Brinchchang6882

In this work we present a simple, inexpensive, and easily scalable industrial paper process to prepare sheets of conductive cellulose fibers coated with polyanilines. First, bare fibers were coated by in situ oxidative polymerization of polyaniline then, the resulting composite fibers were used to fabricate electroactive sheets. https://www.selleckchem.com/products/hpk1-in-2.html The resistivity of the sheets is 14 ± 1 Ω sq-1, a value around 1000 times lower than those reported in literature. The superior electronic proprieties of the sheets were demonstrated by assembling a capacitive touch sensor device with optimized geometry. The touch sensor shows an increase of 3-4 % of the starting electric capacity after compression and a fast response time of 52 ms. To our knowledge this is the first time that a device is prepared in this way and therefore, the herein presented results can bring an significant improvement in the development of low-cost, green and high-tech electronic devices.Exopolysaccharides (EPS) produced by cyanobacteria are complex biomolecules of anionic nature with potential biomedical applications. In this study, the EPS produced by the Nostoc sp. strains PCC7936 and PCC7413 were characterized and evaluated as a biomaterial for new wound dressings. The addition of acetate ions to the culture medium slightly stimulated EPS production, achieving 1463.1 ± 16.0 mgL-1 (PCC7413) and 1372.1 ± 29.0 mgL-1 (PCC7936). Both EPS presented nine monosaccharide residues and a MW > 1000 kDa. The acetate addition changed the monosaccharide molar percentages. FTIR and DLS results confirmed the anionic nature and the presence of sulfate groups in both EPS, which are determinant features for biomedical applications. Both EPS at 1%(w/v) formed gels in the presence of 0.4%(w/v) FeCl3. Results obtained for MTT assay and wound healing in vitro scratch assay revealed hydrogels biocompatibility and ability to promote fibroblast migration and proliferation that was greater in PCC7936. The Nostoc EPS hydrogels presented promising properties to be applied in the treatment of skin injuries.Currently, special emphasis is being given to the design and fabrication of antibacterial nanocomposite hydrogels for wound dressing applications. Herein, we report the synthesis and characterization of hydroxypropyl methylcellulose (HPMC) reinforced with HPMC capped copper nanoparticles (HCu NPs) based nanocomposite hydrogel films (NHFs). Spherical nanostructures of HCu NPs (∼40 nm) were achieved by facile precipitation technique using ascorbic acid as a nucleating agent and subsequently made their NHFs via solution casting method. Spectral, thermal and structural characteristics of the developed materials were carried out. Antibacterial activity of the resultant NHFs showed the MIC and MBC values of 350 and 1400 μg/mL for S. aureus, and 500 and 2000 μg/mL for E. coli, respectively. These results conveyed that the HCu NPs incorporated HPMC NHFs can be used effectively in antibacterial applications.Naturally derived antimicrobial peptides (AMPs) are an attractive source of new antimicrobial agents. However, clinical application of AMPs is associated with poor bioavailability and toxicity. In this study, we address these limitations by designing a new series of chitosan derivatives to mimic the amphiphilic topology of AMPs. The synthesized chitosan derivatives were found to self-assemble into nanoparticles in the aqueous environment. Among the compounds, a chitosan derivative grafted with arginine and oleic acid (CH-Arg-OA) exhibited the most potent antimicrobial activity, especially against Gram-negative bacteria. It also caused minimal cell death when tested in HEK293 and HepG2 cell lines, thus confirming the role of cationicity and lipophilicity for selective bacteria targeting. CH-Arg-OA exhibited its antimicrobial activity by disrupting bacterial membranes and causing the leakage of cytoplasmic contents. Thus, amphiphilic chitosan nanoparticles offer a great promise as a new class of AMPs mimics that is effective against Gram-negative bacteria.As a flexible material, hydrogels have attracted considerable attention in the exploration of various wearable sensor devices. However, the performance of the existing hydrogels is often too single, which limits its further application. Here, a conductive hydrogel with adhesiveness, toughness, self-healing and anti-swelling properties was successfully prepared by adding 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) to the polyacrylic acid/ferric ionic (PAA/Fe3+) cross-linking system. Based on the existence of three types of non-covalent interactions in the hydrogel system, including electrostatic interaction, coordination interaction and hydrogen bonds, the hydrogel possessed excellent mechanical properties (tensile stress and strain were 827 kPa and 1652 %, respectively), self-healing properties (self-healing efficiency reached 83.3 % at room temperature) and anti-swelling properties. In addition, the introduction of HACC also successfully gave the hydrogel outstanding adhesiveness. Moreover, the existence of iron ions provided sensitive conductivity to the hydrogel, which could be used as a flexible sensor for directly monitoring various motions. Therefore, this simple strategy for preparation of multifunctional hydrogels would expand the application of a new generation of hydrogel-based sensors.Replacing polyamide (PA) layer in commercially successful thin film composite (TFC) membranes prepared via interfacial polymerization has been challenging task. Lately, PA is under scrutiny due to its increasing fouling propensity for highly contaminated waters. To mitigate the bio and organic fouling on PA layer in nanofiltration (NF) membranes in a long run, present study attempts to create a new interfacial thin film asymmetric structure using biopolymer chitosan as sustainable alternative. Herein, the effect of