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The biomimetic structure of a polymer hydrogel bearing phosphorylcholine groups was obtained from 2-methacryloyloxyethylphosphorylcholline (MPC) and a novel crosslinker, 2-(methacryloyloxy)ethyl-N-(2-methacryloyloxy)ethyl]phosphorylcholine (MMPC), to prepare biocompatible ocular materials. MMPC is a dimethacrylate with phosphorylcholine-analogous linkage. Previous reports clarified that the affinity of MMPC to MPC enables the water contents and mechanical properties of the poly(MPC) hydrogels to be varied without disturbing the bulk phases. In this study, we examined the protein adsorption resistance, water wettability, oxygen permeability, and electrolyte permeability of the mechanically enhanced poly(MPC) hydrogel crosslinked with MMPC. The amount of protein adsorbed on this hydrogel was 0.9 μg/cm2, which accounted for 30% of Omafilcon A and 3% of Etafilcon A. Water contact angle experiments revealed the high wettability of the poly(MPC) hydrogels. The oxygen permeability and NaCl diffusion constant of the poly(MPC) hydrogels were 64 barrer and 48 × 10−6 cm2/s, respectively. This high permeability resulted from the high water content, similar to the case of the human cornea. These results suggested that poly(MPC) hydrogels have good potential for use in ophthalmologic biomaterials. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009

To prepare the biocompatible surface, a phosphorylcholine (PC) group was introduced on this hydroxyl group generated by surface hydrolysis on the polymer composite composed of polyethylene (PE) and poly (vinyl acetate) (PVAc) prepared by supercritical carbon dioxide. Two different procedures such as two-dimensional (2D) modification and three-dimensional (3D) modification were applied to obtain the steady biocompatible surface. 2D modification was that PC groups were directly anchored on the surface of the polymer composite. 3D modification was that phospholipid polymer was grafted from the surface of the polymer composite by surface-initiated atom transfer radical polymerization (SI-ATRP) of 2-methacryloyloxyethyl phosphorylcholine (MPC). The surfaces were characterized by X-ray photoelectron spectroscopy, dynamic water contact angle measurements, and atomic force microscope. The effects of the poly(MPC) chain length on the protein adsorption resistivity were investigated. The protein adsorption on the polymer composite surface with PC groups modified by 2D or 3D modification was significantly reduced as compared with that on the unmodified PE. Further, the amount of protein adsorbed on the 3D modified surface that is poly(MPC)-grafted surface decreased with an increase in the chain length of the poly(MPC). The surface with an arbitrary structure and the characteristic can be constructed by using 2D and 3D modification. We conclude that the polymer composites of PE/PVAc with PC groups on the surface are useful for fabricating biomedical devices due to their good mechanical and surface properties.

A polymer composite comprised of polyethylene (PE) and poly(vinyl acetate) (PVAc) with a biocompatible surface was developed for use in medical devices by the use of the following two-step processes: (i) the first step was to prepare polymer composite using supercritical carbon dioxide (scCO 2 ) methods and (ii) the second step was to introduce phosphorylcholine groups onto the surface of polymer composite by surface reaction. This article especially reports a detailed study of the syntheses, and mechanical properties and the microstructure of obtained polymer composite by scCO 2 methods. The formation mechanism of PE/PVAc composites was that supercritical impregnation of a monomer and initiator into polymer substrate followed by in situ polymerization within the polymer matrix. Differential scanning calorimetry, wide-angle and small-angle X-ray scattering measurement showed that PE and PVAc were blended at the nanometer level. PVAc generated in the amorphous regions at nanometer level did not affect the crystalline of PE. This microstructure affected mechanical properties such as dynamic viscoelasticity, Young's modulus, fracture stress and strain of the PE/PVAc composite. These properties depended on the composition of the composite that can be controlled with polymerization time. The synthesis method of polymer composite using scCO 2 can be applied to create polymer biomaterials with suitable mechanical properties for the soft tissue, hard tissue, and organs.

