Multifunctional wool fiber treated with ɛ-polylysine

Fabrication of norepinephrine and ε-polylysine engineered magnetic nanocomposites tailored for phosphopeptides analysis

Protein phosphorylation is a highly prevalent post-translational modification that holds a vital position in numerous physiological processes. Prior to mass spectrometry detection, the enrichment of phosphopeptides is critically significant due to their susceptibility to interference from abundant non-phosphopeptides. In this study, the magnetic nanocomposite (Fe3O4@NE@PL) was successfully synthesized and characterized. Fe3O4@NE@PL exhibited strong hydrophilicity, electrophilicity and intermolecular interactions through hydrogen bonds, enabling it to effectively enrich phosphopeptides with excellent sensitivity (0.4 fmol β-casein) and selectivity (β-casein:BSA=1:1000). In addition, Fe3O4@NE@PL was successfully applied to enrich phosphopeptides from complex real biological samples such as human serum and saliva, achieving up to 4 recycles with favorable stability and reusability. This study demonstrates that Fe3O4@NE@PL is a promising adsorbent for phosphopeptides enrichment in proteomics research, providing new ideas for the construction of magnetic enrichment materials.

Modification of wool fibre's structural properties as a cheap adsorbent for the elimination of Cr6+ and Rhodamine6g dye from aqueous solution

Wool, a naturally occurring biopolymer made up of amino acids, is employed as an adsorbent for both modified and unmodified forms of the dyes rhodamine6G (R6G) and Cr6+. The two-step procedure of (i) ring opening polymerization (ROP) and (ii) condensation reaction was used to modify the structure of wool fibre. Both the ROP and the condensation provide steric free chain expanding groups as well as adsorption-improving groups. The FT-IR spectrum, which showed peaks about 1725 and 1630 cm-1 corresponding to the CO and CN stretchings, respectively, confirmed the structural modification. By detecting a slight hump at 8.5 ppm, 1H NMR was able to validate the later functional group. DSC, TGA, FE-SEM, EDX, and water contact angle (WCA) were also used to characterize it. With the aid of a UV-visible spectrophotometer, the quantitative adsorption of both Cr6+ and R6G by modified and unmodified Wool fibre was monitored. For the adsorption of Cr6+ and R6G, the pseudo first order and pseudo second order kinetics were used. The multilayer coating of adsorbate onto adsorbent was confirmed by the Langmuir adsorption isotherm. Thermodynamic parameters were calculated and compared to values found in the literature.

Fiber Surface/Interfacial Engineering on Wearable Electronics

Surface/interfacial engineering is an essential technique to explore the fiber materials properties and fulfil new functionalities. An extensive scope of current physical and chemical treating methods is reviewed here together with a variety of real-world applications. Moreover, a new surface/interface engineering approach is also introduced: self-assembly via π-π stacking, which has great potential for the surface modification of fiber materials due to its nondestructive working principle. A new fiber family member, metal-oxide framework (MOF) fiber shows promising candidacy for fiber based wearable electronics. The understanding of surface/interfacial engineering techniques on fiber materials is advanced here and it is expected to guide the rational design of future fiber based wearable electronics.

Enzymatic preparation of oxidized viscose fibers-based biosorbent modified with ε-polylysine for dyes removal and microbial inactivation

A novel fiber-based biosorbent for dyes removal and microbial inactivation was prepared by enzymatic oxidization of viscose fibers and further modification with ε-polylysine. Glucose oxidase (GOx) was first employed as the enzyme for oxidation of viscose fibers. The consequences illustrated that the hydroxyl group on C1 position of viscose fibers was successfully oxidized with oxidation ratio of 2.43 ± 0.31%. Subsequently, ε-polylysine with average molecular weight of 4.44 ± 1.13 KDa and antimicrobial activity to E. coli of 90.48 ± 1.64 was modified with oxidized viscose fibers by lipase. Experimental results showed that oxidized viscose fibers were successfully modified with ε-polylysine with optimum degree of modification (DM) of 13.56 ± 1.05%. This oxidized viscose fiber modified with ε-polylysine (OVF-PL) displayed good dyes adsorption (or dyes removal) capacity for both anionic and cationic dyes, especially for anion dyes. Furthermore, OVF-PL showed excellent antimicrobial activity against E. coli and B. subtilis, particularly for E. coli, with GIB of 92.65%. Such fiber-based may offer a new pathway for preparing economical and efficient biosorbent for environmental remedy purpose.

Preparation of Antibacterial Cellulose Paper Using Layer-by-Layer Assembly for Cooked Beef Preservation at Ambient Temperature

Positively-charged ε-poly(l-lysine) (ε-PL) and negatively-charged carboxymethyl cellulose (CMC) were alternately deposited on a cellulose paper surface by the layer-by-layer (LBL) assembly technique. The formation of ε-PL/CMC multilayers was confirmed by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FTIR), and zeta potential measurement. The morphologies of the multilayer-modified cellulose paper were observed by scanning electron microscopy (SEM). The ε-PL/CMC multilayers effectively improved not only the antibacterial activity of cellulose paper against both Escherichia coli and Staphylococcus aureus, but also the cellulose paper tensile strength property. Cellulose paper modified with a (ε-PL/CMC)4.5 multilayer exhibited the strongest antibacterial activity, selected for preserving cooked beef for nine days at ambient temperature, could extend the shelf-life of beef for about three days compared with common commercial PE films. The prepared antibacterial paper did not show any evidence of the cytotoxic effect since it could not increase the cytoplasmic lactate dehydrogenase release from L-929 fibroblast cells in contact with the antibacterial paper, suggesting the possibility of utilization in food packaging field.

Layer-by-layer assembled hydrophobic coatings for cellulose nanofibril films and textiles, made of polylysine and natural wax particles

Herein we present a simple method to render cellulosic materials highly hydrophobic while retaining their breathability and moisture buffering properties, thus allowing for their use as functional textiles. The surfaces are coated via layer-by-layer deposition of two natural components, cationic poly-l-lysine and anionic carnauba wax particles. The combination of multiscale roughness, open film structure, and low surface energy of wax colloids, resulted in long-lasting superhydrophobicity on cotton surface already after two bilayers. Atomic force microscopy, interference microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy were used to decouple structural effects from changes in surface energy. Furthermore, the effect of thermal annealing on the coating was evaluated. The potential of this simple and green approach to enhance the use of natural cellulosic materials is discussed.