[show abstract][hide abstract] ABSTRACT: The objective of this study was to investigate the enhanced osteoblast activity of MG-63 cells cultured on titanium (Ti) with a heparin/BMP-2 (Hep/BMP-2) complex. The Ti substrates were initially modified by chemical grafting poly-l-lysine (PLL) using condensing agent, followed by immobilizing the heparin/BMP-2 complex to the PLL-grafted Ti substrate via electrostatic interactions. The surface modification of Ti substrates with PLL and/or Hep/BMP-2 complex were confirmed with scanning electron microscopy, contact angle measurements, and X-ray photoelectron spectroscopy. Immobilized BMP-2 was released from the Hep/BMP-2/Ti substrate in a sustained manner. In vitro studies revealed that osteoblasts grown on Hep/BMP-2/Ti substrate increased ALP activity, calcium deposition, ALP and osteocalcin levels as compared to those grown on pristine Ti or PLL-Ti. These results indicated that heparin/BMP-2 complex immobilized Ti substrate can be useful to effectively improve osteoblast activity.
[show abstract][hide abstract] ABSTRACT: The influences of dielectric properties on the malignant cell adhesion and migration have been investigated. The Wistar Melanomas, primary (WM793) and metastatic (WM1205), respectively, were chosen as the model cell lines because of their pleomorphic and invasive characteristics, and the dielectric relaxation frequencies of the cells were determined using the impedance spectroscopy. Both WM793 and WM1205 showed the enhanced adhesion and the interesting changes in their morphology under the dielectric stimulations. However, it was found that the changed conditions of cell adhesion due to dielectric relaxation did not influence the migrational behavior of the cells.
Fetal ovine model for in-situ esophagus tissue engineering. 08/2013; 9(1). · 3.16 Impact Factor
[show abstract][hide abstract] ABSTRACT: The present study demonstrated that covalently galactosylated poly(D,L-lactic-co-glycolic acid) (PLGA) surface encourages hepatocyte adhesion and growth to form a dense cell network. Galactosylation of the PLGA surface was accomplished by grafting allylamine (AA) using inductively coupled plasma-assisted chemical vapor deposition (ICP-CVD) and conjugating lactobionic acid (LA) with AA via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide (EDC/NHS) activation. The modified surface was characterized by Fourier transform infrared spectroscopy in the attenuated total reflectance, electron spectroscopy of chemical analysis, atomic force microscopy, and contact angle measurement. For evaluation of cell affinity in vitro, primary rat hepatocytes were prepared and seeded onto the modified PLGA surfaces. The galactosylated PLGA surface showed more pronounced hepatocyte adhesion and growth compared to those on the control PLGA surface. The hepatocytes seeded on galactosylated substrates exhibited a radial migration with filopodial growth to form multicellular aggregates, whereas those on control PLGA showed slowly adhered rounded shapes. Moreover, galactosylation increased metabolic hepatocyte activities such as albumin secretion and urea synthesis.
Macromolecular Research 08/2013; 20(1). · 1.64 Impact Factor
[show abstract][hide abstract] ABSTRACT: The extracellular environment is an architectural support for tissue cells and stem cells, which is very important in cell adhesion, migration and differentiation. In this study, we prepared a self-assembled macromolecular matrix, naming it the preosteoblast-derived matrix (PDM). The primary focus was to characterize PDM in component and structure, and then to evaluate its osteogenic potential as a two-dimensional (2D) microenvironment. Preosteoblasts were cultured on a coverslip and then decellularized using a cocktail solution of detergents and enzymes, leaving a matrix without the cellular components. The surface of the PDM had a fibrillar mesh structure, as imaged by scanning electron microscope (SEM). The compositions of PDM, fibronectin, type I collagen, and laminin were identified using immunofluorescent staining. Adjustment of culture time or cell seeding density produced not only different compositional disparity in quantity, but also showed distinct pattern of macromolecule assembly. F-Actin staining revealed that early cell morphology was quite different as the type of substrates changed. Preosteoblasts were much more elongated on PDM to a certain direction and soft in their adhesion. Cells were proliferating faster in PDM as compared to the coverslip (control) or the gelatin-coated surface. When they were cultured for 2 weeks in three different substrates, von Kossa staining exhibited that calcium deposits were much densely formed over PDM. This result was also quantitatively supported by calcium assay. Measurement of alkaline phosphatase (ALP) activity demonstrated the positive effect of PDM, with higher ALP activity than the other groups. The present study indicates that naturally derived macromolecular matrix is able to carry major protein components as well as a fibrillar structure and that it may provide preosteoblasts with a favorable surface microenvironment for osteogenic differentiation.