The surface modification of poly(dimethylsiloxane) (PDMS) substrates by using ABA-type block copolymers comprising poly(2-methacryloyloxyethyl phosphorylcholine (MPC)) (PMPC) and PDMS segments was investigated. The hydrophobic interaction between the swelling-deswelling nature of PDMS and PDMS segments in block copolymers was the main mechanism for surface modification. Block copolymers with various compositions were synthesized by using the atom transfer radical polymerization (ATRP) method. The kinetic plots revealed that polymerization could be initiated by PDMS macroinitiators and it proceeds in a well-controlled manner; therefore, the compositions of the block copolymers were controllable. The obtained block copolymers were dissolved in a chloroform/ethanol mixed solvent. The surface of the PDMS substrate was modified using block copolymers by the swelling-deswelling method. Static contact angle and X-ray photoelectron spectroscopy (XPS) measurements revealed that the hydrophobic surface of the PDMS substrate was converted to a hydrophilic surface because of modification by surface-tethered PMPC segments. Protein adsorption test and L929 cell adhesion test were carried out for evaluating the biocompatibility. As observed, the amount of adsorbed proteins and cell adhesion were drastically reduced as compared to those in the non-treated PDMS substrate. We conclude that this procedure is effective in fabricating biocompatible surfaces on PDMS substrates.

Novel polymer nanoparticles were prepared for the selective capture of a specific protein from a mixture with high effectiveness. The nanoparticle surface was covered with hydrophilic phosphorylcholine groups and active ester groups for easy immobilization of antibodies. Phospholipid polymers (PMBN) composed of 2-methacryloyloxyethyl phosphorylcholine, n-butyl methacrylate, and p-nitrophenyloxycarbonyl polyethyleneglycol methacrylate, were synthesized for the surface modification of poly( l-lactic acid) nanoparticles. Surface analysis of the nanoparticles using laser-Doppler electrophoresis and X-ray photoelectron spectroscopy revealed that the surface of nanoparticles was covered with PMBN. Protein adsorption was evaluated with regard to the nonspecific adsorption on the nanoparticles that was effectively suppressed by the phosphorylcholine groups. The immobilization of antibodies on nanoparticles was carried out under physiological conditions to ensure specific binding of antigens. The antibody immobilized on the nanoparticles exhibited high activity and strong affinity for the antigen similar to that exhibited by an antibody in a solution. The selective binding of a specific protein as an antigen from a protein mixture was relatively high compared to that observed with conventional antibody-immobilized polymer nanoparticles. In conclusion, nanoparticles having both phosphorylcholine and active ester groups for antibody immobilization have strong potential for use in highly selective separation based on the biological affinities between biomolecules.

Activity-dependent neurotrophic protein (ADNP) was discovered as a novel response gene for vasoactive intestinal polypeptide. We have reported that PACAP strongly stimulated ADNP mRNA expression in a mouse neuron/glial cell culture; however, the distribution of ADNP in the brain and its possible co-expression with the PACAP receptor (PAC1R) are unknown. In this study, the specificity of the ADNP antibody used in subsequent immunohistochemistry experiments was first characterized. Mouse brain lysates were analysed by Western blot, with an ADNP-immunopositive signal corresponding to the expected molecular weight of ADNP detected as a 124 kDa band. Immunohistochemical staining to identify ADNP and PAC1R immunoreactivity in mouse brain was then performed. ADNP immunoreactive cells were observed in the cerebral cortex, cerebellum, hippocampus, and medial septum of brain slices. ADNP-immunoreactive cells in the cerebral cortex were multi-polar-shaped and co-immunostained with the astrocyte marker, glial fibrillary acidic protein (GFAP). ADNP-immunoreactive cells in the cerebellum were found to surround Purkinje cells and showed GFAP immunoreactivity. On the other hand, ADNP-immunoreactive cells in the hippocampus and septum were round in shape and co-immunostained with the neuron marker, neuron-specific enorase. All of the ADNP-immunopositive cells co-localized with PAC1R immunoreactivity. These observations suggest that ADNP is expressed in both astrocytes and neurons, and that ADNP expression may be regulated by PACAP.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is known to participate in the regulation of neuronal proliferation and differentiation. While these processes are considered to be mediated via PACAP's actions on the PACAP-specific receptor, PAC1R, the precise distribution of PAC1R during neurodevelopment has not yet to be elucidated in detail. The purpose of this study is to examine the distribution of PAC1R in the neurogenic region of the rostral migratory stream (RMS) from the apical subventricular zone (SVZa) to the olfactory bulb (OB) in infant mice using immunostaining. Co-immunostaining for PAC1R in a variety types of cell were carried out using different markers. These included the neural stem cell markers, nestin and glial fibrillary acidic protein (GFAP), a marker for migrating neuroblasts (doublecortin, DCX), a marker for immature neurons betaIII-tubulin, (Tuj1), and a marker for mature neurons, neuronal nuclei (NeuN). PAC1R-like immunoreactivity (LI) was observed in the RMS. However, the intensity of PAC1R- LI was different depending on the regions which were investigated. PAC1R-LI was strong in nestin- and GFAP-positive cells in the SVZa and was also observed in NeuN-positive cells in the OB. However, the intensities of PAC1R-LI in DCX- and Tuj1-positive cells were weaker than the other markers. These results suggest that PACAP may participate in the neurodevelopment with the stage-specific expression of PAC1R and that PACAP plays important roles in neurons as well as in glial cells.

