Tetraethylene Glycol Dimethacrylate Research Articles

Acrylates and Methacrylates Sensitization in Patients with Orthopedic and Dental Prostheses: Asymptomatic Pre-Implant and Symptomatic Post-Implant Testing.

Acrylates and methacrylates are widely used in dental and orthopedic prostheses, false nails, adhesives, glues, and paints, and are strong sensitizers. The aim of our study was to assess the prevalence of acrylate sensitization in patients before the application of dental or orthopedic prostheses or after the application in case of potentially related contact dermatitis. Methods: The subjects were tested according to haptens reported in safety data sheets, including methyl methacrylate (MMA) 5%, methyl acrylate (MA) 1%, ethyl methacrylate (EMA) 2%, ethyl acrylate (EA) 1%, butylacrylate 0.1%, 2 hydroxyethyl methacrylate (HEMA) 5%, ethylene glycol dimethacrylate 2% (EGDMA), tetraethylene glycol dimethacrylate 2% (TEGDMA), and dimethyl amino ethyl methacrylate 0.2% (DAEMA). Multivariable logistic regression was used to study the factors associated with (meth)acrylate sensitization. Results: Six hundred sixty-five patients (75.4% of the total sample) without contact dermatitis before the placement of any dental or orthopedic prosthesis and 217 patients (24.6% of the total sample) with contact dermatitis potentially due to already placed prostheses were involved. In total, 37 cases of patch test positivity to at least 1 acrylate (4.2%) were found. In the pre-implant population, previous dermatitis and respiratory allergy were associated with increased sensitization to acrylates in multivariable regression analysis (odds ratio [OR] 2.38, 95% confidence interval [CI] 1.05-5.39; OR 2.96, 95% CI 1.32-6.64, respectively). The prevalence of sensitization was 3.5% for EGDMA, 2.7% for EA, 1.5% for 2-HEMA, 1.4% for both MA and MMA, 1.28% for DAEMA, and 0.8% for EMA. No statistically significant difference was found in the prevalence of sensitization between the pre- and post-implant groups. Discussion: Our study found a similar profile of sensitization in pre-implant and post-implant patients, suggesting the need to better study the specificity and sensitivity of patch tests to (meth)acrylate and to define relevance considering a detailed history of exposure.

SiRNA delivery mediated by pH and redox responsive p(DEAEMA-co-HEMA-g-PEGMA) nanogels

Small interfering RNAs (siRNA) have enabled novel, specific, and efficient treatment of diseases, including cancer. To obtain sufficient and well-controlled intracellular delivery, a drug delivery system is essential. Herein a delivery system for siRNA, composed of cationic biodegradable nanogels, is presented. P(DEAEMA-co-HEMA-g-PEGMA) nanogels with varying ratios of 2-diethyl aminoethyl methacrylate (DEAEMA) and 2-Hydroxyethyl methacrylate (HEMA), crosslinked with tetraethylene glycol dimethacrylate or disulfide-crosslinker bis(2-methacryloyloxy ethyl), are synthesized. The pH-depended nanogel swelling facilitates siRNA loading and endosomal disruption. The disulfide-crosslinker ensures siRNA release by GSH-mediated particle disassociating. The nanogels are within the sub-100nm range in their collapsed state, have a PDI ≥0.4, and a ζ-potential ranging from approximately 5-10 in the swollen state and 22–30 V in the collapsed state and have a swelling ratio up to 1.6 in diameter. Furthermore, the nanogels show good serum-stability, and are capable of delivering siRNA with acceptable cytotoxicity levels. The nanogels induced >90% eGFP-silencing in lung cancer cells, and gene-silencing of the cancer target POLR2A led to siRNA-induced cell death in squamous carcinoma cells. The findings suggest that the nanogel-system may function as a carrier vehicle for cytoplasmic delivery of siRNA.

The Effects of Cross-Linking Agents on the Mechanical Properties of Poly (Methyl Methacrylate) Resin.

