Interpenetrating Polymer Network Hydrogels Research Articles

Preparation and ammonium adsorption behavior of interpenetrating polymer networks hydrogel of chitosan‐g‐poly(acrylic acid)/bentonite and chitosan‐glutaraldehyde

AbstractIn this article, new interpenetrating polymer network (IPN) hydrogel as an efficient adsorbent for ammonium was prepared by a two‐step process. First, semi‐IPN hydrogel of chitosan‐g‐poly(acrylic acid)/bentonite (CAB) and chitosan (CTS) was synthesized by grafting polymerization in the presence of exfoliated bentonite as both cross‐linking agent and nanoscale inorganic filler. Second, cross‐linking polymer network of chitosan‐glutaraldehyde (CGA) was formed by reaction of CTS with glutaraldehyde (GA). The obtained IPN hydrogel (CAB/CGA) was characterized by Fourier‐transform infrared spectroscopy, scanning electron microscopy and its swelling degree and PZC value were also measured. These results demonstrate that copolymerized graft reaction was occurred between CTS, AA and bentonite forming CAB, and CGA presented as a cross‐linker in CAB/CGA polymer network. CAB/CGA has a moderate swelling degree of 7.8. CAB/CGA exhibits high adsorption capacity and fast adsorption rate for ammonium. Adsorption process reaches equilibrium in 30 min and fits well to Langmuir adsorption model with a fairly high maximum adsorption capacity of 41.06 mg g−1. The material has a good regeneration ability. After five times of adsorption–desorption, there was almost no decrease in ammonium adsorption capacity. Moreover, the low swelling degree leads to an improvement in material strength and a reduction of equipment cost.

Tailored wrinkles for tunable sensing performance by stereolithography

AbstractConducting polymer hydrogel can address the challenges of stricken biocompatibility and durability. Nevertheless, conventional conducting polymer hydrogels are often brittle and weak due to the intrinsic quality of the material, which exhibits viscoelasticity. This property may cause a delay in sensor response time due to hysteresis. To overcome these limitations, we have designed a wrinkle morphology three‐dimensional (3D) substrate using digital light processing technology and then followed by in situ polymerization to form interpenetrating polymer network hydrogels. This novel design results in a wrinkle morphology conducting polymer hydrogel elastomer with high precision and geometric freedom, as the size of the wrinkles can be controlled by adjusting the treating time. The wrinkle morphology on the conducting polymer hydrogel effectively reduces its viscoelasticity, leading to samples with quick response time, low hysteresis, stable cyclic performance, and remarkable resistance change. Simultaneously, the 3D gradient structure augmented the sensor's sensitivity under minimal stress while exhibiting consistent sensing performance. These properties indicate the potential of the conducting polymer hydrogel as a flexible sensor.

Exploiting light-based 3D-printing for the fabrication of mechanically enhanced, patient-specific aortic grafts

Despite polyester vascular grafts being routinely used in life-saving aortic aneurysm surgeries, they are less compliant than the healthy, native human aorta. This mismatch in mechanical behaviour has been associated with disruption of haemodynamics contributing to several long-term cardiovascular complications. Moreover, current fabrication approaches mean that opportunities to personalise grafts to the individual anatomical features are limited. Various modifications to graft design have been investigated to overcome such limitations; yet optimal graft functionality remains to be achieved. This study reports on the development and characterisation of an alternative vascular graft material. An alginate:PEGDA (AL:PE) interpenetrating polymer network (IPN) hydrogel has been produced with uniaxial tensile tests revealing similar strength and stiffness (0.39 ± 0.05 MPa and 1.61 ± 0.19 MPa, respectively) to the human aorta. Moreover, AL:PE tubular conduits of similar geometrical dimensions to segments of the aorta were produced, either via conventional moulding methods or stereolithography (SLA) 3D-printing. While both fabrication methods successfully demonstrated AL:PE hydrogel production, SLA 3D-printing was more easily adaptable to the fabrication of complex structures without the need of specific moulds or further post-processing. Additionally, most 3D-printed AL:PE hydrogel tubular conduits sustained, without failure, compression up to 50% their outer diameter and returned to their original shape upon load removal, thereby exhibiting promising behaviour that could withstand pulsatile pressure in vivo. Overall, these results suggest that this AL:PE IPN hydrogel formulation in combination with 3D-printing, has great potential for accelerating progress towards personalised and mechanically-matched aortic grafts.

