Poly Ethylene Glycol Dimethacrylate Research Articles

FRET Imaging in Three-dimensional Hydrogels

Imaging of Förster resonance energy transfer (FRET) is a powerful tool for examining cell biology in real-time. Studies utilizing FRET commonly employ two-dimensional (2D) culture, which does not mimic the three-dimensional (3D) cellular microenvironment. A method to perform quenched emission FRET imaging using conventional widefield epifluorescence microscopy of cells within a 3D hydrogel environment is presented. Here an analysis method for ratiometric FRET probes that yields linear ratios over the probe activation range is described. Measurement of intracellular cyclic adenosine monophosphate (cAMP) levels is demonstrated in chondrocytes under forskolin stimulation using a probe for EPAC1 activation (ICUE1) and the ability to detect differences in cAMP signaling dependent on hydrogel material type, herein a photocrosslinking hydrogel (PC-gel, polyethylene glycol dimethacrylate) and a thermoresponsive hydrogel (TR-gel). Compared with 2D FRET methods, this method requires little additional work. Laboratories already utilizing FRET imaging in 2D can easily adopt this method to perform cellular studies in a 3D microenvironment. It can further be applied to high throughput drug screening in engineered 3D microtissues. Additionally, it is compatible with other forms of FRET imaging, such as anisotropy measurement and fluorescence lifetime imaging (FLIM), and with advanced microscopy platforms using confocal, pulsed, or modulated illumination.

Characterization of Ceramic-Hydrogel Composites for Use in Bone Scaffolds Made Using Additive Manufacturing Techniques

Overall, autologous bone grafting continues to be the gold standard for the restoration of bone defects while other practices include metallic meshes and plates. These practices are not always suitable particularly when performing reconstructive surgery in the maxillofacial region as the defects tend to be complex in terms of size and shape. These bone defect usually occur due to trauma, infection or a result of oncologic surgeries and therefore the patient requires large amount of bone grafting material [1]. There is a need for alternative methods such as is artificial bone scaffolds with regenerative medicine approaches in order to enable original tissue regeneration. In order to stimulate tissue regeneration scaffolding materials are required to have certain properties such as biocompatibility, adequate mechanical properties and internal and surface topographical features in order to provide specific biological signals to promote cell attachment and proliferation. Ideally, it would also need to be biodegradable and provide sufficient support for both the particular defect area and cellular ingrowth to degrade over time as new bone tissue is formed [2]. This work analyses the mechanical and chemical properties of Hydroxyapatite (HA) - poly(ethylene glycol) dimethacrylate (PEGDMA) and Hydroxyapatite (HA) - poly(ethylene glycol) diacrylate (PEGDA) based composites used as artificial bone scaffold material with internal structures optimized using finite element analysis (FEA) using Hyperworks OptiStruct (Altair, USA) Topological Optimization and manufactured using commercially available additive manufacturing techniques in order to develop a product that can be introduced directly into the patient. The technique allows implants to be custom made, having the right dimensions and the right mechanical properties. Testing of the ceramic-hydrogel composite include mechanical testing in compression, tension, bending, impact and hardness while chemical analysis include Fourier Transform Infrared spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC). Morphology was analyzed using Scanning Electron Microscopy (SEM) and Laser Scanning Confocal Microscopy.

Polymeric Inverse Glasses for Development of Noniridescent Structural Colors in Full Visible Range.

Amorphous colloidal array with short-range order displays noniridescent structural colors due to the isotropic nature of the colloidal arrangement. The low angle dependence renders the colloidal glasses, which is promising for various coloration applications. Nevertheless, the colloidal glasses are difficult to develop red structural color due to strong cavity-like resonance from individual particles in the blue region. To suppress the cavity mode and develop the colors in the full visible range, we prepare inverse glasses composed of amorphous array of air cavities with short-range order. To produce the structures in a simple and reproducible manner, monodisperse silica particles are dispersed in a photocurable resin of poly(ethylene glycol) dimethacrylate (PEGDMA) at a volume fraction of 0.3. The particles spontaneously form the amorphous array with short-range order, which is rapidly captured in polymeric films by photopolymerization of the resin. Selective removal of silica particles from the polymerized resin leaves behind amorphous array of air cavities. The inverse glasses display structural colors with negligible backscattering in blue due to short optical path and low index in each cavity. Therefore, the colors can be tuned in full visible range by simply controlling the cavity size. The photocurable suspensions of silica particles can be patterned by photolithography, which enables the production of freestanding films containing patterned inverse glasses with noniridescent structural colors.