Cross-linking agents are incorporated into denture base materials to improve their mechanical properties. This study investigated the effects of various cross-linking agents, with different cross-linking chain lengths and flexibilities, on the flexural strength, impact strength, and surface hardness of polymethyl methacrylate (PMMA). The cross-linking agents used were ethylene glycol dimethacrylate (EGDMA), tetraethylene glycol dimethacrylate (TEGDMA), tetraethylene glycol diacrylate (TEGDA), and polyethylene glycol dimethacrylate (PEGDMA). These agents were added to the methyl methacrylate (MMA) monomer component in concentrations of 5%, 10%, 15%, and 20% by volume and 10% by molecular weight. A total of 630 specimens, comprising 21 groups, were fabricated. Flexural strength and elastic modulus were assessed using a 3-point bending test, impact strength was measured via the Charpy type test, and surface Vickers hardness was determined. Statistical analyses were performed using the Kolmogorov-Smirnov Test, Kruskal-Wallis Test, Mann-Whitney U Test, and ANOVA with post hoc Tamhane test (p ≤ 0.05). No significant increase in flexural strength, elastic modulus, or impact strength was observed in the cross-linking groups compared to conventional PMMA. However, surface hardness values notably decreased with the addition of 5% to 20% PEGDMA. The incorporation of cross-linking agents in concentrations ranging from 5% to 15% led to an improvement in the mechanical properties of PMMA.

CuAAC-methacrylate interpenetrating polymer network (IPN) properties modulated by visible-light photoinitiation.

Interpenetrating polymer networks (IPNs) are a class of materials with interwoven polymers that exhibit unique blended or enhanced properties useful to a variety of applications, ranging from restorative protective materials to conductive membranes and hydrophobic adhesives. The IPN formation kinetics can play a critical role in the development of the underlying morphology and in turn the properties of the material. Dual photoinitiation of copper-catalyzed azide-alkyne (CuAAC) and radical mediated methacrylate polymerization chemistries enable the manipulation of IPN microstructure and properties by controlling the kinetics of IPN formation via the intensity of the initiating light. Specifically, azide and alkyne-based polyethylene glycol monomers and tetraethylene glycol dimethacrylate (TEGDMA) were polymerized in a single pot to form IPNs and the properties were evaluated as a function of the photoinitiating light intensity. Morphological differences as a function of intensity were observed in the IPNs as determined by thermomechanical properties and phase-contrast imaging in tapping mode atomic force microscopy (AFM). At moderate intensities (20 mW/cm2) of visible light (470 nm), the TEGDMA polymerization gels first and therefore forms the underlying network scaffold. At low intensities (0.2 mW/cm2), the CuAAC polymerization can gel first. The ability to switch sequence of gelation and IPN trajectory (simultaneous vs. sequential), affords control over phase separation behavior. Thus, light not only allows for spatial and temporal control over the IPN formation but also provides control over their thermomechanical properties, representing a route for facile IPNs design, synthesis, and application.

