Preparation and Properties of Cryogel Based on Poly(2-hydroxyethyl methacrylate- co-glycidyl methacrylate)

How the Crosslinker Amount Influences the Final Properties of Hydroxyethyl Methacrylate Cryogels

The investigation of the mechanical, thermal, and adsorption properties of hydroxyethyl methacrylate (HEMA) cryogels as a function of a reactant ratio is herein reported to better address materials for specific applications. To this aim, cryogels have been synthesized using different monomer/crosslinker (N,N'-methylene-bisacrylamide-MBAA) ratios. The study of SEM images made it possible to identify the trend in the material's macroporosity. As would be expected, the average measured pore width decreased as the amount of MBAA increased while the number of pores grew. Swelling capacity ranges from 8.7 gW/ggel (grams of water per gram of gel) to 9.3 gW/ggel. These values are strictly connected with the pore's size and distribution, revealing that the water uptake for the most crosslinked sample is inferior to other samples. The equilibrium-adsorption capacity (Qe) towards the methylene violet (MV) was also assessed, revealing no remarkable differences after 24 h of a batch test. As expected, thermogravimetric analysis (TGA) also showed no significant changes in stability that ranged from a maximum weight loss temperature (T Max) of 420 °C to 425 °C, which increased as a function of crosslinker content. Conversely, compression strength measurements showed a notable difference of about 50% in modulus (Ec), moving from the higher to the lower HEMA/MBAA ratio. These new comparative results indicate how slight variations in the reactant's ratio can steadily improve the mechanical properties of the HEMA cryogel without affecting its adsorption efficiency. This can be helpful in the design of materials for water and energy purposes. Since swelling properties are needed in the case of biomedical applications, the HEMA/MBAA ratio should be tuned versus high values.

Structure-property relationships of epoxy functionalized enoate ester-based tailored hybrid gels doped with different polysaccharides

Natural polymer-based cryogenically structured hybrid gels as support matrices were prepared by constructing synergistic multiple interactions among copolymer poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) and different polysaccharides; hyaluronic acid (HyA), dextrin (Dex), maltodextrin (MDex), carboxymethyl cellulose (CMC) and xanthan gum (XG). Great improvement in thermal stability was achieved in the presence of CMC and MDex. In the as-prepared state, the highest modulus is observed in HyA-doped hydrogels, while in the swollen-state, CMC-doped hydrogels have a greater modulus. Hybrid cryogels showed higher swelling than hybrid hydrogels in all cases, while maximum swelling was obtained in HyA-doped hybrid cryogels. Solvent selection methodology based on solvent/polymer interaction was presented using 16 solvents with various solubility parameters. The PHG/XG network exhibited a more gradual swelling, whereas water uptake of hybrids doped with Dex and MDex were more pronounced dependent on temperature. The adsorption capacity of hybrid cryogels for methyl orange (MO) is both higher and faster compared to hydrogels, while a decrease in the adsorption capacity of hybrid cryogels at equilibrium was observed in the order of MDex > Dex > XG > CMC > HyA. This study provides a perspective on cryogenically structured hybrid material design by comparatively presenting the effectiveness of different polysaccharides that can be used for MO adsorption in water purification assemblies.

Room-Temperature Self-Healable Blends of Waterborne Polyurethanes with 2-Hydroxyethyl Methacrylate-Based Polymers

The design of self-healing agents is a topic of important scientific interest for the development of high-performance materials for coating applications. Herein, two series of copolymers of 2-hydroxyethyl methacrylate (HEMA) with either the hydrophilic N,N-dimethylacrylamide (DMAM) or the epoxy group-bearing hydrophobic glycidyl methacrylate were synthesized and studied as potential self-healing agents of waterborne polyurethanes (WPU). The molar percentage of DMAM or GMA units in the P(HEMA-co-DMAMy) and P(HEMA-co-GMAy) copolymers varies from 0% up to 80%. WPU/polymer composites with a 10% w/w or 20% w/w copolymer content were prepared with the facile method of solution mixing. Thanks to the presence of P(HEMA-co-DMAMy) copolymers, WPU/P(HEMA-co-DMAMy) composite films exhibited surface hydrophilicity (water contact angle studies), and tendency for water uptake (water sorption kinetics studies). In contrast, the surfaces of the WPU/P(HEMA-co-GMAy) composites were less hydrophilic compared with the WPU/P(HEMA-co-DMAMy) ones. The room-temperature, water-mediated self-healing ability of these composites was investigated through addition of water drops on the damaged area. Both copolymer series exhibited healing abilities, with the hydrophilic P(HEMA-co-DMAMy) copolymers being more promising. This green healing procedure, in combination with the simple film fabrication process and simple healing triggering, makes these materials attractive for practical applications.

