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The poly(2-aminoethyl methacrylate) (p(AEM)) microgels were synthesized by microemulsion polymerization technique and used for in situ metal nanoparticle preparation to render as p(AEM)-M (M: Co or Ni) microgel composites and were used in p(AEM) based poly ionic liquid (PIL) microgels. Next, these p(AEM)) based microgel materials were used as catalysts for hydrogen (H 2) production from both hydrolysis and methanolysis reactions of sodium borohydride (NaBH 4). It was found that the catalytic hydrolysis of the NaBH 4 reaction, catalyzed by p(AEM)-Co microgel composite was completed in 140 min, whereas the methanolysis of NaBH 4 methanolysis catalyzed by the PIL of p(AEM)+Cl− microgels was completed in 5 min both with 250 ± 2 mL H 2 production. Furthermore, p(AEM)-Co microgel composite catalysts maintained 80% catalytic activity after 5 consecutive uses in NaBH 4 hydrolysis. On the other hand, p(AEM)+Cl− microgels were found to afford more than 50% catalytic activity even after 20 repetitive use in NaBH 4 methanolysis due to superior regeneration ability. Moreover, activation energy values for p(AEM)-Co microgel composites catalyzed NaBH 4 hydrolysis reaction were calculated as 38.9 kJ/mol in comparison to 37.3 kJ/mol activation energy of p(AEM)+Cl− microgel catalyzed methanolysis reaction. • P(AEM)-M microgel composites catalyst renders efficient NaBH 4 hydrolysis. • P(AEM)-based PIL as metal-free catalyst affords NaBH 4 methanolysis to produce H 2. • P(AEM)-Co catalyst in NaBH 4 hydrolysis in 5 successive use reduces activity to 80%. • P(AEM)+Cl− catalyst in 20 sequential use scores 50% activity in NaBH 4 methanolysis. • P(AEM) can be considered as versatile catalyst system for H 2 production from NaBH 4. [ABSTRACT FROM AUTHOR]

[Display omitted] • Super porous p(Amphoteric) cryogels, prepared from of anionic and cationic monomers. • The cryogels as excellent template to entrap α-Glucosidase (α-Glu@p(Amphoteric). • The α-Glu@p(Amphoteric) cryogel preserves 91.3 ± 1.7% activity of free α-Glu at pH 6.8. • The α-Glu@(Amphoteric) cryogels can maintained >70% activity between pH 5–8. • The α-Glu@(Amphoteric) cryogels offered excellent storage stability and reusability. Cryogels are one of the most unique materials for enzyme immobilization due to their super-porous elastic structures, and fast response times. Not only can cryogels act as flexible compartmentalization supports for enzymes, but they can also serve as solid protective matrices capable of preserving enzymatic activity over extreme conditions. The contributions of individual anionic and cationic cryogels to improve enzymatic activity can be combined into one as a cyrogels of poly(ampholyte). The present study targets the development of p(Amphoteric) cryogel as support for immobilization of enzymes and modeled in-depth characterizations and applications of α-Glucosidase (α-Glu) enzyme by entrapment ((α-Glu@p(Amphoteric)) during cryogelation. The α-Glu@p(Amphoteric) cryogels had 91.3 ± 1.7% activity at pH 6.8 and 37 °C the optimum conditions for free enzyme. They exhibited excellent pH tolerability with more than 70% activity between pH 5–8 at 37 °C, and more than 50% activity between 20–50 °C at pH 6.8. They showed improved storage stability even at 25 °C with almost 50% activity on the 10th days of storage and extraordinary reusability performances with more than 50% activity after 10th consecutive usages, respectively. [ABSTRACT FROM AUTHOR]