Direct and indirect eluates from bulk fill resin-based-composites

ObjectivesTo compare elutable substances directly released from bulk-fill (BF) resin-based composites (RBCs) with indirect elution from teeth restored with a BF composite. In addition to (co)monomers, the analytical focus was on other potentially toxic ingredients or impurities. Furthermore, the barrier function of the residual dentin/adhesive layer was studied. MethodsSix BF-RBC materials were studied. For each material subgroup, ten human third molar teeth with standard Class-I occlusal cavities were prepared and provided with a three-step adhesive system and the respective composite restoration (tooth groups). Same sized control specimens of the restorative material were prepared (‘direct BF-RBC’ groups). Each specimen was placed in an elution chamber such that the elution media (ethanol/water, 3:1) only contacted the tooth root or ¾ height of each specimen. They were incubated at 37 °C for up to 7 d. Samples of eluate were taken after 1, 2, 4 and 7 d and were analysed by high-temperature gas chromatography/mass spectrometry. Results(Co)monomers such as Bisphenol A ethoxylate dimethacrylate (bisEMA) or tetraethylene glycol dimethacrylate (TEEGDMA) were mostly found in the eluates of the ‘direct BF-RBC’ groups in statistically significantly greater amounts than in the eluates of the ‘tooth groups’. The residual dentin and/or adhesive layers acted as a diffusion barrier for most of the substances except for triethylene glycol dimethacrylate (TEGDMA) or diethylene glycol dimethacrylate (DEGDMA). For TEGDMA up to 3 orders of magnitude more were found in the ‘tooth groups’ compared to the ‘direct BF-RBC’ groups, evidently released by the adhesive system.Substances of Very High Concern (SVHC) including TINUVIN® 328 and BPA were found mainly in the eluates of ‘direct BF-RBC’ groups. SignificanceFor estimation of biocompatibility, a total system, specifically BF-RBC + adhesive, should always be investigated since individual considerations, such as only elution from a BF-RBC, do not correctly reflect the total clinical situation. The focus of elution tests should not only be on the co(monomers), but also on other ingredients or impurities that may be released.

Crosslinking-Dependent Drug Kinetics in Hydrogels for Ophthalmic Delivery.

Drug-diffusion kinetics in 2-hydroxyethyl methacrylate hydrogels were studied as a function of the crosslinking density and porosity. By varying the concentration of the crosslinker, tetraethylene glycol dimethacrylate, we demonstrated how the release of Timolol maleate could be optimized to allow for efficient drug delivery. FTIR and spectrophotometry supplied optical inferences into the functional groups present. By studying the swelling and degradation of hydrogels, supplemented with drug-release kinetics studies, the relationship between these two tenets could be formulated.

Direct and indirect monomer elution from an RBC product family

ObjectiveTo develop a model for quantitative comparison of elutable substances by direct elution from resin-bonded composite (RBC) test specimens versus indirect elutability of substances from RBC-restored teeth. Furthermore, it was to be investigated whether the different composites of the Tetric® RBC product family release different types and amounts of substances. MethodsFour different composite materials from the Tetric® product family were studied. For each material subgroup ten human third molar teeth were prepared with standard Class-I occlusal cavities. These ‘tooth group’ specimens were provided with a three-step adhesive system (incorporating TEGDMA) and the respective composite restoration. Same sized control specimens, of each RBC restorative material, were prepared (‘direct RBC’ groups). All specimens were placed in individual elution chambers such that the elution media (ethanol/water, 3:1) only came into contact with either the tooth root or ¾ height of the ‘direct RBC’ materials. They were incubated at 37 °C for up to 7 d. Samples of the eluant were taken after 1, 2, 4 and 7 d and were analysed by high-temperature gas chromatography/mass spectrometry. ResultsBisphenol A ethoxylate dimethacrylate (bisEMA), bisphenol A glycidyldimethacrylate (bisGMA), tetraethylene glycol dimethacrylate (TEEGDMA), decan-1,10-diol dimethacrylate (DDDMA) were mostly found in the eluates of the ‘direct RBC’ groups in statistically significantly greater amounts than in the eluates of the ‘tooth groups’. Such quantitative differences were also the case with eluates containing bisphenol A (BPA), dicyclohexyl phthalate (DCHP) and drometrizole, which are common in the environment. In contrast to the behavior found with all the other monomers, up to 3 orders of magnitude more triethylene glycol dimethacrylate (TEGDMA) was found in the ‘tooth groups’ compared to the ‘direct RBC’ groups, evidently released by the adhesive system. SignificanceThe release of most of the substances was clearly delayed in the ‘tooth groups’ indicative of their chronic, rather than acute, elution to the oral environment. A barrier function of the residual dentin layer and the adhesion layer can be inferred. The different release patterns of substances from the various composites of the RBC product family is a manifestation of their different and indication-specific compositions. Consideration of an overall restorative care (RBC plus adhesive) system, when assessing the total amount of released substances, is emphasized.