Cotton gauze-hydrogel composites: Valuable tools for electrically modulated drug delivery

ABSTRACTCotton gauze was inserted into a hydrogel network composed of acrylamide, sodium methacrylate, and polyethylene glycol dimethacrylate to fabricate an electroresponsive delivery system for wound dressing. The composite was characterized by swelling measurements, showing that shrinking or swelling depend on the applied voltage. The release profile of incorporated diclofenac sodium salt shows the possibility to modulate the kinetics by changes in the amplitude and duration of applied electric pulses. Mathematical models allow a characterization of release profiles, which are slower when an external voltage of 6, 12, and 18 V is applied, and faster at 24 V.

Investigation of eluted monomers from resin-based root canal sealer by high-performance liquid chromatography analysis.

Objective:The purpose of the current study was to determine the amount of urethane dimethacrylate (UDMA), bisphenol A-glycidyl methacrylate (Bis-GMA), poly (ethylene glycol) dimethacrylate (PEGDMA), bisphenol A ethoxylated dimethacrylate (Bis-EMA), and 2-hydroxyethyl methacrylate (HEMA) eluted from resin-based root canal sealer, epiphany, using high-performance liquid chromatography (HPLC).Materials and Methods:Epiphany was placed into the plastic molds and light-cured with a light emitting diode. After the curing process, each specimen in the first group (n = 12) was immersed in Eppendorf tubes containing a phosphate-buffered saline solution (PBS) and incubated for 45 s. In the second group, each specimen (n = 12) was immersed in Eppendorf tubes containing PBS and incubated for 24 h. Of the specimen extracts, 100 μL were subjected to HPLC. Analysis of data was accomplished with one-way analysis of variance (P < 0.05).Results:All of the samples eluted HEMA, UDMA, Bis-GMA, PEGDMA, and Bis-EMA. A significant difference was determined between the time periods of HEMA, UDMA, PEGDMA, and Bis-EMA (P < 0.05).Conclusion:The results of the current study showed that Epiphany releases HEMA, UDMA, Bis-GMA, PEGDMA, and Bis-EMA in both time periods.

Photo-regulated insulin delivery from glucose-responsive core-shell microspheres prepared by two-step high-speed shear-emulsions

Event Abstract Back to Event Photo-regulated insulin delivery from glucose-responsive core-shell microspheres prepared by two-step high-speed shear-emulsions Ruixue Yin1, Kemin Wang2, Hongbo Zhang1*, Wenjun Zhang3 and Nan Zhang2 1 East China University of Science and Technology, Mechanical and power engineering, China 2 Changzhou University, Materials science and engineering, China 3 University of Saskatchewan, Biomedical engineering, Canada Introduction: Traditional multi-dose subcutaneous injection for diabetes patients too often leads to inadequate glycemic control accompanied by pain. Recently, some implantable insulin delivery devices have been developed to release insulin in response to the blood glucose level [1],[2]. Considering the body weight and insulin resistance of patients, more attention should be paid on further real-time control of insulin release when such insulin devices are implanted inside the body, especially for basal insulin release control. Hence, core-shell microspheres with glucose-responsive core and photo-responsive shell are fabricated to achieve real-time photo-regulated insulin delivery accompanied by glucose-responsive insulin release according to blood glucose level changes. Materials: Concanavalin A (Con A), dextran, poly (ethylene glycol) dimethacrylate (PEGDMA) and bovine insulin were purchased from Yuanye Biotech.Co. (Shanghai, China). Glycidyl methacrylated dextran (Dex-G) and cinnamic acid modified dextran (Dex-C) were synthesized according to literatures[3],[4]. Methods: The core-shell microspheres were fabricated by a two-step high-speed shear-emulsion method. Briefly, a mixture of Dex-G, Con A, insulin and PEGDMA was added dropwise to cyclohexane with span 80 as stabilizer, stirring at 5,000 rpm for 2 min, followed by the addition of initiator. After further hardening and standing, the solid spheres were collected, which were then dispersed in Dex-C/ dichloromethane solution and added into polyvinyl alcohol solution to obtain core-shell microspheres using solid-in-oil-in-water method. Results: The morphology of core-shell microspheres was more regular compared with the core layer (see Fig. 1a and 1c). The diameters of core-layer and core-shell microspheres were 2.78 and 5.23 μm, respectively, with a borad distribution range of the core-shell spheres (see Fig. 1b and 1d). TGA and DTG curves ( see Fig. 1e and 1f) illustrated a higher decomposition temperature of core-shell microspheres. Insulin release behavior in response to step changes in glucose levels in five cycles and under real-time photo-irradiation (λ > 300 nm) were illustrated in Fig. 2, indicating an increase-decrease trend of insulin concentration in response to glucose level changes and a reduced insulin release amount after a small dose of UV irradiation. Discussion: The shape and size of core layer was mainly affected by the shear rate and the amount of crosslinker, while the formation of core-shell microspheres was more stable. The successful fabrication of core-shell microspheres was proved by not only the enlarged diameter of microspheres from 2.78 μm to 5.23 μm, but also the enhanced thermal stability of core-shell microspheres, owing to the introduction of Dex-C in the shell layer with higher decomposition temperature than Dex-G. In vitro insulin release test indicated that the obtained core-shell microspheres could release insulin in a pulsatile mode according to glucose concentration changes, and the release behavior could be regulated by real-time photo-irradiation. Conclusion: Core-shell microspheres are fabricated by a simple two-step high speed-emulsion method. With the combination of glucose-responsive insulin release behavior and real-time photo-regulation of basal insulin release, the obtained microspheres have great potential to be used for diabetes patients. National Natural Science Foundation of China (21404038); The Postdoctoral Science Foundation of China (2014M551345)