Here, we report phosphazene-based covalent organic polymer (COP) structure synthesis from branched polyethyleneimine (PEI) and phosphonitrilic chloride (PNC) as PEI-PNC COP. The zeta potential value of the prepared COP structures, PEI-PNC measured as + 18.6 ± 1.1 mV and increased to + 37.3 ± 1.3 mV after simple protonation with HCl treatment as PEI-PNC+. The specific surface area of PEI-PNC structures was measured as 50.9 m2/g. Interestingly, it was found that the PEI-PNC COP catalyzed NaBH 4 alcoholysis reaction completed in 14 min, whereas the PEI-PNC+ COP catalyzed reaction was completed in 3.5 min with the same amount of H 2 generation, about 253 ± 1 mL. The hydrogen generation rate (HGR) value for the PEI-PNC+ catalyzed reaction was calculated as 3744 ± 234 mL H 2 x (catalyst amount (g) x min)−1 at 25 °C. The activation energy value for the PEI-PNC+ catalyzed reaction was calculated as 20.9 kJ/mol that is comparable low and/or better than metal-based catalysts used for the same purposes. Moreover, the PEI-PNC+ COP structures provide more than 50% activity after 10 consecutive usages and can readily regeneratable via simple HCl treatment. The regeneration ability of the catalyst afforded 100 consecutive uses without a significant loss of catalytic activity. [Display omitted] • Phosphazene-based covalent organic frameworks synthesized from PEI and PNC. • Primary, secondary, and tertiary amine groups containing phosphazene based COPs. • High HGR for PEI-PNC+ COP catalyzed NaBH 4 reaction with 3744 ± 234 mL H 2 x (catalyst amount (g) x min)−1. • 50% activity after 10 consecutive uses of PEI-PNC+ COPs catalysts for H 2 production from NaBH 4. • Up to 100 successive uses of PEI-PNC+ COPs catalyzed NaBH 4 reaction with > 50% activity by simple regeneration process. [ABSTRACT FROM AUTHOR]

Carbon materials can be readily prepared from wood derivatives, monosaccharaides such as pentose/hexose and/or polysaccharides in addition to many starting materials by treatment of thermal, chemical and hydrothermal methods. Here, the porous carbon (PC) particles were prepared by removal of silica particles from previously prepared carbon-silica composites by hydrothermal and carbonization process from sucrose. Then, PC particles were modified with polyethyleneimine (PEI) to prepared amine functionalized PC-PEI particles and protonated with hydrochloric acid, PC-PEI+. Finally, these prepared carbon-based particles were used as catalyst for H 2 release from NaBH 4 methanolysis and PC-PEI+ was found as the most effective catalyst at 25 °C with 4040 ± 126 mL H 2. min−1.g−1 HGR value. The E a value of 23.9 kJ/mol in H 2 release reaction from NaBH 4 methanolysis catalyzed by PC-PEI+ that is comparable and/or better than most of studies reported in literature. The activity% of PC-PEI+ catalyst was 72% after fifth consequential runs. Additionally, the regeneration ability of PC-PEI+ catalyst was also shown that after fifth regeneration process, there is only 5% decrease in activity%. Image 1 • Porous carbon (PC) based catalyst in H 2 release studies from NaBH 4 methanolysis. • Modified PC with PEI as PC-PEI+ as green catalyst for renewable energy utilization. • High Hydrogen Generation Rate (HGR) via metal free PC-PEI catalyst for H 2 production. • Low E a value, 23.9 kJ/mol for PC-PEI+ catalyzed H 2 methanolysis reaction is attained. [ABSTRACT FROM AUTHOR]

In this study, the preparation of hyaluronic acid (HA) cryogels were carried out in the presence of polyethyleneimine (PEI) microgels, and Halloysite Nanotubes (HNTs) clays separately resulted in the corresponding cryogel composites under cryogenic condition (<0 °C). The synthesized HA/PEI cryogel microgel composites, and HA/HNTs cryogel composites were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and by the swelling studies to compare % pore volume and porosity values of the composite materials. The swelling properties and moisture content of HA cryogel, HA/PEI and HA/HNTs cryogel composites were determined at wound healing pH conditions such as pH 5.4, 7.4, and 9 at 37.5 °C. The highest swelling capacity was reached at pH 9 with 4854 ± 50% swelling (S%) within few seconds. The blood compatibility of the HA cryogel and its’ PEI microgel and HNT embedding composite were found to be hemocompatible with maximum of 2.4% hemolysis ratio, and demonstrated high antitrombogenic activity varying in the range of 10.22–17.67 blood clotting indexes. Therefore, these materials can be used as drug carriers, and tested for a model drug, sodium diclofenac (SDF) that can be released from HA/PEI cryogel composites with a linear fashion with long term releasing capabilities up to 9.22 mg/g within 20 h at physiological conditions, pH 7.4, 37.5 °C. [ABSTRACT FROM AUTHOR]

