Pectin-blended anionic polysaccharide films for cationic contaminant sorption from water.

Substantial amounts of industrial, agricultural, medical and domestic water worldwide are polluted by different types of contaminants. Removing these contaminants from effluent by adsorbent materials made from abundant, inexpensive polysaccharides is a feasible and promising approach to deal with this problem. In the present study, pectin blended with four other types of anionic polysaccharides, including alginate, carrageenan, xylan and xanthan, were crosslinked with zinc acetate and formed into thin films. In addition, a negatively charged polyelectrolyte, poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSMA) was coated on the film surface with the goal of increasing the capture of cationic contaminants. The average film thickness was measured by a digital micrometer. Surface morphologies and element analysis were obtained by energy dispersive spectroscopy connected with scanning electron microscopy. The swelling ratio and the mechanical properties of the films were investigated in relationship to their composition and PSSMA coating. The sorption of model cationic pollutants clearly improved for coated films and showed to be predominantly based on the interaction of positively and negatively charged groups between film/coating and contaminants.

The effect of ethanol on hydroxyl and carbonyl groups in biopolyol produced by hydrothermal liquefaction of loblolly pine: (31)P-NMR and (19)F-NMR analysis.

The goal of this study was to investigate the role of ethanol and temperature on the hydroxyl and carbonyl groups in biopolyol produced from hydrothermal liquefaction of loblolly pine (Pinus spp.) carried out at 250, 300, 350 and 390°C for 30min. Water and water/ethanol mixture (1/1, wt/wt) were used as liquefying solvent in the HTL experiments. HTL in water and water/ethanol is donated as W-HTL and W/E-HTL, respectively. It was found that 300°C and water/ethanol solvent was the optimum liquefaction temperature and solvent, yielding up to 68.1wt.% bio-oil and 2.4wt.% solid residue. (31)P-NMR analysis showed that biopolyol produced by W-HTL was rich in phenolic OH while W/E-HTL produced more aliphatic OH rich biopolyols. Moreover, biopolyols with higher hydroxyl concentration were produced by W/E-HTL. Carbonyl groups were analyzed by (19)F-NMR, which showed that ethanol reduced the concentration of carbonyl groups.

Scaffold materials from glycosylated and PEGylated bovine serum albumin.

Bovine serum albumin has been PEGylated and glycosylated to create mimetic materials for the extracellular matrix (ECM) with potential tissue engineering applications. Different surfaces for cell adhesion were achieved by crosslinking the initial albumin product and forming either a coating or a sponge-like three-dimensional morphology to mimic the mesh structure of natural ECM. The biocompatibility of the albumin matrix with mammalian cells was evaluated using cell culture assays with NIH 3T3 cells. The results indicated that glycoprotein composition and specific morphology of the assembly can improve the cell growth environment. These ECM mimetic structures might eventually be considered to serve as alternatives for the more expensive collagen and elastin based ECM substances currently in use in tissue engineering.

Functionalized poly(L-lactide) nanoparticles from electrospun nanofibers.

Crystalline poly(L-lactide) (PLLA) nanoparticles were prepared by aminolysis of electrospun PLLA nanofibers and subsequently labeled by a fluorescent colorant. The size of the nanoparticles could be controlled by either the conditions of the aminolysis reaction or the diameter of the original electrospun fiber. The latter method resulted in higher yield. Although the as-spun nanofibers were generally amorphous, the nanoparticles showed high crystallinity in the typical α-form of PLLA crystals, as revealed by X-ray diffraction and differential scanning calorimetry. Gel-permeation chromatography was used to determine the molecular weight of the formed particles in relation to aminolysis time. After aminolysis, PLLA nanoparticles spontaneously generated amine groups on the surface, which are available for further modifications. In this study the amine groups were reacted with isothiocyanate groups, and fluorescein-5'-isothiocyanate was successfully attached to the PLLA nanoparticles. Smaller particles showed significantly higher fluorescein binding density. Through this simple 'top-down' routine, it was possible to create nanoparticles with tailorable size and specific surface functions. Such materials could serve in bioimaging or nanomedicine applications.