Cyanobacterial Ampholyte Hydrogels Developed by the Cationization of Sulfated Polysaccharides and Their Cell-Compatibility.

Sacran is a cyanobacterial supergiant polysaccharide with carboxylate and sulfate groups that exhibits antiallergic and antiinflammatory properties. However, its high anionic functions restrict cell compatibility. Quaternary ammonium groups were substituted to form sacran ampholytes, and the cell compatibility of the cationized sacran hydrogels was evaluated. The cationization process involved the reaction of N-(3-chloro-2-hydroxypropyl)trimethylammonium chloride with the primary amine or hydroxyl groups of sacran. The degree of cationization ranged from 32 to 87% for sugar residues. Hydrogels of sacran ampholytes were prepared by annealing their dried sheets by thermal cross-linking; these hydrogels exhibited anisotropic expansion properties. The water contact angle on the hydrogels decreased from 26.5 to 15.3° with an increase in the degree of cationization, thereby enhancing hydrophilicity. The IC50 values of sacran ampholytes decreased with an increased degree of cationization, resulting in a reduction in cytotoxicity toward the L-929 mouse fibroblast cell line. This reduction was associated with an increase in the cell proliferation density after 3 days of incubation. Scanning electron microscopy images showed fibroblast intercellular connections. Therefore, the sacran ampholyte hydrogel exhibited increased hydrophilicity and cell compatibility, which is beneficial for various biomedical applications.

Structural Analyses of Polysaccharides Extracted from Cyanobacterial Extracellular Gels and Oriented Liquid Crystalline Microfiber Processing by Poly(vinyl alcohol)-Assisted Electrospinning.

Sacran is a supergiant cyanobacterial polysaccharide that forms mesogenic supercoil rods that exhibit liquid crystalline (LC) gels at deficient concentrations of around 0.5 wt%, and has several bioactive stimuli-responsive functions. Here, we attempted to form oriented microfibers of sacran by electrospinning, following structural analyses of the sacran rods. A heterogeneous acid-hydrolysis method using a protonated cation-exchange resin was adopted to examine the short-time exposition of concentrated acid to sacran rods. From the supernatant, the oligomeric fraction that was soluble in water and methanol was isolated. The oligomeric fraction had a main sugar ratio of α-Glc:ß-Glc:α-Xyl:ß-Xyl:α-Rha of 2:5:1.5:1.5:4 (Glc:Xyl:Rha = 7 (=4 + 3):3:4), and it was speculated that the sacran structure includes rhamnoglucan and xyloglucan (4:3), which are generally rigid enough to exhibit LC. To make oriented microfibers of LC sacran, solubility testing was performed on sacran to find good new solvents of polyhydroxy alcohols such as ethylene glycol, 1,2-propanediol, and glycerol. The oriented film was prepared from a sacran aqueous solution where calcium compound particles deposited on the film are different from polyhydroxy alcohol solutions. Although sacran could not form microfibers by itself, polymer composite microfibers of sacran with poly(vinyl alcohol) were prepared by electrospinning. Cross-polarizing microscopy revealed the molecular orientation of the microfibers.

Metal-Assisted Injection Spinning of Ultra Strong Fibers from Megamolecular LC Polysaccharides.

The molecular orientation of liquid crystalline (LC) hydrogels has the potential to induce a range of functionalities that can deliver great mechanical strength. Sacran is a supergiant LC polysaccharide isolated from the cyanobacterium Aphanothece sacrum with a high amount of anionic functional groups such as sulfates and carboxylates. In this article, ultra-strong sacran hydrogels and their dried fibers were produced by cross-linking under injection flow with trivalent metal ions such as Al3+, Cr3+, Fe3+, In3+, and rare-earth metal ions such Er3+ and Sr3+. Crossed-polarizing microscopy and X-ray diffraction imaging revealed a uniaxial molecular orientation in the LC gel fiber, resulting in outstanding mechanical characteristics.

Dataset of various characterizations for novel bio-based plastic poly(benzoxazole-co-benzimidazole) with ultra-low dielectric constant.

The data presented in this specified data article comprise of various characterization such as: structural, thermal, elemental etc. to understand the novel structure and specific properties of the bio-based plastic as described in the main research article "High-performance poly (benzoxazole/benzimidazole)bio-based plastics with ultra-low dielectric constant from 3-amino-4-hydroxybenzoic acid" [1]. The data of 1H NMR spectra of two monomers and their HCl salt formation required for polymerization, FT-IR spectra of polymer formation before and after thermal ring-closing and additionally supported by the thermogravimetric plots where mass loss due to water is observed around 400 °C (thermal ring closing temperature). Solvent plays effective role to change dielectric properties significantly, complete removal of the remaining solvents was confirmed by X-ray photoelectron spectroscopy (XPS) technique. Wide-angle XRD dataset was presented here to make an idea about degree of crystallinity of the prepared polymers.

Simultaneous Hardening/Ductilizing Effects of Cryogenic Nanohybridization of Biopolyamides with Montmorillonites.

We prepared organic/inorganic bionanohybrid resins of polyamides containing pyrrolidone in the backbone derived from the salt monomers of an itaconic acid biomolecule with various nanofillers, montmorillonites (MMTs), by cryogenic nanohybridizations. The nanohybridizations with MMTs hardened and strengthened the polypyrrolidone bioplastic resins owing to a simple reinforcement of hard filler incorporation. On the other hand, the elongation at break of the resins is unexpectedly increased by the nanohybridization with MMT sodium salt (NaMMT) to enhance the strain energy density, which differed from those of the nanohybrids with other organically modified MMTs. From spectroscopic analyses, we discuss the mechanism of such ductilization effects by NaMMT, the catalytic effect of NaMMT on partially opening the pyrrolidone ring to make polymer backbones flexible and to form carboxyl side chains that are strongly interactive with NaMMT fillers.

(1)H NMR and FT-IR dataset based structural investigation of poly(amic acid)s and polyimides from 4,4'-diaminostilbene.

Structural investigation of polymers by various available analytical methods is important in order to correlate the structure with polymer properties for which understanding of polymer structure is very important factor. The data presented here in this article shows the (1)H NMR spectra used for the characterization of prepared poly(amic acid)s (PAAs). It is often difficult to assigns the peak in NMR of polymers due to its complexity. Data presented here helps in assigning the proton peak in complex NMR of PAAs prepared from aromatic diamines. Further functionality in polymer chains can be confirmed by FT-IR spectra. Change in functionality during some reaction or process can be monitored by disappearance or appearance of peaks in FT-IR. The complete imidization of PAAs to Polyimides (PIs) is difficult to analyze because of the chemical stability i.e. insolubility of PIs in most of the solvent therefore the completion of imidization process was confirmed using FTIR.