[show abstract][hide abstract] ABSTRACT: a b s t r a c t 5-Fluorouracil is clinically used as antitumor drug to treat many types of cancer, which is made available to the target tissues in conjugation with transport protein serum albumin. 5-Fluorouracil which is low toxic when compared to the other drugs of this family and hence its binding characteristics are therefore of prime interest. The steady state and time resolved fluorescence studies, Fourier transform infrared spectroscopy and circular dichroism studies were employed to explain the mode and the mechanism of interaction of 5FU with BSA. 5-Fluorouracil binding is characterized with one high affinity binding site, with the binding constant of the order of 10 4 . The molecular distance r ($1.5 nm) between donor (bovine serum abumin) and acceptor (5-fluorouracil) was estimated according to Forster's theory of non-radiative energy transfer. The feature of 5-fluorouracil induced structural changes of bovine serum albumin has been studied in detail by circular dichroism and Fourier transform infrared spectroscopy analysis. The binding dynamics was expounded by synchronous fluorescence spectroscopy, florescence lifetime measurements and molecular modeling elicits that hydrophobic interactions and hydrogen bonding, stabilizes the 5-fluorouracil interaction with BSA. & 2014 Elsevier B.V. All rights reserved.
Journal of Luminescence 02/2014; 151:1-10. · 2.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: We developed a potential immunostimulatory double-stranded DNA (dsDNA) delivery system by the binding of dsDNA to amino-modified mesoporous silica nanoparticles (MSNs) to form MSN-NH2/dsDNA complexes. Serum stability, in vitro cytotoxicity, cell uptake, and type I interferon-α (IFN-α) induction of MSN-NH2/dsDNA complexes were evaluated. The results showed that MSN-NH2 nanoparticles had no cytotoxicity to Raw 264.7 cells, and MSN-NH2/dsDNA complexes enhanced the serum stability of dsDNA due to the protection by nanoparticles and exhibited a high efficiency of cell uptake due to a small particle size and excellent dispersity. Most importantly, MSN-NH2/dsDNA complexes significantly enhanced the level of IFN-α induction, triggered by cytosolic DNA sensor proteins. Therefore, binding of immunostimulatory DNA to MSNs would play a promising role for enhancing the delivery efficiency of immunostimulatory DNA drugs.
[show abstract][hide abstract] ABSTRACT: To design scaffolds for tissue regeneration, details of the host body reaction to the scaffolds must be studied. Host body reactions have been investigated mainly by immunohistological observations for a long time. Despite of recent dramatic development in genetic analysis technologies, genetically comprehensive changes in host body reactions are hardly studied. There is no information about host body reactions that can predict successful tissue regeneration in the future. In the present study, porous polyethylene scaffolds were coated with bioactive collagen or bio-inert poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (PMB) and were implanted subcutaneously and compared the host body reaction to those substrates by normalizing the result using control non-coat polyethylene scaffold. The comprehensive analyses of early host body reactions to the scaffolds were carried out using a DNA microarray assay. Within numerous genes which were expressed differently among these scaffolds, particular genes related to inflammation, wound healing, and angiogenesis were focused upon. Interleukin (IL)-1β and IL-10 are important cytokines in tissue responses to biomaterials because IL-1β promotes both inflammation and wound healing and IL-10 suppresses both of them. IL-1β was up-regulated in the collagen-coated scaffold. Collagen-specifically up-regulated genes contained both M1- and M2-macrophage-related genes. Marked vessel formation in the collagen-coated scaffold was occurred in accordance with the up-regulation of many angiogenesis-inducible factors. The DNA microarray assay provided global information regarding the host body reaction. Interestingly, several up-regulated genes were detected even on the very bio-inert PMB-coated surfaces and those genes include inflammation-suppressive and wound healing-suppressive IL-10, suggesting that not only active tissue response but also the inert response may relates to these genetic regulations.
