The effect of post-polymerization for photopolymerizable composition based on oligoester methacrylate OCM-2 was studied using IR spectroscopy. Numerical simulation of this process was carried out within the framework of a kinetic model that takes into account changes in the concentration of both the monomer and radicals of growth. It was demonstrated that the increase in conversion due to the post-polymerization depends on the concentration and lifetime of radicals, as well as the ratio of the light pulses length to the repetition period. The influence of post-polymerization on the exposure characteristics of the polymerization process is considered for the cases of exposure to single radiation pulses (scanning lithography) and photoiniation by a periodic sequence of light pulses (using pulse-width modulation of semiconductor light sources).

A new sterically hindered trialkyl-substituted o-benzoquinone, 4,6-di-tert-butyl-3-[(3,5-di-tert-butyl-1H-pyrazol-1-yl)methyl]cyclohexane-3,5-diene-1,2-dione was synthesized. Its spectral, electronic, and structural characteristics were determined, which were found to be similar to those for analogous 3,6- and 3,5-di-tert-butyl-o-benzoquinones. The following sequence was observed for the reactivity in the photoreduction reaction in the presence of N,N-dimethylaniline (DMA): 3,6-di-tert-butyl-o-benzoquinone > 4,6-di-tert-butyl-3-[(3,5-di-tert-butyl-1H-pyrazol-1-yl)methyl]cyclohexane-3,5-diene-1,2-dione > 3,5-di-tert-butyl-o-benzoquinone. The new quinone, like 3,6- and 3,5-di-tert-butyl-o-benzoquinones, in combination with DMA was found to initiate radical polymerization under the irradiation by LED sources in the range from 395 to 630 nm. It was found that the introduction of the pyrazole-containing fragment at position 6 of the quinonoid ring of 3,5-di-tert-butyl-o-benzoquinone led to a sharp increase in the activity of the new compound as a photoinitiator compared to 3,5-di-tert-butyl-o-benzoquinone and made the new quinone comparable with 3,6-di-tert-butyl-o-benzoquinone in the photoinitiating activity. At the same time, a photopolymerizable composition containing a photoinitiating system based on 4,6-di-tert-butyl-3-[(3,5-di-tert-butyl-1H-pyrazol-1-yl)methyl]cyclohexane-3,5-diene-1,2-dione was found to be more stable than the photoinitiating system based on 3,6-di-tert-butyl-o-benzoquinone.

New amphiphilic block copolymers on based benzylmethacrylates or 2,3,4,5,6-pentafluorobenzyl methacrylate and N-isopropylacrylamide with high yields (89–94

The non-toxic amphiphilic bottlebrush polymers capable of self-organization on various interfaces and including cerium ions in structural assemblies without changing their biological properties have great importance for medicine and pharmacy. In the work, we studied the self-assembly in mixed monolayers of two copolymers – methoxy[oligo(propylene glycol)] methacrylate and methoxy[oligo(ethylene glycol)] methacrylate (PK) and its analogue with N-[3-(dimethylamino)propyl]methacrylamide) units quaternized with methyl iodide (PKq), and cholesterol on the aqueous subphase-air interface in the present of cerium compounds. The effect of the polymer-cerium composition on the oxidoruductase activity was investigated as well. The cationic polymer PKq was shown to exhibit higher specific activity of antioxidant enzymes than the non-ionic PK copolymer, increasing the activity of SOD by 20

The possibility of using water-soluble heteronuclear metallamacrocyclic complexes of Sr(II)–Cu(II), Ca(II)–Cu(II), and La(III)–Cu(II) as crosslinking agents for alginate hydrogels has been investigated for the first time. The possibility of ion-induced crosslinking of alginate with metallacrown cations has been experimentally demonstrated. Alginate hydrogel microspheres have been prepared via extrusion, using the metallacrowns as crosslinking agents. The degree of cross-linking of the hydrogels depends on the nature of the central element of the metallacrown. In terms of their crosslinking ability, the considered metallacrowns (MC(M)) are arranged in the following series: MC(La) > MC(Sr) > MC(Ca).

Background/Objectives: This study focuses on the development and evaluation of novel alginate–poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) microcapsules for encapsulating pancreatic islets to address insulin deficiency in diabetes. Methods: In previous research, we fabricated and characterized PMETAC microcapsules, evaluating their stability and permeability in vitro. This study further probes the capsules in vivo, focusing on the functional activity of the encapsulated islets post-transplantation, their viability extension, and the assessment of the immunoprotective, antifibrotic properties, and biostability of the capsules. Results: Rabbit-derived islets were encapsulated and transplanted into diabetic rats. The encapsulated islets maintained insulin secretion for up to 90 days, significantly longer than non-encapsulated ones, which ceased functioning after 7 days. Histological analysis demonstrated high biocompatibility of the PMETAC coating, resulting in minimal fibrotic overgrowth around the capsules. Conclusions: The study highlights the critical role of immunoprotection and the tendency to reduce fibrosis in prolonging islet function. These findings suggest that PMETAC-coated capsules offer a promising solution for cell-based therapies in diabetes by improving graft longevity and reducing fibrotic overgrowth.