Surface-initiated radical polymerization was carried out in order to modify the surface of inorganic solid and metal oxide nanoparticles. Novel (inorganic nanoparticles/polymer) nanocomposites were prepared through a direct polymer grafting reaction from the surfaces of magnetite (Fe3O4) (d=10 and 25 nm) and titanium oxide (TiO2) (d=15 nm) nanoparticles. The initiator for nitroxide-mediated radical polymerization with a phosphoric acid group was chemisorbed onto the nanoparticles and gave controlled polystyrene (PS) and poly(3-vinylpyridine) (P3VP) graft layers on their surfaces. The PS- and P3VP-modified nanoparticles were finely dispersed in organic solvents, whereas protonated P3VP-modified magnetite nanoparticles were dispersed in aqueous phase. The fine dispersion of nanoparticles in the polymer matrix was confirmed by microscopic observation. In order to realize tribological control, atom transfer radical polymerization of (2,2-dimethyl-1,3-dioxolan-4-yl)methyl methacrylate was also carried out from an immobilized initiator on a flat silicon wafer, resulting in a high-density polymer brush that was subsequently converted to a hydrophilic polymer brush consisting of 2,3-dihyroxypropyl methacrylate units. The poly(2,3-dihydroxypropyl methacrylate) brush-immobilized surface showed a low dynamic friction coefficient in water due to the highly stable hydrophilicity.

Polymer-grafted magnetite (Fe3O4) nanoparticles (diameter about 10 nm) were prepared through a direct polymer grafting reaction from their surfaces. The chemisorbed initiator (TEMPO-based alkoxyamine) for nitroxide-mediated radical polymerization with a phosphoric acid group gave controlled polystyrene (PS) and poly(3-vinylpyridine) (P3VP) graft layers on the surface. The graft densities of polymers on the surfaces of magnetite particles were estimated at 0.12−0.20 chains/nm2 by thermogravimetric analysis (TGA). The improvement in the dispersibility of PS-modified magnetite in good solvents was verified by ultraviolet−visible (UV−vis) absorption spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS). In the case of P3VP-modified magnetite, the particles were stably dispersed in good solvents, by protonation, in acid solution, and by quarternization with iodomethane, in neutral aqueous solution. The magnetic response of the polymer-grafted magnetite against an external mag...

Nanopores generated from the gap among electrospun nanofibers can provide vascular tissues with oxygen, nutrients, and growth factors. Here, we report the first fabrication of poly( l -lactide- co -caprolactone- co -glycolide) (PLCG) electrospun nanofibers. A water-soluble amphiphilic copolymer bearing phosphorylcholine groups (PMB30W) and an antiproliferative (rapamycin) were incorporated into PLCG by solvent blending and subsequent electrospinning. The nanostructure of the electrospun PLCG/PMB30W/rapamycin blended fibers was stable during incubation in phosphate-buffered saline without addition of chemical crosslinkers. Amphiphilic characteristics of PMB30W and hydrophobic nature of rapamycin could make the electrospun PLCG/PMB30W/rapamycin blended fibers stable under a physiologic condition. The electrospun PLCG/PMB30W/rapamycin blended fibers may be preferable for vascular prostheses and tissue-engineered vascular grafts.