Multifunctional, Degradable Wearable Sensors Prepared with an Initiator and Crosslinker-Free Method.

The present zwitterionic hydrogel-based wearable sensor exhibits various limitations, such as limited degradation capacity, unavoidable toxicity resulting from initiators, and poor mechanical properties that cannot satisfy practical demands. Herein, we present an initiator and crosslinker-free approach to prepare polyethylene glycol (PEG)@poly[2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) (PSBMA) interpenetrating polymer network (IPN) hydrogels that are self-polymerized via sunlight-induced and non-covalent crosslinking through electrostatic interaction and hydrogen bonding among polymer chains. The PEG@PSBMA IPN hydrogel possesses tissue-like softness, superior stretchability (∼2344.6% elongation), enhanced fracture strength (∼39.5 kPa), excellent biocompatibility, antibacterial property, reliable adhesion, and ionic conductivity. Furthermore, the sensor based on the IPN hydrogel demonstrates good sensitivity and cyclic stability, enabling effective real-time monitoring of human body activities. Moreover, it is worth noting that the excellent degradability in the saline solution within 8 h makes the prepared hydrogel-based wearable sensor free from the electronic device contamination. We believe that the proposed strategy for preparing physical zwitterionic hydrogels will pave the way for fabricating eco-friendly wearable devices.

Formulation and Characterization of Interpenetrating Polymer Network Hydrogel Bead as Drug Carrier System for Extended Release of Sulphonyl Urea Medication

Formulation and Characterization of Interpenetrating Polymer Network Hydrogel Bead as Drug Carrier System for Extended Release of Sulphonyl Urea Medication

Effect of Linear Polyacrylamide on the Properties of semi–IPN Hydrogels Based on N, N’–Dimethylacrylamide, and Maleic Acid

In this work, the semi–interpenetrating polymer network hydrogels based on Polyacrylamide; N, N’–Dimethylacrylamide, and Maleic acid were synthesized and investigated by changing the content of linear polyacrylamide in the obtained materials. The chemical properties, morphology, swelling behaviors in distilled water, and mechanical properties of the hydrogels were investigated. Fourier transform infrared spectra confirmed the polymerization ability of monomers, scanning electronic microscopy images showed that the pore size could be controlled by the added volume of linear polyacrylamide was in the range of 252.8 ± 5.0 ~ 888.5 ± 3.5 µm. The swelling ratio and the mechanical properties of the hydrogels increased with increasing linear polyacrylamide content. All of the results in this work showed that semi–interpenetrating polymer network hydrogels based on Polyacrylamide; N, N’–Dimethylacrylamide, and Maleic acid had a high swelling ratio, good water retention, thermal properties, and mechanical properties. Potential applications of the obtained hydrogels are in progress.

Fabrication of Interpenetrating Polymer Network-Based Hydrogel for Colon-Targeted Release of Nateglinide

Nateglinide is an anti-diabetic agent that experiences modest first-pass metabolism and poor aqueous solubility. This paper explores the preparation, characterization, and evaluation of interpenetrating polymer network composite hydrogels of chitosan and poly(meth(methacrylic)) acid as a potential carrier for the drug. Interpenetrating polymer network composite hydrogels of chitosan and poly(meth(methacrylic) acid incorporating nateglinide were prepared using N,Nꞌ-methylene bisacrylamide and glutaraldehyde as cross-linkers. The polymerization of chitosan, entrapment of the drug, and its interaction in prepared hydrogels were checked by FTIR spectroscopy, DSC, and powder XRD studies. The hydrogels were evaluated for their swelling behavior and in vitro drug release. The morphology of the hydrogels before and after dissolution was studied using SEM. The hydrogels showed a 93.29 ± 4.65% yield and 91.28 ± 2.22% drug loading. The hydrogels exhibited pH-sensitive swelling behavior. The in vitro release profile confirmed that the drug release depended on the swelling of hydrogels and showed a biphasic release pattern. Chitosan-poly(meth(methacrylic)) acid interpenetrating polymer network hydrogel, with its biodegradable nature and pH-sensitive release of nateglinide, is an attractive option to be further explored for targeted controlled drug delivery formulations for the drug.

