The aim of this research is to develop polymeric micelle system as a targetable bone imaging carriers without nonspecific phagocytosis which is made of polyethylene oxide (PEO) and polycaprolactone (PCL). Diamino-PEO, which has two amino groups in its structure, was used to conjugate both PCL and ligand for specific radioisotope. PCL was conjugated to one amino group of diamino-PEO by using diaminohexyl cyclocarbodiimide (DCC), coupling agent. Hydroxyphenylpropionic acid (HPP), diethylenetriamine pentaacetic acid (DTPA) and mercaptoacetyl glycine glycidyl glycine (MAG3), as ligands for specific radioisotopes, were coupled to the rest of amino group of diamino-PEO by the same method as described. Formation of ligand-conjugated block copolymers, critical micelle concentration (CMC) of the copolymers, hydrodynamic radii, and morphology of the micelles were investigated. Besides, 125I-labelling efficiency and biodistribution of the micelles were examined. PEO-PCL block copolymer micelles demonstrated CMC of 25 mg/l and size of 60 nm, which may be adequate for blood vessel and bone imaging. 125I-labelling efficiency was above 90%, and was more stable at human serum for 24 h. 125I-labelled polymeric micelles showed higher blood maintenance and bone uptake when compared to stannous colloid, used as a control. A noticeable decrease in liver or spleen uptake could be achieved by the micelles. Therefore, radioisotope carrying PEO-PCL micelle system was suggested as a useful tool for effective diagnostic bone targeting and imaging.

This study was aimed to develop an ascending release push-pull osmotic pump (APOP) system with a novel mechanism and an easy manufacture process. Theoretical analysis showed that the key to obtain the non-zero order drug release was to break the balance between the drug suspension release rate in the drug layer and the swelling rate of the core, and an ascending drug release rate was achieved when the former was slower than the latter. A polymer (Polyox WSR N-12K) was introduced as a suspension agent in drug layer to slow down the hydration rate of drug layer. Influence of the composition of drug layer (PEO category, total amount, drug loading and fraction of NaCl), push layer (NaCl amount), and also the level of coating weight gain on the drug release profiles was investigated. Observation of hydration state was estimated by taking photos, and also was confirmed by the theories. Paliperidone was delivered successfully by APOP at an ascending release rate up to 20 h in vitro. The in vivo plasma concentration of paliperidone in beagle dogs increased gradually up to 19 h. The APOP with an easy manufacture process was a promising strategy to deliver drug at an ascending rate.

OBJECTIVE

To determine the changes in the visual centers of rats following monocular visual deprivation after postnatal eyelid opening (PEO).

METHODS

Monocular eyelid suture was performed on rats on days 1, 3, 5, 7, 14, and 28 after PEO, and the glucose metabolism was measured 1, 2, 5, and 7 days after the eyelid suture. Ex vivo autoradiography with (14)C- or (18)F-labeled 2-deoxy-D-glucose was carried out. Effects of monocular enucleation or dark rearing were also determined.

RESULTS

Monocular eyelid suture did not decrease the glucose metabolism in any contralateral visual structures on day 1 after visual deprivation in the <em>PEO</em>1 or <em>PEO</em>3 lid-sutured rats. However, there was a decrease on day 1 after the eyelid suture in <em>PEO</em>7 and older rats. Similarly, monocular enucleation on <em>PEO</em>1 did not reduce the glucose metabolism in the visual cortex (VC), but enucleation on <em>PEO</em>7 and thereafter did. Eyelid suture on <em>PEO</em>8 following dark rearing until <em>PEO</em>7 did not reduce the glucose metabolism 1 day after suture, but reduced it at 7 days after suture.

CONCLUSIONS

Glucose metabolism was altered by visual deprivation on PEOPEO were required for initiation of visual function in the rat visual system.

