Poly Ethylene Glycol Dimethacrylate Research Articles

Hydrogel bioprinted microchannel networks for vascularization of tissue engineering constructs.

Vascularization remains a critical challenge in tissue engineering. The development of vascular networks within densely populated and metabolically functional tissues facilitate transport of nutrients and removal of waste products, thus preserving cellular viability over a long period of time. Despite tremendous progress in fabricating complex tissue constructs in the past few years, approaches for controlled vascularization within hydrogel based engineered tissue constructs have remained limited. Here, we report a three dimensional (3D) micromolding technique utilizing bioprinted agarose template fibers to fabricate microchannel networks with various architectural features within photocrosslinkable hydrogel constructs. Using the proposed approach, we were able to successfully embed functional and perfusable microchannels inside methacrylated gelatin (GelMA), star poly(ethylene glycol-co-lactide) acrylate (SPELA), poly(ethylene glycol) dimethacrylate (PEGDMA) and poly(ethylene glycol) diacrylate (PEGDA) hydrogels at different concentrations. In particular, GelMA hydrogels were used as a model to demonstrate the functionality of the fabricated vascular networks in improving mass transport, cellular viability and differentiation within the cell-laden tissue constructs. In addition, successful formation of endothelial monolayers within the fabricated channels was confirmed. Overall, our proposed strategy represents an effective technique for vascularization of hydrogel constructs with useful applications in tissue engineering and organs on a chip.

Fabrication and characterization of reinforced electrospun poly(vinylidene fluoride-co-hexafluoropropylene) nanofiber membranes

In this study, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber membranes with different amounts of polyethylene glycol (PEG) and polyethylene glycol dimethacrylate (PEGDMA) oligomer were fabricated via electrospinning. The obtained nanofiber membranes were subsequently thermal treated to produce physically bonded structures and chemically cross-linked networks, which were confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR) and wide-angle X-ray diffraction (WAXD). Young’s modulus of electrospun nanofiber membrane with the composition of PVDF-HFP/PEG/PEGDMA (6/1/3, w/w/w) was approximately three times for the case of nanofiber membrane and four times for the case of single nanofiber higher than that of pure PVDF-HFP nanofiber, respectively. The characteristic of cell cycling performance was demonstrated as the possibility of its application at ambient temperature. The electrospun PVDF-HFP nanofiber membrane presented great electrolyte uptake because the membrane had higher porosity due to the structural features of nonwoven fabric, and the amorphous regions in PVDF-HFP could trap large amounts of liquid electrolyte. Also, the cell performance of the membrane as the separator declared high discharge capacity. As the result, the reinforced electrospun composite nanofiber membrane was found to be a promising candidate as a separator for lithium-ion batteries.

A polymeric device for controlled transscleral multi-drug delivery to the posterior segment of the eye

The design of drug delivery systems that can deliver multiple drugs to the posterior segment of the eye is a challenging task in retinal disease treatments. We report a polymeric device for multi-drug transscleral delivery at independently controlled release rates. The device comprises a microfabricated reservoir, controlled-release cover and three different fluorescent formulations, which were made of photopolymeized tri(ethyleneglycol)dimethacrylate (TEGDM) and poly(ethyleneglycol)dimethacrylate (PEGDM). The release rate of each fluorescent is controlled by varying the PEGDM/TEGDM ratio in its formulation and the cover. The release kinetics appeared to be related to the swelling ratio of the PEGDM/TEGDM polymers. When the devices were implanted onto rat sclerae, fluorescence was observable in the ocular tissues during 4weeks’ implantation and distributed locally around the implantation site. Our polymeric system, which can administer multiple compounds with distinct kinetics, provides prolonged action and less invasive transscleral administration, and is expected to provide new tools for the treatment of posterior eye diseases with new therapeutic modalities.

