Butanediol Diglycidyl Ether Research Articles

The Heptazine-Based Materials through Intrinsically Modification for the Cycloaddition of CO2 and Bisepoxides.

For the efficient utilization of CO2 into valuable product, the attractive carbon nitride catalysts have been widely studied. In this work, heptazine-related materials with varying degree of polymerization were designed by an intrinsically modification strategy and employed in the cycloaddition of CO2 with the bisepoxide 1, 4-butanediol diglycidyl ether (BDODGE). We initially figured out that the sample prepared at 450 °C contained more melem hydrate, exhibiting the best performance. The epoxides conversion and corresponding cyclic carbonates selectivity could achieve 93.1 % and 99.3 % at 140 °C for 20 h without any cocatalyst and solvent, respectively. Results of the catalytic tests suggested that the high catalytic activity was dependent on big size porous structure and the synergetic effect of active amino groups and -OH groups. The role of water in maintaining the specific structure and providing active site has been proved. Moreover, the CN-450-W catalyst exhibited outstanding recycling stability. And finally, a plausible reaction mechanism was proposed.

Water-Insoluble, Thermostable, Crosslinked Gelatin Matrix for Soft Tissue Implant Development.

In this present study, the material science background of crosslinked gelatin (GEL) was investigated. The aim was to assess the optimal reaction parameters for the production of a water-insoluble crosslinked gelatin matrix suitable for heat sterilization. Matrices were subjected to enzymatic degradation assessments, and their ability to withstand heat sterilization was evaluated. The impact of different crosslinkers on matrix properties was analyzed. It was found that matrices crosslinked with butanediol diglycidyl ether (BDDE) and poly(ethylene glycol) diglycidyl ether (PEGDE) were resistant to enzymatic degradation and heat sterilization. Additionally, at 1 v/v % crosslinker concentration, the crosslinked weight was lower than the starting weight, suggesting simultaneous degradation and crosslinking. The crosslinked weight and swelling ratio were optimal in the case of the matrices that were crosslinked with 3% and 5% v/v BDDE and PEGDE. FTIR analysis confirmed crosslinking, and the reduction of free primary amino groups indicated effective crosslinking even at a 1% v/v crosslinker concentration. Moreover, stress-strain and compression characteristics of the 5% v/v BDDE crosslinked matrix were comparable to native gelatin. Based on material science measurements, the crosslinked matrices may be promising candidates for scaffold development, including properties such as resistance to enzymatic degradation and heat sterilization.

Lignosulfonate and glycidyl ether modified urea formaldehyde wood adhesives for interior particleboard production

Purpose The purpose of this study is the development of sustainable and low-formaldehyde emission wood adhesive formulations. Design/methodology/approach Three-step urea formaldehyde (UF) resin has been in situ modified with calcium lignosulfonate (LS) and/or 1,4 butanediol diglycidyl ether (GE). The structural, chemical, thermal and morphological characterizations were carried out on resin samples. These resins have been applied for particleboard pressing, and UF, UF-LS and UF-GE were evaluated as P2 classes according to EN 312. Findings The results show that the improved LS- or diglycidyl ether-modified UF wood adhesives were successful in their adhesive capacity, and the formaldehyde content of the final product was obtained as low as 8 mg/100 g. This paper highlights that the presented adhesive formulations could be a potential eco-friendly and cost-effective alternative to formaldehyde-based wood adhesives for interior particleboard production. Research limitations/implications Combination of LS and GE resulted in weaker mechanical properties and fulfilled P1 class particleboards due to temperature and duration conditions. Therefore, in situ usage of LS or GE in UF resins is highly recommended for particleboard pressing. Formaldehyde content of particleboards was determined with the perforator method according to EN 12460-5 and all of the particleboards exhibited E1 class. LS was more efficient in decreasing formaldehyde content than GE. Practical implications This study provides the application of particleboards with low formaldehyde emission. Social implications The developed LS- and diglycidyl ether-modified UF resins made it possible to obtain boards with significantly low formaldehyde content compared with commercial resins. Originality/value The developed formaldehyde-based resin formulation made it possible to produce laboratory-scale board prototypes using LS or GE without sacrificing of press factors and panel quality.