To improve dispersion property of alkyl chain modified-quantum dot (QD), we prepared new surfactants with polymerization initiator for surface modification of the QD. That is, sodium 2-alkylsulfanylthiocarbonylsulfanyl-2-methyl propionate with various alkyl chain length (C8, C10, C12, C14, and C16). These compounds also have a specific functional group, which has potential to initiate reversible addition–fragmentation chain transfer (RAFT) polymerization with various vinyl monomers. So, we investigated the relation between chain length of these double functional RAFT reagents and critical micelle concentration (CMC), and the solubilization ability for QD (emission wavelength: 605 nm). As a result, the CMC depended on the chain length and the RAFT reagents with C12 and C14 chains indicated high solubilization abilities for QD due to their good hydrophilic–lipophilic balance.

Direct electron transfer (DET) from biomolecules to electrode is a process without electron-mediators, thus superior selectivity and sensitivity is expected in order to monitor electron transfer between electrode and biomolecules without any mediator interference. However, DET is difficult because a redox center which is an electron active center of proteins such as enzymes is buried deep. So, a unique electrode nanostructure to reach the redox center is a critical factor. Here we have systematically investigated terms for DET using various nanofiliformed electrode morphologies and enzyme concentrations. It is pointed out that the reaction site is below 100 nm, the ration amounts of adsorbed enzyme per surface area are below 1.0 are contributed to the DET. As a great application, we have developed a biosensor monitoring the hydrogen peroxide (H(2)O(2)) detecting capability from peroxidase directly. For the fabricated HRP/nTOF/Ti-electrodes observed the catalytic current value was linear according to the increase in the concentration of H(2)O(2) up to 100 μM, which indicates a good potential for an H(2)O(2) biosensor.

Surface-modified magnetite (Fe3O4) nanoparticles (d = 10 nm) was prepared by direct polymerization of styrene on their surface. With use of nitroxyl-mediated initiator for radical polymerization with the phosphonic acid group, magnetite particles with a controlled polystyrene graft layer on the surface were successfully prepared. The surface-modified magnetite was dispersed in good solvents for polystyrene such as chloroform, toluene, ethyl acetate, and benzene.

To develop new functional fluorescence probe based on semiconductor nanoparticles, such as quantum dots (QD)s, we investigated polymer particle embedding QDs and covered with artificial cell membrane-biointerface. These nanoparticles were prepared by assembling 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer as a platform and biomolecules immobilized on the surface of the nanoparticles. The fluorescence property of QDs remained after embedding in the polymer nanoparticles. The MPC polymer surface showed high resistance to non-specific cellular uptake due to the phosphorylcholine groups in the side chain. On the other hand, when cell-penetration oligopeptide, octaarginine was immobilized on the surface, they could permeate the membrane of cells effectively and good fluorescence based on QDs could be observed. Cytotoxicity and inflammation reaction was not produced by these nanoparticles even after immobilization of octapeptide. In conclusion, we could obtain stable fluorescence polymer nanoparticles covered with artificial cell membrane, which are useful as an excellent bioimaging probe and as a novel evaluation tool for biomolecular function in the target cells.

End-functional 2-methacryloyloxyethyl phosphorylcholine (MPC) co-polymers containing two different monomer units, 2-hydroxyethyl methacrylate (HEMA) and n-butyl methacrylate (BMA), with varying hydrophilicities were synthesized to investigate the effect of the conjugated hydrophilic polymer on the heat-induced conformational changes of a protein. MPC co-polymer-conjugated proteins containing the HEMA unit (PMH) could withstand thermal conformational changes better than those containing the more hydrophobic BMA unit (PMB). The changes in protein tertiary structures were estimated via the excitation of tryptophan. PMH-conjugated proteins could withstand heat-induced intensity changes better than the PMB-conjugated proteins. Thus, hydrophilic units in the conjugated polymer are probably essential in suppressing the heat-induced conformational changes of a protein. The changes in secondary and tertiary structures of poly(MPC)-(PMPC) and poly(HEMA) (PHEMA)-conjugated proteins were compared to validate the effect of MPC units on heat-induced conformational change. Although the thermally induced conformational changes in the secondary and tertiary structures of PHEMA-conjugated proteins were partially suppressed, the effect on PMPC-conjugated proteins was much greater, with significant conformational preservation. This is due to the specific hydration state of the hydrophilic PMPC chain, which reduces interaction between the protein molecules.