Microwave-assisted Functionalization of Poly(ethylene glycol) and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation

One of the main benefits to using poly(ethylene glycol) (PEG) macromers in hydrogel formation is synthetic versatility. The ability to draw from a large variety of PEG molecular weights and configurations (arm number, arm length, and branching pattern) affords researchers tight control over resulting hydrogel structures and properties, including Young’s modulus and mesh size. This video will illustrate a rapid, efficient, solvent-free, microwave-assisted method to methacrylate PEG precursors into poly(ethylene glycol) dimethacrylate (PEGDM). This synthetic method provides much-needed starting materials for applications in drug delivery and regenerative medicine. The demonstrated method is superior to traditional methacrylation methods as it is significantly faster and simpler, as well as more economical and environmentally friendly, using smaller amounts of reagents and solvents. We will also demonstrate an adaptation of this technique for on-resin methacrylamide functionalization of peptides. This on-resin method allows the N-terminus of peptides to be functionalized with methacrylamide groups prior to deprotection and cleavage from resin. This allows for selective addition of methacrylamide groups to the N-termini of the peptides while amino acids with reactive side groups (e.g. primary amine of lysine, primary alcohol of serine, secondary alcohols of threonine, and phenol of tyrosine) remain protected, preventing functionalization at multiple sites. This article will detail common analytical methods (proton Nuclear Magnetic Resonance spectroscopy (;H-NMR) and Matrix Assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-ToF)) to assess the efficiency of the functionalizations. Common pitfalls and suggested troubleshooting methods will be addressed, as will modifications of the technique which can be used to further tune macromer functionality and resulting hydrogel physical and chemical properties. Use of synthesized products for the formation of hydrogels for drug delivery and cell-material interaction studies will be demonstrated, with particular attention paid to modifying hydrogel composition to affect mesh size, controlling hydrogel stiffness and drug release.

Microwave-assisted Functionalization of Poly(ethylene glycol) and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation

One of the main benefits to using poly(ethylene glycol) (PEG) macromers in hydrogel formation is synthetic versatility. The ability to draw from a large variety of PEG molecular weights and configurations (arm number, arm length, and branching pattern) affords researchers tight control over resulting hydrogel structures and properties, including Young’s modulus and mesh size. This video will illustrate a rapid, efficient, solvent-free, microwave-assisted method to methacrylate PEG precursors into poly(ethylene glycol) dimethacrylate (PEGDM). This synthetic method provides much-needed starting materials for applications in drug delivery and regenerative medicine. The demonstrated method is superior to traditional methacrylation methods as it is significantly faster and simpler, as well as more economical and environmentally friendly, using smaller amounts of reagents and solvents. We will also demonstrate an adaptation of this technique for on-resin methacrylamide functionalization of peptides. This on-resin method allows the N-terminus of peptides to be functionalized with methacrylamide groups prior to deprotection and cleavage from resin. This allows for selective addition of methacrylamide groups to the N-termini of the peptides while amino acids with reactive side groups (e.g. primary amine of lysine, primary alcohol of serine, secondary alcohols of threonine, and phenol of tyrosine) remain protected, preventing functionalization at multiple sites. This article will detail common analytical methods (proton Nuclear Magnetic Resonance spectroscopy (;H-NMR) and Matrix Assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-ToF)) to assess the efficiency of the functionalizations. Common pitfalls and suggested troubleshooting methods will be addressed, as will modifications of the technique which can be used to further tune macromer functionality and resulting hydrogel physical and chemical properties. Use of synthesized products for the formation of hydrogels for drug delivery and cell-material interaction studies will be demonstrated, with particular attention paid to modifying hydrogel composition to affect mesh size, controlling hydrogel stiffness and drug release.

A novel pH-sensitive interferon-β (INF-β) oral delivery system for application in multiple sclerosis

pH-sensitive microparticles were prepared using trimethyl-chitosan (TMC), poly(ethylene glycol)dimethacrylate (PEGDMA) and methacrylic acid (MAA) by free radical suspension polymerization, for the oral delivery of interferon-β (INF-β). The microparticles were subsequently compressed into a suitable oral tablet formulation. A Box-Behnken experimental design was employed for generating a series of formulations with varying concentrations of TMC (0.05-0.5 g/100 mL) and percentage crosslinker (polyethylene glycol diacrylate) (3-8%, w/w of monomers), for establishment of an optimized TMC-PEGDMA-MAA copolymeric microparticles. For pragmatism, insulin was initially employed as the model peptide for undertaking the preliminary experimentation and the optimized formulation was subsequently evaluated using INF-β. The prepared copolymeric microparticulate system was characterized for its morphological, porositometric and mucoadhesive properties. The optimized microparticles with 0.5 g/100 mL TMC and 3% crosslinker had an INF-β loading efficiency of 53.25%. The in vitro release of INF-β was recorded at 74% and 3% in intestinal (pH 6.8) and gastric (pH 1.2) pH from the oral tablet formulation, respectively. The tablet was further evaluated for plasma concentration of INF-β in the New Zealand White rabbit, and compared to a known subcutaneous formulation. The system showed an astounding effective release profile over 24h with higher INF-β plasma concentrations compared with the subcutaneous injection formulation.