Engineered 3D tumor microenvironment recapitulating stiffness of lung tissue to explore drug resistance of lung carcinoma

Despite clinical advances, the development of anticancer drugs faces high failure rates owing to cancer drug resistance and insufficient understanding of the native tumor microenvironment. Polymeric hydrogels are promising engineered 3D cancer models owing to their tunable properties and structural similarities to the native extracellular matrix. However, precisely mimicking the native cancer microenvironment remains challenging. In this study, we present interpenetrating polymer network (IPN) hydrogels with independent stiffness control as an engineered 3D lung carcinoma model for drug screening and basic cancer research. These IPN hydrogels are formed via horseradish peroxidase/hydrogen peroxide (H2O2)-mediated dual-crosslinking reactions, showing independently tunable stiffness at various H2O2 concentrations. Using this ability, we create engineered 3D lung cancer models that simulate normal and cancerous lung tissue stiffness with encapsulation of non-small cell lung cancer cells. We perform drug resistance tests using this system and compare the drug responses in various preclinical cancer models in vitro and in vivo. Finally, we investigate the biological mechanism underlying the acquired resistance of lung carcinoma cells to epidermal growth factor receptor inhibitors. In summary, our engineered 3D cancer model can serve as an advanced preclinical platform for drug screening and cancer biology, including the biological mechanisms of acquired drug resistance.

Fabrication and rheological properties of a novel interpenetrating network hydrogel based on sage seed hydrocolloid and globulin from the hydrocolloid extraction by-product

In this study, interpenetrating polymer network hydrogels were developed based on sage seed gum (SSG) and globulin protein (Glo) extracted from the mucilage-free seeds. By combining Glo hydrogel with the SSG network the inherent weak gelation of the single SSG system was compensated. As the fraction of Glo increased, various properties of the interpenetrating polymer network (IPN) hydrogels improved substantially. Electrophoretic analysis under reducing conditions showed that Glo dissociated into subunits of approximately 30 kDa and 20 kDa, suggesting it comprises 11S globulin. FTIR spectrum revealed new peaks at 1645 cm−1 and 1537 cm−1 in the amide I and II regions, respectively, for the IPN hydrogels, indicating interactions between two hydrogel networks. Based on the weight loss measurements, the IPN hydrogels exhibited lower mass loss, particularly at higher Glo fractions up to 6 %. The IPN hydrogels also displayed enhanced elasticity, pseudoelasticity, thixotropy, and creep resistance compared to SSG hydrogel, indicating suitability for food, pharmaceutical, and biomedical applications. More broadly, this research provides a sustainable strategy toward innovative material development while advancing bio-based hydrogels.

Development of a Controlled Released System Based on IPN Types Hydrogel for Cartilage Repair

The aim of this study is to develop a controlled Fluconazole and Naproxen releasing system for cartilage repair. A series of interpenetrating polymer network (IPN) type of hydrogels were prepared by using 2-Hydroxyethyl methacrylate (HEMA) and gelatin in different ratios. The hydrogels were synthesized by using ammonium persulfate (APS) and sodium metabisulfite (SBS) as initiator pair and ethylene glycol dimethacrylate (EGDMA) and glutaraldehyde (GA) as cross linkers. The prepared hydrogels were characterized via hydrogel formation and swelling/degradation measurements, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) analysis. From swelling tests, it is observed that semi-IPN hydrogels swell much more than full-IPNs which crosslinked by two agents, EGDMA and GA. The higher ratios of HEMA/gelatin negatively affect swelling values. In general, the IPN hydrogel discs were not affected by the variation of temperature. The release studies of Fluconazole and Naproxen were performed at 37 ⁰C and it is found that the swelling and release profiles were similar to each other. The releases of drugs increase rapidly at first and then complies nearly 36 h-48 h. Because of the looser and porous structure, semi-IPN hydrogels have higher release values than full-IPNs.

Development of Gelatin Methacryloyl/Sodium Alginate Interpenetrating Polymer Network Hydrogels for Bone Regeneration by Activating the Wnt/β-Catenin Signaling Pathway via Lithium Release.