Effect of Young�s modulus on neural differentiation of human induced pluripotent stem cell derived neural stem cells.

Event Abstract Back to Event Effect of Young’s modulus on neural differentiation of human induced pluripotent stem cell derived neural stem cells. Matthew C. Mosley1, 2, Hyun Ju Lim1, 2, Jing Chen1, 2, Shenglan Li1, 2, Ying Liu1, 2 and Laura Smith Callahan1, 2, 3 1 University of Texas Medical School at Houston, Neurosurgery, United States 2 University of Texas Health Science Center at Houston, Center for Stem Cells & Regenerative Medicine, United States 3 University of Texas Medical School at Houston, Nanomedicine & Biomedical Engineering, United States Introduction: The Young’s modulus of culture substrates has been shown to have a significant effect on the lineage choice and differentiation state of stem cells[1],[2]. Typically, these studies have examined a mechanical range over several orders of magnitude using discrete samples to identify optimal mechanical regions for the differentiation of specific lineages. However, a more detailed examination of the region of interest for a specific lineage, such as neurons, could further improve the optimization of biomaterial mechanics for specific applications. In this study the optimal range for neural differentiation of human induced pluripotent stem cell (hiPSC) derived neural stem cells (NSC) will be examined using poly ethylene glycol dimethacrylate (PEGDM) hydrogels containing a continuous gradient in Young’s Modulus. Material and Methods: 50 mm × 10 mm × 1 mm hydrogel gradients were fabricated by dispensing 10% and 55% 10 kDa PEGDM solutions containing 0.1% Matrigel through two syringe pumps running in inverse linear ramping profiles ranging from 0 mL/h to 52 mL/h, respectively, over 75s into a custom mold, followed by photopolymerization with 2.3 mJ/cm2 for 7 min. After swelling in PBS, one 9.6-mm disc was punched out every 10 mm along each gradient. Discs were then evaluated for swelling ratio, mesh size and mechanical properties. For cellular experiments, the discs were placed in the wells of 48-well plates, seeded with ND2.0 hiPSC derived NCS and cultured with serum-free neural differentiation media for 14 days with medium exchanges every other day. Cell-seeded constructs were stained for neuron-specific β3-tubulin (TUJ1) and length of neurite extension was measured. Cultured cells on constructs were harvested for analyses of gene expression. Statistical significance was determined using one-way or two-way ANOVA in conjunction with the paired t-test with a p-value of < 0.05. Results and Discussion: The Young’s modulus of gradient samples ranged from 0.5 kPA to 3.5 kPA. Gene expression of TUJ1 (immature neuron marker) in cells cultures cultured on hydrogels decreases with increasing hydrogel Young’s modulus (Figure 1). The gene expression of PAX6 (neural stem cell marker), MAP2 (mature neuron marker), GFAP (astrocyte marker) and Oligo2 (oligodendrocyte progenitor marker) were not affected by Young’s modulus changes in this range and oligodendrocyte marker, PDGFRa, was not detected over the time course. Maximal neurite extension was observed in cells cultured on hydrogels with a Young’s modulus of 0.91 kPa (Figure 2). Conclusion: Hydrogel Young’s modulus effects hiPSC derived NSC gene expression of TUJ1 and neurite extension, but does not have a significant effect on the gene expression of other tested neural lineage markers. Modulation of matrix mechanics for neural differentiation is an important matrix property requiring futher optimization and study to fully understand its complex effect on cellular differentiation. Funding from Mission Connect a TIRR Foundation program and William Stamps Farish Fund supported this work.