Influence of Discrete and Continuous Culture Conditions on Human Mesenchymal Stem Cell Lineage Choice in RGD Concentration Gradient Hydrogels

Stem cells have shown lineage-specific differentiation when cultured on substrates possessing signaling groups derived from the native tissue. A distinct determinant in this process is the concentration of the signaling motif. While several groups have been working actively to determine the specific factors, concentrations, and mechanisms governing the differentiation process, many have been turning to combinatorial and gradient approaches in attempts to optimize the multiple chemical and physical parameters needed for the next advance. However, there has not been a direct comparison between the cellular behavior and differentiation of human mesenchymal stem cells cultured in gradient and discrete substrates, which quantitates the effect of differences caused by cell-produced, soluble factors due to design differences between the culture systems. In this study, the differentiation of human mesenchymal stem cells in continuous and discrete polyethylene glycol dimethacrylate (PEGDM) hydrogels containing an RGD concentration gradient from 0 to 14 mM were examined to study the effects of the different culture conditions on stem-cell behavior. Culture condition was found to affect every osteogenic (alkaline phosphatase, Runx 2, type 1 collagen, bone sailoprotein, and calcium content) and adipogenic marker (oil red and peroxisome proliferator-activated receptor gamma) examined regardless of RGD concentration. Only in the continuous gradient culture did RGD concentration affect human mesenchymal stem-cell lineage commitment with low RGD concentrations expressing higher osteogenic differentiation than high RGD concentrations. Conversely, high RGD concentrations expressed higher adipogenic differentiation than low RGD concentrations. Cytoskeletal actin organization was only affected by culture condition at low RGD concentrations, indicating that it played a limited role in the differences in lineage commitment observed. Therefore, the role of discrete versus gradient strategies in high-throughput experimentation needs to be considered when designing experiments as we show that the respective strategies alter cellular outcomes even though base scaffolds have similar material and chemical properties.

Polyethylene Glycol and Polyethylene Glycol/Hydroxyapatite Constructs Produced through Stereo-Thermal Lithography

Stereo-thermal lithography (STLG) is an innovative system that uses ultraviolet (UV) radiation and near-infrared (IR) radiation simultaneously to initiate the curing reaction in a liquid solution, containing both UV and IR photoinitiator. In this research work, poly (ethylene glycol) dimethacrylate (PEGDMA) and PEGDMA/hydroxyapatite (HA) constructs were produced using the STLG system, operating in the UV mode, and characterised regarding the morphology and water absorption properties. Constructs were produced with different geometries and shapes by introducing several variations in the processing parameters, such as the irradiation time and the layer thickness. Results show the ability of the system to produce constructs at the micro-scale with very good definition and resolution. The irradiation time is the critical processing parameter, strongly affecting the water absorption and the structural integrity of the constructs.

The spatiotemporal control of erosion and molecular release from micropatterned poly(ethylene glycol)-based hydrogel

Hydrogels have been extensively studied as a carrier of various hydrophilic molecular compounds and cells for local delivery and subsequent controlled release. One of key design parameters in the hydrogel assembly is an ability to control spatiotemporal gel degradation, in order to tailor release rates of multiple drugs and also regulate phenotypic activities of co-cultured cells. To achieve this goal, this study presents a simple but innovative implantable, microfabricated hydrogel patch that undergoes micropatterned surface erosion at controlled rates and subsequently discharges two molecular compounds of interests at desired rates. This device was prepared by first fabricating a non-degradable poly(ethylene glycol) dimethacrylate (PEGDMA) hydrogel patch containing micro-pockets of controlled spacing and subsequently filling micro-pockets with a hydrogel of poly(ethylene imine) (PEI) and PEG diacrylate (PEGDA) that was tailored to degrade at controlled rates. Separate incorporation of vascular endothelial growth factor (VEGF)121 and VEGF165, known to orchestrate vascular development, into the PEI-PEGDA gel and PEGDMA hydrogel resulted in enhanced neovascularization at the implantation sites due to bimodal, sequential release of two VEGF isoforms. We believe that the hydrogel patch fabricated in this study will be highly useful to better understand a broad array of complex biological processes and also improve the efficacy of molecular cargos in varied applications.