PLoS ONE 01/2014; 9(1):e85132. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Novel silica hollow flowers (1–5 μm) were synthesized using globular apatite flowers as sacrificed template via a sol–gel route and then employed as biocompatible carrier of bone morphogenetic protein-2 (BMP-2) to stimulate osteoblast differentiation. Apatite was bio-mimetically synthesized from a well-known Kokubo’s simulated body fluid (SBF), then coated with silica in a Stöber-type silica sol–gel system, and finally dissolved in an acetic solution to yield silica hollow flowers. Analyses of SEM and TEM images show that the resultant silica flowers had a porous and hollow structure due to removal of apatite template by acetic treatment and their shell was constructed by numerous silica nanosheets (∼10 nm in silica shell). A larger specific surface of 890 m2/g was obtained for silica hollow flowers compared to silica-coated apatite due to the presence of porous and hollow structure. Silica hollow flowers had no significant toxicity after incubation with osteoblast MC3T3-E1 cells, indicating a good biocompatibility. They favored adsorption and supported a sustained release behavior of BMP-2. The released BMP-2 was biological active and enhanced osteoblast differentiation with higher ALP activity and larger amount of osteocalcin. The present silica hollow flowers are thus applicable to delivery system in tissue generation.
[show abstract][hide abstract] ABSTRACT: An environmental cell with a 50-nm-thick cathodolumi-nescent window was attached to a scanning electron microscope, and diffraction-unlimited near-field optical imaging of unstained living human lung epithelial cells in liquid was demonstrated. Electrons with energies as low as 0.8 – 1.2 kV are sufficiently blocked by the window without damaging the specimens, and form a sub-wavelength-sized illumination light source. A super-resolved optical image of the specimen adhered to the opposite window surface was acquired by a photomultiplier tube placed below. The cells after the observation were proved to stay alive. The image was formed by enhanced dipole radiation or energy transfer, and features as small as 62 nm were resolved.
[show abstract][hide abstract] ABSTRACT: Since the discovery of carbon nanotubes by Iijima et al., [ 1 ] carbon nanotubes and inorganic nanotubes have become very important in electronic, photothermal, and biomedical applica-tions because of their unique one-dimensional tubular struc-tures, high surface-to-volume ratios, and excellent mechanical properties and biocompatibilities. [ 2–5 ] Inorganic nanotubes have been micropatterned with highly organized spatial microstruc-tures for the realization of physicochemical and biomedical properties that are superior to those of the individual nano-tubes. Miyako et al. micropatterned sodium dodecyl sulfate (SDS) carbon-nanotube agarose gel to create photothermal materials, [ 2 ] and Park et al. micropatterned carbon nanotube monolayers on Au fi lms coated on glass slides in order to direct the growth of mesenchymal stem cells. [ 3 ] In addition, Zhang et al. micropatterned carbon nanotubes on silicon substrates to guide neurite growth, [ 4 ] while Pittrof et al. micropatterned TiO 2 nanotubes on Ti foils for the site-selective nucleation of bone-like apatite, which stimulated bone generation. [ 5 ] However, in most cases, the micropatterning procedure not only involved multiple complex steps, but also generally needed a supporting substrate, seriously limiting the practical applications of these micropatterned samples. Therefore, the fabrication of free-standing, micropatterned inorganic nanotubes is still a signifi -cant challenge. In the present study, we developed the facile and large-scale fabrication of free-standing, micropatterned silica nanotubes via a hybrid hydrogel-based template route. Silica nanotubes are typical inorganic nanotubes, and have been explored as die-lectric materials for nanoelectronics applications, [ 6 ] as carriers for anti-cancer drugs and DNA, and as biocompatible matrices for enzymes. [ 7–9 ] Compared with other kinds of nanotubes such as carbon and titania nanotubes, silica nanotubes are not only more easily fabricated via an ambient and low-cost sol-gel route, but also exhibit better biocompatibility because of their hydrophilic silanol groups (Si–OH) and silicate networks (Si– O–Si). [ 10 ] Thus, micropatterned silica nanotubes may be inter-esting and useful for practical applications. Figure 