A wide variety of synthetic approaches from homogeneous precursor solutions have so far been developed for precise structural design of materials in multiscale. In organic templating approaches for porous materials design, we have recently developed a new approach to fabricate colloidal polystyrene-block-poly(oxyethylene) (PS-b-PEO) templated large pores that can be controlled in thick films of aluminum organophosphonate (AOP). In this study, we extended this approach using colloidal PS-b-PEO aggregates to aerosol-assisted synthesis for the fabrication of spherical particles. Structural variations (morphology and porous structure) depended on the synthetic conditions, which were mainly investigated by using electron microscopies (SEM and TEM). In addition to the insight on the colloidal PS-b-PEO templating of spherical pores in AOP spheres, it was found that colloidal PS-b-PEO aggregates were flexible for further design of pore shape that was strongly affected by external morphology. In this context, we proposed this method as flexible colloidal PS-b-PEO templating to fabricate unusual macroporous structures during morphological control from precursor solutions containing colloidal PS-b-PEO aggregates. The insights will be promising for precise construction of unique devices using porous materials templated by colloidal organic aggregates. In addition, we found a useful water adsorption-desorption behavior over the macroporous AOP bulky powders when the macropores were connected through large pores, which is also significant for future development of AOP-based porous materials.

A new separation medium, poly(N-isopropylacrylamide)-g-poly(ethyleneoxide) (PNI-PAM-g-PEO) solution, used for double-stranded (ds) DNA separation by capillary electrophoresis (CE) is presented. This type of grafted copolymer has a good self-coating ability for quartz capillary tubing and a slightly temperature-dependent viscosity-adjustable property, making it easier to use. One bp resolution was achieved within 12.5 min by using 8% w/v PNIPAM-gPEO in 1 x TBE (Tris-borate-ethylenediaminetetraaceticacid) buffer with an effective column length of 10 cm and an applied electric field strength of 200 V/cm. The PNIPAM-g-PEO solutions had a high sieving ability for relatively small sized DNAs with the relative standard derivation for the first 10 runs being less than 0.9% by using the same polymer solution. With 8% w/v PNIPAM-g-PEO solution in a 1.5 cm column and 2400 V as the running voltage, phiX174/HaeIII digest could be clearly separated within 24 s.

The study of brain structure and connectivity using diffusion magnetic resonance imaging (dMRI) has recently gained substantial interest. However, the use of dMRI still faces major challenges because of the lack of standard materials for validation. The present work reports on brain tissue-mimetic materials composed of hollow microfibers for application as a standard material in dMRI. These hollow fibers were fabricated via a simple and one-step coaxial electrospining (co-ES) process. Poly(ε-caprolactone) (PCL) and polyethylene oxide (PEO) were employed as shell and core materials, respectively, to achieve the most stable co-ES process. These co-ES hollow PCL fibers have different inner diameters, which mainly depend on the flow rate of the core solution and have the potential to cover the size range of the brain tissue we aimed to mimic. Co-ES aligned hollow PCL fibers were characterized using optical and electron microscopy and tested as brain white matter mimics on a high-field magnetic resonance imaging (MRI) scanner. To the best of our knowledge, this is the first time that co-ES hollow fibers have been successfully used as a tissue mimic or phantom in diffusion MRI. The results of the present study provide evidence that this phantom can mimic the dMRI behavior of cellular barriers imposed by axonal cell membranes and myelin; the measured diffusivity is compatible with that of in vivo biological tissues. Together these results suggest the potential use of co-ES hollow microfibers as tissue-mimicking phantoms in the field of medical imaging.

This study evaluated local tissue reaction around the β-tricalcium phosphate (β-TCP) block and compared results with β-TCP block grafting and periosteal expansion osteogenesis (PEO). The mandibular premolars were extracted from five dogs and buccal corticotomy was performed. Narrow alveolar ridge models were created at 4 weeks. The β-TCP block graft, such as veneer graft, was used on the right side and PEO using β-TCP block on the left side. Changes of alveolar width, histological findings and histomorphometrical analysis were evaluated. There were no problems with materials at any of the sites at any time. In both groups, the width increased after surgery and results were stable 8 weeks after surgery. Newly formed bone tissue was observed inside the β-TCP block in both sides. Histological findings differed especially at the division between mandibular bone and β-TCP block. Histomorphometric analyses revealed that β-TCP had been absorbed (mean decrease 28%) and new bone had formed (mean increase 43%) at 8 weeks postoperatively on both sides. The β-TCP block worked as a space-maker under the soft tissue, including the periosteum, and acted as a substitute for original bone. This bone substitute was effective material for bone augmentation in both methods.

