Selective Adsorption of Hemoglobin in Human Whole Blood with a Nickel Monosubstituted Silicotungstic Acid Hybrid

A nickel monosubstituted polyoxometalate (POM)/polyaniline organic-inorganic hybrid SiW₁₁Ni/PANI was synthesized using the liquid-phase method at room temperature to achieve the solidification of water-soluble POMs. The SiW₁₁Ni/PANI hybrid was characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, and zeta potential. On the basis of π-π stacking and affinity interaction between the SiW₁₁Ni/PANI hybrid and proteins, the SiW₁₁Ni/PANI hybrid showed good adsorption selectivity to hemoglobin (Hb). At pH 7.0, 0.5 mg of SiW₁₁Ni/PANI resulted in an adsorption efficiency of 92.4% for 1 mL of 100 μg mL^-1 Hb. The adsorption behavior of Hb on the surface of the hybrid fitted with the Langmuir model, and the maximum adsorption capacity was 692 mg g^-1. The adsorbed Hb was eluted by BR (0.04 mol L^-1, pH 9), providing a recovery of 94%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis assay results indicated that the Hb in human whole blood could selectively be adsorbed by the SiW₁₁Ni/PANI hybrid, and the obtained Hb was with high purity. It could expand the application of POMs in life science due to the application of the POM hybrid in protein isolation/purification.

Novel quaternarized N-halamine chitosan and polyvinyl alcohol nanofibrous membranes as hemostatic materials with excellent antibacterial properties

The aim of this study was to develop novel nanofibrous membranes based on the quaternary ammonium N-halamine chitosan (CSENDMH) and polyvinyl alcohol (PVA) for antibacterial and hemostasis wound dressing. To improve the antimicrobial properties of nanofibrous membranes, a new chitosan-quaternary ammonium N-halamine derivative was successfully synthesized, and the structure was analyzed by 1H NMR and 13C NMR, fourier transform infrared (FTIR) spectroscopy, and elemental analysis. The morphological and water absorption ability studies showed that the membrane had a uniform bead-free network and high porosity structure like natural extracellular matrix as well as high hydrophilicity. For in vitro evaluation of the hemostatic effect, the membranes showed excellent blood clotting capacity, especially the PVA/CSENDMH membranes. The antimicrobial assay demonstrated excellent antibacterial activity of nanofibrous membranes against both gram-negative and gram-positive bacteria. Furthermore, the cytocompatibility assay results indicated that human fibroblasts could adhere and proliferate on the membranes, thus corroborating their biocompatibility.

A review on applications of chitosan-based Schiff bases

Biopolymers have become very attractive as they are degradable, biocompatible, non-toxic and renewable. Due to the intrinsic reactive amino groups, chitosan is vibrant in the midst of other biopolymers. Using the versatility of these amino groups, various structural modifications have been accomplished on chitosan through certain chemical reactions. Chemical modification of chitosan via imine functionalization (RR'CNR″; R: alkyl/aryl, R': H/alkyl/aryl and R″: chitosan ring) is significant as it recommends the resultant chitosan-based Schiff bases (CSBs) for the important applications in the fields like biology, catalysis, sensors, water treatment, etc. CSBs are usually synthesized by the Schiff condensation reaction between chitosan's amino groups and carbonyl compounds with the removal of water molecules. In this review, we first introduce the available synthetic approaches for the preparation of CSBs. Then, we discuss the biological applications of CSBs including antimicrobial activity, anticancer activity, drug carrier ability, antioxidant activity and tissue engineering capacity. Successively, the applications of CSBs in other fields such as catalysis, adsorption and sensors are demonstrated.

Preparation of organic–inorganic hybrid membranes with superior antifouling property by incorporating polymer-modified multiwall carbon nanotubes

Schematic illustration of (a) the polymerization of dopamine, and (b) preparation of the PVP-modified MWCNTs.

Synthesis and Antimicrobial Activity of N-(6-Carboxyl Cyclohex-3-ene Carbonyl) Chitosan with Different Degrees of Substitution

Five products of N-(6-carboxyl cyclohex-3-ene carbonyl) chitosan as antimicrobial agents were prepared by reaction of chitosan with tetrahydrophthalic anhydride (THPA) at different degrees of substitution (DS). The antimicrobial activity was evaluated against four plant bacteria and eight fungi. The results proved that the inhibitory property and water solubility of the synthesized chitosan derivatives, with increase of the DS, exhibited a remarkable improvement over chitosan. The product with a DS of 0.40 was the most active one with MIC of 510, 735, 240, and 385 mg/L against Erwinia carotovora, Ralstonia solanacearum, Rhodococcus fascians, and Rhizobium radiobacter, respectively, and also in mycelial growth inhibition against Alternaria alternata (EC50 = 683 mg/L), Botrytis cinerea (EC50 = 774 mg/L), Botryodiplodia theobromae (EC50 = 501 mg/L), Fusarium oxysporum (EC50 = 500 mg/L), F. solani (EC50 = 260 mg/L), Penicillium digitatum (EC50 = 417 mg/L), Phytophthora infestans (EC50 = 298 mg/L), and Sclerotinia sclerotiorum (EC50 = 763 mg/L). These compounds based on a biodegradable and biocompatible chitosan could be used as potentially antimicrobial agents in crop protection instead of hazardous synthetic pesticides.

Quaternized polysulfone and graphene oxide nanosheet derived low fouling novel positively charged hybrid ultrafiltration membranes for protein separation

Low fouling positively charged hybrid UF membranes with adjustable charge density fabricated from a blend of PSf/QPSf and GO nanosheets by solution casting and NIPS method. Cross-section SEM image and observed lysozyme transport values at varied pH.

Synthesis of highly stable and high water retentive functionalized biopolymer-graphene oxide modified cation exchange membranes

Usage of polymer electrolyte membranes in energy based devices is substituting the conventional electrolytes.

Performance of novel a Ag-n-TiO2/PVC reinforced hollow fiber membrane applied in water purification: in situ antibacterial properties and resistance to biofouling

To improve the anti-biofouling properties of membranes, Ag-embedded nano-sized titanium dioxide (Ag-n-TiO₂) particles were utilized as biocidal agents to modify polyvinyl chloride (PVC) membranes.

Chitosan as a sustainable organocatalyst: a concise overview

Increased demand for more sustainable materials and chemical processes has tremendously advanced the use of polysaccharides, which are natural biopolymers, in domains such as adsorption, catalysis, and as an alternative chemical feedstock. Among these biopolymers, the use of chitosan, which is obtained by deacetylation of natural chitin, is on the increase due to the presence of amino groups on the polymer backbone that makes it a natural cationic polymer. The ability of chitosan-based materials to form open-network, macroporous, high-surface-area hydrogels with accessible basic surface sites has enabled their use not only as macrochelating ligands for active metal catalysts and as a support to disperse nanosized particles, but also as a direct organocatalyst. This review provides a concise overview of the use of native and modified chitosan, possessing different textural properties and chemical properties, as organocatalysts. Organocatalysis with chitosan is primarily focused on carbon-carbon bond-forming reactions, multicomponent heterocycle formation reactions, biodiesel production, and carbon dioxide fixation through [3+2] cycloaddition. Furthermore, the chiral, helical organization of the chitosan skeleton lends itself to use in enantioselective catalysis. Chitosan derivatives generally display reactivity similar to homogeneous bases, ionic liquids, and organic and inorganic salts. However, the introduction of cooperative acid-base interactions at active sites substantially enhances reactivity. These functional biopolymers can also be easily recovered and reused several times under solvent-free conditions. These accomplishments highlight the important role that natural biopolymers play in furthering more sustainable chemistry.