Hemocompatibility, swelling and thermal properties of hydrogels based on 2-hydroxyethyl acrylate, itaconic acid and poly(ethylene glycol) dimethacrylate

Two series of novel hydrogels, based on 2-hydroxyethyl acrylate (HEA), itaconic acid (IA), and two poly(ethylene glycol) dimethacrylates (PEGDMA), of different ethylene glycol chain lengths, were prepared by free radical crosslinking copolymerization. The influence of different ethylene glycol chain lengths and concentration in P(HEA/IA/PEGDMA) hydrogels on biocompatibility, swelling and thermal properties was investigated. All samples in contact with blood showed a mean hemolysis value <1.0 % in the direct contact assay, and even <0.5 % in the indirect contact assay, for in vitro testing conditions. Swelling studies, conducted in a physiological pH and temperature range, showed pH sensitivity and relatively small changes of equilibrium swelling with temperature, which varied with PEGDMA molecular weight. The glass transition temperatures (Tg) of P(HEA/IA/PEGDMA) networks were in the range 28.1–36.9 °C, respectively, and also dependent on copolymer composition. Due to good biocompatibility, favorable swelling, and thermal properties these hydrogels show good potential for biomedical uses.

Detection of leachables and cytotoxicity after exposure to methacrylate‐ and epoxy‐based root canal sealers in vitro

Root canal sealing materials may have toxic potential in vitro depending on the cell line, cytotoxicity assay, material chemistry, and degree of polymer curing. The aims of the present study were to detect leaching components from epoxy- or methacrylate-based root canal sealers and to investigate the degree of cytotoxicity after exposure to extracts from these materials. Qualitative determination of substances released from the materials was performed by gas- and liquid chromatography/mass spectrometry. Submandibular salivary gland acinar cell death (apoptosis/necrosis) was determined using a fluorescence staining/microscopy technique. The major leachable monomer from the epoxy-based material was bisphenol-A diglycidyl ether (BADGE), whereas leachables from the methacrylate-based materials were mainly triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), hydroxyethyl methacrylate (HEMA), and polyethyleneglycol dimethacrylate (PEGDMA). Exposure to diluted extracts of cured methacrylate-based materials caused a postexposure time-dependent increase in cell death. This effect was not demonstrated as a result of exposure to undiluted extract of cured epoxy-based material. Extracts of all fresh materials induced apoptosis significantly, but at lower dilutions of the epoxy- than the methacrylate-based materials. The degree of leaching, determined from the relative chromatogram peak heights of eluates from the methacrylate-based sealer materials, corresponded with the degree of cell death induced by extracts of these materials.

Methacrylate-based Diol Monolithic Stationary Phase for the Separation of Polar and Non-Polar Compounds in Capillary Liquid Chromatography

A monolithic capillary column prepared with glycidyl methacrylate (GMA) and poly(ethylene glycol) dimethacrylate (PEGDMA) was investigated and used in capillary liquid chromatography. The polymer monolith was synthesized in the presence of methanol and decanol as the biporogenic solvents by in situ polymerization of GMA and PEGDMA, and the optimum composition of monomer and porogen was investigated. After polymerization, glycidyl groups were hydrolyzed with sulfuric acid to produce diol groups at the surface of the porous monolith via epoxy-ring-opening. The GMA content in the polymerization mixture affected the hydrophilicity of the monolith. The separation capability was evaluated by separation of phenol compounds, phthalic acids, and polycyclic aromatic hydrocarbons. The poly(GMA-PEGDMA) monolithic capillary column exhibited satisfactory stability.