In this study, we propose substrate-independent modification for creating a protein-repellent surface based on dopamine-melanin anchoring layer used for subsequent binding of poly(ethylene oxide) (PEO) from melt. We verified that the dopamine-melanin layer can be formed on literally any substrate and could serve as the anchoring layer for subsequent grafting of PEO chains. Grafting of PEO from melt in a temperature range 70-110 °C produces densely packed PEO layers showing exceptionally low protein adsorption when exposed to the whole blood serum or plasma. The PEO layers prepared from melt at 110 °C retained the protein repellent properties for as long as 10 days after their exposure to physiological-like conditions. The PEO-dopamine-melanin modification represents a simple and universal surface modification method for the preparation of protein repellent surfaces that could serve as a nonfouling background in various applications, such as optical biosensors and tissue engineering.

A PEO-containing surface coating was investigated as a means to control neurite outgrowth in the presence of serum. Various ratios of end-group-activated tri-block copolymer Pluronic F108 were used to immobilize the extracellular matrix protein fibronectin (FN). Primary cultures of dorsal root ganglion neurons were cultured on F108-immobilized FN or, as a control, on FN adsorbed from solution directly to polystyrene. Although FN surface concentration could be controlled in a dose-dependent manner by either technique, dose-dependent control of neuronal behaviors was best achieved on F108-immobilized FN. This effect was similar regardless of the presence of serum in the culture medium. F108-immobilized FN supported twofold greater maximal neurite outgrowth than did directly adsorbed FN. Furthermore, at similar surface concentrations, F108-FN was significantly more active in promoting neurite outgrowth. Polypropylene filament bundles treated with F108-immobilized FN supported robust outgrowth from explants of dorsal root ganglia, demonstrating the utility of the surface coating on clinically relevant materials with more complex shapes. The ability to control neuronal behaviors in a serum-resistant manner, coupled with enhanced biologic activity, demonstrates the potential for surfactant-based immobilization as a method for generating biointeractive materials for tissue engineering.

Capillary electrophoresis (CE) with polyacrylamide gels has already been demonstrated to allow single-base resolution of single-stranded DNA. However, linear polyacrylamide is not an ideal matrix because of a high viscosity and difficulties in preparing the polymer with well defined pore sizes. Alternatively, poly(ethyleneoxide) (PEO) with a large range of molecular masses from 300,000 to 8,000,000 is available commercially. In addition, it is easy to prepare homogeneous solutions to provide highly reproducible separation performance with sufficient resolution. Single-base resolution of double-stranded DNA between 123 and 124 base pairs can be achieved by the use of homogeneous matrices prepared from PEO (2.5% M(r) 8,000,000), and even better resolution is achieved by using mixed polymer matrices. With further work, it should be possible to change the fractions and the total amounts of polymers to achieve even higher resolution for different samples with different size ranges of fragments. Another advantage of mixed polymer matrices is that relatively high resolution can be obtained while maintaining a relatively low viscosity compared to linear polyacrylamide with identical contents of formamide and urea, which makes it easier to fill these matrices into small capillaries.

Many hydrogel materials of interest are homogeneous on the micrometer scale. Electrospinning, the formation of sub-micrometer to micrometer diameter fibers by a jet of fluid formed under an electric field, is one process being explored to create rich microstructures. However, electrospinning a hydrogel system as it reacts requires an understanding of the gelation kinetics and corresponding rheology near the liquid-solid transition. In this study, we correlate the structure of electrospun fibers of a covalently cross-linked hydrogelator with the corresponding gelation transition and kinetics. Polyethylene oxide (PEO) is used as a carrier polymer in a chemically cross-linking poly(ethylene glycol)-high molecular weight heparin (PEG-HMWH) hydrogel. Using measurements of gelation kinetics from multiple particle tracking microrheology (MPT), we correlate the material rheology with the the formation of stable fibers. An equilibrated, cross-linked hydrogel is then spun and the PEO is dissolved. In both cases, microstructural features of the electrospun fibers are retained, confirming the covalent nature of the network. The ability to spin fibers of a cross-linking hydrogel system ultimately enables the engineering of materials and microstructural length scales suitable for biological applications.

