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Here, boric acid (H3BO3) and its dewatered form, boron trioxide (B2O3) were tested as catalysts for hydrogen (H2) evolution in the methanolysis of sodium borohydride (NaBH4) in methanol. Parameters such as catalyst types and their amounts, NaBH4 concentration, and the reaction temperature affecting the hydrogen generation rate (HGR) were studied. It has been found that H3BO3 and B2O3 catalyzed methanolysis reaction of NaBH4 follow up first-order kinetics relative to the concentration of NaBH4. Furthermore, the conversion and activity of these catalysts were examined to determine their performance in ten consecutive use. Interestingly, H3BO3 and B2O3 have demonstrated superior catalytic performances in methanolysis of NaBH4 comparing to the studies published in literature with the activation energy of respectively 22.08 kJ.mol-1, and 23.30 kJ.mol-1 in H2 production. The HGR was calculated as 6481 mL.min-1.g-1 and 5163 mL.min-1.g-1 for H3BO3 and B2O3 catalyst, respectively for 50 mg catalyst at 298 K. These results are comparably better than most metal nanoparticle catalysts used for H2 production in addition to the naturally occurring boron-based environmentally friendliness of these materials. [ABSTRACT FROM AUTHOR]

Summary: Sand samples from Tampa (T) and Panama (P) City beaches in Florida were used as catalysts for dehydrogenation of NaBH4 in methanol. T and P sand samples were sieved to <250, 250 to 500, and >500 μm sizes, and the smallest fractions resulted in faster hydrogen generation rates (HGR), 565 ± 18 and 482 ± 24 mL H2 (min.g of catalyst)−1, respectively. After various base/acid treatments, HGR values of 705 ± 51 and 690 ± 47 mL H2 (min g of catalyst)−1 for HCl‐treated T and P sand samples were attained, respectively. Next, T and P sand samples were modified with polyethyleneimine (PEI) that doubled the HGR values, 1344 ± 103, and 1190 ± 87 mL H2 (min.g of catalyst)−1 and increased ~8‐fold, 4408 ± 187, and 3879 ± 169 mL H2 (min g of catalyst)−1, correspondingly after protonation (PEI+). The Ea values of T and P sand samples were calculated as 24.6 and 25.9 kJ/mol, and increased to 36.1, and 36.6 kJ/mol for T‐PEI+ and P‐PEI+ samples, respectively. [ABSTRACT FROM AUTHOR]

Maltose, a natural disaccharide, was crosslinked with divinyl sulfone to prepare poly(maltose) (p(MAL)) micro/nanoparticles via one step microemulsion system with ≥90% ± 5% yield in a size rage of 0.5–100 μm for the first time. P(MAL) was modified (m‐p(MAL)) with ethylenediamine (EDA), polyethyleneimine (PEI), and taurine (TA) to render additional functionalities, that is, amine and sulfate groups. The isoelectronic point of bare p(MAL) particles were calculated at pH 2.2 ± 0.5 and was changed to 1.3 ± 0.5, 4.3 ± 1.0, and 8.1 ± 0.7 for TA (p(MAL)/TA), EDA (p(MAL)/EDA), and PEI (p(MAL)/PEI) modification, respectively. Bare p(MAL) particles were found to be biocompatible up to 2 mg/ml with hemolysis and blood clotting tests, whereas the modified p(MAL) particles were found to be biocompatible at 1 mg/ml concentration. Additionally, it was found that TA‐ and PEI‐modified p(MAL) particles induced blood clotting mechanisms. Sodium diclofenac as model drug was released at proportions of 8.7% ± 1.3%, 3.9% ± 0.2%, 8.8% ± 0.9%, and 31.6% ± 0.4% of the loaded drug in phosphate buffered saline solution from p(MAL), p(MAL)/TA, p(MAL)/EDA, and p(MAL)/PEI, respectively. The inhibition of antimicrobial activity of p(MAL)/PEI particles at 20 mg/ml concentration for Escherichia coli and Staphylococcus aureus strain was determined as 99.86% ± 0.3% and 99.79% ± 0.25%, respectively. [ABSTRACT FROM AUTHOR]