Synthesis of a thermoresponsive crosslinked MEO2MA polymer coating on microclusters of iron oxide nanoparticles

Encapsulation of magnetic nanoparticles (MNPs) of iron (II, III) oxide (Fe3O4) with a thermopolymeric shell of a crosslinked poly(2-(2-methoxyethoxy)ethyl methacrylate) P(MEO2MA) is successfully developed. Magnetic aggregates of large size, around 150–200 nm are obtained during the functionalization of the iron oxide NPs with vinyl groups by using 3-butenoic acid in the presence of a water soluble azo-initiator and a surfactant, at 70 °C. These polymerizable groups provide a covalent attachment of the P(MEO2MA) shell on the surface of the MNPs while a crosslinked network is achieved by including tetraethylene glycol dimethacrylate in the precipitation polymerization synthesis. Temperature control is used to modulate the swelling-to-collapse transition volume until a maximum of around 21:1 ratio between the expanded: shrunk states (from 364 to 144 nm in diameter) between 9 and 49 °C. The hybrid Fe3O4@P(MEO2MA) microgel exhibits a lower critical solution temperature of 21.9 °C below the corresponding value for P(MEO2MA) (bulk, 26 °C). The MEO2MA coating performance in the hybrid microgel is characterized by dynamic light scattering and transmission electron microscopy. The content of preformed MNPs [up to 30.2 (wt%) vs. microgel] was established by thermogravimetric analysis while magnetic properties by vibrating sample magnetometry.

Bioinformatics and Molecular Insights to Anti-Metastasis Activity of Triethylene Glycol Derivatives.

The anti-metastatic and anti-angiogenic activities of triethylene glycol derivatives have been reported. In this study, we investigated their molecular mechanism(s) using bioinformatics and experimental tools. By molecular dynamics analysis, we found that (i) triethylene glycol dimethacrylate (TD-10) and tetraethylene glycol dimethacrylate (TD-11) can act as inhibitors of the catalytic domain of matrix metalloproteinases (MMP-2, MMP-7 and MMP-9) by binding to the S1’ pocket of MMP-2 and MMP-9 and the catalytic Zn ion binding site of MMP-7, and that (ii) TD-11 can cause local disruption of the secondary structure of vascular endothelial growth factor A (VEGFA) dimer and exhibit stable interaction at the binding interface of VEGFA receptor R1 complex. Cell-culture-based in vitro experiments showed anti-metastatic phenotypes as seen in migration and invasion assays in cancer cells by both TD-10 and TD-11. Underlying biochemical evidence revealed downregulation of VEGF and MMPs at the protein level; MMP-9 was also downregulated at the transcriptional level. By molecular analyses, we demonstrate that TD-10 and TD-11 target stress chaperone mortalin at the transcription and translational level, yielding decreased expression of vimentin, fibronectin and hnRNP-K, and increase in extracellular matrix (ECM) proteins (collagen IV and E-cadherin) endorsing reversal of epithelial–mesenchymal transition (EMT) signaling.

An alternate methodology for studying diffusion and elution kinetics of dimethacrylate monomers through dentinal tubules

ObjectiveEthoxylated bisphenol A dimethacrylate (bisEMA) is a base monomer in several dental resin composites. It was the main aim of the present study to determine if bisEMA can reach the dental pulp by generally passive diffusion through the coronal dentinal tubules stimulated via eluent liquids surrounding the root structures only. MethodsIn 20 human third molar teeth, standard Class-I occlusal cavities were prepared and provided either with an adhesive system alone or additionally with a composite restoration, according to the instructions of the manufacturer. The teeth were placed in an elution chamber such that the elution media only came into contact with the tooth root/tooth base where they were incubated at 37 °C for up to 7 d. Samples were taken after 1, 2, 4 and 7 d. Gas chromatography/mass spectrometry was used to identify bisEMA and other monomers in ethanol/water (3:1) and aqueous eluates. ResultsbisEMA was only found in ethanol/water eluates, where the teeth had received a composite restoration. Traces of bisEMA with up to three ethylene oxide units could be detected in these eluates. Depending on the dentin thickness, different elution kinetics of bisEMA were determined. Regardless of the treatment of teeth, triethylene glycol dimethacrylate (TEGDMA) and tetraethylene glycol dimethacrylate (TEEGDMA) were found in ethanolic/aqueous eluates in equal amounts. Most TEGDMA and TEEGDMA diffused through the dentin within the first 24 h. SignificanceDepending on the dentin layer thickness, bisEMA was released for varied time periods, resulting in varied concentrations and exposure times for the different cells of the dental pulp. The concentrations of TEGDMA and TEEGDMA were greatest for cells of the dental pulp within the first 24 h.