Bioresorbable linear poly(ester-ether urethane)s with different hydrophilic character were synthesized from block copolymers of poly(epsilon-caprolactone)-poly(ethylene oxide)-poly(epsilon-caprolactone) (PCL-PEO-PCL) as macrodiols, and L-lysine diisocyanate (LDI). A series of PCL-PEO-PCL triblock copolymers with different PEO and PCL chain length was obtained by reacting PEO with epsilon-caprolactone. Polyurethanes were synthesized by reacting the triblock copolymers with LDI in solution using stannous 2-ethylhexanoate as catalyst. The prepared triblock copolymers and polyurethanes were fully characterized by proton nuclear magnetic resonance spectroscopy, size exclusion chromatography, differential scanning calorimetry, and wide-angle X-ray diffraction. Water uptake, hydrolytic stability, and tensile properties of polyurethanes with different composition were evaluated and discussed in terms of the chain length and molecular weight of the polymers and its block components. Water uptake seems to depend on the ethylene oxide unit content of the polyurethane regardless of the triblock structure. Mechanical properties of the synthesized polymers were strongly affected by the molecular weight achieved during polymerization. The use of triblock macrodiols with different hydrophilicity allowed the preparation of a series of polyurethanes having a broad range of properties.

A solvent evaporation induced aggregating assembly (EIAA) method has been demonstrated for synthesis of highly ordered mesoporous silicas (OMS) in the acidic tetrahydrofuran (THF)/H(2)O mixture by using poly(ethylene oxide)-b-poly(methyl methacrylate) (PEO-b-PMMA) as the template and tetraethylorthosilicate (TEOS) as the silica precursor. During the continuous evaporation of THF (a good solvent for PEO-b-PMMA) from the reaction solution, the template molecules, together with silicate oligomers, were driven to form composite micelles in the homogeneous solution and further assemble into large particles with ordered mesostructure. The obtained ordered mesoporous silicas possess a unique crystal-like morphology with a face centered cubic (fcc) mesostructure, large pore size up to 37.0 nm, large window size (8.7 nm), high BET surface area (508 m(2)/g), and large pore volume (1.46 cm(3)/g). Because of the large accessible mesopores, uniform gold nanoparticles (ca. 4.0 nm) can be introduced into mesopores of the OMS materials using the in situ reduction method. The obtained Au/OMS materials were successfully applied to fast catalytic reduction of 4-nitrophenol in the presence of NaHB(4) as the reductant. The supported catalysts can be reused for catalytic reactions without significant decrease in catalysis performance even after 10 cycles.

An ideal surface for many biomedical applications would resist non-specific protein adsorption while at the same time triggering a specific biological pathway. Based on the approach of selectively binding albumin to free fatty acids, stearyl groups were immobilized onto poly(styrene) backbone via poly(ethylene oxide) side chains. X-ray photoelectron spectroscopy (XPS) analysis indicates substantial surface enrichment of the stearyl poly(ethylene oxide) (SPEO). In an aqueous environment, the surface rearrangement is limited, as proved by dynamic contact angle tests. The comb-like copolymer presents a special hydrophobic surface with high SPEO surface density, which may be due to the 'tail like' SPEO architecture at the copolymer/water interface. Protein adsorption tests confirm that the comb-like surfaces adsorb high levels of albumin and resist fibrinogen adsorption very significantly. The surfaces prepared in this research attract and reversibly bind albumin due to the synergistic action of the PEO chains and the stearyl end groups.

We present a method for characterizing the adsorption of solutes in microfluidic devices that is sensitive to both long-lived and transient adsorption and can be applied to a variety of realistic device materials, designs, fabrication methods, and operational parameters. We have characterized the adsorption of two highly adsorbing molecules (FITC-labeled bovine serum albumin (BSA) and rhodamine B) and compared these results to two low adsorbing species of similar molecular weights (FITC-labeled dextran and fluorescein). We have also validated our method by demonstrating that two well-known non-fouling strategies [deposition of the polyethylene oxide (PEO)-like surface coating created by radio-frequency glow discharge plasma deposition (RF-GDPD) of tetraethylene glycol dimethyl ether (tetraglyme, CH(3)O(CH(2)CH(2)O)(4)CH(3)), and blocking with unlabeled BSA] eliminate the characteristic BSA adsorption behavior observed otherwise.