Hyaluronic acid (HA) particles with divinyl sulfone (DVS) crosslinking at 10% mole ratio (HA macromolecule repeating units) were prepared and demonstrated as versatile drug carriers with sustainable and long-term release capabilities for cancer drugs, corticosteroid, and antibiotics. Two different methods were chosen in drug loading process; encapsulation for cancer drugs, 5-fluorouracil (5FU), mitomycin C (MMC), and doxorubicin (Dox), and dual drug conjugation for anti-inflammatory glucocorticoid dexamethasone (Dex) and antibiotic ciprofloxacin (Cipro) drugs, respectively. It was demonstrated that HA particles prepared during drug encapsulation were attained smaller sizes with 833 ± 46, 867 ± 50, 728 ± 41 nm for 5FU, MMC, and Dox, respectively. Bare and drug loaded HA particles were shown to be blood compatible with the highest hemolytic ratio of 3.1 ± 0.12% for HA-Dex-Cipro conjugates and fairly good blood clotting index with minimum 71.7 ± 6.0% for MMC encapsulated HA particles. Drug release studies from HA particles indicated that depending on the types of cancer drugs, it is possible to gradually release the drug in long-term up to 300 h in linear fashions with the highest release of 9.34 ± 2.25 mg/g for 5FU. Similarly, drug conjugated HA-Dex-Cipro particles were also showed linear dual drug release up to 100 h at physiological conditions, pH 7.4 and 37.5 °C. [ABSTRACT FROM AUTHOR]

Due to the intriguing properties of Chitosan (CS), many efforts have been paid for CS‐based fiber preparation. As it is impossible to prepare CS fiber directly, facilitating polymers such as polyvinyl alcohol (PVA) possessing necessary properties that enable CS‐based fiber fabrication is used. For this purpose, 3 wt% of CS in 90% acetic acid solution and 6 wt% PVA solution in DI water used in CS/PVA fiber preparation at different proportions for example, 2:1, 9:1 and 10:1 by weight to fabricate fibers by electrospinning method. Furthermore, to render fluorescent property to CS/PVA (9:1) fibers, N‐doped carbon dots (C‐dots) added into fiber precursor during fiber preparation. The emission peak of C‐dots based fibers that with fluorescent features was observed at around 436 nm. The morphological, structural and, thermal characterizations of CS‐based fibers were done with scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analyzer, respectively. Anti‐bacterial activity of bare CS/PVA was increased with the increase in amounts of C‐dots embedding. The inhibition of zone of CS/PVA (9:1) fibers was increased from 1.8 ± 0.2 cm to 2.1 ± 0.3 cm and 2.9 ± 0.4 cm against E. coli by increasing the amounts of C‐dots from 2.9 mg and 5 mg. Also, the same behavior was observed against S. aureus where the inhibition zone is increased from 2.5 ± 0.1 cm to 3.2 and 3.5 cm by doubling the C‐dots amounts in CS/PVA fiber. Moreover, bare and C‐dots containing CS/PVA fibers were found blood compatible (nonhemolytic) up to 1 mg/mL concentration according to hemolysis and blood clotting tests. [ABSTRACT FROM AUTHOR]

Here, a microgel of poly(L‐Lysine) (p(LL)) from an amino acid, L‐Lysine, was synthesized by microemulsion technique using AOT as surfactant in gasoline. The prepared p(LL) microgel was shown to be hydrolytically degradable at pH values of 5.4, 7.4, and 9 in phosphate buffer solution (PBS). The protonated p(LL) microgel was loaded with model drugs such as naproxen and riboflavin and found to release about 80% of loaded naproxen in 180 minutes and 70% of loaded riboflavin in about 120 minutes suggesting the potential of p(LL) microgels to act as fast drug delivery vehicles. Furthermore, p(LL) microgels were chemically modified with 1‐bromoethane (BE), 1‐bromooctane (BO), and 1‐bromoethylamine (BEA) to render antimicrobial capabilities. It was found that protonated p(LL) microgels had 29 ± 1 mm inhibition zone diameter for Pseudomonas aeruginosa ATCC 10145. Furthermore, minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) values for Staphylococcus aureus ATCC 6538 were also calculated as 1 and 2.5 mg/mL concentrations, respectively, for protonated p(LL) microgels. [ABSTRACT FROM AUTHOR]

We present mechanically strong macroporous, squeezable dextran cryogels as a column filling material for the removal and separation of binary organic dye and pesticide mixtures from aquatic medium. Dextran cryogels were prepared from aqueous solutions of dextran of various molecular weights (MWs) in the presence of 20 to 50 mol% divinyl sulfone (DVS) as a cross‐linker at −18°C. The cryogels have interconnected irregular pores of 100 μm in sizes, and exhibit 69‐84% reversible squeezability without damaging the 3D dextran network. Their total open pore volumes (6.3‐10 mL g−1), weight swelling ratios in water (1380%‐2200%), and mechanical parameters could easily be adjusted by both DVS mol% and MW of dextran. Dextran cryogel with the highest modulus (3.8 ± 0.5 MPa), compressive stress (8 ± 2 MPa) and plateau stress (0.46 ± 0.04 MPa) was obtained at 50 mol% DVS using dextran with a MW of 15 to 25 kg·mol−1. Dextran cryogels are hydrolysable at pH = 1 and 9 but stable at 7.4 independent on both the degree of cross‐linking and MW of dextran. At below 50 mol% DVS, they are blood compatible and possess slight thrombogenic effect with blood clotting index value of 98% ± 5%. They are also capable to separate binary dye and pesticide mixtures from aqueous solutions via ionic interactions. [ABSTRACT FROM AUTHOR]