Hydrogels have gained significant attention as biomaterials due to their remarkable properties resembling those of the extracellular matrix (ECM). In the present investigation, we successfully synthesized interpenetrating polymer network (IPN) hydrogels using gelatin methacryloyl (GelMA) and sodium alginate (SA), incorporating various concentrations of lithium chloride (LiCl; 0, 5, and 10 mM), aiming to develop a hydrogel scaffold for bone regeneration. Notably, the compressive modulus of the IPN hydrogels remained largely unaffected upon the inclusion of LiCl. However, the hydrogel with the high concentration of LiCl exhibited reduced fragmentation after compression testing. Intriguingly, we observed a significant improvement in cellular biocompatibility, primarily attributed to activation of the Wnt/β-catenin signaling pathway induced by LiCl. Subsequently, we evaluated the efficacy of the newly developed IPN-Li hydrogels in a rat cranial defect model and found that they substantially enhanced bone regeneration. Nevertheless, it is important to note that the introduction of high concentrations of LiCl did not significantly promote osteogenesis. This outcome can be attributed to the excessive release of Li+ ions into the extracellular matrix, hindering the desired effect. Overall, the IPN-Li hydrogel developed in this study holds great promise as a biodegradable material for bone regeneration applications.

Biodegradable polymer‐based hydrogel as a bioactive carrier for dermatological cosmetics and pharmaceutical applications

AbstractA novel biodegradable interpenetrating polymer network hydrogel impregnated with a plant extract was designed using a simple one‐pot free radical polymerization of polyacrylamide (PAM), poly(vinyl alcohol) (PVA) and gelatin (Gel). PAM/PVA/Gel hydrogels with different Gel contents (Gel‐0–Gel‐40) reached a maximum water absorbency of 1443%, which was approximately three times greater than PAM hydrogel. Biocompatibility assessment of all hydrogels on L929 fibroblast cells demonstrated no toxicity. Gel‐10 hydrogel with a water absorbency of 1120% presented the optimal tensile strength of 363 kPa. The compressive modulus of Gel‐10 hydrogel was 36.2 kPa with the ability to maintain shape under load. Gel‐10 hydrogel demonstrated a good adhesive property on various surfaces including paper, glass, aluminium and skin. A release study revealed a sustained release characteristic which involved Fickian diffusion. A plant extract, Quercus infectoria (Qi), was successfully impregnated as a bioactive agent into Gel‐10 hydrogel and demonstrated a broad spectrum of antibacterial activity against both Gram‐positive and Gram‐negative bacteria. In addition, the Qi‐impregnated hydrogel possesses an excellent radical scavenging activity with 94.6% inhibition and antityrosinase activity with 88.4% inhibition. Studies on biodegradation in soil indicated that the external surfaces of Gel‐10 hydrogel were destroyed. The percentage weight loss of Gel‐10 hydrogel was 66.7%. Additionally, the water absorbency of Gel‐10 after a soil burial test was significantly decreased (421%), compared with 1120% before the test (P < 0.001). Gel‐10 hydrogel could be applied as a bioactive carrier in dermatological cosmetics and pharmaceutical products to prevent infections, deleterious effects from free radicals, and skin pigmentation disorders. © 2023 Society of Industrial Chemistry.

Calcium silicate‐reinforced pH‐sensitive alginate‐gellan gum composite hydrogels for prolonged drug delivery

AbstractThis study disclosed the synthesis and characterization of externally and/or internally crosslinked alginate‐gellan gum composite interpenetrating polymer networks (IPN) and IPN hydrogel microspheres for controlled delivery of gliclazid. The internal cross‐linking of the polymer sol was accomplished via slow release of Ca2+ ions from calcium silicate in presence of gluconic acid d‐lactone. The microspheres had spherical shape with smooth surface morphology. The IPN or composite IPN hydrogel microspheres had drug entrapment efficiency of 70%–76%. Incorporation of gellan gum or gellan gum/calcium silicate in the alginate sol sustained the release of drug in simulated gastrointestinal fluids over 12 h without any sign of particle disintegration. Inclusion of calcium silicate in alginate gels was ineffective in controlling drug release under simulated gastrointestinal milieu. The drug release obeyed anomalous diffusion mechanism after inclusion of gellan gum or gellan gum‐calcium silicate in the alginate gel microspheres. Fourier‐transform infrared (FTIR) spectroscopy and zeta analysis confirmed absence of drug‐polymer chemical interaction. The thermal and x‐ray diffraction analyses suggested that the drug transformed into amorphous state after incorporation into composite hydrogel system. Hence, it may be advantageous to combine internal and external gelation procedures for creating composite IPN or IPN hydrogel microspheres for avoiding burst effect of alginate microspheres and managing desired drug release patterns in vitro.