Engineering discoidal polymeric nanoconstructs with enhanced magneto-optical properties for tumor imaging

The in vivo performance of nanoparticles is affected by their size, shape and surface properties. Fabrication methods based on emulsification and nano-precipitation cannot control these features precisely and independently over multiple scales. Herein, discoidal polymeric nanoconstructs (DPNs) with a diameter of 1000 nm and a height of 500 nm are demonstrated via a modified hydrogel-template strategy. The DPNs are obtained by mixing in one synthesis step the constituent polymers – poly(lactic acid-co-glycolic acid) (PLGA) and polyethylene glycol (PEG) dimethacrylate – and the payload with magneto-optical properties – 5 nm ultra-small super-paramagnetic iron oxide nanoparticles (SPIOs) and Rhodamine B dye (RhB). The DPN geometrical features are characterized by multiple microscopy techniques. The release of the Rhodamine B dye is pH dependent and increases under acidic conditions by the enhanced hydrolysis of the polymeric matrix. Each DPN is loaded with ∼100 fg of iron and can be efficiently dragged by static and external magnetic fields. Moreover, the USPIO confinement within the DPN porous structure is responsible for a significant enhancement in MRI relaxivity (r2 ∼ 500 (mMs)−1), up to ∼5 times larger than commercially available systems. These nanoconstructs suggest a general strategy to engineer theranostic systems for anti-angiogenic treatment and vascular imaging.

Engineering of new crosslinked functional PEG micrometer-sized particles of narrow size distribution for enzyme immobilization

New functional crosslinked poly(ethylene glycol) (PEG) micrometer-sized particles of narrow size distribution were prepared by dispersion co-polymerization in an aqueous continuous phase of the monomers methacrylate polyethylene glycol carboxylic acid (MA-PEG-COOH) or methacrylate polyethylene glycol amine (MA-PEG-NH2) with polyethylene glycol methacrylate ether (MA-PEG-OCH3) and the crosslinker monomer polyethylene glycol dimethacrylate (PEDMA). The effect of various polymerization parameters, e.g., total monomer concentration, crosslinker monomer concentration, initiator concentration and stabilizer concentration and Mw on the size, size distribution and polymerization yield of the produced particles has been studied. As a model for enzyme immobilization, trypsin was covalently bound to the functional PEG particles. A substantial loss in the activity and an increase in the stability of the conjugated enzyme, as compared to the free one, were demonstrated.

Imprinted hydrogels for tunable hemispherical microlenses

We report on the development of an ultraviolet curable hydrogel, based on combinations of poly(ethylene glycol) dimethacrylate (PEGMA), acrylic acid (AA) and N-Isopropylacrylamide (NIPPAm) for imprint lithography processes. The hydrogel was successfully imprinted to form dynamic microlens arrays. The response rate of the microlenses by volume change to water absorption was studied optically showing tunable focalisation of the light. Important optical refractive index change was measured between the dry and wet state of the microlenses. Our work suggests the use of this newly developed printable hydrogel for various imprinted components for sensing and imaging systems.

Maximizing phenotype constraint and extracellular matrix production in primary human chondrocytes using arginine–glycine–aspartate concentration gradient hydrogels

New systematic approaches are necessary to determine and optimize the chemical and mechanical scaffold properties for hyaline cartilage generation using the limited cell numbers obtained from primary human sources. Peptide functionalized hydrogels possessing continuous variations in physico-chemical properties are an efficient three-dimensional platform for studying several properties simultaneously. Herein, we describe a polyethylene glycol dimethacrylate (PEGDM) hydrogel system possessing a gradient of arginine–glycine–aspartic acid peptide (RGD) concentrations from 0mM to 10mM. The system is used to correlate primary human osteoarthritic chondrocyte proliferation, phenotype maintenance and extracellular matrix (ECM) production to the gradient hydrogel properties. Cell number and chondrogenic phenotype (CD14:CD90 ratios) were found to decline in regions with higher RGD concentrations, while regions with lower RGD concentrations maintained cell number and phenotype. Over three weeks of culture, hydrogel regions containing lower RGD concentrations experience an increase in ECM content compared to regions with higher RGD concentrations. Variations in actin amounts and vinculin organization were observed within the RGD concentration gradients that contribute to the differences in chondrogenic phenotype maintenance and ECM expression.