1 (a) illustrates the fabrication procedure for the large-scale production of free-standing, micropatterned silica nano-tubes. Collagen fi bril hydrogels (named Co) were reassembled in vitro in a silicone rubber mold (1 cm × 1 cm × 0.2 cm) by neutralizing 0.5% (w/v) acid-soluble type-I collagen with phosphate buffered saline (PBS, 1370 mM NaCl, 27 mM KCl, 80 mM Na 2 HPO 4 , and 15 mM KH 2 PO 4) in a collagen/PBS volume ratio of 9/1 at 37 ° C for 2 h. They were then soaked in a conventional Stöber-type sol-gel system consisting of tetraethy-lorthosilicate (TEOS, 1 mL), ethanol (9 mL), water (9 mL), and ammonia (28%, 0.5 mL) at room temperature for 12 h to yield a silica-coated collagen fi bril hybrid hydrogel (named SiCo). Sub-sequently, the SiCo was placed on either a fl at polydimethylsi-loxane (PDMS) sheet or a microgrooved PDMS mold (200 μ m in ridge width, 180 μ m in groove width, and 50 μ m in depth, 1 cm × 1 cm), which was maintained at 50 ° C in an incubator. At the same time, a force (5 N) was applied to the SiCo sur-face. After 12 h, the SiCo was compressed and dried to produce silica-coated collagen fi bril hybrid membranes with either a fl at surface (named FSiCo) or a microgrooved surface (named MGSiCo). Finally, both FSiCo and MGSiCo were calcined at 600 ° C for 2 h to remove the collagen fi brils and produce the corresponding silica nanotube membrane with either a fl at sur-face (named FSi) or a microgrooved surface (named MGSi). Figure 1 (b) shows the photographs of Co, SiCo, MGSiCo, and MGSi. Scanning electron microscopy images of FSiCo (a, b), MGSiCo (c, d), and MGSi (e) are shown in Figure 2 . When SiCo was compressed and dried on the fl at PDMS sheet, the resultant FSiCo (Figure 2 (a)) exhibited a similar fl at and smooth surface with a porous and fi brous structure (Figure 2 (b)) owing to the presence of the collagen fi brils. When SiCo was compressed and dried on the microgrooved PDMS mold, the resultant MGSiCo (Figure 2 (c)) exhibited a typical microgroove/ridge surface topography (about 200 μ m in groove width and about 180 μ m in ridge width). The high-magnifi cation image in Figure 2 (d) clearly shows that both the ridge and microgroove parts were fi brous, indicating that the silica-coated collagen fi bril hybrid hydrogel could be micropatterned well. After calcination, the
[show abstract][hide abstract] ABSTRACT: Semiconductor nanoparticles (or quantum dots, QDs) exhibit unique optical
and electronic properties such as size-controlled fl uorescence, high quantum
yields, and stability against photobleaching. These properties allow QDs to be
used as optical labels for multiplexed imaging and in drug delivery detection
systems. Luminescent silicon QDs and surface-modifi ed silicon QDs have
also been developed as potential minimally toxic fl uorescent probes for bioapplications.
Silicon, a well-known power electronic semiconductor material, is
considered an extremely biocompatible material, in particular with respect
to blood. This review article summarizes existing knowledge related to and
recent research progress made in the methods for synthesizing silicon QDs,
as well as their optical properties and surface-modifi cation processes. In addition,
drug delivery systems and in vitro and in vivo imaging applications that
use silicon QDs are also discussed.
[show abstract][hide abstract] ABSTRACT: This paper reviews the recent progress in the preparation of oxide-based and heteroatom-doped particles. Surfactant-templated oxide particles, e.g. silica and titania, are possible candidates for various potential applications such as adsorbents, photocatalysts, and optoelectronic and biological materials. We highlight nanoporous oxides of one element, such as silicon or titanium, and those containing multiple elements, which exhibit properties that are not achieved with individual components. Although the multicomponent nanoporous oxides possess a number of attractive functions, the origin of their properties is hard to determine due to compositional/structural complexity. Particles with a well-defined size and shape are keys for a quantitative and detailed discussion on the unique complex properties of the particles. From this viewpoint, we review the synthesis techniques of the oxide particles, which are functionalized with organic molecules or doped with heteroatoms, the physicochemical properties of the particles and the possibilities for their photofunctional applications as complex systems.