Interpenetrating polymer network based hydrogel: A smart approach for corroborating wound healing of various capacity

AbstractHemorrhage of high intensity usually leads to severe mortality accidents, disaster, and warfare. The concomitant wound thereby induces immense psychological as well as physical trauma to the patients. Hence, a faster hemostasis with smart wound healing approaches are highly essential to deal such critical/life threatening situations. The traditional approaches such as implementation of gauze and bandages are found to be having limited scope for controlling hemorrhage, because of non‐biodegradability, high susceptibility towards infection, unsuitability for irregular wound and ineffective towards wound healing. By virtue of the merits revealed by remodeling interpenetrating polymer network (IPN) based hydrogels (biocompatibility, high porosity, tunability, biomimetic and better retention, and proliferative wound healing tendency), have drawn a rigorous attention to out play their ancestors. This review includes the involvement of numerous synthetic routes, types and physicochemical properties of IPN based hydrogels loaded with diverse therapeutic agents towards wound repair/healing. Moreover, some of the recent patents have been portrayed in the manuscript, dignifying the potentiality of fascinating IPN hydrogels towards effective wound healing. More research is required to engineer multifaceted IPN hydrogels to attain huge potential against the challenges and future perspectives in wound healing.

Structure and properties of fibrin/polyvinyl alcohol interpenetrating polymer network hydrogel as a modifying coating for small-diameter vascular grafts

Background: Interpenetrating polymer network (IPN) hybrid hydrogels enable regulating their properties by varying the composition and concentration of their components. Fibrin is an available natural polymer with ideal biological properties but low strength and tendency to retraction. Polyvinyl alcohol hydrogels are stable, comparable in strength to biological tissues but bioinert. Fibrin/polyvinyl alcohol (F/PVA) IPN can overcome the shortcomings of each component and create an improved material for tissue engineering.Objective: To assess the possibility of and conditions for obtaining a homogeneous IPN by subsequent fibrin polymerization and polyvinyl alcohol cryostructuring while preserving as much as possible mechanical and biological properties beneficial for tissue engineering.Methods: F/PVA IPN was obtained by subsequent fibrin polymerization (30 mg/mL) and polyvinyl alcohol cryostructuring (15, 30, and 60 mg/mL). We studied the structure using a scanning electron microscope, histology, infrared spectroscopy, and X-ray diffraction analysis. We tested mechanical properties and shrinkage of the samples. Biological features were assessed in vitro in terms of viability, cell count, proliferative and metabolic activity of EA.hy926 endothelial cell culture.Results: Our study found the maximum amount of fibrin on the surface of F30PVA15 IPN and its minimum amount on the surface of F30PVA60. These results were supported by the high biological appeal of F30PVA15 compared with F30PVA30 and F30PVA60. F30PVA60 hydrogels demonstrated shrinkage resistance compared to the template; F30PVA30 and F30PVA15 samples decreased by 1.4 and 2.5 times, respectively. Although the mechanical strength of all monocomponent hydrogels and IPN samples did not compare to that of the internal thoracic vein, F30PVA30 and F30PVA60 demonstrated better results than F30PVA15 and fibrin alone.Conclusion: Our method allows obtaining shrink-resistant IPN hydrogels with improved mechanical and tolerable biological properties at polyvinyl alcohol concentrations of > 15 mg/mL and < 60 mg/mL. However, the insufficient strength of this material limits its use in vascular engineering to a modifying coating. Received 25 January 2023. Revised 17 March 2023. Accepted 29 March 2023. Funding: This research was funded by the complex program of basic research under the Siberian Branch of the Russian Academy of Sciences within the basic research topic of Research Institute for Complex Issues of Cardiovascular Diseases No. 0419-2022-0001 “Molecular, cellular and biomechanical mechanisms of the pathogenesis of cardiovascular diseases in the development of new treatment methods based on personalized pharmacotherapy, minimally invasive medical devices, biomaterials and tissue-engineered implants”. Conflict of interest: The authors declare no conflict of interest. Contribution of the authorsConception and study design: V.G. Matveeva, M.A. RezvovaData collection and analysis: V.G. Matveeva, M.A. Rezvova, T.V. Glushkova, E.O. Krivkina, A.V. SergeevaStatistical analysis: V.G. Matveeva, M.A. Rezvova, T.V. Glushkova, A.V. SergeevaDrafting the article: V.G. MatveevaCritical revision of the article: V.G. Matveeva, M.A. Rezvova, L.V. Antonova, L.S. BarbarashFinal approval of the version to be published: V.G. Matveeva, M.A. Rezvova, T.V. Glushkova, A.V. Sergeeva, E.O. Krivkina, L.V. Antonova, L.S. Barbarash