A library of zwitterionic phosphorylcholine surfactants with various alkyl chain lengths and compositions was readily prepared from a combination of 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) and various alkanethiol compounds via Michael-type addition. The critical micelle concentration (CMC) was evaluated by surface tensiometry. At the CMC, the surface tension of these aqueous solutions decreased significantly to below 40 mN/m. For the zwitterionic surfactants composed of MPC, and fluoroalkane and alkanedithiol, the surface tension was approximately 24, and 50 mN/m, respectively. From the equation log (CMC) = A - Bn, where n is the number of carbon atoms in the alkyl chain, A and B were calculated as 1.09 and 0.44, respectively. The value of the slope B was between that of ionic (B = 0.30) and nonionic surfactants (B = 0.50). Despite the ionic nature of the surfactants, their behavior was closer to that of nonionic surfactants.

Background Materials with excellent biocompatibility on interfaces between artificial system and biological system are needed to develop any equipments and devices in bioscience, bioengineering and medicinal science. Suppression of unfavorable biological response on the interface is most important for understanding real functions of biomolecules on the surface. So, we should design and prepare such biomaterials. Scoop of review One of the best ways to design the biomaterials is generated from mimicking a cell membrane structure. It is composed of a phospholipid bilayered membrane and embedded proteins and polysaccharides. The surface of the cell membrane-like structure is constructed artificially by molecular integration of phospholipid polymer as platform and conjugated biomolecules. Here, it is introduced as the effectiveness of biointerface with highly biological functions observed on artificial cell membrane structure. Major conclusions Reduction of nonspecific protein adsorption is essential for suppression of unfavorable bioresponse and achievement of versatile biomedical applications. Simultaneously, bioconjugation of biomolecules on the phospholipid polymer platform is crucial for a high-performance interface. General significance The biointerfaces with both biocompatibility and biofunctionality based on biomolecules must be installed on advanced devices, which are applied in the fields of nanobioscience and nanomedicine. This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine.

To develop biocompatible polymer modification method on a quantum dot (QD) surface, we have studied poly(2-methacryloyloxyethyl phosphorylcholine) (poly(MPC)) grafting on trioctylphosphine oxide (TOPO)-coated QD (CdSe/ZnS) surface using new strategy with a double functional reversible addition-fragmentation chain transfer (RAFT) agent. Sodium 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionate (DMP-Na) was focused and prepared as the double functional RAFT agent. As the first function, the DMP-Na possessed surface activity that forms micelle in aqueous solution and solubilize the TOPO-coated QD into the solution. The DMP-Na indicated critical micelle concentration (CMC) from surface tension measurement in an aqueous medium. Over CMC, the QD was able to be solubilized into DMP-Na micelle and showed multicolor fluorescence spectra with narrow full-width at half maximum (FWHM) corresponding to diameter of the QD. Additionally, as the second function, the DMP-Na possessed chain transfer agent ability that synthesizes a poly(MPC)-grafted QD in an aqueous medium. In this strategy, fluorescence properties with narrow FWHM and peak top did not change before and after solubilization into the DMP-Na micelle aqueous solution and even after polymerization of the MPC initiated from the DMP-Na. The poly(MPC)-modified QD showed good biocompatibility based on the poly(MPC) properties, and was able to suppress uptake by HeLa cells despite diameter of the poly(MPC)-modified QD was approximately 12 nm.

To obtain a stable and highly sensitive bioimaging fluorescence probe, polymer nanoparticles with embedded quantum dots were covered with an artificial cell membrane. These nanoparticles were designed by assembling phospholipid polar groups as a platform, and oligopeptide was immobilized as a bioaffinity moiety on the surface of the nanoparticles. The polymer nanoparticles showed resistance to cellular uptake from HeLa cells owing to the nature of the phosphorylcholine groups. When arginine octapeptide was immobilized at the surface of the nanoparticles, they were able to penetrate the membrane of HeLa cells effectively. Cytotoxicity of the nanoparticles was not observed even after immobilization of oligopeptide. Thus, we obtained stable fluorescent polymer nanoparticles covered with an artificial cell membrane, which are useful as an excellent bioimaging probe and as a novel evaluation tool for oligopeptide functions in the target cells.

