betadex and acrylic-acid

In this work, novel sodium alginate-based double-network hydrogel beads were prepared and applied for the water-retention and slow release of fertilizers (WSF). The WSF beads were prepared by ion-crosslinking and the free radical polymerization of acrylic acid, acrylamide, and polymerizable β-cyclodextrin in the presence of urea-loaded halloysites. The WSF beads were characterized using SEM, FTIR, and TGA. Their swelling capacity and water retention were measured by a weighing method and their slow-release behavior was studied by spectrophotometry. The water retention and slow release results showed that the fertilizer displayed improved urea release and water retention properties, indicating that halloysite nanotubes clearly improved the performance of fertilizers. In addition, the experimental data of the slow release of urea in water and soil better fitted the Korsmeyer-Peppas model compared with the Higuchi model, a zero-order model or a first order mode. The release behavior of the fertilizer beads followed a Fickian diffusion mechanism.

Topics: Acrylamide; Acrylates; Alginates; beta-Cyclodextrins; Clay; Fertilizers; Hydrogels; Hydrogen-Ion Concentration; Nanotubes; Polymerization; Spectroscopy, Fourier Transform Infrared; Water

To fabricate thermo- and pH-sensitive hydrogels functionalized with β-cyclodextrin (β-CD) moieties, β-CD polymer bearing methacrylate (CDP-g-GMA) used as a reactive and functional crosslinker was synthesized, and then copolymerized with N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) in aqueous solution via UV-initiated free radical polymerization. The stimulus-responsiveness of the resultant hydrogels has been carried out by measuring the swelling ratio at different temperatures and pH values. The results showed that the thermo- and pH-sensitivities of the produced hydrogels were significantly dependent on the compositions of the hydrogels, and the dual sensitivities exhibited good reversible process. The interior morphology observed by SEM exhibited that the pore size of the hydrogels could be tailored by pH of the local medium. Using a water-soluble cationic dye methyl violet (MV) as a model drug, MV loading and release profiles of the hydrogels as potential drug controlled release carriers were evaluated. The MV release rate from CD-functionalized hydrogels was much slower than that from the hydrogel without β-CDs at both pH 2.0 and pH 7.4. The release of MV from CD-functionalized hydrogels at pH 2.0 was faster than that at pH 7.4, the release kinetics of MV from the CD-functionalized hydrogels displayed a sustained release profile, and the release mechanism followed Fickian diffusion.

Topics: Acrylamides; Acrylates; beta-Cyclodextrins; Cross-Linking Reagents; Drug Carriers; Gentian Violet; Hydrogels; Hydrogen-Ion Concentration; Methacrylates; Molecular Structure; Particle Size; Temperature

A novel biodegradable β-cyclodextrin/acrylic acid/sodium alginate (CSA) hydrogel with a three-dimensional network structure was self-assembled by inverse suspension copolymerization. The CSA resin was pH sensitive and had good water absorption properties in pH 6-8 buffer solutions. At a β-CD:AA:SA mass ratio of 1:9:3 the CSA water absorbency was found to be 1403 g/g and the CSA hydrogel strength was 4.968 N. In 0.005-0.1 mol/L chloride salt and sulfate salt solutions the CSA water absorbencies increased as follows: NaCl>KCl>MgCl2>CaCl2>FeCl3, and Na2SO4>K2SO4>FeSO4>Al2(SO4)3, respectively. The release of water from the CSA hydrogel occurred slowly over 120 h. The biodegradation efficiency of the resin reached 85.3% for Lentinula edodes. The super water absorbency, good salt resistance and excellent water retention properties of CSA make it suitable for application as an agricultural water retention agent in saline soils.

