Nanocellulose as Modifier for Hollow Fiber Ultrafiltration PSF Membranes

In the present work, a study was conducted for the first time on the modification of hollow fiber UF PSF membranes by cellulose nanofibrils. Two approaches to membrane modification were analyzed: 1) introduction of CNF into the molding solution; 2) additions of CNF to the internal coagulant. Analysis of the transport properties of the investigated membranes showed that the first approach allows increasing the porosity of hollow fiber PSF membranes, due to which the permeability increases from 82 to 287 l / m2 h bar compared to the original membranes. Rejection of dye Blue Dextran (MM = 69 kg / mole) is reduced by 20%. The addition of CNF to the outside coagulant led to the formation of not only the inside selective layer, but also the outer one, while the permeability increases 1.5 times, and the rejection of the dye also increases from 96 to 99%.

Preparation of Polyacrylonitrile Membranes by Vapor Induced Phase Separation

The porous membranes made of polyacrylonitrile (PAN) were developed by vapor induced phase separation (VIPS) technique. The effect of vapor exposure time on membrane permeability and a porous structure was investigated. All membranes exposed in water vapors have a sponge-like structure in contrast to the finger-like structure of PAN membrane obtained by non-solvent induced phase separation (NIPS) method. The obtained membranes demonstrated water permeance up to 405 kg/m2•h•bar and the retention of Blue Dextran (MW 70 kDa) on the level of 52-83%.

Human Hair Keratin Microspheres Prepared by the Water-In-Oil Emulsion Solvent Diffusion Method for Hydrophilic Drug Carrier

Human hair keratin (HK) was prepared with reducing agent and used in solution to construct microspheres by the simple emulsion solvent diffusion method. The obtained microspheres were observing under scanning electron microscope (SEM). The shape, size distribution and content of microspheres were influenced by W:O ratios. A and 1% w/v keratin solution and 100 mL of oil phase were optimal conditions for fabrication of HK microspheres. The authors studied drug loading efficiency of the HK microspheres by using blue-dextran a model drug and found that the drug loading efficiency as well as releasing profile of blue-dextran were gradually increased by increasing keratin concentration. In conclusion, HK microspheres could be used as hydrophilic carrier molecules for drug delivery system application.

Polymer brush decorated nanoparticles immobilised on polymer monoliths for enhanced biopolymer elution

Polymer monoliths uniformly covered with polymer brush nanoparticles are fabricated and the elution properties investigated with myoglobin and blue dextran.

A THERMOPHILIC MICROBE PRODUCING DEXTRANASE FROM HEATED SUGAR CANE

A thermophilic aerobe microorganism designated NP4, was isolated from the heated sugar cane. It grew on dextran, and produced a thermoactive extracellular dextranase. Screening and isolation was done by assay of dextranase activity semi quantitatively on solid medium containing blue dextran. It provided several colonies with different morphology exhibited decolourized zones around, on culture plates containing blue dextran 2000R. The screening resulted in isolation of one microbe which efficiently assimilate dextran as carbon source. Dextranase production from the choised strain in liquid medium was conducted at room temperature for 8 hours with shaking speed of 125 rpm. The dextranase enzyme showed optimum pH of 8 and optimum temperature of 60 oC. Keywords: thermophilic aerobe, sugar cane, dextranase activity.

Partitioning of charged and neutral dextran-dye derivatives in biphasic cellulose nanocrystal suspensions

The partitioning behaviour of dye-labeled dextrans of high molecular weight in aqueous suspensions of native cellulose nanocrystals was studied. Cellulose concentrations lie in the isotropic–nematic coexistence region. Blue dextrans of various molecular weights and degrees of substitution of dye molecules (anionic Cibacron blue 3G-A) were investigated. Increasing the total concentration of blue dextran and degree of dye substitution led to increasing partition coefficients. Increasing dextran molecular weight resulted in higher partition coefficients, in agreement with theory. Partition coefficients were larger than predicted theoretically using a second virial coefficient approximation. Electrostatic and entropic contributions to the partition coefficient of blue dextran are discussed. Dextrans labeled with neutral fluorescein isothiocyanate did not partition preferentially in this system.Key words: partition coefficient, cellulose nanocrystals, dextrans, degree of substitution, polyelectrolyte.