Synthetic photocrosslinkable polysaccharide sulfates

Methacrylic acid/butyl acrylate onto feruloylated bagasse xylan: Graft copolymerization and biological activity

In this paper, feruloylated bagasse xylan (FBX) was synthesized with a method based on homogeneous catalytic esterification of bagasse xylan (BX) with ferulic acid (FA) in the presence of triethylamine as a catalyst, and it was further grafted with methacrylic acid (MAA) and butyl acrylate (BA) to synthesize FBX-g-MAA/BA grafted copolymer by using ammonium persulfate as initiator and N,N-methylene acrylamide as cross-linker. The effects of reaction variables including reaction time, temperature and reactant concentration on the esterification and graft reactions were investigated carefully by conducting orthogonal tests. A maximum degree of substitution (DS) of 1.76 for the esterification and a maximum graft ratio (GR) of 31% can be achieved by performing the reaction at optimized reaction parameters. The molecular docking was further performed to study the binding mode of the final product into the active site of human Caprin-2 C1q domain (4OUM, cause gastric cancer protein), liver cancer protein (1UV0) and lung cancer protein (3B9S). The software generated results were in satisfactory agreement with the evaluated biological activity. The anticancer performances of BX, FBX and FBX-g-MAA/BA copolymer were investigated by using a 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazoliumbromide (MTT) method. The results indicated that the inhibition ratio of FBX-g-MAA/BA copolymer on BEL-7407 (liver cancer cells) can reach 25.28% ± 4.01%, which is two times higher than that of BX.

Topochemical Engineering of Cellulose-Based Functional Materials

Topochemical engineering is a method of designing the fractionation (disassembly) and fabrication (assembly) of highly engineered functional materials using a combination of molecular and supramolecular techniques. Cellulose is one of the naturally occurring biopolymers, currently considered to be an important raw material for the design and development of sustainable products and processes. This feature article deals with new insights into how cellulose can be processed and functionalized using topochemical engineering in order to create functional fibers, enhance biopolymer dissolution in water-based solvents, and control the shaping of porous materials. Subsequently, topochemical engineering of cellulose offers a variety of morphological structures such as highly engineered fibers, functional cellulose beads, and reactive powders that find relevant applications in pulp bleaching, enzyme and antimicrobial drug carriers, ion exchange resins, photoluminescent materials, waterproof materials, fluorescent materials, flame retardants, and template materials for inorganic synthesis. The topochemical engineering of biopolymers and biohybrids is an exciting and emerging area of research that can boost the design of new bioproducts with novel functionalities and technological advancements for biobased industries.

Photoresponsive cellulose fibers by surface modification with multifunctional cellulose derivatives

Eucalyptus bleached kraft pulp fibers were modified by adsorption of novel bio-based multifunctional cellulose derivatives in order to generate light responsive surfaces. The cellulose derivatives used were decorated with both cationic groups (degree of substitution, DS of 0.34) and photoactive groups (DS of 0.11 and 0.37). The adsorption was studied by UV-vis spectroscopy, surface plasmon resonance (SPR) and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). The adsorption isotherms followed the Freundlich model and it turned out that the main driving force for the adsorption was electrostatic interaction. Moreover, strong indications for hydrophobic interactions between the fibers and the derivatives and the derivatives themselves were found. ToF-SIMS imaging revealed an even distribution of the derivatives on the fiber surfaces. The modified fibers underwent fast photocrosslinking under UV-irradiation as demonstrated by light absorbance and fluorescence measurements. Thus, our results proved that the modified fibers exhibited light-responsive properties and can potentially be used for the manufacture of smart bio-based materials.

Receptor-targeted iron oxide nanoparticles for molecular MR imaging of inflamed atherosclerotic plaques

In a number of literature reports iron oxide nanoparticles have been investigated for use in imaging atherosclerotic plaques and found to accumulate in plaques via uptake by macrophages, which are critical in the process of atheroma initiation, propagation, and rupture. However, the uptake of these agents is non-specific; thus the labeling efficiency for plaques in vivo is not ideal. We have developed targeted agents to improve the efficiency for labeling macrophage-laden plaques. These probes are based on iron oxide nanoparticles coated with dextran sulfate, a ligand of macrophage scavenger receptor type A (SR-A). We have sulfated dextran-coated iron oxide nanoparticles (DIO) with sulfur trioxide, thereby targeting our nanoparticle imaging agents to SR-A. The sulfated DIO (SDIO) remained mono-dispersed and had an average hydrodynamic diameter of 62 nm, an r(1) relaxivity of 18.1 mM(-1) s(-1), and an r(2) relaxivity of 95.8 mM(-1) s(-1) (37 °C, 1.4 T). Cell studies confirmed that these nanoparticles were nontoxic and specifically targeted to macrophages. In vivo MRI after intravenous injection of the contrast agent into an atherosclerotic mouse injury model showed substantial signal loss on the injured carotid at 4 and 24 h post-injection of SDIO. No discernable signal decrease was seen at the control carotid and only mild signal loss was observed for the injured carotid post-injection of non-sulfated DIO, indicating preferential uptake of the SDIO particles at the site of atherosclerotic plaque. These results indicate that SDIO can facilitate MRI detection and diagnosis of vulnerable plaques in atherosclerosis.