Topics: Acrylates; Alginates; beta-Cyclodextrins; Glucuronic Acid; Hexuronic Acids; Hydrogel, Polyethylene Glycol Dimethacrylate; Sodium Chloride; Solutions; Spectroscopy, Fourier Transform Infrared; Water

A novel molecularly imprinted photonic polymer (MIPP) using maleic anhydride modified β-cyclodextrin (β-CD) and acrylic acid as functional monomers has been presented for amino acid sensing. Reactive β-CD monomer carrying vinyl carboxylic acid functional groups was first synthesized. MIPP was fabricated by filling precursor solution into the interstitial spaces of polystyrene photonic crystal templates, followed by a thermal polymerization at 55 °C. Characterization showed that the MIPP possessed an opal photonic crystal structure. This β-CD-based MIPP could undergo a swelling change from 590 nm to 704 nm and still retain the molecular imprinting recognition ability during the sensing of L-phenylalanine (L-Phe). A function relationship was found between the diffraction wavelength shift and the logarithm of L-Phe concentration in the range of 10(-8)M to 10(-4)M at pH 6. A wavelength shift of 114 nm for L-Phe was observed within 30s, whereas there were no obvious shifts for d-Phe, L-tyrosine and L-tryptophan, indicating that the β-CD-based MIPP had high specificity and rapid response to L-Phe. The developed MIPP sensor has been applied to detect L-Phe in compound amino acid injection sample.

Topics: Acrylates; beta-Cyclodextrins; Crystallization; Hydrogen-Ion Concentration; Maleic Anhydrides; Molecular Imprinting; Phenylalanine; Photons; Polymerization; Polystyrenes; Sensitivity and Specificity; Stereoisomerism; Temperature

Poly(hydroxyethyl methacrylate) (pHEMA) hydrogels were functionalized with pendant alpha-, beta- and gamma-cyclodextrins (CD) with the aim of improving the biocompatibility and increasing the ability to host drug molecules. Pendant alpha-, beta- and gamma-CDs did not affect swelling of the hydrogels but slightly decreased the water contact angle. Protein deposition was notably dependent on the nature of the CD, due to their different affinities for hydrophobic moieties of proteins. Lysozyme and albumin sorption was hindered by gamma-CD. Functionalization with beta-CD also reduced protein sorption, although less so, while alpha-CD decreased lysozyme deposition but enhanced albumin sorption compared with control pHEMA hydrogels. Loading of the hydrogels with miconazole was carried out by immersion in drug suspension followed by autoclaving. Functionalization with gamma-CD doubled the affinity of the network for the drug and resulted in the highest amount loaded (up to 170 mgg(-1)). Sustained delivery was observed for several days. Some miconazole-loaded hydrogels completely prevented Candida albicans biofilm formation as assayed in an in vitro microbiological test.

Topics: Acrylates; Adsorption; Albumins; alpha-Cyclodextrins; Antifungal Agents; beta-Cyclodextrins; Biocompatible Materials; Biofilms; Candida albicans; Drug Delivery Systems; gamma-Cyclodextrins; Hydrogels; Materials Testing; Miconazole; Microbial Sensitivity Tests; Muramidase

The surface behavior of monoacylated beta-cyclodextrins, with hydrocarbon chains of 16, 14, and 10 carbons, has been assessed by the measurement of the surface pressure, surface (dipole) potential, optical reflectivity, and surface topography in monolayers at the air-water interface. For all the derivatives studied, the intermolecular organization adopted along compression-decompression isotherms reveals a rich variety of packing states which imply profound reorganization of the hydrophobic and hydrophilic moieties of the beta-cyclodextrin derivatives in the film, depending on the lateral surface pressure. The intermolecular arrangements are consistent with the adoption of a different and defined orientation of the cyclic oligosaccharide unit, relative to the interfacial plane and the aqueous subphase. This is different from the behavior of the per-substituted derivatives, and none of the changes exhibited by the monosubstituted forms are consistent with the oligosaccharide ring remaining in a fixed orientation along the interface when the surface pressure is varied.

Topics: Acrylates; Air; beta-Cyclodextrins; Hydrocarbons; Microscopy, Electron; Models, Molecular; Molecular Structure; Pressure; Surface Properties; Water