Synthesis of pH-responsive amphiphilic branched macro-RAFT agent and the application in surfactant-free emulsion polymerization

Branched polymers have obviously different physical properties from their linear analogues such as low viscosity, high solubility, uncommon rheological properties and large amounts of functional groups. A series of branched poly(methyl acrylate)-block-poly(acrylic acid)s (PMA-b-HBPAAs) and branched poly(acrylic acid)-block-poly(methyl acrylate)s (PAA-b-HBPMAs) were successfully synthesized via RAFT polymerization using polyethylene glycol dimethacrylate (PEGDMA) as a branching agent, followed by a hydrolysis reaction. The structure of the branched copolymer was confirmed by Gel Permeation Chromatography (GPC), proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectrometry (FT-IR). Then the emulsifying performance and pH responsive behavior of these amphiphilic branched macromolecules were investigated. Furthermore, these amphiphilic branched macromolecules were used as surfactants and polymerization mediators for emulsion polymerization of styrene (St) at two pH (5.5 and 12.6), respectively. Due to the balanced hydrophilicity and hydrophobicity, PMA80-b-HBPAA120 proved to be an efficient surfactant both at pH = 12.6 and pH = 5.5. The influence of the pH, the length of the hydrophilic block of the PAA segments and hydrophobic PMA segments of the amphiphilic branched macromolecule have been studied.

The green preparation of poly N-vinylpyrrole nanoparticles

The UV-catalytic preparation of polyN-vinylpyrrole nanoparticles using a green oxidant H2O2in the presence of polyvinylpyrrolidone (PVP).

Strontium folate loaded biohybrid scaffolds seeded with dental pulp stem cells induce in vivo bone regeneration in critical sized defects.

Strontium folate (SrFO) is a recently developed bone promoting agent with interest in medical and pharmaceutical fields due to its improved features in comparison to current strontium based therapies for osteoporosis and other bone diseases. In this work SrFO derivative was synthesized and loaded into biohybrid scaffolds obtained through lyophilisation of semi-interpenetrating networks of chitosan polyethylene glycol dimethacrylate and beta tri-calcium phosphate (βTCP) fabricated using free radical polymerization. The scaffolds were seeded with pluripotent stem cells obtained from human dental pulp and their potential to regenerate bone tissues were assessed using a critical sized defect model of calvaria in rats and compared with those obtained without SrFO. The results obtained both in vitro and in vivo demonstrated excellent cyto-compatibility with resorption of scaffolds in 4-6 weeks and a total regeneration of the defect, with a more rapid and dense bone formation in the group with SrFO. Thus, the use of stem cells sourced from human dental pulp in combination with SrFO are very promising systems for their application in compromised osseous tissue regeneration.

2G42 高分子薄膜を用いたインジェクション可能な薬剤徐放デバイスの開発

A drug delivery system (DDS) device that consists of microspheres and polymeric film was fabricated and tested. Collagen microspheres (COLs) were embedded in photopolymerized polyethylene glycol dimethacrylate (PEGDM) film. The result showed COLs in the film were uniformly distributed and parts of COLs were exposed on the surface of the device. In vitro release study confirmed that devices could release FITC-dextran (FD40) continuously for over 10 days. It is found that there is a linear relationship between self-deployment time and the number of turns of the sheet. The flexible sheet type device that is injectable by a syringe needle holds great promise to locally deliver drug to specific organs such as eye or bladder.