Summary: Polymeric microgels were prepared from dextran (Dex) by crosslinking linear natural polymer dextran with divinyl sulfone (DVS) with a surfactant‐free emulsion technique resulting in high gravimetric yield of 78.5 ± 5.3% with wide size distribution. Dex microgels were chemically modified, and then used as catalyst in the methanolysis of NaBH4 to produce H2. The chemical modification of Dex microgel was done on epichlorohydrin (ECH)‐reacted Dex microgels with ethylenediamine (EDA), diethylenetriamine (DETA), and triethylenetetraamine (TETA) in dimethylformamide (DMF) at 90°C for 12 hours. The modified dextran‐TETA microgels were protonated using treatment with hydrochloric acid (HCl) and m‐Dex microgels‐TETA‐HCl was found to be a very efficient catalyst for methanolysis of NaBH4 to produce H2. The effects of reaction temperature and NaBH4 concentration on H2 generation rates were investigated and m‐Dex microgels‐TETA‐HCl catalyst possessed excellent catalytic performances with 100% conversion and 80% activity at end of 10 consecutive uses and was highly re‐generatable with simple HCl treatment. Interestingly, m‐Dex microgels‐TETA‐HCl catalyst can catalyze NaBH4 methanolysis reaction in a mild temperature range 0 to 35°C with Ea value of 30.72 kJ/mol and in subzero temperature range, −20 to 0°C with Ea value of 32.87 kJ/mol, which is comparable with many catalysts reported in the literature. [ABSTRACT FROM AUTHOR]

Polyethyleneimine (PEI) cryogels with interconnected superporous morphology were synthesized via the cryopolymerization technique. Then, conductive polymers, poly(Aniline) (PANi), poly(Pyrrole) (PPy), and poly(Thiophene) (PTh) were prepared within these PEI cryogels. Then, the conductive polymer embedding PEI composites' characterization was carried morphologically using scanning electron microscope (SEM) by means of Fourier Transform Infrared Radiation (FT-IR) spectrometer, and by means of electrical conductivity measurements using an electrometer. Among all the prepared cryogel conductive polymer composites, the highest value in terms of conductivity was determined for PEI/PANi cryogel composites with 4.80 x 10-3 S.cm-1. Afterward, to prepare polymeric ionic liquid (PIL) forms of PEI and PEI/PANi composites. To assess the effect of anions on the conductivities of the prepared composites, PEI-based cryogels were anion ex-changed after protonation with HCl by treatment of aqueous solutions of sodium dicyanamide (Na+[N(CN)2]-), ammonium hexafluorophosphate (NH4+[PF6]-), sodium tetrafluoroborate (Na+[BF4]-), and potassium thiocyanate (K+[SCN]-), separately. Furthermore, PEI-based cryogel composites and their PIL forms were tested as a sensor for CO2 gas. The higher conductivity changes were observed on bare PEI cryogel and PEI+[BF4]- PIL cryogels with 1000-fold decrease on conductivity upon 240 min CO2 exposure. The sensitivity and recovery percent of bare PEI and PEI+[BF4]- PIL cryogels were shown almost the same with a two-fold decrease in the presence of 0.009 mole of CO2 gas, and approximately 30% recovery after the fifth consecutive reuse. [ABSTRACT FROM AUTHOR]

Purpose: To evalauted natural polymeric biomaterials including hyaluronic acid (HA) and its copolymeric form HA:Suc nanoparticles (NPs) as drug carrier systems for delivery of hydrophobic small molecule kinase EF2-kinase inhibitor in breast and pancreatic cancer cells. Methods: In vitro cellular uptake studies of Rhodamine 6G labaled HA:Suc nanoparticles were evaluated by using flow cytometry analysis and fluorescent microscopy in breast (MDA-MB-231 and MDA-MB-436) and pancreatic cancer cells (PANC-1 and MiaPaca-2). Besides, in vitro release study of compound A (an EF2-kinase inhibitor) as a model hydrophobic drug was performed in the cancer cells. Results: These biological evaluation studies indicated that HA and HA:Suc NPs provided a highly effective delivery of compound A were into breast and pancreatic cancer cells, leading to significant inhibition of cell proliferation and colony formation of breast and pancreatic cancer cells. Conclusion: HA-sucrose NPs incorporating an EF2-Kinase inhibitor demonstrate significant biologic activity in breast and pancreatic cancer cells. This is the first study that shows natural polymeric drug carriers succesfully deliver a hydrofobic cancer drug into cancer cells. [ABSTRACT FROM AUTHOR]