Macromolecular Research 08/2013; 20(8). · 1.64 Impact Factor
[show abstract][hide abstract] ABSTRACT: The objective of the present study was to investigate in vitro biocompatibility of ultra high molecular weight polyethylene (UHMWPE)/zirconia-polymerized composite (PC) using human peripheral blood mononuclear cells (PBMCs). This study was undertaken to compare the levels of free radical generations for neat UHMWPE and PC through irradiation sterilization, and their response to PBMCs viability. Electron spin resonance (ESR) studies showed that γ-ray irradiation of the samples generated free radicals; the extent was inversely related to zirconia content, and the free radicals strongly influenced cell viability. DNA fragmentation and DAPI staining assays revealed that cell death was associated with the induction of apoptosis. Flow cytometry also showed that cell death was largely dependent upon both early and late apoptosis, and, importantly, oxidized PC (ox-PC) exhibited a significantly lower rate for late apoptosis compared to that of oxidized UHMWPE (ox-UHMWPE).
Macromolecular Research 08/2013; 21(1). · 1.64 Impact Factor
[show abstract][hide abstract] ABSTRACT: The objective of the present study was to evaluate non-woven chitosan/poly(lactic-co-glycolic acid) fibrous scaffold (chitosan/PLGA FS) prepared by a co-electrospinning process for tissue engineering applications, as compared to chitosan and PLGA FSs. The morphological, structural, and mechanical properties of the FSs were assessed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy-attenuated total reflection mode (FTIR-ATR), and a universal testing machine (UTM). The biocompatibility of the FSs was also evaluated in vitro in cultures of mouse fibroblasts and in vivo by subcutaneous implantation studies in rats. SEM image of the chitosan/PLGA FS showed morphological similarities to the natural ECM, characterized by high surface-to-volume ratio, high porosity, and variable pore size distributions. The FTIR-ATR spectrum of chitosan/PLGA FS revealed incorporation of the characteristic bands of chitosan and PLGA, indicating the co-existence of two fibrous structures. The poor mechanical properties of chitosan FS was improved by co-electrospinning with PLGA. In vitro L929 cell proliferation assay revealed that the cytocompatibility of chitosan/PLGA FS was increased compared to that of PLGA. In addition, chitosan/PLGA FS showed the improved ability to resolve foreign body reactions compared to PLGA FS due to the presence of chitosan.
Macromolecular Research 08/2013; 21(8). · 1.64 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to examine the degree of adherence of silicone oil to various intraocular lenses (IOLs) through comparison of the physico-chemical properties of the oil and IOLs. Four kinds of IOLs comprising various biomaterials were examined: PMMA (720A™), PHEMA (IOGEL 1103™), Acrysof (MA60BM™), and silicone (SI30NB™). Each lens was immersed in silicone oil or carboxylated silicone (CS-PDMS) oil for 72 h. For determination of the changes in chemical and elemental compositions on the surfaces of IOLs caused by the contact with silicone oil, IOLs were washed and rinsed with n-pentane to remove as much of the adsorbed silicone oil as possible, then subjected to Fourier transform infrared spectroscopic (FTIR) and X-ray photoelectron spectroscopic (XPS) analyses.The results of FTIR studies strongly indicate that washing with n-pentane completely removed the adhered silicone oil on the surfaces of PHEMA and Acrysof IOLs, whereas the residual silicone oil was detected on the surfaces of PMMA and silicone IOLs. XPS studies showed that silicone oil coverage of PMMA lenses was 12%, even after washing with n-pentane. In the case of silicone IOLs, the relative O1s peak area of carboxyl group in the residual CS-PDMS oil was found to be ∼2.7%. Considering that 2.8% carboxyl group-substituted silicone oil was used in the present study, CS-PDMS oil covered the entire surface of the silicone IOLs.
[show abstract][hide abstract] ABSTRACT: The purpose of this study is to understand the effect of chitin on macrophage mediated immunity, which is a significant factor to wound healing and tissue regeneration. In this work, water soluble chitin (WSC) was prepared by re-acetylation of chitosan and was treated with the murine RAW 264.7 macrophage cell lines (ATCC TIB-71). WSC induced classical activation in the RAW 264.7 cells, accompanied by the induction of associated genes. The results suggest that WSC is one of the functional chitin molecules that are responsible for the immune response, especially present in macrophage classical activation.