In order to provide a protein adsorption resistant surface even when the surface was in contact with a protein solution under completely dry conditions, a new phospholipid copolymer, poly (2-methacryloyloxyethyl phosphorylcholine (MPC)- co-2-vinylnaphthalene (vN)) (PMvN), was synthesized. Poly(ethylene terephthalate) (PET) could be readily coated with PMvN by a solvent evaporation method. Dynamic contact angle measurements with water revealed that the surface was wetted very rapidly and had strong hydrophilic characteristics; moreover, molecular mobility at the surface was extremely low. When the surface came in contact with a plasma protein solution containing bovine serum albumin (BSA), the amounts of the plasma protein adsorbed on the dry surface coated with PMvN and that adsorbed on a dry surface coated with poly(MPC-co-n-butyl methacrylate) (PMB) were compared. Substantially lower protein adsorption was observed with PMvN coating. This is due to the rapid hydration behavior of PMvN. We concluded that PMvN can be used as a functional coating material for medical devices without any wetting pretreatment.

The aim of this study is to improve the biocompatibility of titanium alloy (Ti) implants by immobilization of multilayered phospholipid polymer hydrogel able to reduce protein adsorption and cell adhesion. We fabricated and characterized a multilayered hydrogel on Ti substrate via a layer-by-layer self-assembly deposition method using a phospholipid polymer bearing a phenylboronic acid moiety and poly(vinyl alcohol) (PVA). The water-soluble phospholipid polymer (PMBV) was synthesized from 2-methacrylocyloxyethyl phosphorylcholine, n-butyl methacrylate, and 4-vinylphenylboronic acid (VPBA). The PMBV reacted with PVA and formed a hydrogel due to covalent linkage between the VPBA units and hydroxyl groups of PVA. The hydrogel layer growth on the Ti surface was initialized by the deposition of one layer of photoreactive PVA bonded by UV irradiation to the Ti surface, which was modified with an alkylsilane compound. The multilayered hydrogel was built up by alternating the deposition of the PMBV and PVA; this was monitored by several methods: static contact angle measurement, X-ray photoelectron spectroscopy, and attenuated Fourier-transform infrared spectroscopy. The results revealed clearly the progressive construction of the multilayered hydrogel on the Ti substrate. The PMBV/PVA multilayer prepared on the Ti substrate reduced the adhesion of L929 cells compared with that on an untreated Ti substrate. Thus, we concluded that the formation of the multilayered hydrogel is effective to improve the biocompatibility on Ti-based medical devices.

The molecular composite composed of polyethylene (PE) and poly(vinyl acetate) (PVAc) prepared using supercritical carbon dioxide (scCO2) and its surface modification for biocompatible surface demonstrated the creation of novel polymer biomaterials. In this study, this modification process was applied to the PE narrow tube (inside diameter: 300μm, outside diameter: 600μm, length: 5m). It was confirmed that PVAc was uniformly generated in PE tube by infrared imaging measurement of cross-section. After the acetyl group on the surface was hydrolyzed, phospholipid polymer was immobilized to the hydroxyl group on the surface of the tube. The phospholipid polymer immobilized surface showed a drastic reduction in protein adsorption. The surface of the minute and slender tube can be effectively modified using the feature of carbon dioxide whose surface tension is near zero. The modification technology by scCO2 is a promising for creation of variously-shaped new biomaterials.