Poly(2-hydroxyethylmethacrylate)-graphene oxide (p(HEMA)-GO) cryogel composites were prepared by including GO during cryopolymerization. The GO within p(HEMA) cryogels was reduced by treating p(HEMA)-GO cryogel composites with the aqueous solutions of hydriodic acid, hydrazine, ascorbic acid, tannic acid, and sodium borohydride. The changes in conductivities of p(HEMA)-GO and its reduced forms, p(HEMA)-r-GO cryogel composites, were compared. The conductivity of bare p(HEMA), and p(HEMA)-GO cryogel were almost the same at 1.03 × 10 − 10 ± 1.3 × 10 − 11 and 1.08 × 10 − 10 ± 5.8 × 10 − 12 S·cm − 1 , respectively; whereas, upon reduction, the conductivity of p(HEMA)-r-GO cryogel composites increased to 4.80 × 10 − 7 ± 5.9 × 10 − 8 S·cm − 1 (~ 4000-fold increase). Moreover, upon in situ synthesis of conductive polyaniline (p(An)) within p(HEMA)-r-GO cryogel composites as p(HEMA)-r-GO/p(An) semi-interpenetrating polymer network (semi-IPN), the conductivity increased 250-fold more than p(HEMA)-r-GO composite, and 1 million-fold more than the bare p(HEMA) or p(HEMA)-GO cryogels with a conductivity value of 1.38 × 10 − 4 ± 2.5 × 10 − 5 S·cm − 1 . Furthermore, p(HEMA)-r-GO composite and p(HEMA)-r-GO/p(An) composite semi-IPN conductive cryogel systems were tested as sensor materials for HCl and NH 3 gases. The conductivity of p(HEMA)-r-GO composite increased 3-fold upon 15 min HCl gas exposure, and decreased 4-fold after 15 min NH 3 gas exposure. Also, the conductivity of p(HEMA)-r-GO/p(An) composite semi-IPN conductive cryogel systems were increased 2-fold and decreased 46-fold upon 15 min exposures to HCl and NH 3 gas, respectively. [ABSTRACT FROM AUTHOR]

Polyethyleneimine (PEI)-based hydrogels with different morphologies as bulkgel, microgel, and a cryogel form were synthesized, and used as templates for in situ Co, Ni, and Cu metal nanoparticles preparation. Because of the size, porosity and morphological differences of the prepared PEI-based hydrogels (bulkgel, microgel and cryogel), interesting and versatile applications were shown. The prepared PEI-M (M: Co, Ni) hydrogel composite systems were used as catalysts for the hydrolysis of NaBH 4 for H 2 production, in the reduction reaction of 4-, and 2- nitrophenols (4-NP, and 2-NP) to their corresponding amino forms, 4-AP and 2-AP, respectively, and in the decolorization reaction of methylene blue (MB) and Eosin Y (EY) dyes (EY) (M: Cu). It was shown that without a metal catalyst, bare NaBH 4 is not good source of H 2 sources e.g., in the hydrolysis of NaBH 4 for H 2 production, the self-hydrolysis of NaBH 4 can only produce 152 ± 2.5 mL H 2 in 280 min whereas the same amount of NaBH 4 can produce 250 mL for under 60 min in the presence of Co nanoparticles within PEI matrices. It was found that the reduction reactions of 4-, and 2-nitrophenols to 4-, and 2- aminophenols, and the decolorization of dyes also required metal nanoparticles catalysts within PEI hydrogel. The hydrogen generation rate (HGR, ml H 2 /(g of cat)(min)), and turnover frequency (TOF, mol H 2 /(mol cat)(min)) values were calculated and compared for PEI hydrogels with different sizes and morphologies. Higher HGR and TOF values were observed in H 2 production using PEI-Co microgel composite catalyst systems than PEI-Co bulk hydrogel and cryogel composite catalyst systems with 424 ml H 2 /(g of cat)(min) and 0.98 mol H 2 /(mol cat)(min) respectively. The higher TOF value was observed for the reduction reaction of 4-, and 2-NPs to their corresponding amino forms as 0.881, and 1.323 mol H 2 /(mol cat)(min), respectively catalyzed by PEI-Ni cryogel composite systems than PEI-Ni microgel and bulkgel composite catalyst system. Better E a value for H 2 production was calculated for PEI-Ni microgel composite systems with 38.3 J/mol K. And the activation energy values for reduction of 4-NP to 4-AP by PEI-Cu composite cryogel system, and for reduction of 2-NP to 2-AP by PEI-Ni composite cryogel system were calculated as 15.2 and 29.6 J/mol K, respectively. The catalytic performances of PEI-Cu hydrogel composite system for decolorization of MB and EY in different media such as sea water, creek water, tap water, and distilled water were compared and the PEI-Cu cryogel composite provided the fastest decolorization capabilities for both dyes. Interestingly, amongst all the media, MB and EY decolorization in seawater by PEI-Cu cryogel was accomplished in 2 and 9 min with 96.3% and 97.3% decolorization, respectively, with the same catalyst system. [ABSTRACT FROM AUTHOR]