[show abstract][hide abstract] ABSTRACT: Host genomic alterations in addition to human papillomavirus (HPV) are needed for cervical precursor lesions to progress to invasive cancer because only a small percentage of women infected by the virus develop disease. However, the genomic alterations during the progression of cervical lesions have not been systematically examined. The aim of this study was to identify differential genomic alterations among cervical intraepithelial neoplasia CIN1, CIN2, CIN3 and cervical squamous cell carcinoma (SCC). Genomic alterations were examined for 15 cases each of CIN1, CIN2, CIN3 and SCC by array-based comparative genomic hybridization (array CGH). The chromosomal regions showing significant differential in DNA copy number aberrations (DCNAs) among CIN1, CIN2, CIN3 and SCC were successfully identified by resampling-based t-test. The chromosomal regions of 5q35.3 and 2q14.3 showed significant DCNAs between CIN1 and CIN2, and between CIN2 and CIN3, respectively, while a significant difference in DCNAs between CIN3 and SCC was observed at 1q24.3, 3p14.1, 3p14.2, 5q13.2, 7p15.3, 7q22.1 and 13q32.3. In addition, the status of DCNAs in 1q43, 2p11.2, 6p11.2, 7p21.1, 7p14.3, 10q24.1, 13q22.3, 13q34 and 16p13.3 was conserved throughout the progression of CIN to SCC. The presence of differential and common DCNAs among CIN1, CIN2, CIN3 and SCC supports that the CIN progression may include continual clonal selection and evolution. This approach also identified 34 probe sets consistently overexpressed when amplified, suggesting an unbiased identification of candidate genes in SCC during cervical cancer progression.
International Journal of Oncology 09/2012; · 2.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: Wet processing of hydroxyapatite is useful in the preparation of a green body with a complex structure such as a porous body. For successful wet processing, a suspension with low viscosity and high solid loading is essential. The optimization of the suspension is typically achieved through the careful control of the parameters such as the amount of dispersant and the pH. The milling time was also presented as a significant parameter for the preparation of the suspension in this work. Excessive milling brought about an increase in viscosity, which subsequently resulted in a green body with reduced density. Due to the loose network of primary particles in the green body, the densification was not successfully achieved. The loose packing in the green body was attributed to the reduction of the absolute zeta potential with the increase in milling time.
Current Applied Physics 09/2012; 12:S71–S75. · 1.81 Impact Factor
[show abstract][hide abstract] ABSTRACT: Surface modification of biomaterials has been highlighted by biomedical engineers as a facile method for improving cell-biomaterial interactions without the expense and time required to develop new materials. In the present study, we investigated the influence of ion-etching on the surface characteristics of chitosan films using XPS and ATR FT-IR. The physiological behavior of human dermal fibroblasts (hDFs) grown on such surfaces was studied by evaluating adhesive and proliferative properties, and by examining surface morphologies of hDFs using AFM. hDFs displayed different shapes depending on the ion-etching time. hDFs grown on chitosan films ion-etched for 5 min displayed better development of lamellipodia and filopodia around the hDF periphery than did cells grown on nonmodified chitosan film, whereas hDFs did not spread well on films ion-etched for 20 min. Films ion-etched for 5 min or less had higher NH(2) and COOH contents, leading to enhanced hDF adhesion and proliferation.
[show abstract][hide abstract] ABSTRACT: In this work, the in vivo biodegradation of, biocompatibility of, and host response to various topographic scaffolds were investigated. Randomly oriented fibrous poly(L-lactide) (PLLA) nanofibers were fabricated using the electrospinning technique. A PLLA scaffold was obtained by salt leaching. Both the electrospun PLLA nanofibers and the salt-leaching PLLA scaffolds formed three-dimensional pore structures. Cytotoxicity studies, in which rat muscle-derived stem cells (rMDSCs) were grown on electrospun PLLA nanofibers or the salt-leaching PLLA scaffolds, revealed that the rMDSCs cell count on the PLLA nanofibers was slightly higher than that on the salt-leaching PLLA scaffolds. An in vivo study was carried out by implanting the scaffolds subcutaneously into rats to test the biodegradation, biocompatibility, and host response at regular intervals over 0-4 weeks. The degradation of the PLLA nanofibers 1, 2, and 4 weeks after initial implantation was more extensive than that observed for the salt-leaching PLLA scaffolds. PLLA nanofibers seeded the growth of larger fibrous tissue masses due to in vivo cellular infiltration into the randomly oriented fibrillar structures of the PLLA nanofibers. In addition, the inflammatory cell accumulation in PLLA nanofibers was lower than that in the salt-leaching PLLA scaffolds. These results indicate that the electrospun PLLA nanofibers may serve as a good scaffold to elicit fibrous cellular infiltration, to minimize host response, and to enhance tissue-scaffold integration.