Nanoparticles are widely applied as diagnostic reagents, drug-delivery carriers or bioaffinity beads. In particular, magnetic particles have been widely used in the study of biomedical applications. When we look ahead to the future, it is needed to construct precisely designed surface containing such as high bioaffinity and capability to capture of small amount protein or specific protein among various protein. As a method to construct precisely designed biocompatible polymer surface, atom transfer radical polymerization (ATRP) was widely used as a living free radical polymerization. ATRP has advantages such as control of molecular weight, narrow polydispersivity, easy synthesis of block copolymer, and preparation of high density polymer brush under mild condition. Previously, we have demonstrated synthesis of poly (2-methacryloyloxyethyl phosphorylcholine (MPC)) brush on ferric oxide (Fe3O4) by ATRP from immobilized initiator includes bromine that ATRP moiety. Here, it is known that poly(MPC) has been not affected for reduction of nonspecific binding, salt concentrations, pH and temperature. In this state, the poly(MPC)-grafted Fe3O4 could not be used for diagnostic material and collection material using magnetic interaction because poly(MPC) suppress protein adsorption. To introduce immobilization part for protein, p-nitrophenyloxycarbonyl polyethylene glycol methacrylate (MEONP) monomer that has active ester was polymerized as a block component. The poly(MPC-b-MEONP)-grafted Fe3O4 could capture proteins via active ester to amine of proteins. However, on careful consideration, this immobilization method had disadvantage for capture protein because immobilization part located in the side chain, not locate most outer surface. We focused on bromine (Br) located on end group of poly(MPC) brush, probably locate most outer surface. If the end group would be modified easily, the technique will be most effective modification. We adapted the reduction from azide (N3) to amine (NH2), after Br was exchanged to N3. This reduction has been called “staudinger reduction”. Generally, Click chemistry that reaction between N3 and alkyne is famous as a reaction of N3. On the other hand, the modification technique has wide application range due to amine group. At first, bromine was converted into azide, N3 using NaN3. Furthermore, the N3 was reduced to NH2 using PPh3 and H2O. The purification of magnetic nanoparticles with end group modified poly(MPC) brush was easy because of use of external magnetic interaction. The surface characterization at each step was estimated by XPS and FT-IR spectrum measurement. The absorbance signal attributed to N3 was appeared around 2000 cm-1 from FT-IR spectrum and N1s signal according to NH2 was observed at 399 eV from XPS measurement. The surface NH2 could react to carboxyl group or convert into other functional groups easily. The end group modification will be a useful for various bioaffinity bead applications.

Neuropeptide W (NPW) is an endogenous ligand for GPR7, a member of the G-protein-coupled receptor family. NPW plays an important role in the regulation of both feeding and energy metabolism, and is also implicated in modulating responses to an acute inflammatory pain through activation of the hypothalamus-pituitary-adrenal axis. GPR7 mRNA has been shown to be expressed in the hypothalamus, pituitary gland and adrenal cortex. Similarly, NPW expression has been demonstrated in the brain and pituitary gland. However, the precise distribution of NPW-producing cells in the adrenal gland remains unknown. The aim of this study was to explore the distribution and localization of NPW immunoreactivity in the rat adrenal gland. Total RNA was prepared from the hypothalamus, pituitary gland and adrenal gland. RT-PCR revealed the expression of NPW mRNA in these tissues, while in situ hybridization demonstrated the presence of NPW mRNA in the adrenal medulla. When immunohistochemistry was performed on sections of adrenal gland, NPW-like immunoreactivity (NPW-LI) was observed in the medulla but not in the cortex. Moreover, NPW-LI was found to be co-localized in cells which expressed dopamine beta hydroxylase but not phenylethanolamine-N-methyltransferase. The finding that NPW is expressed in noradrenalin-containing cells in the adrenal medulla suggests that it may play an important role in endocrine function in the adrenal gland.

The phosphorylcholine group functional methacrylate monomer, 2-methacryloyloxyethyl phosphorylcholine (MPC), was graft polymerized from the polydimethylsiloxane (PDMS) substrate using ultraviolet irradiation and using benzophenone as a photoinitiator. The varying monomer concentrations and irradiation times were investigated in order to verify the relationships between graft density and protein resistance under specific biological conditions. The ellipsometry analysis revealed that the layer thickness of the grafted polymer depended on the monomer concentrations after the irradiation for 1 min, however, it stabilized thereafter in all the specified conditions. The curve fitting of the C1s spectrum obtained by X-ray photoelectron spectroscopy analysis showed that the amount of grafted polymer increased with an increase in both monomer concentration and irradiation time. Atomic force microscopic images revealed that the terminations among the graft chains became dominant due to magnified chain mobility followed by growth of their length. In vitro albumin and fibrinogen adsorption results indicated that the resistance to protein adsorption was easily tuned by the specified conditions due to the controlled graft density. Lubrication was dramatically enhanced by the grafting and it was further promoted by an increase in the graft density in good solvents, indicating that the interactions between the graft chains and the solvents resulted in the lubrication system. These basic findings regarding the grafted PDMS surface are important for versatile applications, including its use as a biomaterial and microfluidic device.