Effect of heavy ion irradiation on optical property of radiation-crosslinked hydroxypropyl cellulose gel containing methacrylate monomers

Effects of dose rate and liner energy transfer (LET) on the optical property of a polymer gel dosimeter irradiated with swift heavy ions were investigated. The polymer gel dosimeters that consist of 2-hydroxyethyl methacrylate, polyethylene glycol dimethacrylate, and tetrakis(hydroxymethyl)phosphonium chloride with radiation-crosslinked hydroxypropyl cellulose gel matrix were prepared. The dosimeters were irradiated with 150MeV/u He ions, 290MeV/u C ions, and 500MeV/u Fe ions at HIMAC, and then were optically analyzed by using a UV–Vis spectrophotometer. Absorbance of the irradiated dosimeters increased with an increase in the dose up to 10Gy. The absorbance at the dose of 5Gy decreased with increasing dose rate in all of the heavy ions. The dosimeter irradiated with Fe ions exhibited the lowest dose response of the absorbance. It was found that the sensitivity of the dosimeters decreased with increasing dose rate as well as LET of the incident heavy ions.

Photo-polymerization, swelling and mechanical properties of cellulose fibre reinforced poly(ethylene glycol) hydrogels

The application of hydrogels as load-bearing biomedical components is often limited by their mechanical properties. Often an attempt to improve a hydrogel's stiffness is accompanied by a loss of toughness and swelling properties. In this work, we show that the addition of nanofibrillated cellulose (NFC) provides a mean to tailor both the swelling and the mechanical properties of the hydrogel. Various volume fractions of NFC were added to poly(ethylene glycol) dimethacrylate (PEGDM) precursors with two different molecular weights (6 and 20 kDa). The viscosity measurements of the precursor solutions indicated that the dispersed NFCs form a network-like structure in the hydrogel precursor. Such a structure, as observed in the photo-rheology experiments, serves as a light-scattering source when the solution is illuminated by UV light, which provides a uniform polymerization of the hydrogel in three-dimension and reduces the curing time. Mechanical properties of the neat and composite hydrogels were characterized using monotonic and cyclic compression tests. NFC reinforcement increases the hydrogel's stiffness by a factor 2 and 3.5 for the PEGDM matrixes with molecular weights of 6 and 20 kDa respectively without compromising their toughness. Moreover, the desired stiffness and swelling properties can be simultaneously achieved by adapting the reinforcement concentration and the hydrogel cross-link density. The obtained composite hydrogels offer enhanced and tuneable properties and are proposed for injectable and photo-curable load-bearing implants.

Transscleral Controlled Delivery of Geranylgeranylaceton Using a Polymeric Device Protects Rat Retina Against Light Injury.

We evaluated the effects of a transscleral drug delivery device, consisting of a reservoir and controlled-release cover, which were made of photopolymerized polyethylene glycol dimethacrylate and triethylene glycol dimethacrylate, combined at different ratios. Geranylgeranylacetone (GGA), a heat-shock protein (HSP) inducer, was loaded into the device. The GGA was released from the device under zero-order kinetics. At both 1 week and 4 weeks after device implantation on rat sclera, HSP70 gene and protein expression were up-regulated in the sclera-choroid-retinal pigment epithelium fraction of rat eyes treated with the GGA-loaded device compared with rat eyes treated with saline-loaded devices or eyes of non-treated rats. Flash electroretinograms were recorded 4 days after white light exposure (8000lx for 18h). Electroretinographic amplitudes of the a- and b-waves were preserved significantly in rats treated with GGA-loaded devices compared with rats treated with saline-loaded devices. Histological examination showed that the outer nuclear layer thickness was preserved in rats that had the GGA-loaded device. These results may show that transscleral GGA delivery using our device may offer an alternative method to treat retinal diseases.