The formation and surface behavior of mixed monolayers and LB films of two betulin methacrylate-containing polymers with molar fraction of betulin methacrylate equal to 10

Islet allotransplantation offers a promising cell therapy for type 1 diabetes, but challenges such as limited donor availability and immunosuppression persist. Microencapsulation of islets in polymer-coated alginate microcapsules is a favored strategy for immune protection and maintaining islet viability. This study introduces Poly [2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) as an innovative coating material for microcapsules. PMETAC enhances biocompatibility and durability, marking a significant advancement in islet encapsulation. Our approach combines alginate with PMETAC to create Langerhans islet microcapsules, simplifying material composition and preparation and ultimately lowering costs and increasing clinical applicability. Our comprehensive evaluation of the stability (including osmotic stability, thermal stability, and culture condition stability) and cytotoxicity of a novel microencapsulation system based on alginate-PMETAC-alginate offers insights into its potential application in islet immunoisolation strategies. Microcapsules with PMETAC content ranging from 0.01 to 1% are explored in the current work. The results indicate that the coatings made with 0.4% PMETAC show the most promising outcomes, remaining stable in the mentioned tests and exhibiting the required permeability. It was shown that the islets encapsulated in this manner retain viability and functional activity. Thus, alginate microcapsules coated with 0.4% PMETAC are suitable for further animal trials. While our findings are promising, further studies, including animal testing, will be necessary to evaluate the clinical applicability of our encapsulation method.

In this work, we synthesized three bottlebrush copolymers based on methoxy[oligo(ethylene glycol)]methacrylate, methoxy[oligo(propylene glycol)]methacrylate and N-[3-(dimethylamino)propyl] methacrylamide quaternized by methyl iodide with quaternized unit fraction equaled to 5 and 20

Two new photoinitiators of the α,α-bis(arylidene)cyclopentanone series having an unsymmetrical structure and containing two methacrylate units have been synthesized. The electrochemical and photoluminescent properties of the initiators have been studied. In the presence of the initiators, photopolymerization of pentaerythritol triacrylate was carried using radiation at λ = 365/405 nm (one-photon process) and focused femtosecond laser radiation with a wavelength of 780 nm (two-photon process). For each initiator, “fabrication windows” were determined and 3D microstructures of complex architecture were fabricated by DLW nanolithography.

To increase the surface hydrophobicity of organic-inorganic copolymers containing nanostructured polytanoxide, they were modifified with flfluorine-containing monomers which were introduced into the composition of the monomer mixture, followed by polymerization-polycondensation. The flfluorinated monomers used were 2,2,3,3,4,4,5,5-octaflfluoropentylacrylate, 1,1,1,3,3,3-hex aflfluoroisopropylacrylate, 2,2,3,3-tetraflfluoropropylmethacrylate. The surfaces of the synthesized terpolymers were examined by X-ray flfluorescence analysis and atomic force microscopy. The inflfluence of the nature of the third monomer on the content of titanium and flfluorine atoms in the surface layer and in the chips of the samples as well as on the topography of their surface was determined. The difference in the elemental composition affects the initial hydrophobicity of the samples surface and their ability to hydrophilize the surface under UV exposure. Terpolymers with 1,1,1,3,3,3-hexaflfluoroisopropylacrylate links exhibit the highest wetting angle - 102° - in the absence of UV exposure. However, the "hydrophobicity-hydrophilicity" switching mode is most clearly seen in the terpolymers with 2,2,3,3,4,4,5,5-octaflfluoropentylacrylate links when the wetting angle can be reversibly changed from 86° to 10°.

The amphiphilic block copolymer poly(N-isopropylacrylamide)–Ge(C6F5)2–poly(2,2,3,3-tetrafluoropropyl methacrylate) was prepared by the reaction of chain transfer to bis-(pentafluorophenyl)germane during the polymerization of N-isopropylacrylamide and the subsequent postpolymerization of isolated functional polymers in 2,2,3,3–tetrafluoropropyl methacrylate. The conversion of the block copolymer was 68% and the molecular weight of the sample was 490,000 g/mol. The colloidal chemical properties of Langmuir monolayers and Langmuir-Blodgett films of synthesized block copolymer have been studied. For comparison, a functional polymer, namely, poly-N-isopropylacrylamide with terminal –Ge(C6F5)2H group, was synthesized and studied. The concentrations of spreading solutions were selected and the effect of subphase acidity on the formation of monolayers of macromolecules of the block copolymer was studied. It was found that regardless of the acidity of the subphase, high pressure of fracture of films are characteristic of monolayers of collapse pressures πmax = (48–61) mN/m. The morphology of the Langmuir-Blodgett films of functional polymer exhibit isolated elongated micelles with high densities in the form of “octopus” on the periphery of which there are terminal hydrophobic groups. For the Langmuir-Blodgett film of block copolymer, a comb-like structure is observed with characteristic protrusions.