Science and Technology of Advanced Materials 04/2013; 14(2):023002. · 3.75 Impact Factor
[show abstract][hide abstract] ABSTRACT: The identification of physicochemical factors that govern toxic effects of nanomaterials (NMs) is important for the safe design and synthesis of NMs. The release of metal cations from NMs in cell culture medium and the role of the metal cations in cytotoxicity are still under dispute. Here, we report that removal of NMs such as ZnO nanoparticles (NPs) by centrifugation, the procedure commonly used for the estimation of released ion concentration in nanotoxicology, was incomplete even at a relative centrifugal force of 150 000 × g. In this sense, the Zn concentration in supernatant measured by inductively coupled plasma-mass spectrometry cannot be regarded as the concentration of free Zn(2+) ions which were released from ZnO NPs in cell culture medium. This suggests the urgent need to develop relevant analytical techniques for nanotoxicology. The toxic contribution of released Zn(2+) ions to the A549 cell lines was estimated to be only about 10%. We conclude that the cytotoxicity associated with ZnO NPs is not a function of the Zn concentration, suggesting that other factors play an important role in the toxic effect of ZnO NPs.
[show abstract][hide abstract] ABSTRACT: Chitosan–silica/CpG oligodeoxynucleotide (ODN) nanohybrids were synthesized to stimulate Toll-like receptor 9-mediated induction of interleukin-6 (IL-6). The chitosan–silica hybrid was first synthesized from a mixture of chitosan and 3-glycidoxypropyl trimethoxysilane under acidic conditions via a sol–gel process, and then used to condense CpG ODN2006x3-PD to yield chitosan–silica/CpG ODN nanohybrids. Scanning electron micros-copy and atomic force microscopy showed that the chitosan–silica/CpG ODN nanohybrids had an elliptic shape with a diameter of 100–200 nm. After soaking in HAc–NaAc buffer solution (pH 5.5), the nanohybrids exhibited sustained release of CpG ODN. When the nanohybrids were separately exposed to 293XL-hTLR9 cells and periph-eral blood mononuclear cells, no significant toxicity was observed. An immunochemical assay for cellular uptake revealed that the nanohybrids were taken up by the cells and located in endolysosomes. An enzyme-linked immunosorbent assay for cytokines indicated that the nanohybrids effectively stimulated the induction of IL-6. Chitosan–silica/CpG ODN nanohybrids underwent cellular uptake and enhanced induction of IL-6 to a greater degree than conventional chitosan/CpG ODN nanocomplexes, indicating that they have an enhanced delivery efficiency.
Materials Science and Engineering C 04/2013; 33(6):3382. · 2.40 Impact Factor
[show abstract][hide abstract] ABSTRACT: Silica nanotubes have been extensively applied in the biomedical field. However, very little attention has been paid to the fabrication and application of micropatterned silica nanotubes. In the present study, microgrooved silica nanotube membranes were fabricated in situ by microgrooving silica-coated collagen hybrid fibril hydrogels in a Teflon microfluidic chip followed by calcination for removal of collagen fibrils. Scanning electron microscopy images showed that the resulting silica nanotube membranes displayed a typical microgroove/ridge surface topography with ∼50 µm microgroove width and ∼120 µm ridge width. They supported adsorption of bone morphogenetic protein 2 (BMP-2) and exhibited a sustained release behavior for BMP-2. After culturing with osteoblast MC3T3-E1 cells, they induced an enhanced osteoblast differentiation due to the release of biologically active BMP-2 and a strong contact guidance ability to directly align and elongate osteoblasts due to the presence of microgrooved surface topography, indicating their potential application as a multi-functional cell-supporting matrix for tissue generation.
Science and Technology of Advanced Materials 02/2013; 14:015005. · 3.75 Impact Factor
[show abstract][hide abstract] ABSTRACT: The magnetic 10Fe5Ca MBG scaffolds (Fe3O4–CaO–SiO2–P2O5 system) have been prepared by a combination of polyurethane sponge and P123 as co-templates and an evaporation-induced self-assembly (EISA) process through the substitution of Fe3O4 for CaO in the 15Ca MBG scaffolds (CaO–SiO2–P2O5 system). The structure, magnetic heating, drug release, physicochemical and biological properties were systematically investigated. The results showed that the 10Fe5Ca MBG scaffolds had the interconnected macroporous structure with pore sizes ranging from 200 to 400 μm and the mesoporous wall with a peak pore size of ca. 3.34 nm. Also, the 10Fe5Ca MBG scaffolds exhibited similar mechanical strength, apatite-forming ability and sustained drug release behavior compared to the 15Ca MBG scaffolds. Importantly, the substitution of Fe3O4 for CaO in the MBG scaffolds induced a slower ion dissolution rate and more significant potential to stabilize the pH environment, and facilitated osteoblast cell proliferation, alkaline phosphatase (ALP) activity and osteogenic expression. In particular, the 10Fe5Ca MBG scaffolds could generate heat in an alternating magnetic field. Therefore, the magnetic 10Fe5Ca MBG scaffolds have potential for the regeneration of the critical-size bone defects caused by bone tumors by a combination of magnetic hyperthermia and local drug delivery therapy.