Synthesis of new photoactive urethane carbohydrates and their behavior in UV or femtosecond laser-induced two-photon polymerization

Three methacrylated glycomonomers (CMA-1–3) were synthesized, characterized, and photocrosslinked in hydrophilic conetworks. The UV photobehavior of monomers was evaluated through FTIR spectrometry using Irgacure 819/Irgacure 2959 as photoinitiator, and the results showed that Irgacure 2959 is a better photoinitiator, the conversion degree (DC) varying in the range of 69–89.2% and the maximum rate of polymerization () being ~10 s−1. The addition of poly(ethylene glycol) dimethacrylate (PEG-DMA) or benzophenone macromer (BP-UDMA) as co-monomer improved the and DC (up to 100% after 300 s of irradiation in the latter). Specific analysis (gel fraction, water uptake, morphology) of the photopolymerized networks A1–A3 (CMA-1–3/PEG-DMA) and B1–B3 (CMA-1–3/BP-UDMA) demonstrated that B1–B3 films have interconnected inner pores, with irregular shapes and different sizes. The grid structures created through the two-photon polymerization of B1–B3 formulations in the presence of Irg819 are clearer and have a controlled porosity, of relevance for promising bioapplications.

Application of clotrimazole via a novel controlled release device provides potent retinal protection.

Age-related macular degeneration is the leading cause of legal blindness among older individuals. Therefore, the development of new therapeutic agents and optimum drug delivery systems for its treatment are crucial. In this study, we investigate whether clotrimazole (CLT) is capable of protecting retinal cells against oxidative-induced injury and the possible inhibitory effect of a sustained CLT-release device against light-induced retinal damage in rats. In vitro results indicated pretreatment of immortalized retinal pigment epithelium cells (RPE-J cells) with 10–50 µM CLT before exposure to oxygen/glucose deprivation conditions for 48 h decreased the extent of cell death, attenuated the percentage of reactive oxygen species-positive cells, and decreased the levels of cleaved caspase-3. The device consists of a separately fabricated reservoir, a CLT formulation, and a controlled release cover, which are made of poly(ethyleneglycol) dimethacrylate (PEGDM) and tri(ethyleneglycol) dimethacrylate (TEGDM). The release rate of CLT was successfully tuned by changing the ratio of PEGDM/TEGDM in the cover. In vivo results showed that use of a CLT-loaded device lessened the reduction of electroretinographic amplitudes after light exposure. These findings indicate that the application of a polymeric CLT-loaded device may be a promising method for the treatment of some retinal disorders.

Fewer Bacteria Adhere to Softer Hydrogels.

Clinically, biofilm-associated infections commonly form on intravascular catheters and other hydrogel surfaces. The overuse of antibiotics to treat these infections has led to the spread of antibiotic resistance and underscores the importance of developing alternative strategies that delay the onset of biofilm formation. Previously, it has been reported that during surface contact, bacteria can detect surfaces through subtle changes in the function of their motors. However, how the stiffness of a polymer hydrogel influences the initial attachment of bacteria is unknown. Systematically, we investigated poly(ethylene glycol) dimethacrylate (PEGDMA) and agar hydrogels that were 20 times thicker than the cumulative size of bacterial cell appendages, as a function of Young's moduli. Soft (44.05-308.5 kPa), intermediate (1495-2877 kPa), and stiff (5152-6489 kPa) hydrogels were synthesized. Escherichia coli and Staphylococcus aureus attachment onto the hydrogels was analyzed using confocal microscopy after 2 and 24 h incubation periods. Independent of hydrogel chemistry and incubation time, E. coli and S. aureus attachment correlated positively to increasing hydrogel stiffness. For example, after a 24 h incubation period, there were 52 and 82% fewer E. coli adhered to soft PEGDMA hydrogels than to the intermediate and stiff PEGDMA hydrogels, respectively. A 62 and 79% reduction in the area coverage by the Gram-positive microbe S. aureus occurred after 24 h incubation on the soft versus intermediate and stiff PEGDMA hydrogels. We suggest that hydrogel stiffness is an easily tunable variable that could potentially be used synergistically with traditional antimicrobial strategies to reduce early bacterial adhesion and therefore the occurrence of biofilm-associated infections.