Facilitation of Cell Cycle and Cellular Migration of Rat Schwann Cells by O-Carboxymethyl Chitosan to Support Peripheral Nerve Regeneration.

O-carboxymethyl chitosan (CM-chitosan), holds high potential as a valuable biomaterial for nerve guidance conduits (NGCs). However, the lack of explicit bioactivity on neurocytes and poor duration that does not match nerve repair limit the restorative effects. Herein, CM-chitosan-based NGC is designed to induce the reconstruction of damaged peripheral nerves without addition of other activation factors. CM-chitosan possesses excellent performance in vitro for nerve tissue engineering, such as increasing the organization of filamentous actin and the expression of phospho-Akt, and facilitating the cell cycle and migration of Schwann cells. Moreover, CM-chitosan exhibits increased longevity upon cross-linking (C-CM-chitosan) with 1, 4-Butanediol diglycidyl ether, and C-CM-chitosan fibers possess appropriate biocompatibility. In order to imitate the structure of peripheral nerves, multichannel bioactive NGCs are prepared from lumen fillers of oriented C-CM-chitosan fibers and outer warp-knitted chitosan pipeline. Implantation of the C-CM-chitosan NGCs to rats with 10-mm defects of peripheral nerves effectively improve nerve function reconstruction by increasing the sciatic functional index, decreasing the latent periods of heat tingling, enhancing the gastrocnemius muscle, and promoting nerve axon recovery, showing regenerative efficacy similar to that of autograft. The results lay a theoretical foundation for improving the potential high-value applications of CM-chitosan-based bioactive materials in nerve tissue engineering.

PAAS-β-CDp-PAA as a high-performance easily prepared and water-soluble composite binder for high-capacity silicon anodes in lithium-ion batteries

The hyperbranched hydroxyl-rich water-soluble β-cyclodextrin polymer (β-CDp) is synthesized by the reaction between β-cyclodextrin and 1, 4-butanediol diglycidyl ether with a facile and environmentally friendly method, which is systematically confirmed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric (TG). A water-soluble PAAS-β-CDp-PAA binder is prepared by the esterification reaction between partially neutralized sodium polyacrylate (PAAS), β-CDp, and polyacrylic acid (PAA). Moreover, the optimized PAAS6-β-CDp1-PAA3 binder, with a three-dimensional (3D) cross-linked network structure constructed by covalent bonds, hydrogen bonds, and electrostatic interactions, displays a stronger adhesion between the active material and the current collector, effectively promotes the diffusion of Li+, and maintains the structural integrity of the electrode during charge-discharge cycling. Thus Si/PAAS6-β-CDp1-PAA3 electrode exhibits a higher initial discharge specific capacity of 3869 mAh g−1 with a columbic efficiency of 89.79% at 200 mA g−1, and a discharge specific capacity of 2513 mAh g−1 with a capacity retention rate of 71.10% is achieved after 100 cycles.

Purification of crosslinked, highly viscous and viscoelastic hyaluronic acid hydrogels by dynamic diafiltration

The current study shows a new possibility to purify crosslinked hydrogels based on hyaluronic acid (HA) to remove the residual crosslinking agent 1,4 - butanediol diglycidyl ether (BDDE) and its byproduct 1,4-butanediol di-(propan-2,3-diolyl) ether (EPD) using a crossflow filtration (CFF) device. Therefore, a dynamic crossflow-filtration (DCF) device with rotating and semipermeable ceramic filter discs (5 nm, 60 nm, 2000 nm) was used. No negative impacts on the thermal stability and rheological characteristics of the biopolymer could be shown. Furthermore, it was discovered, that 7 diafiltration volumes (DV) are sufficient to reduce the residual contaminants to < 0.1 % from the initial concentration and that the hyaluronic acid (HA) rejection coefficient (R) is 0.99 regardless of the chosen membrane pore size, while the permeability of BDDE and EPD remains at almost 100 %. No correlation between the membrane pore size and the flux could be found. For all membranes, the flux is surprisingly dropping after 0.5 DV was processed, which could be linked to the HA swelling and membrane pore blocking effects. The highest flux was determined for the 60 nm membrane with 32 Lm-2h−1 at steady state. The stability of the biopolymer is neither negatively influenced by the applied shear forces due to the rotational membrane velocity, nor by the applied thermal stress conditions for 6 months at 25 °C, 60 % relative humidity (r.h.) and 40 °C, 75 % r.h. The presented results show that a dynamic diafiltration can be regarded as a promising alternative to conventional purification methods.