Adsorption of proteins (fibrinogen, albumin, and gamma globulin) from plasma onto surface-modified PUs (PU-PEO, PU-SO3, and PU-PEO-SO3) was evaluated. Adsorbed fibrinogen at steady state decreased in the order PU-SO3>> PU>> PU-PEO-SO3>> PU-PEO, suggesting that sulfonate groups have specific high affinity to fibrinogen. The intermediate fibrinogen adsorption on PU-PEO-SO3 can be explained by the compensatory effect between the low protein binding affinity of the PEO chain and the high fibrinogen binding affinity of the sulfonate group. In addition, PU-PEO-SO3 showed a very fast fibrinogen adsorption due to the high accessibility of the sulfonate group to fibrinogen by the poly(ethylene oxide) (PEO) spacer. The kinetic profiles of their surfaces showed that as the adsorption time increases, fibrinogen initially adsorbed was decreased and a plateau reached, demonstrating that all the surfaces exhibited the Vroman effect (the fibrinogen displacement phenomenon). PU-PEO showed the least fibrinogen and albumin adsorption among PUs, confirming the known nonadhesive property of PEO chains. It is very interesting that PU-PEO-SO3 exhibited the highest adsorption of albumin and the lowest adsorption of IgG. Therefore, it may be concluded that such adsorption behaviors of proteins to PU-PEO-SO3 contribute to improved blood compatibility.

We report the use of near-field electrospinning (NFES) as a route to fabricate composite electrodes. Electrodes made of composite fibers of multi-walled carbon nanotubes in polyethylene oxide (PEO) are formed via liquid deposition, with precise control over their configuration. The electromechanical properties of free-standing fibers and fibers deposited on elastic substrates are studied in detail. In particular, we examine the elastic deformation limit of the resulting free-standing fibers and find, similarly to bulk PEO composites, that the plastic deformation onset is below 2% of tensile strain. In comparison, the apparent deformation limit is much improved when the fibers are integrated onto a stretchable, elastic substrate. It is hoped that the NFES fabrication protocol presented here can provide a platform to direct-write polymeric electrodes, and to integrate both stiff and soft electrodes onto a variety of polymeric substrates.

Insulin-immobilized polyurethanes (PU) were prepared by the graft polymerization of acrylic acid on oxygen plasma-treated PU, followed by a coupling reaction with polyethylene oxide (PEO) and subsequently with insulin. Modified PUs were characterized by measuring the water contact angle, the electron spectroscopy for chemical analysis and the attenuated total reflection Fourier-transform infrared spectroscopy. The wettabilities of the PU surfaces were increased by the introduction of acrylic acid, PEO and insulin. The amount of insulin immobilized was controlled by changing the concentrations of grafted acrylic acid and PEO. The interactions of human fibroblasts with surface-modified PUs were investigated using [3H]-thymidine incorporation and optical microscopy. Compared to the PU control, the proliferation of cells on the insulin-immobilized PUs was accelerated irrespective of the presence of serum while it was not influenced by PEO grafting. It seemed to be certain, from the experiments with high performance liquid chromatography, that A chain of insulin mainly reacted with the amine-end group of PEO grafted during the immobilization reaction.