Fabric‐hydrogel composite membranes for culturing microalgae in semipermeable membrane‐based photobioreactors

ABSTRACTIn this article, we demonstrate that hydrogel‐based composite membranes are used as semipermeable materials for the construction of photobioreactors (PBRs). PBRs are developed to culture microalgae using nutrients dissolved in seawater, and thus they need to be fabricated with membranes possessing sufficient material‐transport properties. While hydrogels are characterized by their highly swelling nature in water and therefore have desirable transport of dissolved matter, they lack the mechanical strength to be cast into thin structures of large surface area. This issue motivated us to design a new concept, i.e., fabric‐hydrogel composite membranes (FHCMs). A cotton fabric inside the hydrogel matrix endows the composite with tensile strength, which enables casting of FHCMs into thin membranes. Several FHCMs were prepared with 2‐hydroxyethyl methacrylate (HEMA), cross‐linking poly(ethylene glycol) dimethacrylate (PEGDMA) and a sheet of gauze by controlling the composition of the monomers and water. In the permeability measurement of nitrate ions, a key ingredient for the growth of microalgae, the permeability coefficient reached as high as 1.2 x 10−8 m2 min−1, which is roughly three times higher than that of a commercially available semipermeable membrane (3.3 x 10−9 m2 min−1). In the following evaluation of microalgal culture, a PBR constructed with a FHCM was able to maintain sufficient ion concentration and pH of the culture broth, supporting microalgal growth. These results suggest that the composite membranes with hydrogel and fabric have potential in the application of microalgal culture for bio‐diesel production in a marine environment. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 108–114

Fabrication of a Large‐Area Hierarchical Structure Array by Combining Replica Molding and Atmospheric Pressure Plasma Etching

A novel approach to produce a large‐area hierarchical structure array is presented. The method combines replica molding and atmospheric pressure plasma (APP) etching processes. Liquid blends consisting of siliconized silsesquioxane acrylate (Si‐SSQA), polyethylene glycol dimethacrylate (PEGDMA), and photoinitiator are used as roughness formable materials during APP etching. Microstructures composed of the Si‐SSQA/PEGDMA mixtures are fabricated by replica molding. Nanoroughness is realized on the microstructures by argon/oxygen (Ar/O2) APP etching in air. The nano­roughness on molded microstructures is efficiently controlled by varying the weight ratio of Si‐SSQA to PEGDMA and the etching time. The hierarchical structures fabricated by combining replica molding and Ar/O2 APP etching show superhydrophilicity with a long‐term stability, resulting in the formation of hydroxyl‐terminated silicon oxide layer with the reorientation limit. On the other hand, the hierarchical structures treated with a perfluorinated self‐assembled monolayer (SAM) show increased the water contact angles of up to 161° depending on the morphology of the hierarchical structures. The increment of water contact angles is consistent with increment of the nano‐/microroughness of hierarchical structures.

Desorption of 3,3'-diindolylmethane from imprinted particles: An impact of cross-linker structure on binding capacity and selectivity.

Here, seven cross-linkers (six polar diacrylates or dimethacrylates of different lengths between double bonds, and one aromatic-divinylbenzene) were used to examine the impact of the cross-linker on binding capacity and selectivity of 3,3'-diindolylmethane (DIM) imprinted material. DIM participates in the suppression of viability of human ovarian and human breast cancer cell lines, but has low bioavailability. The investigations of novel imprinted polymer matrices for improvement of DIM release could allow to utilize not only a potency of DIM but also similar alkaloids, which are the important compounds with pharmacological activity. The bulk, thermal radical copolymerization of the cross-linkers in the presence of 3,3'-diindolylmethane (the template) and allylamine (the functional monomer) in dimethyl sulfoxide or in carbon tetrachloride (porogens) was carried out. The binding capacities of imprinted and non-imprinted polymers were compared, and two polymers (these were prepared using ethylene glycol dimethacrylate and polyethylene glycol dimethacrylate as the cross-linkers) with the highest selectivity and binding capacity were selected to desorption test. The desorption profile of polymer prepared using polyethylene glycol dimethacrylate as the cross-linker revealed sustained release of 3,3'-diindolylmethane, and this system was selected for further optimization of the cross-linker amounts. The morphology and structure of the selected particles were analyzed using SEM micrographs, (13)C CP/MAS NMR spectroscopy, and BET measurements. The desorption of 3,3'-diindolylmethane from poly(allylamine-co-polyethylene glycol dimethacrylate) particles was in accordance with pseudo-second-order kinetics and the simplified Higuchi model indicated the diffusion controlled release of 3,3'-diindolylmethane.