Formation of Stem Cell Aggregates and Their Differentiation on Surface-Patterned Hydrogels Based on Poly(2-hydroxyethyl Methacrylate).

Micropillar patterns were fabricated and used to study cell adhesion, morphology, and function. Micropillars were produced in poly(2-hydroxyethyl methacrylate (HEMA)/N,N-(dimethylaminoethyl)methacrylate (DMAEMA)/tetraethylene glycol dimethacrylate (TEGDMA)) hydrogels using soft lithography, had dimensions of 1 μm diameter, and were either 2.05 or 4.91 μm tall. The patterned hydrogel substrates increased adhesion and induced the formation of cellular aggregates. Digital micrographs were used to quantify aggregate size and number. Differentiation of hMSCs toward adipocytes and chondrocytes was performed using the respective complete culture and differentiation medium for 2 weeks. Cells were stained for Oil red O, Alcian blue, and Type II collagen. Hydrogel substrates supported the differentiation of hMSCs to adipocytes and chondrocytes. The taller micropillar patterns supported the attachment and growth of larger aggregates and were more amenable to aid chondrogenic differentiation.

Hybrid polymeric systems of mesoporous silica/hydroxyapatite nanoparticles applied as antitumor drug delivery platform

AbstractIn this study, we report the production of a mesoporous silica/hydroxyapatite‐based nanocomposite containing copper (Cu) functionalized with methacrylic acid (MAA), a pH‐sensitive polymer. The functionalization of the nanoparticles surface was performed using the microwave method in order to anchor the cross‐linking tetraethylene glycol dimethacrylate (TEGDMA), onto the nanoparticles surface followed by MAA polymerization. The materials were characterized by XRD, XRF spectroscopy, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, thermal analysis, zeta potential, and elemental analysis. Studies of the incorporation and release of the antitumor methotrexate drug were performed in order to evaluate the potential use of these drug carrier systems in cancer therapy. Moreover, the in vitro cytotoxicity of the samples in fibroblast and SAOS‐2 cells was investigated, and the activity of the adipose‐derived stem cell alkaline phosphatase on nanocomposites was studied by in vitro assays. The results indicate that the Cu‐containing nanocomposites can be easily produced and that these compositions have beneficial effects in stem cells, maintaining cell viability, and allowing alkaline phosphatase expression. In conclusion, data from this work show that the nanocomposites obtained have adequate characteristic to be used as drug delivery platform. Furthermore, the biomaterial is a promising structure for treatment of bone tumor.

Cross-linking network based on Poly(ethylene oxide): Solid polymer electrolyte for room temperature lithium battery

In this paper, we develop a facile UV-derived in-situ dual-reaction to prepare a flexible poly(ethylene oxide) (PEO)-based solid polymer electrolyte (SPE), which is applied for ambient-temperature all-solid-state lithium battery. By modifying the amorphous domain of PEO through cross-linking with tetraglyme (TEGDME) and introducing a rigid linear oligomer of tetraethylene glycol dimethacrylate (TEGDMA) into the matrix, a SPE is obtained with high ionic conductivity (2.7 × 10−4 S cm−1 at 24 °C) and enhanced mechanical strength. The as-prepared SPE shows superior electrochemical properties with decent lithium transference number of 0.56, wide electrochemical stability window above 5 V vs. Li+/Li and low interfacial resistance. By means of galvanostatic cycling studies in Li//Li symmetrical and LiFePO4//Li cells, we further demonstrate that the SPE exhibits excellent cycling performance with minimization of lithium dendrite formation.