[show abstract][hide abstract] ABSTRACT: a b s t r a c t Toll-like receptor 9 (TLR9) recognizes a synthetic ligand, oligodeoxynucleotide (ODN) containing cyto-sine–phosphate–guanine (CpG). Activation of TLR9 by CpG ODN induces a signal transduction cascade that plays a pivotal role in first-line immune defense in the human body. The three-dimensional structure of TLR9 has not yet been reported, and the ligand-binding mechanism of TLR9 is still poorly understood; therefore, the mechanism of human TLR9 (hTLR9) ligand binding needs to be elucidated. In this study, we constructed several hTLR9 mutants, including truncated mutants and single mutants in the predicted CpG ODN-binding site. We used these mutants to analyze the role of potential important regions of hTLR9 in receptor signaling induced by phosphorothioate (PTO)-modified CpG ODN and CpG ODNs only consist entirely of a phosphodiester (PD) backbone, CpG ODN2006x3-PD that we developed. We found truncated mutants of hTLR9 lost the signaling activity, indicating that both the C-and N-termini of the extracellular domain (ECD) are necessary for the function of hTLR9. We identified residues, His505, Gln510, His530, and Tyr554, in the C-terminal of hTLR9-ECD that are essential for hTLR9 activation. These residues might form positive charged clusters with which negatively charged CpG ODN could interact. Furthermore, we observed ODN–PD induced interleukin-6 (IL-6) through TLR9 in a CpG-sequence-dependent manner in human peripheral blood mononuclear cells and B cells, whereas ODN–PTO induced IL-6 in a CpG-sequence-independent manner. These finding are relevant for the mechanism of hTLR9 activation by CpG ODNs.
[show abstract][hide abstract] ABSTRACT: Recently, one of the interferon-induced transmembrane (IFITM) family proteins, IFITM3, has become an important target for the activity against influenza A (H1N1) virus infection. In this protein, a post-translational modification by fatty acids covalently attached to cysteine, termed S-palmitoylation, plays a crucial role for the antiviral activity. IFITM3 possesses three cysteine residues for the S-palmitoylation in the first transmembrane (TM1) domain and in the cytoplasmic (CP) loop. Because these cysteines are well conserved in the mammalian IFITM family proteins, the S-palmitoylation on these cysteines is significant for their functions. IFITM5 is another IFITM family protein and interacts with the FK506-binding protein 11 (FKBP11) to form a higher-order complex in osteoblast cells, which induces the expression of immunologically relevant genes. In this study, we investigated the role played by S-palmitoylation of IFITM5 in its interaction with FKBP11 in the cells, because this interaction is a key process for the gene expression. Our investigations using an established reporter, 17-octadecynoic acid (17-ODYA), and an inhibitor for the S-palmitoylation, 2-bromopalmitic acid (2BP), revealed that IFITM5 was S-palmitoylated in addition to IFITM3. Specifically, we found that cysteine residues in the TM1 domain and in the CP loop were S-palmitoylated in IFITM5. Then, we revealed by immunoprecipitation and western blot analyses that the interaction of IFITM5 with FKBP11 was inhibited in the presence of 2BP. The mutant lacking the S-palmitoylation site in the TM1 domain lost the interaction with FKBP11. These results indicate that the S-palmitoylation on IFITM5 promotes the interaction with FKBP11. Finally, we investigated bone nodule formation in osteoblast cells in the presence of 2BP, because IFITM5 was originally identified as a bone formation factor. The experiment resulted in a morphological aberration of the bone nodule. This also indicated that the S-palmitoylation contributes to bone formation.