Characterization of structural and functional properties of soy protein isolate and sodium alginate interpenetrating polymer network hydrogels.

This study used enzymatic and Ca2+ cross-linking methods to prepare edible soy protein isolate (SPI) and sodium alginate (SA) interpenetrating polymer network hydrogels to overcome the disadvantages of traditional interpenetrating polymer network (IPN) hydrogels, such as poor performance, high toxicity, and inedibility. The influence of changes in SPI and SA mass ratio on the performance of SPI-SA IPN hydrogels was investigated. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the structure of the hydrogels. Texture profile analysis (TPA), rheological properties, swelling rate, and Cell Counting Kit-8 (CCK-8) were used to evaluate physical and chemical properties and safety. The results showed that, compared with SPI hydrogel, IPN hydrogels had better gel properties and structural stability. As the mass ratio of SPI-SA IPN changed from 1:0.2 to 1:1, the gel network structure of hydrogels also tended to be dense and uniform. The water retention and mechanical properties of these hydrogels, such as storage modulus (G'), loss modulus (G"), and gel hardness increased significantly and were greater than those of the SPI hydrogel. Cytotoxicity tests were also performed. The biocompatibility of these hydrogels was good. This study proposes a new method to prepare food-grade IPN hydrogels with mechanical properties of SPI and SA, which may have strong potential for the development of new foods. © 2023 Society of Chemical Industry.

Salt-resistant agarose-polyvinylpyrrolidone composite hydrogel with pitted-surface towards highly efficient water desalination and purification

In recent years, solar energy interfacial evaporation technology has been extensively explored for seawater desalination and wastewater treatment. However, salt accumulation and complex fabrication of evaporator largely constrains the applications of this technology in practice. Here, one type of interpenetrating polymer network hydrogel composing of agarose (AG) and polyvinylpyrrolidone (PVP) using polypyrrole (PPy) as the light absorbent was fabricated via “hot-ice” template method, which was featured with pitted-surface and microchannels structure. The evenly arranged pits on the surface of the hydrogel can absorb the sunlight as much as possible and convert it into heat energy, improving the efficiency of photothermal absorption. The water channels generated by the formation of CaCl2·6H2O crystals can transport water from the bottom to the evaporation interface elevating the transmission rate and accelerating the exchange of gradient salt concentration. As consequences, excellent salt resistance of the hydrogel can be obtained, achieving seawater evaporation rate as high as 3.2 kg m−2 h−1. In addition, the outstanding ion rejection performance, strong acid/alkali purification capability, and good treatment capacity for heavy metal ions and dye wastewater were also demonstrated.

Chitosan interpenetrating polymer network hydrogels for oil–water and emulsion separation

AbstractHydrogels have obtained extensive attention in oil–water separation due to their high hydrophilicity and weak viscosity. However, most hydrogels have limited applications due to their subpar mechanical qualities. The interpenetrating network gives the hydrogel material high mechanical properties due to the presence of physical and chemical crosslinking. Hence, polyvinyl alcohol/chitosan/polyacrylamide interpenetrating polymer network hydrogel (HAPC‐Gel) was created in this study. HAPC‐Gel coating filter cloth showed underwater super‐oleophobic (the oil contact angles about 159°) and could stably separate oil–water mixtures in different oil phases and complex environments (acids, bases, salts), and the removal rate is still above 99% after 20 cycles of separation. Furthermore, the water could be divided from the oil‐in‐water emulsion. These results indicate that HAPC‐Gel composites have promising applications in oil–water separation.