Venlafaxine-loaded sustained-release poly(hydroxyethyl methacrylate-co-itaconic acid) hydrogel composites: their synthesis and in vitro/in vivo attributes

Hydrogels have potential applications as sustained-release drug delivery systems, as an example in treatment of major depressive disorders. This paper reports some works carried out to obtain a new type of copolymeric hydrogel for an anti-depressant drug. The copolymerization of itaconic acid, hydroxyethyl methacrylate (HEMA), and tetraethyleneglycol dimethacrylate was performed. The gels were evaluated for swelling, diffusion coefficient, drug incorporation, in vitro dissolution, and in vivo performance in rabbits after oral administration. The pharmacokinetic parameters like bioavailability, Cmax and Tmax were calculated for hydrogels in comparison to oral solution containing equivalent amount of venlafaxine. The HEMA-based matrices showed negligible swelling and release rate of venlafaxine, which were also very low in a buffer of pH 1.2. However, both the swelling and release rate of venlafaxine were faster at high pH (6.5 and 7.5). The Tmax of the formulation with the highest swelling and release rate (T1) were found at 600 min compared to that at 180 min for oral solution having equivalent quantity of venlafaxine. AUC0–∞ for oral hydrogel was 2.1 times greater than that for oral solution of venlafaxine. Similarly, MRT for hydrogel was 3.1 times more than that for oral solution. However, Cmax for oral cross-linked hydrogel composite was significantly lower than that for equivalent amount of oral drug solution. The synthesized hydrogel composites showed a promising ability for sustained release of venlafaxine both in vitro and in vivo. It was found that venlafaxine delivery through oral route was practical.

Identification and Functional Characterization of Anti-metastasis and Anti-angiogenic Activities of Triethylene Glycol Derivatives.

We had previously reported anticancer activity in the water extract (WEX) of Ashwagandha leaves, and identified Triethylene glycol (TEG) as an active tumor suppressor component. In this study, we investigated anti-migratory and anti-angiogenesis activities of WEX and TEG. We conducted in vitro and in vivo experiments using TEG, and its two derivatives, Triethyleneglycol dimethacrylate (TD-10), and Tetraethyleneglycol dimethacrylate (TD-11). The data revealed strong anticancer and anti-metastasis potentials in the derivatives. Non-toxic, anti-migratory doses of the derivatives showed inhibition of canonical Wnt/β-catenin axis and consequent downregulation of EMT-signaling proteins (Vimentin, MMPs and VEGF). These results endorse that the TD-10 and TD-11 have potential to safely put a check on the aggressiveness of the metastatic cells and therefore represent promising candidates for the treatment of metastatic cancers.

Tunable elasticity and thermodynamic parameters of hydroxypropyl methacrylate‐based gels with varying extents of monomer concentration: Statistical mechanics treatments of physical observations

ABSTRACTThe present article reports the scaling laws relating the preparation conditions with the equilibrium swelling degree and the crosslinking density of a new family of hydroxyl functional hydrogels (Hgs) prepared by free radical crosslinking polymerization of hydroxypropyl methacrylate (HPMA) in aqueous solution with tetraethylene glycol dimethacrylate (TEGDMA) as crosslinker. For comparison of physical properties, chemical and mechanical stability, HPMA cryogels (Cgs) were also prepared using the cryotropic gelation technique by conducting the gelation reactions at subzero temperatures. The measurements of the equilibrium swelling degree and the elastic properties of poly(hydroxypropyl methacrylate) (PHPMA) gel samples having different initial monomer concentration were treated according to the scaling theory to explain the rubbery behavior of the resulting Hgs. The obtained scaling relation between the reduced modulus and the swelling degree indicated limiting chain extensibility which is neglected in the Flory–Rehner theory. The effective crosslink density and polymer–solvent interaction parameter of PHPMA Hgs were used to interpret the observed deviation. Results showed that the properties of PHPMA Hgs and Cgs can be controlled by varying the HPMA and TEGDMA content. Increase of total monomer concentrations causes a pronounced decrease in the equilibrium swelling degree, and an increase in the elastic response of PHPMA Hgs and Cgs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45889.