Transscleral Sustained Vasohibin-1 Delivery by a Novel Device Suppressed Experimentally-Induced Choroidal Neovascularization

We established a sustained vasohibin-1 (a 42-kDa protein), delivery device by a novel method using photopolymerization of a mixture of polyethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and collagen microparticles. We evaluated its effects in a model of rat laser-induced choroidal neovascularization (CNV) using a transscleral approach. We used variable concentrations of vasohibin-1 in the devices, and used an enzyme-linked immunosorbent assay and Western blotting to measure the released vasohibin-1 (0.31 nM/day when using the 10 μM vasohibin-1 delivery device [10VDD]). The released vasohibin-1 showed suppression activity comparable to native effects when evaluated using endothelial tube formation. We also used pelletized vasohibin-1 and fluorescein isothiocyanate-labeled 40 kDa dextran as controls. Strong fluorescein staining was observed on the sclera when the device was used for drug delivery, whereas pellet use produced strong staining in the conjunctiva and surrounding tissue, but not on the sclera. Vasohibin-1 was found in the sclera, choroid, retinal pigment epithelium (RPE), and neural retina after device implantation. Stronger immunoreactivity at the RPE and ganglion cell layers was observed than in other retinal regions. Significantly lower fluorescein angiography (FA) scores and smaller CNV areas in the flat mounts of RPE-choroid-sclera were observed for the 10VDD, VDD (1 μM vasohibin-1 delivery device), and vasohibin-1 intravitreal direct injection (0.24 μM) groups when compared to the pellet, non-vasohibin-1 delivery device, and intravitreal vehicle injection groups. Choroidal neovascularization can be treated with transscleral sustained protein delivery using our novel device. We offer a safer sustained protein release for treatment of retinal disease using the transscleral approach.

Arraying Cell Cultures Using PEG‐DMA Micromolding in Standard Culture Dishes

A robust and effortless procedure is presented, which allows for the microstructuring of standard cell culture dishes. Cell adhesion and proliferation are controlled by three-dimensional poly(ethylene glycol)-dimethacrylate (PEG-DMA) microstructures. The spacing between microwells can be extended to millimeter size in order to enable the combination with robotic workstations. Cell arrays of microcolonies can be studied under boundary-free growth conditions by lift-off of the PEG-DMA layer in which the growth rate is accessible via the evolution of patch areas. Alternatively, PEG-DMA stencils can be used as templates for plasma-induced patterning.

Effect of viscoelasticity on the spherical and flat adhesion characteristics of photopolymerizable acrylate polymer networks

This research is the first of its kind to study the comparison between spherical and flat probe adhesion behavior as a function of viscoelasticity. Viscoelastic properties were tailored through the use of acrylate networks synthesized from tert-butyl acrylate and poly(ethylene glycol) dimethacrylate (PEGDMA) solutions. The molecular weight and the weight fraction of PEGDMA crosslinker was altered to maintain a constant glass transition temperature of approximately 57°C, but systematically vary the viscoelastic properties and the rubbery moduli (1–62MPa). Dynamic mechanical analysis was performed to characterize the low-strain thermo-mechanical behavior of the materials. Viscoelastic behavior of the materials was characterized by creep testing and was observed to inversely correlate with crosslinking density. The samples tested with the spherical probe exhibited low pull-off forces at temperatures well above and well below the glass transition temperature of the material. A maximum in pull-off force was observed in the vicinity of the glass transition temperature owing to the viscoelastic energy dissipative processes. The peak in pull-off force was observed to decrease with an increase in crosslinking density and modulus. Adhesion measurements using the flat probe demonstrated a strong dependence of pull-off force on the modulus of the material above the glass transition temperature. It is concluded that viscoelasticity is a dominating factor in increasing the pull-off force values in the vicinity of the glass transition, while it plays a little or no role for temperatures +/−20°C away from transition region , opening the possibility of thermally switchable adhesives.

ChemInform Abstract: One‐Pot Synthesis of Macrocyclic Tetralactones via the Sequential Inter‐ and Intramolecular [2 + 2] Photocycloaddition Reaction of Di‐2‐pyrones with Polyethylene Glycol Dimethacrylates.

AbstractPhotocycloaddition between polyethylene glycol‐di‐2‐pyrones and polyethylene glycol dimethacrylates such as (I) and (II) yields macrocyclic crown ether‐type compounds by [2 + 2] addition of the C5‐C6 and C5‐C6double bonds of (I) to the two olefin moieties of (II), generating 19‐ to31‐membered rings.