Preparation of nickel-chelated iminodiacetate-functionalized macroporous agarose monolith using modular and clickable building blocks for affinity separation of histidine-tagged recombinant proteins

Selective separation and purification of protein from complex medium is required to completely investigate the structure and function of the target protein. In this study, a composite macroporous agarose monolith containing iminodiacetate-chelated Ni²⁺ ligands was synthesized for selective separation and purification of histidine-tagged recombinant proteins. The large and interconnected pores in the monolith enabled fast binding of proteins with high matrix tolerance in treating complex mediums. To realize the selective protein binding, the iminodiacetate was directly conjugated to epoxy-functionalized agarose monolith via simple chemical reactions between epoxy and imino groups. After chelated Ni²⁺, the composite monolith could bind histidine-tagged recombinant proteins through the coordination interaction between transition metal ions and the imidazole ring of histidine. To further increase the binding capacities of the monolith, a hydrophilic intermediate polymer chain containing multiple iminodiacetate immobilization sites was conjugated to the azide-functionalized agarose monolith via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The morphology and chemical composition of the composite agarose monolith were characterized systematically. The protein binding capacities of the obtained composite agarose monolith were subsequently investigated. The binding capacities of the composite agarose monolith towards the model proteins Gp10 and Lys84 were 0.93 and 0.51 mg/mL, respectively. The protein binding of the composite agarose monolith could be manipulated by adjusting the temperature and concentrations of imidazole. These results demonstrate that the composite agarose monolith could be used as an affinity medium for rapid separation and purification of histidine-tagged recombinant proteins from biological samples.

Fabrication of copolymer brushes grafted superporous agarose gels: Towards the ultimate ideal particles for efficient affinity chromatography

A composite immobilized-metal affinity agarose particle was designed for the selective separation and purification of histidine-tagged proteins from complicated biological samples. The composite particle was constructed using superporous agarose particles as supporting matrix, flexible copolymer brushes as scaffolds to render higher ligand densities, and Ni²⁺-chelated iminodiacetic acids as recognition elements. Superporous agarose composite particles endow high permeability and interfering substance tolerance. The copolymer brush was prepared by surface-initiated atom transfer radical polymerization of N-isopropylacrylamide and glycidyl methacrylate, followed by iminodiacetic acids and Ni²⁺ ions. The physical and chemical properities of the composite particle were thoroughly investigated. The composite particles were shown to be able to selectively separate histidine-tagged recombinant proteins in the presence of high quantities of interfering chemicals in a model protein-binding experiment. By altering the temperature, the protein binding of the composite particles can be modulated. The superporous agarose particles supported polymer brush enables fast and efficient separation and purification of target proteins with high permeability, low backpressure, and high interfering matrix tolerance, which pave the path for bioseparation through designing and fabrication of novel agarose particles-based functional materials.

Poly(Hydroxyethyl Methacrylate) Immunoaffinity Cryogel Column for the Purification of Human Immunoglobulin M

Human immunoglobulin M (hIgM) antibodies are considered as hopeful tools for diseases therapy. Therefore, chromatography approaches are used to purify hIgM with a single step. In this study, we prepared a poly(hydroxyethyl methacrylate) based immunoaffinity p(HEMA-I) cryogel column by using cyanamide to immobilize antihuman immunoglobulin on the p(HEMA) cryogel for purification of hIgM in aqueous solution and artificial human plasma. The characterization of the p(HEMA) cryogel column was performed by using a scanning electron microscope (SEM), micro-computerized tomography (µ-CT), Fourier transform infrared spectroscopy (FTIR), swelling degree and macro-porosity. Further, the optimizations of various parameters were performed such as, pH, ionic strength, temperature and concentration of hIgM in aqueous solutions. In addition, the Langmuir adsorption model was supported by experimental results. Maximum adsorbed amount of hIgM corresponded to 11.1 mg/g at pH 5.75 [morpholino ethanesulfonic acid (MES buffer)]. Our results indicated that the p(HEMA-I) cryogel column can be reused at least 10 times without significant loss in adsorption capacity. As a natural source, artificial human plasma was selected for hIgM adsorption and the purity of hIgM was evaluated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).

Redefining the chemistry of super-macroporous materials: when dendritic molecules meet polymer cryogels

Dendritic cryogels modify the functionality and properties against conventional cryogels and improve the Immunoglobulin G (IgG) adsorption.