Application of Injectable, Crosslinked, Fibrin-Containing Hyaluronic Acid Scaffolds for In Vivo Remodeling.

The present research aimed to characterize soft tissue implants that were prepared with the use of crosslinked hyaluronic acid (HA) using two different crosslinkers and multiple reagent concentrations, alone or in combination with fibrin. The effect of the implants was evaluated in an in vivo mouse model, after 4 weeks in one group and after 12 weeks in the other. The explants were compared using analytical methods, evaluating microscopic images, and a histology analysis. The kinetics of the degradation and remodeling of explants were found to be greatly dependent on the concentration and type of crosslinker; generally, divinyl sulfone (DVS) resists degradation more effectively compared to butanediol diglycidyl ether (BDDE). The presence of fibrin enhances the formation of blood vessels, and the infiltration of cells and extracellular matrix. In summary, if the aim is to create a soft tissue implant with easier degradation of the HA content, then the use of 2–5% BDDE is found to be optimal. For a longer degradation time, 5% DVS is the more suitable crosslinker. The use of fibrin was found to support the biological process of remodeling, while keeping the advances of HA in void filling, enabling the parallel degradation and remodeling processes.

Drug Delivery from Hyaluronic Acid-BDDE Injectable Hydrogels for Antibacterial and Anti-Inflammatory Applications.

Hyaluronic acid (HA) injectable biomaterials are currently applied in numerous biomedical areas, beyond their use as dermal fillers. However, bacterial infections and painful inflammations are associated with healthcare complications that can appear after injection, restricting their applicability. Fortunately, HA injectable hydrogels can also serve as drug delivery platforms for the controlled release of bioactive agents with a critical role in the control of certain diseases. Accordingly, herein, HA hydrogels were crosslinked with 1 4-butanediol diglycidyl ether (BDDE) loaded with cefuroxime (CFX), tetracycline (TCN), and amoxicillin (AMX) antibiotics and acetylsalicylic acid (ASA) anti-inflammatory agent in order to promote antibacterial and anti-inflammatory responses. The hydrogels were thoroughly characterized and a clear correlation between the crosslinking grade and the hydrogels’ physicochemical properties was found after rheology, scanning electron microscopy (SEM), thermogravimetry (TGA), and differential scanning calorimetry (DSC) analyses. The biological safety of the hydrogels, expected due to the lack of BDDE residues observed in 1H-NMR spectroscopy, was also corroborated by an exhaustive biocompatibility test. As expected, the in vitro antibacterial and anti-inflammatory activity of the drug-loaded HA-BDDE hydrogels was confirmed against Staphylococcus aureus by significantly decreasing the pro-inflammatory cytokine levels.

Correlating the thermomechanical properties of a novel bio-based epoxy vitrimer with its crosslink density

Vitrimers have covalent crosslink structures as normal thermoset polymers, but they possess unique properties of being able to go through plastic deformation due to their crosslinks being dynamically exchangeable above a particular temperature. This new type of polymers is getting increased attention owing to their reprocessing, remolding, and recycling properties, along with the thermoset characteristics. As a thermoset, the materials’ degree of crosslinking, namely crosslink density, is essential to their physical and mechanical properties. Herein, a series of dynamic epoxy crosslinking networks with different crosslink densities were prepared by changing the ratio of two epoxies N,N-diglycidyl-4-glycidyloxyaniline, and butanediol diglycidyl ether but keeping the same stoichiometric ratios when cured with a hardener synthesized from bio-based lignin-derived vanillin. The reaction enthalpy (ΔH) and glass transition temperature (Tg) were shown to decrease with decreasing crosslink density. The dynamic behavior of the resins was attributed to the dynamically exchangeable imine bonds brought in by the curing agent. The dynamic properties under various temperatures were analyzed to determine the activation energy for bond exchange (Ea) and relaxation times (τ). The results revealed that the resin with the highest crosslink density showed the highest τ as well as the highest Ea. The resins with higher crosslink density showed higher mechanical and thermal properties but lower strength retention efficiency (SRE). This study provides important insights into understanding the properties of this bio-based epoxy vitrimer.