Graft copolymers of collagen and polymethyl methacrylate were synthesized in a suspension of an acetic acid dispersion of fish collagen and methyl methacrylate in the presence of tributylborane. The copolymers were characterized by IR spectroscopy, gel permeation chromatography, and differential scanning calorimetry. The glass transition temperature is determined for the obtained copolymers. Changes in the synthesis temperature in a range of 25–60 °C did not significantly affect the fraction and molecular weight of the graft polymethyl methacrylate. Microphotographs obtained by scanning electron microscopy and atomic force microscopy indicate the destruction of the fibrillous structure of collagen in the copolymer at the synthesis temperature higher than 25 °C. The hydrophilicity and light transmission of films of the synthesized copolymer samples were studied.

The possibility of optically forming adjacent monolithic and porous fragments of a given geometry in a photopolymer layer by scanning stereolithography is considered. Using computer simulation of the diffusion process during such photo-curing, the optimal modes of scanning with a light spot both for obtaining a monolithic polymer and for implementing the self-formation of a porous structure in one photopolymerizable composition with a nonreactive component are determined. The results of experiments on the creation of porous polymer layers reinforced with monolithic stiffeners made from polyfunctional monomers using a scanning polymerizing spot with a diameter exceeding the pore size are presented.

The process of two-wave photopolymerization of a UV-curable composition with an optically degrading inhibitor is considered. By numerical simulation, it is shown that in the composition layer uniformly exposed to UV-radiation, such systems allow getting segments with different conversion under the action of inhomogeneous visible light. Based on the data on the photopolymerization kinetics of the compositions from triethylene glycol dimethacrylate (TEGDMA) and bisphenol-A glycidyl dimethacrylate (bis-GMA) with the UV-initiator 2,2-dimethoxy-2-phenylacetophenone (DMPA), it was shown that 3,5-di-tert-butyl-o-benzoquinone (35Q) with N,N-dimethylaniline (DMA, "Aldrich", 99%) can serve as an inhibitor that degrades under action of visible radiation. Combining inhomogeneous visible light generated with a conventional DLP-projector and uniform UV-radiation of LED (365 nm) the two-wave lithographic process was implemented to create polymeric 2D-structures in 20 mu m layer of the compositions from TEGDMA (70)/bis-GMA (30)/DMPA (0.05 wt%)/35Q (0.5 wt%)/DMA (1 wt%).

New well-photobleachable initiating systems based on unsubstituted and four 6-CH2X-substituted 3,5-di-tert-butyl-o-benzoquinones (X = H, OCH3, dimethylpyrazole and benzimidazole fragments) and tertiary amines were used for photocuring different methacrylic resins under visible light irradiation. A photoreduction of these o-quinones in the presence of a series of N,N-dimethylanilines under of visible irradiation was studied. Photoinitiating properties of this series of o-benzoquinones in the presence of N,N-dimethylaniline were investigated on the example of the curing resin based on triethylene glycol dimethacrylate (TEGDMA). The photoinitiation system based on o-quinone with dimethylpyrazole fragment and N,N-dimethylaniline has the highest efficiency in this series. It was shown that the use of this initiating system allows to photocure thick layers of TEGDMA/bis-GMA (30/70 wt%) resin (0.5 cm) under the action of both LEDs with lambda(max) 465, 520 and 630 nm. A deep photopolymerization of the composition layer (46 cm thickness) under radiation of LED@ 600 nm (540 mW cm(-2)) was carried out. The average speed of the front of photopolymerization is 2.56 cm/min.

The simple low‐cost method for synthesis and post‐functionalization of thick macroporous polymer monoliths was proposed and realized by example of obtaining and hydrophobization of monoliths based on mono‐ and triethylene glycol dimethacrylates. Described procedures comprise using of ubiquitous visible‐light projection system and single photoinitiator (9,10‐phenanthrenequinone) in both cases. This approach eliminates the need in “material” photomasks and permit to operate with computer generated virtual photomask to form the pattern of functionalization. Macroporous polymer monoliths of 2 and 4 mm in thickness with a system of interconnected pores were synthesized and hydrophobized. The thick layers of functionalized porous polymer with wetting pattern through the entire sample thickness with the water contact angle for hydrophobic parts reaching120–125° were obtained. POLYM. ENG. SCI., 60:682–689, 2020. © 2020 Society of Plastics Engineers

An atactic poly-d,l-lactide (PLA) is obtained via ring-opening polymerization (ROP) of lactide stereoisomers mixture catalyzed by the magnesium and calcium acenaphthylenebisamido complexes. The polymer is characterized by gel-permeation chromatography, NMR spectroscopy, and mass spectrometry. The hydrolytic degradation behavior, cytotoxicity, and cell adhesion of the resulting PLA are evaluated. The polymer degrades in phosphate-buffered saline, releasing water-soluble low molecular products that significantly influence dermal fibroblast growth. Polymer demonstrates no cytotoxicity that, along with cell adhesion and their high proliferative activity toward the PLA obtained, proves its biocompatibility.