Correction: Wound healing properties of hyaluronan derivatives bearing ferulate residues

Correction for 'Wound healing properties of hyaluronan derivatives bearing ferulate residues' by Giuseppe Valacchi et al., J. Mater. Chem. B, 2015, DOI: 10.1039/c5tb00661a

Neoglycoconjugates of Mannan with Bovine Serum Albumin and Their Interaction with Lectin Concanavalin A

Neoglycoconjugates were prepared from mannan isolated from yeast Saccharomyces cerevisiae and activated by periodate oxidation to create aldehyde groups. Various degrees of oxidation introduced 11-28 aldehyde groups per mannan molecule and simultaneously resulted in a molar mass decrease from 46 to 44.5-31 kDa. The activated mannans were subsequently conjugated with bovine serum albumin forming neoglycoconjugates. Some parameters of these mannan-bovine serum albumin conjugates were characterized: saccharide content 25-30% w/w, molar mass within the range 169-246 kDa, and polydispersion (M w /M n ) from 2.8 to 3.6. The interaction of these conjugates with lectin concanavalin A was studied using three different methods: (i) quantitative precipitation in solution; (ii) sorption to concanavalin A immobilized on bead cellulose; and (iii) kinetic measurement of the interaction by surface plasmon resonance. Quantitative precipitation assay showed only negligible differences in the precipitation course of original mannan and the corresponding mannan-bovine serum albumin conjugates. Both the sorption method (equilibrium method) and the surface plasmon resonance measurement (kinetic method) demonstrates that the values of dissociation constant K D of all synthetic neoglycoconjugates were within the range 1

Self-Structuring in Water of Polyamidoamino Acids with Hydrophobic Side Chains Deriving from Natural α-Amino Acids

This paper reports on synthesis, acid-base properties and self-structuring in water of chiral polyamidoamino acids (PAACs) obtained by polyaddition of N,N'-methylenebisacrylamide with L-alanine, L-valine and L-leucine (M-L-Ala, M-L-Val, M-L-Leu) with potential for selective interactions with biomolecules. The polymers maintained the acid-base properties of amino acids. In water, the circular dichroism spectra of PAACs revealed pH-dependent structuring in the range 3-11 and in the wavelength interval 200-280 nm. Taking as reference the values at pH 3, the differential molar ellipticities were plotted in the pH interval 3-11. Sigmoidal curves were obtained presenting inflection points at pH 8.1, 6.8 and 7.3 for M-L-Ala, M-L-Val and M-L-Leu, respectively, corresponding to the amine half-ionization. Theoretical modeling showed that PAACs assumed stable folded conformations. Intramolecular interactions led to transoid arrangements of the main chain reminiscent of protein hairpin motif. Oligomers with ten repeat units had simulated gyration radii consistent with the hydrodynamic radii obtained by dynamic light scattering

Films made from poly(vinyl alcohol-co-ethylene) and soluble biopolymers isolated from postharvest tomato plant

Blended films were obtained from polyvinyl alcohol‐co‐ethylene (EVOH) with 52 kDa weight average molecular weight (Mw) and three water soluble biopolymers isolated from exhausted tomato plants hydrolysates. Two biopolymers contained mainly polysaccharides and had 27 and 79 kDa Mw, respectively. The third contained mainly lignin‐like C moieties and had 392 kDa MW. The films were fabricated with a biopolymer/EVOH w/w ratio ranging from 0.1 to 0.9. All blends had molecular weight and solubility which were substantially different from the starting materials. They were characterized for the chemical nature, and the thermal, rheological, and mechanical properties. Evidence of a chemical reaction between the biopolymers and EVOH was found. Generally, the films exhibited higher mechanical strength but lower strain at break then the neat EVOH. The best performing blended film was fabricated from the 27 kDa Mw polysaccharide. This contained less than 10% biopolymer. It exhibited 1043 MPa Young's modulus and 70% strain at break against 351 MPa modulus and 86% strain for neat EVOH. The results offer scope for investigating biopolymers sourced from other biowastes to understand more the reasons of the observed effects and exploit their full potential to modify or to replace synthetic polymers