Synthetisation of an affinity matrix (Procainamide Sepharose Cl-6b) for brain cholinesterase purification and separation source from Monopterus albus

Affinity chromatography for acetylcholinesterase; AChE namely Procainamide Sepharose CL-6B was synthesised through the coupling method between soluble procainamide hydrochloride immobilised by a cross-linked agarose size exclusion, sepharose CL-6B. 1, 4-butanediol diglycidyl ether plays a role in building up a productive and rigid connecting of a biospecific ligand (Procainamide hydrochloride) to an insoluble matrix (Sephacryl CL-6B). Local freshwater eel brain was extracted and centrifuge at high speed. The supernatant was collected, and seven different volumes were separately loaded on to the column for isocratic purification where 12 fractions were collected at the end of elution stage. This study shows 1000 μL of extractant; considered as the maximum volume to load onto the column. Lastly, a stepwise elution was performed with five different concentrations of NaCl, and each of 1 mL fraction was collected then assay for determination of enzyme activity and protein content. The data shows AChE was successfully purified with percentage recovery of 38 % after 21 purification fold. Kinetic study strengthens the data where the efficient coefficient ratio of ATCi was much higher compared to PTCi and BTCi at 3.03, 2.67 and 1.52 Vmax⋅Km −1, respectively, prove that the collected fraction predominantly contained with AChE, which is a targeted enzyme to be used as a sensitive biosensor to detect the presence of carbamate and organophosphate contamination in the environment.

Crosslinked Hyaluronic Acid Gels with Blood-Derived Protein Components for Soft Tissue Regeneration.

Hyaluronic acid (HA) is an ideal initial material for preparing hydrogels, which may be used as scaffolds in soft tissue engineering based on their advantageous physical and biological properties. In this study, two crosslinking agents, divinyl sulfone (DVS) and butanediol diglycidyl ether, were used to investigate their effect on the properties of HA hydrogels. As HA hydrogels alone do not promote cell adhesion on the scaffold, fibrin and serum from platelet-rich fibrin (SPRF) were combined with the scaffold; the aim was to create a material intended to be used as soft tissue implant that facilitates new tissue formation, and degrades over time. The chemical changes were characterized and cell attachment capacity of the protein-containing gels was examined using human mesenchymal stem cells, and viability was assessed using live-dead staining. Fourier-transform infrared measurements revealed that linking fibrin into the gel was more effective than linking SPRF. The scaffolds were found to be able to support cell adherence onto the hydrogels, and the best result was achieved when HA was crosslinked with DVS and contained fibrin. The most promising derivative, 5% DVS-crosslinked fibrin-containing hydrogel, was injected subcutaneously into C57BL/6 mice for 12 weeks. The scaffold was proven to be biocompatible, remodeling, and vascularization occurred, while shape and integrity were maintained. Impact statement Fibrin was combined with crosslinked hyaluronic acid (HA) for regenerative application, the structure of the combination of crosslinked HA with blood-derived protein was analyzed and effective coating was proven. It was observed that the fibrin content led to better mesenchymal stem cell attachment in vitro. The compositions showed biocompatibility, connective tissue and vascularization took place when implanted in vivo. Thus, a biocompatible, injectable gel was produced, which is a potential candidate for soft tissue implantation.