Polyethylene imine (PEI) particles were synthesized by a microemulsion polymerization technique, and were used as template for metal nanoparticle preparation. The PEI particles were loaded with Co(II), Ni(II) and Cu(II) ions from water and with CoCl2, NiCl2 and CuCl2 from ethanol and treated with NaBH4 to reduce the corresponding metal nanoparticles in situ. The PEI-M (Co, Ni, and Cu) composites were used in hydrogen generation from the hydrolysis of NaBH4 and NH3BH3 (AB). The PEI-Co composite catalyst system had better catalytic performances in the hydrolysis reactions of NaBH4 and AB than the other metal containing composites. The turnover frequency (TOF) value of PEI-Co in the hydrolysis of AB was found to be almost 12.5 fold more than NaBH4 hydrolysis. It is reported here that the PEI template offered better characteristics than the other templates providing many advantages; for example, the metal loading capacity of PEI increased by sequential loading and reduction cycles, and very high conversion (100%) and activity (100%) were obtained when PEI-Ni was used in fifteen consecutive runs for NaBH4 hydrolysis. The PEI-M composites have mild activation energy in comparison to the literature but better, more flexible characteristics, and very fast kinetics in AB hydrolysis. [ABSTRACT FROM AUTHOR]

Hydrogels with reactive thiourea functional groups were prepared by radiation-induced crosslinking of N-(Hydroxymethyl) acrylamide (HMA) and N-allyl thiourea (ATU) at different ATU content and irradiation doses. P(HMA-co-ATU) hydrogels were then utilized as template for in situ metal nanoparticle (MNP) preparation by the reduction of Ni2+, Co2+, and Cu2+ ions within the hydrogel matrix using sodium borohydride (NaBH 4) as reducing agent. These MNP@p(HMA-co-ATU) hydrogel composites (MNP = Co, Ni, and Cu) were further used as catalysts in the reduction reaction of 4-nitrophenol (4-NP) to 4-aminophenol (AP). Various parameters such as the effect of ATU content, the total dose used in the hydrogel preparation, MNPs type, and temperature on the catalytic activity of hydrogel composites were investigated. The activation energy, enthalpy, and entropy of Ni@p(HMA-co-ATU) hydrogels for the reduction reaction of 4-NP to 4-AP were calculated as 42.5 kJ mol−1, 38.9 kJ mol−1, and −187.3 J mol−1 K−1, respectively. • Radiation induced synthesis of poly(HMA-co-ATU) hydrogel at different ATU content is reported. • Higher irradiation dose rendered higher ATU content in poly(HMA-co-ATU) hydrogels. • P(HMA-co-ATU) hydrogels were used as reactor for in situ Ni, Co or Cu metal nanoparticle preparation. • P(HMA-co-ATU)-Ni hydrogel composites have shown the best catalytic performance in 4-Nitrophenol reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • − 3D super porous poly(β-Cyclodextrin) cryogels in 1–100 µm pore size are prepared. • - Poly(β-Cyclodextrin) cryogels with blood compatibility and partially hydrolytic degradable. • - Poly(β-Cyclodextrin) cryogels can release hydrophilic and hydrophobic drugs simultaneously. Here, one step, simple preparation of superporous p(β-cyclodextrin) (p(β-CD)) cryogels in the presence of various ratios of crosslinker, divinyl sulfone (DVS) e.g., 100, 150, 200% mole with respect to the mole ratio of 6 hydroxyl groups on β-CD unit under cryogenic conditions were reported for the first time. The swelling properties, and