Properties of quaternized and cross-linked hydroxyethylcellulose composite films

Although trimetylammonium-2-hydroxypropyl-hydroxyethylcellulose (QHEC) is a well-known polysaccharide material, some of its properties have not been previously studied in detail. Therefore, we applied a combination of multidimensional nuclear magnetic resonance (NMR) in D2O on hydroxyethylcellulose (HEC) and HEC derivatives, and size-exclusion chromatography with multi-angle laser light scattering (SEC-MALS) in carbonate buffer at pH 10; while Fourier-transform infrared spectroscopy (FTIR), the X-ray diffraction (XRD), the thermogravimetry/differential/differential thermogravimetry (TG/DTG/DTA) and atomic force microscopy (AFM) in film form. SEC-MALS revealed various water-solubility of prepared derivatives: HEC (98%) > CHEC (72%) > QHEC (26%) > QCHEC (14%). Due to its substituents, the HEC macromolecule forms coil structures with varying gyration radii: QHEC (38–260 nm) > QCHEC (10–230 nm) > CHEC (21–100 nm) > HEC (23–50 nm). FTIR analysis of all prepared films confirmed their identical structure compared to that observed in liquid form in D2O. Onset temperatures (OT) of films degradation decreased in order: HEC (222 °C) > QCHEC (162 °C) > CHEC (142 °C) > QHEC (141 °C). The X-ray diffraction confirmed residual crystallinity of cellulose II (CII) in all four types of prepared films and was linked to ~ 2% water-insolubility of HEC derivatives revealed by SEC-MALS. Atomic force microscopy (AFM) showed significant differences in surface morphology among the four prepared films with surface roughness of: HEC (25 nm) > QCHEC (5.8 nm) > QHEC (4.2 nm) > CHEC (2.8 nm). Various spherical particles were found in case of HEC, circular depressions/holes approximately 4 μm in diameter were observed in case of QHEC. Except for the HEC, all other films showed granular surface probably due to insoluble components. Based on the mechanisms of quaternization and crosslinking and the results of analysis on water-soluble part and films we could assume that there are similarities in structures between the soluble and insoluble products of the reactions.Ministry of Education, Science, Research and Sport, (2/0071/22)Ministry of Education, Science, Research and Sport of the Slovak Republic; Centre for Scientific and Technical Information of the Slovak Republic; Vedecka Grantova Agentura MSVVaS SR a SAV [2/0071/22

Freely Suspended Cellular “Backpacks” Lead to Cell Aggregate Self-Assembly

Cellular “backpacks” are a new type of anisotropic, nanoscale thickness microparticle that may be attached to the surface of living cells creating a “bio-hybrid” material. Previous work has shown that these backpacks do not impair cell viability or native functions such as migration in a B and T cell line, respectively. In the current work, we show that backpacks, when added to a cell suspension, assemble cells into aggregates of reproducible size. We investigate the efficiency of backpack−cell binding using flow cytometry and laser diffraction, examine the influence of backpack diameter on aggregate size, and show that even when cell−backpack complexes are forced through small pores, backpacks are not removed from the surfaces of cells.National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (Award DMR-08-19762)National Science Foundation (U.S.) (Graduate Research Fellowship)United States. Dept. of DefenseUnited States. Air Force Office of Scientific ResearchHoward Hughes Medical Institute (Investigator)United States. Dept. of Defense (National Defense Science and Engineering Graduate Fellowship 32 CFR 168a

Global conformation analysis of irradiated xyloglucans

Xyloglucan isolated and purified from tamarind seed was subjected to various degrees of γ-irradiation treatments, from 10 to 70 kGy, monitored for radiation damage and then studied using a new combined hydrodynamic approach with regards to conformation and flexibility. Radiation products were analysed with regard to molecular weight (weight average) Mw from size exclusion chromatography coupled to multi-angle laser light scattering (SEC-MALLs), intrinsic viscosity [η] and sedimentation coefficient so20,w. Sedimentation coefficient distributions and elution profiles from SEC-MALLs confirmed the unimodal nature of the molecular weight distribution for each sample in solution. The chain flexibility was then investigated in terms of the persistence length, Lp of the equivalent worm-like chain model. The traditional Bushin-Bohdanecky (intrinsic viscosity) and Yamakawa-Fujii (sedimentation coefficient) relations were used separately then combined together by minimisation of a target function according to a recently published procedure [Ortega, A., & García de la Torre, J. (2007). Equivalent radii and ratios of radii from solution properties as indicators of macromolecular conformation, shape, and flexibility. Biomacromolecules, 8, 2464-2475 [see also Ortega, A. Metodologías computacionales para propiedades en disolución de macromoléculas rígidas y flexibles. Ph.D. Dissertation, Universidad de Murcia, 2005]] and yielded an estimate for Lp in the range 4-9 nm using floated and fixed mass per unit length analysis protocols and "point" global analysis: irradiated xyloglucans behave as flexible structures in common with pressure/heat treated materials. © 2008 Elsevier Ltd. All rights reserved