Compatibilization and toughness modification of linear aliphatic epoxy compound on paving epoxy asphalt

Epoxy asphalt (EA), which is usually prepared by diglycidyl ether of bisphenol A (DGEBA), curing agent and asphalt, is a kind of high-performance pavement material in highway construction. However, because of rigid molecular structure of DGEBA, poor compatibility with asphalt and high cross-linking density of three-dimensional network, cured EA usually has high strength but poor toughness especially at low temperature. In order to solve the problem of insufficient toughness of EA below glass-transition temperature (Tg) and eliminate the potential brittle fracture of EA mixture, linear aliphatic epoxy compounds, which have low viscosity, good molecular flexibility, similar solubility parameter and polarity with asphalt or DGEBA resin, can be used as phase structure controller and toughner to modify EA. By introducing a little of linear aliphatic epoxy compound, such as 1, 4-butanediol diglycidyl ether (BDDGE) or 1, 6-hexanediol diglycidyl ether (HDDGE), not only the viscosity of EA could be significantly decreased during the curing process, but also the phase compatibility of EA could be improved. An obvious reduction in storage modulus (E′) at low temperature and decreased Tg also prove that BDDGE or HDDGE modified EA have better toughness than neat EA at low temperature. The optimum amount of linear aliphatic epoxy compound based on its mixture with DGEBA should be 10–15 wt%.

Preparation of green waterborne polyurethane with improved hydrolysis repellency from CO2 derived amino-alcohol

Carbon dioxide based amino-alcohol compound (CO2-AA) with both alcohol and amino units in the molecular was prepared by chemical fixation of CO2 with 1, 4-butanediol diglycidyl ether and ethylenediamine, which was further used as chain extender to the preparation of waterborne polyurethanes (CO2-WPUs). Since the reacting activity of isocyanate groups in WPU prepolymer with NH2 was much faster than that with OH, hydroxyl groups could be maintained in the system and strengthen the hydrogen bonding interaction in WPU endowing the materials with some special properties. Specifically, the unique structure of CO2-AA improved mechanical, water/solvents resistance and hydrolysis/oxidation resistance properties of CO2-WPUs. Mechanical properties of the CO2-WPUs changed slightly during immersion in water, 0.25% NaOH and 6.00% H2O2 solution, while the WPUs prepared from typical chain extender ethylenediamine almost lost their mechanical properties after immersed in the solutions for 5 h. Moreover, the CO2-WPU films showed considerable thermal stability. The study suggested the novel CO2-AA might be a promising chain extender to improve the water/solvent resistance and hydrolysis/oxidation resistance of WPU.

Novel hyaluronic acid-tyrosine/collagen-based injectable hydrogels as soft filler for tissue engineering

In this study, we fabricated multifunctionalized hydrogel scaffolds based on hyaluronic acid (HA)-tyrosine and human-like collagen (HLC) by crosslinking with 1, 4-butanedioldiglycidyl ether (BDDE) for soft tissue fillers. The physicochemical of HA-tyrosine/BDDE (HTB) and various proportions of HA-tyrosine/BDDE/HLC (HTBH) hydrogels were characterized by swelling ratio, mechanical strength, morphology and thermal stability. The results demonstrated various HTBH hydrogels had superior performance in mechanical properties than HTB hydrogels. The biodegradation in vitro results demonstrated the degradation of HTBH hydrogels were slower than HTB hydrogels, and residual masses of HTBH hydrogels varied with different proportions of HA-tyrosine and HLC in the presence of the combination of HAse/collagenase I. The cell counting kit-8 (CCK-8), Hoechst/PI staining and cell adhesion of various HTBH hydrogels showed less cytotoxic and superior fibroblast attachment than those of HTB hydrogels. Moreover, subcutaneous injections of HTBH hydrogels containing high proportions of HLC in mice and rabbits all exhibit better biocompatibility and anti-biodegradation compared to HTB hydrogels after 1, 4, 8, 12 and 16 weeks. Hematoxylin-eosin staining (H&E), immunohistochemical and transmission electron microscope (TEM) analysis results indicated HTBH hydrogels had less intense inflammatory responses with increase proportion of HLC. Taken together, HTBH hydrogels had great potential application as ideal soft tissue fillers with excellent mechanical properties, biological stability and biocompatibility.

Comparative Properties of Hyaluronic Acid Hydrogel Cross-linked with 1, 4-Butanediol Diglycidyl Ether Assayed Using a Marine Hyaluronidase

Hyaluronic acid (HA) hydrogels for injection were fabricated using 1, 4-butanediol diglycidyl ether (BDDE) as a cross-linker. We used hyaluronidase fermented by the marine bacteria Arthrobacter globiformis A152, to comprehensively investigate the effects of BDDE concentration on swelling degree, modification degree, morphology, HA content, anti-enzyme ability, and residual free cross-linker. The results showed that within a certain range, the measured modification degrees of the HA hydrogels and HA contents changed linearly with increased concentration of the cross-linker. However, the change in anti-enzyme ability was not linear, potentially reflecting the influence of the spatial network structure.

