIRT1 inhibitor) or SIRT1 knockdown by small interfering RNA blocked LPS-stimulated IL-17 and IL-23 expression. Further investigation showed that LPS decreased osteoblast markers (i.e., ALP, OPN, and BSP) and concomitantly increased osteoclast markers (i.e., RANKL and M-CSF). This response was attenuated by inhibitors of the PI3K, p38, ERK, JNK, NF-κB, and SIRT1 pathways. These findings, for the first time, suggest that human periodontopathogen P. gingivalis LPS is implicated in periodontal disease bone destruction and may mediate IL-17 and IL-23 release from hPDLCs. This process is dependent, at least in part, on SIRT1-Akt/PI3K-MAPK-NF-κB signaling.

Simvastatin inhibits osteoclast differentiation by scavenging reactive oxygen species.

Osteoclasts, together with osteoblasts, control the amount of bone tissue and regulate bone remodeling. Osteoclast differentiation is an important factor related to the pathogenesis of bone-loss related diseases. Reactive oxygen species (ROS) acts as a signal mediator in osteoclast differentiation. Simvastatin, which inhibits 3-hydroxy-3-methylglutaryl coenzyme A, is a hypolipidemic drug which is known to affect bone metabolism and suppresses osteoclastogenesis induced by receptor activator of nuclear factor-κB ligand (RANKL). In this study, we analyzed whether simvastatin can inhibit RANKL-induced osteoclastogenesis through suppression of the subsequently formed ROS and investigated whether simvastatin can inhibit H2O2-induced signaling pathways in osteoclast differentiation. We found that simvastatin decreased expression of tartrate-resistant acid phosphatase (TRAP), a genetic marker of osteoclast differentiation, and inhibited intracellular ROS generation in RAW 264.7 cell lines. ROS generation activated NF-κB, protein kinases B (AKT), mitogen-activated protein kinases signaling pathways such as c-JUN N-terminal kinases, p38 MAP kinases as well as extracellular signal- regulated kinase. Simvastatin was found to suppress these H2O2-induced signaling pathways in osteoclastogenesis. Together, these results indicate that simvastatin acts as an osteoclastogenesis inhibitor through suppression of ROS-mediated signaling pathways. This indicates that simvastatin has potential usefulness for osteoporosis and pathological bone resorption.