The effectiveness of thermoseparating polymer-based aqueous two-phase systems (ATPS) in the enzymatic hydrolysis of starch was investigated. In this work, the phase diagrams of PEO-PPO-2500/ammonium sulfate and PEO-PPO-2500/magnesium sulfate systems were determined at 25 degrees C. The partition behavior of pure alpha-amylase and amyloglucosidase in four ATPS, namely, PEO-PPO/(NH(4))(2)SO(4), PEO-PPO/MgSO(4), polyethylene glycol (PEG)/(NH(4))(2)SO(4), and PEG/MgSO(4), was evaluated. The effects of phase-forming component concentrations on the enzyme activity and partitioning were assessed. Partitioning of a recombinant, thermostable alpha-amylase (MJA1) from the hyperthermophile, Methanococcus jannaschii was also investigated. All of the studied enzymes partitioned unevenly in these polymer/salt systems. The PEO-PPO-2500/MgSO(4) system was extremely attractive for starch hydrolysis. Polymer-based starch hydrolysis experiments containing PEO-PPO-2500/MgSO(4) indicated that the use of ATPS had a significant effect on soluble starch hydrolysis. Batch starch hydrolysis experiments with PEO-PPO/salt two-phase systems resulted in higher production of maltose or glucose and exhibited remarkably faster hydrolysis. A 22% gain in maltose yield was obtained as a result of the increased productivity. This work is the first reported application of thermoseparating polymer ATPS in the processing of starches. These results reveal the potential for thermoseparating polymer-enhanced extractive bioconversion of starch as a practical technology.

Surfaces of commercial polyurethanes (PUs) were modified by poly(ethylene oxide) (PEO) grafting and/or heparin immobilization for long-term biomedical applications. PU surfaces were treated with diisocyanate and then reacted with PEO or heparin. The heparin immobilized by various methods on the PU surface was very stable, with concentrations of 1.45-1.84 micrograms/cm2. Surface structure and characteristics of each modified PU were examined by performing the following surface analyses: attenuated total reflection infrared (ATR-IR), electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM), and dynamic contact angle measurements. The reaction scheme and surface chemical structure of modified PUs were confirmed by ATR-IR and ESCA, respectively. SEM results showed that the PU-PEO surface was very smooth and that the smoothness of the heparinized PU surfaces varied, depending upon the solvent and coupling agent used in the process. The hydrophilicity of the surface was significantly increased after PEO grafting or heparin immobilization. Increase in the chain length of the grafted PEO resulted in significant increases in hydrophilicity and surface mobility.

The antimicrobial peptide nisin shows potent activity against Gram-positive bacteria including the most prevalent implant-associated pathogens. Its mechanism of action minimizes the opportunity for the rise of resistant bacteria and it does not appear to be toxic to humans, suggesting good potential for its use in antibacterial coatings for selected medical devices. A more quantitative understanding of nisin loading and release from polyethylene oxide (PEO) brush layers will inform new strategies for drug storage and delivery, and in this work optical waveguide lightmode spectroscopy was used to record changes in adsorbed mass during cyclic adsorption-elution experiments with nisin, at uncoated and PEO-coated surfaces. PEO layers were prepared by radiolytic grafting of Pluronic® surfactant F108 or F68 to silanized silica surfaces, producing long- or short-chain PEO layers, respectively. Kinetic patterns were interpreted with reference to a model accounting for history-dependent adsorption, in order to evaluate rate constants for nisin adsorption and desorption, as well as the effect of pendant PEO on the lateral clustering behavior of nisin. Nisin adsorption was observed at the uncoated and F108-coated surfaces, but not at the F68-coated surfaces. Nisin showed greater resistance to elution by peptide-free buffer at the uncoated surface, and lateral rearrangement and clustering of adsorbed nisin was apparent only at the uncoated surface. We conclude peptide entrapment at the F108-coated surface is governed by a hydrophobic inner region of the PEO brush layer that is not sufficient for nisin entrapment in the case of the shorter PEO chains of the F68-coated surface.