PLoS ONE 01/2013; 8(9):e75831. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Cytosine-phosphate-guanine (CpG) oligodeoxynucleotides activate Toll-like receptor 9, leading to induction of proinflammatory cytokines, which play an important role in induction and maintenance of innate and adaptive immune responses. Previously, we have used boron nitride nanospheres (BNNS) as a carrier for delivery of unmodified CpG oligodeoxynucleotides to activate Toll-like receptor 9. However, because CpG oligodeoxynucleotides and BNNS are both negatively charged, electrostatic repulsion between them is likely to reduce the loading of CpG oligodeoxynucleotides onto BNNS. Therefore, the efficiency of uptake of CpG oligodeoxynucleotides is also limited and does not result in induction of a robust cytokine response. To ameliorate these problems, we developed a CpG oligodeoxynucleotide delivery system using chitosan-coated BNNS as a carrier.
To facilitate attachment of CpG oligodeoxynucleotides onto the BNNS and improve their loading capacity, we prepared positively charged BNNS by coating them with chitosan preparations of three different molecular weights and used them as carriers for delivery of CpG oligodeoxynucleotides.
The zeta potentials of the BNNS-CS complexes were positive, and chitosan coating improved their dispersity and stability in aqueous solution compared with BNNS. The positive charge of the BNNS-CS complexes greatly improved the loading capacity and cellular uptake efficiency of CpG oligodeoxynucleotides. The loading capacity of the CpG oligodeoxynucleotides depended on the molecular weight of chitosan, which affected the positive charge density on the surface of the BNNS. CpG oligodeoxynucleotides loaded onto BNNS-CS complexes significantly enhanced production of interleukin-6 and tumor necrosis factor-α by peripheral blood mononuclear cells compared with CpG oligodeoxynucleotides directly loaded onto BNNS, or when Lipofectamine™ 2000 was used as the carrier. The molecular weight of the chitosan used to coat the BNNS affected the magnitude of cytokine induction by varying the strength of condensation of the CpG oligodeoxynucleotides.
Although the loading capacity of BNNS coated with low molecular weight chitosan preparations was the lowest of all the preparations, they induced the highest levels of cytokines.
International Journal of Nanomedicine 01/2013; 8:1783-1793. · 3.46 Impact Factor
[show abstract][hide abstract] ABSTRACT: Silver-nanoparticles (NPs) have become increasingly common in various applications, raising some safety concerns. In this study, the cytotoxic and genotoxic effects of silver-NPs on primary Syrian hamster embryo (SHE) cells were investigated. Cell viability was assessed using a methyl tetrazolium (MTT) assay, and genotoxic potential was evaluated using a cytokinesis-block micronucleus (CBMN) assay. The results showed that dose-dependent cytotoxicity was induced after 24 h of exposure to silver-NPs. The micronucleation frequency (MNF) also increased significantly in a dose-dependent manner (P < 0.05), suggesting that silver-NPs induce genotoxicity. This is consistent with an increased MNF observed in primary SHE cells. The results of cell cycle analysis indicate that the cell cycles became arrested in the GO/G1 phase and that the S phase shortened after only 8 h of silver-NP exposure, suggesting that DNA replication had been inhibited, which in turn inhibited further cell proliferation. The rate of late-stage apoptosis increased after 12 h of silver-NP exposure, and both early- and late-stage apoptosis were obviously increased after 72 h of exposure than in controls. This study demonstrated that silver-NPs could induce strong cytotoxicity and significant genotoxicity in primary SHE cells and that this is probably due to silver-NP-induced apoptosis and the inhibition of cell proliferation.