Cytotoxicity and DNA double-strand breaks in human gingival fibroblasts exposed to eluates of dental composites

ObjectivePreviously, single composite components were used to study cytotoxicity and induction of DNA double-strand breaks (DNA-DSBs) of dental composite resins. In the present study, cytotoxicity and induction of DNA-DSBs in human gingival fibroblasts (HGFs) were investigated with dental composite eluates consisting of multiple components. The eluates were qualified and quantified. MethodsThe composites Esthet.X® HD, Venus®, X-tra fil®, CLEARFIL™ AP-X, Admira® Fusion and QuiXfil® were polymerized and immersed into Dulbecco’s modified Eagle’s medium (DMEM) for 72h. Subsequently, HGFs were incubated with the corresponding composite eluates. The cell viability of HGFs was obtained from an XTT assay. DNA-DSBs were determined using a γ-H2AX assay. The qualification and quantification of eluates were performed by gas chromatography/mass spectrometry (GC/MS). ResultsHGFs exposed to the eluates of all investigated composites showed no significant loss of cell viability, compared to negative control. Significant DNA-DSBs induction could be found in HGFs exposed to the eluates of Esthet.X® HD (0.43±0.05 foci/cell) and Venus® (0.39±0.04 foci/cell), compared to control (0.22±0.03 foci/cell). A total of 12 substances were detected from the investigated composite eluates. Five of them were methacrylates: tetraethyleneglycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA), ethyleneglycol dimethacrylate (EGDMA) and trimethylolpropane trimethacrylate (TMPTMA). The highest concentration of HEMA (110.5μM), HPMA (86.08μM) and TMPTMA (4.50μM) was detected in the eluates of QuiXfil®. The highest concentration of TEGDMA was 1080μM in Venus® eluates and the highest concentration of EGDMA was 3.18μM in Esthet.X® HD eluates. SignificanceSignificant DNA-DSBs induction can be found in HGFs exposed to the eluates of Esthet.X® HD and Venus®. The interactive effects among released (co)monomers and additives may influence the cytotoxicity and induction of DNA-DSBs, compared to exposure with single composite component.

Dynamical modeling and experimental aspects of multi-responsive hydroxy-functional methacrylate-based gels with tunable swelling induced by multivalent ions

Novel materials displaying multi-responsive property were developed by forming crosslinked copolymer systems that exhibit distinct temperature, pH and salt-sensitivity independently. An investigation of the mechanical properties of a novel multi-responsive poly(hydroxypropyl methacrylate) (PHPMA)-based hydrogel system was carried out with two major objectives. First was to study the effect of various preparation conditions; reaction temperature, comonomer content on the elasticity as well as on the absorbency of resulting hydroxy-functional methacrylate-based gels and the second was to interpret their water uptake data by various kinetic models. Experiments were conducted to characterize the equilibrium swelling and temperature/pH-dependent phase transitions of PHPMA-based copolymeric gels prepared by radical crosslinking copolymerization in aqueous solution with tetraethyleneglycol dimethacrylate (TEGDMA) as crosslinker. The aqueous equilibrium swelling properties of PHPMA hydrogels and cryogels containing methacrylate-based comonomer were described using N,N-dimethylaminopropyl methacrylate (DMAEMA) having weakly basic cationic groups. For PHPMA-based copolymeric hydrogels, the scaling laws relating the optimum preparation conditions with the crosslinking density N and the swelling degree qv were derived. Dynamic kinetics profiles were evaluated to outline the swelling/deswelling response of the resulting hydrogels and cryogels which presents useful information when designing specific applications that pursue or require the absorption of pH-sensitive or ionic-strength-sensitive molecules.