Hydraulic Abrasion-Resistant Elastic Epoxy Resin Materials

The abrasion of hydraulic concrete structures caused by the washing action of flowing water is a common problem and cannot be solved by simply increasing the strength of the concrete. To ensure safe operation, increase in service life and reduction of maintenance costs of hydraulic concrete structures and the development of abrasion-resistant materials are required. In this work, polyurethane-modified epoxy resin was synthesized using the interpenetrating network technology (IPN). After many mixing experiments, the ratio of polyether amine to alicyclic amine in Component B was determined to be 29 : 14 and the ratio of Component A to Component B was 7 : 3. With these ratios, elastic epoxy achieved a tensile strength of more than 15 MPa and an elongation rate of more than 20%, thus balancing strength and toughness. The effects of the curing conditions, the ratio of Component A to Component B, and diluents and fillers on tensile strength and elongation of the elastic epoxy resin were analyzed. The results of the analysis indicated that the curing duration should be over 7 days, the optimal proportion of Component A to Component B should be 7 : 3, and the diluent of the elastic epoxy material should be the bifunctional butanedioldiglycidyl ether (622). The reliability of this material was determined by pull-out testing, adhesion, and tensile strength testing. The underwater steel ball test and ring test were adopted as the abrasion-resistance tests for the elastic epoxy resin material. The results showed that the abrasion-resistance performance of elastic epoxy coating improved hundreds of times over that of common concrete. Although the wearing strength was reduced with pressure, the elastic epoxy coating still retained excellent abrasion-resistance performance. At last, future application prospects of elastic epoxy improvement products are introduced and need further reach.

Investigation of poly (1-vinyl imidazole co 1, 4-butanediol diglycidyl ether) as a leveler for copper electroplating of through-hole

A leveler containing quaternary ammonium cations, namely poly (1-vinyl imidazole co 1, 4-butanediol diglycidyl ether) (VIBDGE) was synthesized and studied in this work. Quantum chemical calculations and molecular dynamics simulation of VIBDGE were employed to get insight to the adsorption model by assessing the molecular configuration and electronic orbital parameters. The simulation results reveal that VIBDGE will spontaneously absorb on the copper surface because of its tiling way, the generated nitrogen ions and the large molecular volume of VIBDGE. Galvanostatic measurements (GMs) and cyclic voltammetry (CV) tests were performed to investigate the electrochemical behaviors of VIBDGE and its synergistic mechanism with other additives. The results of GMs demonstrate VIBDGE exhibits good inhibiting performance in copper deposition. However, the reactant, namely 1-vinyl imidazole and 1, 4-butanediol diglycidyl ether, have no inhibition effect. Additionally, GMs results show that adsorption competition between bis-(sodium sulfopropyl)-disulfide (SPS) and VIBDGE is kinetically controlled and a steady state can be achieved regardless of the injection order of additives. The steady potential at lower rpm is less polarized and thus very beneficial for achieving uniform plating of through-hole (TH). The CV testes show that VIBDGE is capable of inhibiting copper deposition in the absence of chloride ions and chloride ions have a synergistic effect with VIBDGE. In addition, VIBDGE and PEG have competitive adsorption in copper deposition process. Consistent with the results of the GMs, the CV results illustrate that in the VIBDGE-SPS-PEG-Cl- system, the amount of copper deposited in the center of TH is more than that of the surface. Through the results of electroplating, it is confirmed that VIBDGE-SPS-PEG-Cl- system significantly improves the throwing power which is in accordance with simulation and electrochemical experiments.