hydrolytic degradation of p(β-CD) cryogels was directly related to the used crosslinker ratio. It was observed that the p(β-CD) cryogels showed higher swelling% in DMSO and DMF than in DI water. The prepared p(β-CD)-1 cryogel that was 100% crosslinked exhibited 14 ± 3.7%, 34 ± 4.8%, and 45 ± 6.2% weight losses within 20 days in pH 5.4, 7.4, and 9.0 buffer solutions, respectively. An acceptable hemolysis index of < 5% and a blood coagulation index, >89% were observed for the p(β-CD) cryogels at 1 mg/mL concentrations. Additionally, the potential useability of p(β-CD) cryogels as in vitro drug delivery systems for both hydrophilic vancomycin, and hydrophobic tetracycline as model drugs were individually illustrated at pH 7.4 in PBS. The cumulative drug release from p(β-CD) cryogels, in sustained release profiles with 76.7 ± 9.0 mg/g of vancomycin (89.9 ± 10.5% of the loaded amount) and 146.5 ± 19.4 mg/g tetracycline g (83.1 ± 6.3% of the loaded amount) were attained in 6 and 54 h, respectively at pH 7.4 in PBS. Most importantly, p(β-CD) cryogels exhibited simultaneous loading and releasing the ability for both hydrophilic vancomycin, and hydrophobic tetracycline drugs by concurrently releasing 37.0 ± 2.7 mg/g (23.4 ± 1.8% of the loaded amount), and 36.3 ± 1.3 mg/g (23.6 ± 0.8% of the loaded amount), respectively at pH 7.4 (PBS) in 10 h. [ABSTRACT FROM AUTHOR]

• PEI based hydrogels aimed at water purification from toxic metal oxyanions. • PEI bulkgel, cryogel and microgel are effective in removing arsenate and dichromate. • PEI materials possess rapid and effective alternative in eliminating toxic metal ions. • Superior reusability of PEI hydrogels ensures higher water purification capabilities. Among the various metal ions, chromate (Cr(VI)) and arsenate (As(V)) are the two most hazardous toxic ion species and are found in nature in the form of dichromate and arsenate anions. In this investigation, polyethyleneimine (PEI)-based hydrogels were prepared with microgel, cryogel, and bulkgel morphologies employing glycerol diglycidyl ether as a crosslinker. The prepared PEI-based hydrogels were used to remove dichromate and arsenate anions from aqueous media. PEI microgel, cryogel, and bulkgels weighing 50 mg of each adsorbed 84.7 ± 0.8, 76.5 ± 5.2, and 108.9 ± 2.4 mg.g−1 of dichromate anions and 15.9 ± 0.7, 45.4 ± 1.9, and 79.2 ± 11.6 mg.g−1 of arsenate anions in 30, 120, and 240 min, respectively. The dichromate and arsenate anions adsorption of PEI-based hydrogels were found to fit to the pseudo-second-order kinetic, and nonlinear Langmuir isotherm models, respectively with higher R2 values. The highest distribution coefficient (K d) value of PEI-based hydrogels for dichromate adsorption was obtained on the cryogel forms of PEI as 1.89 ± 0.05. Likewise, the highest K d value for the arsenate adsorption was calculated on PEI-based bulkgels as 0.46 ± 0.01. The thermodynamic parameters of PEI based hydrogels in the adsorption of dichromate and arsenate anions e.g., ΔG (all negative (except for the arsenate adsorption by PEI microgels), and ΔH that is around 2−10 kJ.mol−1, and ΔS what is around 0.01−0.02 kJ.mol−1. K−1 were calculated. The reusability studies showed that PEI-based hydrogels can be used for at least 5 consecutive adsorption-desorption cycles with almost 70 % anion removal efficiency after the fifth cycle. [ABSTRACT FROM AUTHOR]