Carbonic Anhydrase Enhanced UV-Crosslinked PEG-DA/PEO Extruded Hydrogel Flexible Filaments and Durable Grids for CO2 Capture.

In this study, poly (ethylene glycol) diacrylate/poly (ethylene oxide) (PEG-DA/PEO) interpenetrating polymer network hydrogels (IPNH) were extruded into 1D filaments and 2D grids. The suitability of this system for enzyme immobilization and CO2 capture application was validated. IPNH chemical composition was verified spectroscopically using FTIR. The extruded filament had an average tensile strength of 6.5 MPa and elongation at break of 80%. IPNH filament can be twisted and bent and therefore is suitable for further processing using conventional textile fabrication methods. Initial activity recovery of the entrapped carbonic anhydrase (CA) calculated from esterase activity, showed a decrease with an increase in enzyme dose, while activity retention of high enzyme dose samples was over 87% after 150 days of repeated washing and testing. IPNH 2D grids that were assembled into spiral roll structured packings exhibited increased CO2 capture efficiency with increasing enzyme dose. Long-term CO2 capture performance of the CA immobilized IPNH structured packing was tested in a continuous solvent recirculation experiment for 1032 h, where 52% of the initial CO2 capture performance and 34% of the enzyme contribution were retained. These results demonstrate the feasibility of using rapid UV-crosslinking to form enzyme-immobilized hydrogels by a geometrically-controllable extrusion process that uses analogous linear polymers for both viscosity enhancement and chain entanglement purposes, and achieves high activity retention and performance stability of the immobilized CA. Potential uses for this system extend to 3D printing inks and enzyme immobilization matrices for such diverse applications as biocatalytic reactors and biosensor fabrication.

The first results of obtaining a hybrid hydrogel based on fibrin and polyvinyl alcohol: comparison with monocomponent hydrogels

Fibrin displays promising characteristics for tissue engineering. However, it has suboptimal physical and mechanical properties when used as a material for cardiovascular applications. Obtaining an interpenetrating polymer network (IPN) hydrogel based on fibrin and polyvinyl alcohol (PVA) can improve the physical and mechanical characteristics and shrink behavior of fibrin.Aim: To perform sequential polymerization of fibrin and PVA to obtain IPN hydrogel and analyze its properties in comparison with monocomponent hydrogels.Material and Methods. Fibrinogen was isolated from the peripheral blood of patients using ethanol precipitation, then polyvinyl alcohol dissolved in saline was added to it. First, fibrin polymerization was initiated by adding calcium chloride to the solution. Then, it was followed by polyvinyl alcohol undergoing freeze–thaw cycles. Thus, a hydrogel based on fibrin and PVA, samples from pure fibrin and pure polyvinyl alcohol were prepared. We studied the structure of hydrogels, their physical and mechanical properties, shrink behavior and biological activity. Statistical data processing was carried out using the GraphPad Prism 6 software.Results. 3D structure of the hydrogel is presented by polyvinyl alcohol polygonal cavities with a network of thin fibrin fibers. The distribution of components was equal in the inside of the samples, while polyvinyl alcohol prevails on the surface. Elongation (247 (220.0; 293.2)%; p = 0.0005) and Young’s modulus (0.09 (0.11; 0.13) mPa; p = 0.0001) of the hydrogel were statistically significantly higher compared to fibrin values. The hydrogel did not shrink, unlike fibrin that shrunk (11-fold decrease in volume). The number of adherent endothelial cells on the hydrogel matrices was 8 times higher than on polyvinyl alcohol, but 10 times lower than on fibrin. There was no proliferative activity of cells on polyvinyl alcohol, but 13.6% of proliferating cells were noted on the IPN hydrogel, and 59.52% on fibrinConclusion. Using sequential polymerization to obtain the IPN hydrogel based on fibrin and polyvinyl alcohol provides an equal distribution of fibers in the thickness of the material, making it possible to obtain hydrogels with improved mechanical properties and shrink behavior. However, the components on the surface of the IPN hydrogel need to be redistributed - more polyvinyl alcohol should be added still maintaining a relatively low adhesiveness of the material. Therefore further research is necessary to create the most optimal conditions for cell activity.