A new amino-alcohol originated from carbon dioxide and its application as chain extender in the preparation of polyurethane

In this work, CO2 was chemically fixed by reacting with 1, 4-butanediol diglycidyl ether in the presence of a basic polystyrene resin catalyst. Under the 100% conversion of 1, 4-butanediol diglycidyl ether, five-membered cyclocarbonate with a selectivity of 98.5% was obtained. The cyclocarbonate was then reacted with an excess of 1, 2-ethylenediamine and the product was characterized by Fourier transform infrared spectrometer and nuclear magnetic resonance spectrometer. The results confirmed the successful synthesis of NH2 terminated product with a selectivity of 98.9%, accompanied by the formation of hydroxyls on β-C to the carbonyl groups, which can be regarded as a new amino-alcohol. Further, the obtained amino-alcohol was applied for the preparation of polyurethane urea as chain extender in a prepolymer way. Since the reactivity of isocyanate with NH2 is much faster than that with OH, the OH groups can be maintained in the system and hence strengthen the hydrogen bonding in polyurethane urea, which endows the materials with some unique properties. Comparing with the polyurethanes yielded from 1, 6-hexanediamine and 1, 6-hexanediol, polyurethane urea synthesized from the new amino-alcohol possessed better water/solvents resistance, considerable mechanical and thermal properties.

Preparation, characterization and application research of a sustained dexamethasone releasing electrode coating for cochlear implantation

Cochlear inflammatory response after cochlear implantation (CI) is an important mechanism for implantation trauma and hearing loss. The hearing loss was also caused by damage to auditory hair cells (HCs), whereas ion homeostasis within the cochlea can ensure survival of HCs. In our study, pure hyaluronic acid (HA) was crosslinked with 1, 4-butanediol diglycidyl ether (BDDE) and the successful preparation of the cross-linked hydrogel (CHA) was confirmed by rheological characteristics and FTIR spectra. Artificial perilymph (APL) was prepared to simulate the ion homeostasis microenvironment within scala tympani of human cochlear, and served as the major component of artificial perilymph soaked CHA (APL-CHA). The conductivity experiment indicated that APL-CHA is more suitable to the requirements of the electrical conductivity in scala tympani. The electrode coating process found that the extrusion coating method have advantages of controllable adhesive capacity of APL-CHA, uniform coating thickness and smooth surface as compared to common method. Due to CI surgery application requirement, optimization of coating process was selected as follows: extrusion coating method, degree of 3.6 vol%, pinhole diameter of 32G (110 μm), pressure of 200 ± 15.81 Psi. Controlled dexamethasone 21-phosphate sodium salt (DSP) release of 20 days could be demonstrated using the hydrogel filled reservoir via a validated HPLC method. The morphological structure of CHA showed different sizes of porous structure among APL-CHA provided structural basis for drug delivery. L929 fibroblasts culture and Spiral Ganglion Neuron Explants culture results revealed that APL-CHA possesses fine biological compatibility. APL-CHA shows a promising application in CI surgery and has great potential in preventing hearing loss with well simulation of ion homeostasis within the cochlear, local DSP delivery for target anti-inflammatory, approximate conductivity within the scala tympani and optimization of electrode coating process.

Covalent immobilization of organophosphorus hydrolase enzyme on chemically modified cellulose microfibers: Statistical optimization and characterization

Organophosphorus hydrolase (OPH) from Flavobacterium ATCC 27551 was covalently immobilized on epoxy modified plant cellulose powder. The Taguchi method was applied to optimize the conditions of cellulose activation and binding of the OPH to the carrier surface. The chemical modification of cellulose by covalent coupling with 1, 4-butanediol diglycidyl ether was demonstrated using the FTIR technique. TEM analysis proved good linkage of the OPH over the support surface. At the identified optimum condition of affecting parameters, the activity yield of immobilized OPH on the modified cellulose was found to be 68.32%. The kinetic parameters, Km and Vmax values, were calculated and it was determined that the catalytic efficiency of the immobilized OPH was about 4.85-fold lower than that of free enzyme. The storage, thermal, and pH stabilities of the immobilized OPH were improved compared with free counterpart. The results revealed that after incubation for 24 h at 55 °C, the soluble and immobilized OPH retained 8% and 35% of their initial activities, respectively. Furthermore, the immobilized OPH showed a 59% residual activity when used ten times repeatedly. Therefore, plant cellulose as a low-cost carrier has shown excellent properties for enzyme immobilization to be used as biocatalytic material in large scale applications.