In this study, metal-organic frameworks (MOFs) based on l -Glutamic acid (L-Glu), a natural amino acid as organic linker and Co (II), Ni (II), and Cu (II) metal ions were used in construction with 37.1 ± 5.3%, 41.4 ± 6.1%, 49.2 ± 4.9% yields, respectively in ethanol under reflux. The prepared L-Glu-M (M: Co(II), Ni(II), and Cu(II)) MOFs were characterized in terms of their porosity, optical, thermal, electrical, and structural properties. Correspondingly, 102.1 m2/g, 83.7 m2/g, and 71.0 m2/g specific surface areas and 2.72 cm3/g, 0.46 cm3/g, and 0.07 cm3/g pore volumes were measured for L-Glu-based Co, Ni, and Cu MOFs. Moreover, the antimicrobial studies of L-Glu-M MOFs on Escherichia coli ATCC 8739, as gram-negative, and Staphylococcus aureus ATCC 6538 as gram-positive bacteria revealed that the highest inhibition zones with 42 ± 2 mm and 44 ± 1 mm were observed for L-Glu-Co MOFs. The hemolysis induction of L-Glu-M MOFs was evaluated, except L-Glu-Cu that induced 8.3 ± 0.4% hemolysis, and the hemolytic characters of other MOF preparations were found to reside in safety margins possessing ≤4% hemolysis ratios. The blood clotting index of L-Glu-M MOFs were measured as 87.4 ± 6.3% (Co(II)), 91.8 ± 10.1% (Ni(II)), and 95.7 ± 4.8% (Cu(II)) with neglectable interference to clotting mechanisms. Cytocompatibility of L-Glu-based MOFs were demonstrated that all MOF preparations with 25 μg/mL concentrations maintained approximately 90% cell viabilities. Furthermore, Glu-based MOFs were demonstrated to possess sensory properties for NH 3 vapor and could be employed in at least five cycles of repeated use. Therefore, L-Glu-M based MOFs can provide useful avenues in material science for a variety of biomedical and industrial applications. Image 1 • Amino acid MOFs from an amino acid, l -Glutamic acid (L-Glu) as linker are reported. • L-Glu-based MOFs are antibacterial, hemocompatible, and biocompatible. • L-Glu-based Ni, Co, and Cu MOFs revealed remarkable sensory responses to NH 3 vapor. • Prepared natural amino acid-based MOFs promise versatile usability in biomedicine. [ABSTRACT FROM AUTHOR]

Tannic acid/Polyethylene imine (TA/PEI) polyplex particles in spherical form were synthesized via the electrostatic interaction between the TA molecules' phenolic groups and PEI positively charged ammonium groups. The size of polyplex particles was observed to be between 500 nm and 5 μm via SEM images. It was found that the TA/PEI polyplex particles showed thermal durability of 4.8 wt% residue in comparison to both components, TA or PEI, at 900 °C. Hydrolytic degradation of TA/PEI polyplex particles at different pHs e.g., pH 1.5 similar to stomach conditions, pH 7.4 similar to physiologic conditions, and pH 9 similar to intestinal conditions were investigated by UV–Vis spectroscopy by measuring degraded TA amount at 37.5 °C over two days and 65%, 31%, and 52% weight losses were found, respectively. FC, TEAC, and DPPH tests were used to determine the antioxidant properties of TA/PEI polyplex particles. The antimicrobial properties of TA/PEI polyplex particles were determined using micro-dilution and disc diffusion methods against gram-negative Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 10145, gram-positive Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 6633 bacteria strains, and Candida albicans ATCC 10231 yeast strain. MIC values of TA/PEI polyplex particles were found to change between 0.025 and 0.1 mg/mL concentration depending on the type of microorganism and indicate that the polyplex particles possess strong antimicrobial activity. [ABSTRACT FROM AUTHOR]