Tailoring the physico-chemical properties and elasticity of poly(hydroxy-functional methacrylate)-based cationically charged gel beads: Combined hydrophobicity and mechanical durability through frozen droplets

This study describes the experimental methodology to obtain hydroxy-functional methacrylate-based gel beads in millimeter-sized under production conditions by addition of the frozen pre-gel solution into the silicon oil as continuous phase using tetraethyleneglycol dimethacrylate (TEGDMA) as the crosslinking agent. Weakly basic cationic comonomer N,N-dimethylaminoethyl methacrylate (DMAEMA) was included into the polymerization procedure for the production of uniform polycationic moities exhibiting a drastic response against pH. The aim of this work is to determine the actual conditions for optimum bead production and to provide poly(hydroxypropyl methacrylate-co-N,N-dimethylaminoethyl methacrylate)-based P(HPMA-co-DMAEMA) gel beads with simple tools for the physical characterization. By the proposed experimental method, the physico-chemical properties of P(HPMA-co-DMAEMA) gel beads can be controlled by adjusting the pH, temperature of solution, ionic strength as well as the structure of the gel network. From the uniaxial compression tests, the swelling dependent stress–strain characteristics of resulting gel beads was evaluated. The obtained results were consistent with Hertzian elasticity, and were analyzed in terms of the compression modulus of the bead samples. It was found that force acting on the gel beads is the power-law function of the deformation F≈ΔD1.48 which is very close to the theoretical exponent 1.5 predicted by the Hertz equation. The water absorption capacities of P(HPMA-co-DMAEMA) gel beads with basic functional groups were repeatedly measured to obtain the optimal preparation conditions according to the variations of the bead diameters. Its maximal water absorption capacity appeared as 48 times among from 2.3mm to 11.0mm of swollen bead diameters. The swelling equilibria in various aqueous solutions were used to estimate the physico-chemical parameters asa function of gel bead size and swelling equilibrium capacity by correlating with the Flory-Rehner theory.

Biochemical piezoresistive sensors based on hydrogels for biotechnology and medical applications

Abstract. Many conventional analysis techniques achieve a high-detection sensitivity; however, they are equipment or time expensive due to a multi-step procedure. Sensor concepts, introduced in this work, using piezoresistive pressure sensor chips with integrated analyte-sensitive hydrogels enable inexpensive and robust biochemical sensors, which are miniaturized and in-line capable. For these sensor setups, it is important to optimize current established analyte-sensitive, reversible and biocompatible hydrogels for pH and glucose monitoring of chemical and biochemical processes. Therefore, low-viscous monomer mixtures based on hydroxypropyl methacrylate (HPMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), tetraethylene glycol dimethacrylate (TEGDMA) and ethylene glycol (EG) were prepared in molar ratios of 70∕30∕01∕20, 60∕40∕01∕20 and 60∕40∕02∕20, respectively. Redox-polymerization of these pre-gel solutions were realized with N,N,N′,N′-tetramethylethylenediamine and ammonium persulfate. The reversible pH-sensitive swelling behavior of hydrogels with compositions were compared. By using the photoinitiator 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, the free radical photopolymerization could be implemented leading to an increase of the swelling degree (SG). Glucose-sensitive hydrogels were prepared via immobilization of glucose oxidase in HPMA–DMAEMA–TEGDMA–EG hydrogel discs. These showed increasing swelling degrees with higher glucose concentrations in aqueous media and a reversible swelling behavior. The synthesized hydrogels were integrated in different piezoresistive sensors of different designs. The pH-depending course of the output voltage of a dip sensor with photopolymerized 60∕40∕02∕20 hydrogel was studied in detail. Besides the usage of a dip sensor, two implantable, parylene C-coated setups are presented. The implantable sensor with long isolated gold bond wires was proved to be functional even after storage in aqueous media for several days.