This study examined the compression of solvated polymer brushes on bioengineered surfaces during the initial stages of Staphylococcus Aureus (S. aureus) adhesion from gentle flow. A series of PEG [poly(ethylene glycol)] brushes, 7 to 17 nm in height and completely non-adhesive to proteins and bacteria, were modified by the incorporation of sparse isolated ~10 nm cationic polymer "patches" at their bases. These nanoscale regions, which lacked PEG tethers, were electrostatically attractive towards negative bacteria or proteins. S. aureus drawn to the interface by multiple adhesive patches compressed the PEG brush in the remaining contact region. The observed onset of bacterial or fibrinogen capture with increases in patch content was compared with calculations. Balancing the attraction energy (proportional to the number of patches engaging a bacterium during capture) against steric forces (calculated using the Alexander-DeGennes treatment) provided perspective on the brush compression. The results were consistent with a bacteria-surface gap on the order of the Debye length in these studies. In this limit of strong brush compression, structural features (height, persistence length) of the brush were unimportant so that osmotic pressure dominated the steric repulsion. Thus, the dominant factor for bacterial repulsion was the mass of PEG in the brush. This result explains empirical reports in the literature that identify the total PEG content of a brush as a criteria for prevention of bioadhesion, independent of tether length and spacing, within a reasonable range for those parameters. Bacterial capture was also compared to that of protein capture. It was found, surprisingly, that the patchy brushes were more protein-than bacteria-resistant. S. aureus adhesion driven by patches within otherwise protein-resistant PEG brushes was explained by the bacteria's greater tendency to compress large areas of brush to interact with many patches. By contrast, proteins are thought to penetrate the brush at a few sites of PEO-free patches. The finding provides a mechanism for the literature reports that in-vitro protein resistance is a poor predictor of in-vitro implant failure related to cell-surface adhesion.

In order to investigate the interaction between various sulfonated polyurethanes (PUs) and blood, a commercial PU surface was chemically modified by poly(ethylene oxide) (PEO), dodecanediol(DDO), and propane sultone to give hydrophilic, hydrophobic, and negative sulfonated surfaces, respectively. The blood compatibility of modified PUs was evaluated by an in vitro platelet adhesion test, activated partial thromboplastin time (APTT), and prothrombin time (PT) measurements as well as an ex vivo rabbit A-A shunt method. In the platelet adhesion test, the hydrophilic PEO grafted PUs showed less platelet adhesion than untreated PU and hydrophobic DDO grafted PU. Sulfonated PU-PEO exhibited a lower degree of adhesion and shape change of platelet. The APTT and PT, especially APTT, of the sulfonated PUs were extended, whereas those of PU-PEO and PU-DDO did not show any significant change compared with untreated PU. Meanwhile, in the ex vivo experiment, hydrophilic PEO grafted PUs showed longer occlusion times than untreated PU or hydrophobic DDO grafted PU. In addition, the incorporation of SO3 groups at the end of PU-DDO and PU-PEO, particularly PU-PEO-SO3, exhibited an enormous prolongation in occlusion time, indicating a synergistic effect of the hydrophilic PEO and the negative SO3 groups on thromboresistance. These occlusion times corresponded well to in vitro evaluation results: the less adhesion and shape change of platelet and the longer APTT and PT, the more extended the ex vivo occlusion time.

As a potential alternative to currently available skin substitutes and wound dressings, we explored the use of bioactive scaffolds made of plant-derived proteins. We hypothesized that 'green' materials, derived from renewable and biodegradable natural sources, may confer bioactive properties to enhance wound healing and tissue regeneration. We optimized and characterized fibrous scaffolds electrospun from soy protein isolate (SPI) with addition of 0.05% poly(ethylene oxide) (PEO) dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol, and from corn zein dissolved in glacial acetic acid. Fibrous mats electrospun from either of these plant proteins remained intact without further cross-linking, possessing a skin-like pliability. Soy-derived scaffolds supported the adhesion and proliferation of cultured primary human dermal fibroblasts. Using targeted PCR arrays and qPCR validation, we found similar gene expression profiles of fibroblasts cultured for 2 and 24 h on SPI substrates and on collagen type I at both time points. On both substrates there was a pronounced time-dependent upregulation of several genes related to ECM deposition remodelling, including MMP-10, MMP-1, collagen VII, integrin-α2 and laminin-β3, indicating that both plant- and animal-derived materials induce similar responses from the cells after initial adhesion, degrading substrate proteins and depositing extracellular matrix in a 'normal' remodelling process. These results suggest that 'green' proteins, such as soy and zein, are promising as a platform for organotypic skin equivalent culture, as well as implantable scaffolds for skin regeneration. Future studies will determine specific mechanisms of their interaction with skin cells and their efficacy in wound-healing applications.