Journal of Nanoscience and Nanotechnology 01/2013; 13(1):161-70. · 1.15 Impact Factor
[show abstract][hide abstract] ABSTRACT: Toll-like receptor 9 (TLR9) recognizes a synthetic ligand, oligodeoxynucleotide (ODN) containing cytosine-phosphate-guanine (CpG). Activation of TLR9 by CpG ODN induces a signal transduction cascade that plays a pivotal role in first-line immune defense in the human body. The three-dimensional structure of TLR9 has not yet been reported, and the ligand-binding mechanism of TLR9 is still poorly understood; therefore, the mechanism of human TLR9 (hTLR9) ligand binding needs to be elucidated. In this study, we constructed several hTLR9 mutants, including truncated mutants and single mutants in the predicted CpG ODN-binding site. We used these mutants to analyze the role of potential important regions of hTLR9 in receptor signaling induced by phosphorothioate (PTO)-modified CpG ODN and CpG ODNs only consist entirely of a phosphodiester (PD) backbone, CpG ODN2006x3-PD that we developed. We found truncated mutants of hTLR9 lost the signaling activity, indicating that both the C- and N-termini of the extracellular domain (ECD) are necessary for the function of hTLR9. We identified residues, His505, Gln510, His530, and Tyr554, in the C-terminal of hTLR9-ECD that are essential for hTLR9 activation. These residues might form positive charged clusters with which negatively charged CpG ODN could interact. Furthermore, we observed ODN-PD induced interleukin-6 (IL-6) through TLR9 in a CpG-sequence-dependent manner in human peripheral blood mononuclear cells and B cells, whereas ODN-PTO induced IL-6 in a CpG-sequence-independent manner. These finding are relevant for the mechanism of hTLR9 activation by CpG ODNs.
Biochemical and Biophysical Research Communications 12/2012; · 2.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: Mesostructured surfactant-silica monolithic films were prepared using a supramolecular templating method. The effect of the templating in the monolithic films on the interfacial interactions was evaluated and elucidated using the atomic force microscope techniques combined with other surface analyses to produce different surface structures and force curves depending on the surfactants. The transparent and flexible surfactant-silica monolithic films were prepared to exhibit the ordered nanostructures. The monolithic films templated by nonionic triblock copolymers (poly(ethylene oxide (EO))-poly(propylene oxide (PO))-poly(ethylene oxide (EO))) of EO20PO70EO20 (P123) and EO106PO70EO106 (F127) significantly exhibited flat surfaces and the higher viscoelastic properties which were supported by surface stiffness and adhesive force, whereas the monolithic film by cationic alkylammonium surfactant indicated a rough surface and the plastic deformation property by application of force. This indicated that the higher molecular weight of the EO and PO phases enhanced the phase segregation in the silica surfaces due to the higher solubility differences between both blocks to consolidate the surfactant-silica interfacial interactions. Therefore, the different surface structural and mechanical properties attributed to the interfacial organic-inorganic interaction patterns were successfully clarified.
[show abstract][hide abstract] ABSTRACT: The fabrication of novel collagen-silica hybrid membranes with tailored biodegradation and strong cell
contact guidance ability is reported in the present study. Collagen-silica hybrids were first synthesized
by reacting 3-glycidoxypropyltrimethoxysilane (GPTMS), which functioned as both the cross-linker
and the silica source, with acid-soluble type I porcine collagen monomers. Subsequently, they were
coated and dried on the surface of polydimethylsiloxane (PDMS) chips with either flat or microgroove
surfaces to produce the corresponding collagen-silica hybrid membrane with a flat or microgroove
surface. Scanning electron microscopy images showed that membranes formed on flat PDMS chips
exhibited smooth and dense surfaces, while those formed on microgrooved PDMS chips exhibited
typical microgroove surfaces with a 10 mm groove width, 8 mm ridge width, and 0.5 mm depth. Despite
the difference in surface topography, both flat and microgrooved collagen-silica membranes exhibited
stronger resistance against collagenase enzyme than the original collagen membrane due to the presence
of silica, and the biodegradation rate of the samples was controllable through adjustment of the
GPTMS content. Upon incubation with C2C12 skeletal myoblasts, both samples supported cell
attachment, proliferation, and differentiation, suggesting good biocompatibility. However, a
significant difference in cell morphology was observed. Cells on the flat membranes were randomly
distributed, while those on the microgrooved samples were highly aligned and elongated, indicating
that the microgrooved membranes exhibit much stronger cell contact guidance ability. The
immunochemical assay showed that both flat and microgrooved samples supported the differentiation
of C2C12 myoblasts to form multinucleated myotubes; however, the presence of the microgrooved
surface topography significantly enhanced cell differentiation....
Journal of Materials Chemistry 10/2012; 22:21885. · 5.97 Impact Factor