chitosan-silver on porous support structure and filtration performance were systematically investigated. Further, the membranes were characterized for their functionality and surface characteristics using ATR-IR, FESEM, AFM, UV-vis spectroscopy and contact angle measurements, respectively. New asymmetric membrane performances in cross flow process were evaluated in terms of pure water flux, NaCl (∼40 %), red brown/organic dye (>98 %) and tannery wastewater flux and rejection (>98 %). With a higher pure water flux (>100 L m-2 h-1) compared to control (40 L m-2 h-1) at 4 bar, membrane showed exceptional antifouling behaviors in comparison to commercial PA membrane. Further, surface characteristics of the membranes before and after rigorous testing were evaluated using AFM micrographs and SEM imaging.A fully biobased benzoxazine monomer, V-fa (using vanillin and furfurylamine) was grafted onto chitosan (CS) at different weight ratios (CXVY) using "grafting to" benign Schiff base chemistry. Incorporation of V-fa onto CS increased the tensile strength and improved chemical resistance of the CS-graft-V-fa films. Reversible labile linkages, expansion of CS galleries and leaching out of phenolic species from biobased polymer films led to an improved antibacterial activity against Staphylococcus aureus, which is ∼125 times higher than the bare CS film, V-fa and oligomeric V-fa. The leached out species from films were analyzed extensively by NMR, FTIR, GPC, ABTS and HRMS analysis. Oxidative-stress seems to be responsible for antibacterial activity. Current work illustrates an attractive synthetic approach and the improved antibacterial performance of biobased CS-graft-poly(V-fa) films which may hold as a potential alternative for wound-healing and implant applications in future.The physicochemical properties and structural changes of potato starch esterified with octenyl succinic anhydride (OSA) assisted with pulsed electric field (PEF) were investigated. Results showed that PEF treatment during esterification resulted in a significant modification of pasting properties. The pasting temperature at 2-6 kV/cm reduced by 7.6-15.1 °C for PEF-assisted OSA starches but only by 3 °C for OSA modified starch without PEF treatment as compared to that of native starch. PEF-assisted esterification could reduce the reaction time and improve the reaction efficiency over the control by 6.1-39.1 %. A novel schematic model on structure-functionality relationship for PEF-assisted OSA modified starch was proposed. Structural disorganizations of starch induced lower pasting temperature and paste viscosity. The results suggest that PEF could be a potential eco-friendly and cost-effective physical technique to prepare starch products with desired paste behaviors and to broaden its application area especially in papermaking and textile industries.Cellulose-lignin composite carbon fibers have shown to be a potential environmentally benign alternative to the traditional polyacrylonitrile precursor. With the associated cost reduction, cellulose-lignin carbon fibers are an attractive light-weight material for, e.g. wind power and automobile manufacturing. The carbon fiber tenacity, tensile modulus and creep resistance is in part determined by the carbon content and the molecular orientation distribution of the precursor. This work disassociates the molecular orientation of different components in cellulose-lignin composite fibers using rotor-synchronized solid-state nuclear magnetic resonance spectroscopy and X-ray scattering. Our results show that lignin is completely disordered, in a mechanically stretched cellulose-lignin composite fiber, while the cellulose is ordered. In contrast, the native spruce wood raw material displays both oriented lignin and cellulose. The current processes for fabricating a cellulose-lignin composite fiber cannot regain the oriented lignin as observed from the native wood.The aim of the present study was to explore the effect of CP and TA on stability of oil in water emulsion stabilized by the two components, so as to fabricate the most efficient chitin based emulsifying agents. It was found that there was synergistic effect for CP and TA in stabilizing emulsion, specifically, the complex of chitin particles (CP) (3 g/L) with tannic acid (TA) (2 g/L) produced the most physically and oxidatively stable oil-in-water emulsion compared with other groups in this study. This is because CP-TA (3/5) complex had the lowest zeta potential, the lowest the oil water interfacial tension, the highest viscosity and the highest content of TA with excellent antioxidant activity. Furthermore, this is because there was intense interaction between CP and TA in CP-TA complex from results of FTIR, XRD and ITC, which then result in the formation of large CP-TA particles.Anti-inflammatory drugs such as dexamethasone (DEX) are commonly administered to cancer patients along with anticancer drugs, however, the effect of DEX on human cancers is poorly understood. In this article, we have tailored self-assembled nanoparticles derived from hyaluronic acid (HA) wherein, anti-inflammatory DEX was used as a hydrophobic moiety for inducing amphiphilicity. The HA-DEX micelles were subsequently loaded with chemotherapeutic agent, doxorubicin (DOX) (HA-DEX-DOX) and was utilized to deliver drug cargo to human cancer cells expressing different levels of CD44 receptors. We found that DEX suppressed the cytotoxicity of DOX in HCT116, while it synergistically enhanced cytotoxicity in MCF-7 cells. When we tested DOX and HA-DEX-DOX in an ex-vivo human whole blood, we found activation of complement and the coagulation cascade in one group of donors. Encapsulation of DOX within the nanoparticle core eliminated such deleterious side-effects. The HA-DEX-DOX also polarized bone-marrow-derived anti-inflammatory M2 macrophages, to pro-inflammatory M1 phenotype with the upregulation of the cytokines TNF-α, iNOS and IL-1β.