The incidence of stroke is gradually increasing in the industrialized world, and is a major cause of long-lasting disability. Several different strategies have been investigated as a means of either preventing the occurrence of stroke or suppressing the subsequent enlargement of the in-farct volume. However, due to the narrowness of the therapeutic time window, we are still far from achieving an effective response. One finding that has offered new hope is the discovery that neurogenesis, long regarded as an impossibility in the adult brain, does indeed occur. This raises the possibility that the damaged brain might in fact be able to recover as well as other tissues and organs. In this paper, we will review both existing and potential strategies for the treatment of cerebrovascular disease. In particular, we will focus on the prospects of pituitary adenylate cyclase-activating polypeptide (PACAP), a neuropeptide that has been shown to exert both neuroprotective and neurogenic effects.

Potassium-doped nanostructured titanium oxide films were fabricated using a wet corrosion process with various KOH solutions. The doped condition of potassium in TiO2 was confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Nanotubular were synthesized at a dopant concentration of 0.27%, these structures disappeared. To investigate the electrical properties of K-doped TiO2, pseudo metal–oxide–semiconductor field-effect transistor (MOSFET) samples were fabricated. The samples exhibited a distinct electrical behavior and p-type characteristics. The electrical behavior was governed by the volume of the dopant when the dopant concentration was 0.18%.

A small-diameter polymer composite tubing comprising polyethylene (PE) and poly(vinyl acetate) (PVAc) with a biocompatible surface was developed for application to medical devices. In this study, the following modification process was applied to the narrow PE tubing (inside diameter: 300 μm, outside diameter: 600 μm, length: 5.0 m). The polymer composite (PE/PVAc) was prepared by supercritical impregnation of a vinyl acetate monomer and initiator into PE tubing, followed by in situ radical polymerization within the polymer matrix. Infrared imaging measurement of a cross-section confirmed that PVAc was uniformly generated in the PE tubing. After the acetyl groups on the surface were hydrolyzed, a phospholipid polymer with both phosphorylcholine groups and silane coupling groups was immobilized onto the hydroxyl groups on the surface. These reactions were performed over the entire surface of the PE tubing with a high-aspect-ratio uniformly. This surface possessing the phospholipid polymer shows high hydrophilicity and a remarkable ability to suppress protein adsorption. This novel surface modification by molecular composite formation using supercritical CO2 can modify areas such as the lumenal surface of very narrow PE tubing which are difficult to modify in conventional modification methods. This new procedure could have applications for the preparation of new polymeric materials, including biomaterials.

We carried out the phase selective preparations of hollow spheres of ccp- and hcp-Co, Co3O4, α-Fe, Fe3O4 and α-Fe2O3 with a diameter of ca. 600 nm and a shell thickness of 40 nm, using polystyrene (PS)-bead templates. The 600 nm PS beads were uniformly coated with cobalt or iron hydroxides by means of a homogeneous precipitation method. These cobalt-salt/PS hybrid particles were calcined in air at 400 °C and were transformed into Co3O4 hollow spheres. The hcp-Co hollow spheres were obtained by a reduction reaction of the Co3O4 particles under a stream of a 1 ∶ 1 mixed gas of H2 and N2 at 400 °C; in contrast, the ccp-Co hollow spheres were obtained by the calcination of the parent cobalt-salt/PS particles under H2–N2 at 400 °C. Hollow spheres of Fe3O4 and α-Fe2O3 were selectively prepared by calcination of iron-salt/PS particles at 400–500 °C in two different atmospheres, namely under H2–N2 and in air, respectively. Furthermore, the α-Fe2O3 particles were reduced into α-Fe under H2–N2 at 350 °C without any changes in morphology. These spheres were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) analyses. Magnetic measurements revealed a significant temperature dependence of the coercive field for the Fe3O4 (magnetite) particles, whereas the magnetic properties of the other particles were generally similar to those of the corresponding bulk samples. Surface chemical modifications were carried out on the Fe3O4 hollow spheres; the surfaces were grafted with poly(4-N-methylvinylpyridinium) brushes. This treatment was found to induce good dispersibility in water.