Journal of Biomedical Materials Research Part A 03/2012; 100(7):1751-60. · 2.83 Impact Factor
[show abstract][hide abstract] ABSTRACT: There are growing demands for bioactive titanium implants that could shorten the healing period, promote faster rehabilitation, and thereby increase the success rate of treating patients with poor bone quality. A synthetic receptor-binding peptide mimicking bone morphogenetic protein-2 (BMP-2) was covalently linked to a titanium alloy with two types of topography-machined (TiMA) and rough (TiGB)-by using a chemical conjugation process. In vivo osseointegration capacity was evaluated chronologically using histomorphometric analysis at 2, 4, and 8 weeks after implantation in the distal femurs of rabbits. In the histologic examinations, peri-implant bone formation was more active around TiGB than TiMA. Compared to the control groups (nonconjugated TiMA and TiGB) at 2, 4, and 8 weeks, the peptide-conjugated groups (TiMA-P and TiGB-P) had more mature new bone, thicker trabeculae, more rapid bone maturation, and higher affinity index (percentage of new bone contact length) in histomorphometric analysis. Particularly, differences in the affinity index between the peptide-conjugated and nonconjugated groups were more pronounced at the early phase of peri-implant healing (2 and 4 weeks). However, at 8 weeks, enhanced bone formation was less prominent according to peptide conjugation, especially in specimens with a rough surface. The titanium alloys in the rabbit femurs led to a significant increase of bone growth when modified with bioactive peptides, especially during the early phase of bone healing. These results confirm that biochemical modifications of titanium surfaces can enhance the rate of bone healing compared with that of untreated titanium surfaces.
Connective tissue research 02/2012; 53(5):359-65. · 1.55 Impact Factor
[show abstract][hide abstract] ABSTRACT: Scaffold for cell therapy was prepared with poly (lactide-co-glicolide,
PLA/PGA (10:90). By using melt-spinning and draw texturing process, we
could prepare microfibrous bulky suture which had heterogeneous
macropore. Microfibrous structure has great potentiality as biomimicking
architecture for cell growth and maintaining cell functions. The result
of cell seeding showed that pore size, pore distribution, and fiber
fineness of sutures were suitable as a biocompatible scaffold in vitro
for NIH 3T3 Fibroblast cell. Also, we expect that prepared scaffold for
cell-therapy will provide numerous benefits as a noninvasive alternative
for tissue engineering applications.
[show abstract][hide abstract] ABSTRACT: Regenerative medicine, one of the most exciting and dynamic life science fields, is an emerging biomedical technology for assisting and accelerating the regeneration and repair of lost or damaged organs or body parts. Modern regenerative medicine is increasingly using three-dimensional structured scaffolds because they represent a wide range of morphological and geometric in vivo possibilities that can be tailored for each specific regenerative medicine application. This review focuses on polymeric scaffolds, a highly promising regenerative medicine strategy, summarizing some important issues related to various natural and synthetic scaffolding biomaterials, techniques on the design and fabrication of three-dimensional polymeric scaffolds to mimic the properties of the extracellular matrix, and clinical applications of polymeric scaffolds for tissue regeneration.
[show abstract][hide abstract] ABSTRACT: To effectively harness the great potential of stem cells, we designed a dual growth factor delivery system for the application toward stem cell differentiation into specific lineages. This system carries a core-shell structure within microcapsules made of poly(L-lactide-co-glycolide) (PLGA) and alginate, which were fabricated using a coaxial electro-dropping method. Both PLGA and alginate were supplied from the inner and outer nozzles, respectively. The size and shape of microcapsules were greatly varying depending on the variables: nozzle size, applied voltage, volumetric feeding ratio (PLGA:alginate), feeding rate, and polymer concentrations. Once proper conditions were met, single or multi PLGA cores were found settled within the microcapsules. From the microscopic images, wrinkled surfaces of microcapsules were observed, along with the PLGA cores inside the alginate domain. When two different microcapsules were made, switching the position of bone morphogenetic protein (BMP)-2 and dexamethasone (Dex) for either core or shell domain, their release profiles were very unique on a temporal basis, based on their location in the microcapsules. An initial burst of biomolecules was highly suppressed when either biomolecule was loaded in the PLGA core. It was clear that the osteogenic biomolecules encapsulated in the microcapsule could be released together and their concentrations were disparate at each time point. Meanwhile as the hydrogel constructs including rat bone marrow stromal cells (BMSCs) and osteogenic factor-loaded microcapsules were cultured for up to 4 weeks, the gene expressions levels of osteopontin, type I collagen, and osteocalcin were significantly upregulated as compared to the control group. The present coaxial system was very effective in manufacturing PLGA core-alginate shell microcapsules and in encapsulating multiple biomolecules essential for stem cell differentiation.
Journal of Controlled Release 10/2010; 147(2):193-201. · 7.63 Impact Factor