Rational design of novel water-soluble ampholytic cellulose derivatives

Solvent-free ball milling activation of cellulose for efficient surface modification and pyrolysis

Due to the innate recalcitrancy caused by robust hydrogen bonding interaction, cellulose cannot be easily processed into high-valued materials or chemicals. Herein, a solvent-free ball milling treatment was conducted to activate microcrystalline cellulose (MCC). The research results demonstrated that ball milling treatment rapidly reduced the average particle size (Ð) and crystalline index (CrI) of MCC. Ball milling treatment for 1 h resulted in the Ð and CrI of MCC decreasing from 48 μm and 84.5 % to 23.3 μm and 25.4 %, respectively. Further prolonging the ball milling time from 1 h to 4 h slightly reduced the Ð and CrI of cellulose but led to the degradation of cellulose. Furthermore, the ball milling-activated cellulose (BMC) was chemically modified for preparing polylactic acid (PLA)/modified cellulose (m-BMC) composite films. Benefitting from the decreased Ð and valid surface modification of BMC, the tensile strength and elongation at break of the achieved PLA/m-BMC improved by 77.2 % and 189.3 % compared with the PLA/MCC, respectively. Besides, ball milling for 1 h improved the relative contents of saccharides in the pyrolysis products of cellulose from 33.2 % to 60.4 %. This work provided some basic understanding of ball milling activation of cellulose for further efficient surface modification and pyrolysis.

Sulfonic acid functionalized cellulose-derived (nano)materials: Synthesis and application

The preparation/application of heterogeneous (nano)materials from natural resources has currently become increasingly fascinating for researchers. Cellulose is the most abundant renewable polysaccharide on earth. The unique physicochemical, structural, biological, and environmental properties of this natural biopolymer have led to its increased application in many fields. The more desirable features of cellulose-based (nano)materials such as biodegradability, renewability, biocompatibility, cost-effectiveness, simplicity of preparation, environmentally friendly nature, and widespread range of applications have converted them into promising compounds in medicine, catalysis, biofuel cells, and water/wastewater treatment processes. Functionalized cellulose-based (nano)materials containing sulfonic acid groups may prove to be one of the most promising sustainable bio(nano)materials of modern times in the field of cellulose science and (nano)technology owing to their intrinsic features, high crystallinity, high specific surface area, abundance, reactivity, and recyclability. In this review, the developments in the application of sulfonated cellulose-based (nano)materials containing sulfonic acid (-SO3H) groups in catalysis, water purification, biological/biomedical, environmental, and fuel cell applications have been reported. This review provides an overview of the methods used to chemically modify cellulose and/or cellulose derivatives in different forms, including nanocrystals, hydrogels, films/membranes, and (nano)composites/blends by introducing sulfonate groups on the cellulose backbone, focusing on diverse sulfonating agents utilized and substitution regioselectivity, and highlights their potential applications in different industries for the generation of alternative energies and products.

Synthesis of biomass hyperbranched polyamide resin from cellulose and citric acid for wood adhesive

Traditional wood adhesives have the problems of excessive dependence on fossil resources and environmental pollution. Cellulose, a renewable biomass resource with a low price and huge output, provides a basis for preparing biomass wood adhesives. In this study, a new type of polyamide resin was prepared by modifying microcrystalline cellulose and reacting with natural citric acid. Specifically, toluenesulfonyl cellulose (TS) was synthesized, and functional amino cellulose (AC) was prepared by a nucleophilic substitution reaction with hyperbranched polyamide (HP). Then cellulose-based hyperbranched polyamide resin (CHP) was prepared by polycondensation with citric acid. The structure of CHP resin was investigated by FTIR, XPS, 13C NMR and GPC, and plywood was prepared to study its mechanical properties. Due to the formation of hyperbranched cross-linked network structure inside the resin, the prepared plywood has excellent properties. The dry shear strength reaches 2.24 MPa, and the strength reaches 1.25 and 1.31 MPa after soaking in water at 63 °C and 93 °C for 3 h. The resin in this study has a simple preparation process and excellent performance, which provides a solid foundation for developing high-performance cellulose-based wood adhesives.

Polysaccharides-Based Injectable Hydrogels: Preparation, Characteristics, and Biomedical Applications

Polysaccharides-based injectable hydrogels are a unique group of biodegradable and biocompatible materials that have shown great potential in the different biomedical fields. The biomolecules or cells can be simply blended with the hydrogel precursors with a high loading capacity by homogenous mixing. The different physical and chemical crosslinking approaches for preparing polysaccharide-based injectable hydrogels are reviewed. Additionally, the review highlights the recent work using polysaccharides-based injectable hydrogels as stimuli-responsive delivery vehicles for the controlled release of different therapeutic agents and viscoelastic matrix for cell encapsulation. Moreover, the application of polysaccharides-based injectable hydrogel in regenerative medicine as tissue scaffold and wound healing dressing is covered.

Coupling of 3-Aminopropyl Sulfonic Acid to Cellulose Nanofibers for Efficient Removal of Cationic Dyes

A novel anionic nanostructured cellulose derivate was prepared through the coupling of TEMPO-oxidized cellulose nanofibers with 3-aminopropyl sulfonic acid (3-APSA). 3-APSA grafting was variously investigated by FT-IR spectroscopy and transmission electron microscopy (TEM) analysis, confirming a high reaction degree. The surface morphology investigated via scanning electron microscopy (SEM) revealed a more uniform organization of the nanofibers after the 3-APSA coupling, with improvements in terms of fiber packing and pore interconnectivity. This peculiar morphology contributes to improving methylene blue (MB) adsorption and removal efficiency at different operating conditions (pH, initial time, and initial concentration). The results indicated a maximum adsorption capacity of 526 mg/g in the case of 3-APSA grafted nanofibers, over 30% more than that of non-grafted ones (370 mg/g), which confirm a relevant effect of chemical modification on the adsorbent properties of cellulose nanofibers. The adsorption kinetics and isotherms of the current adsorbents match with the pseudo-second-order kinetic and Langmuir isotherm models. This study suggests the use of chemical grafting via 3-APSA is a reliable and facile post-treatment to design bio-sustainable and reusable nanofibers to be used as high-performance adsorbent materials in water pollutant remediation.

Simple Strategy Preparing Cyclodextrin Carboxylate as a Highly Effective Carrier for Bioactive Compounds

Many phytochemicals suffer from poor water dispersity and storage stability, which restrict their application within aqueous-based commercial products. β-Cyclodextrin (β-CD) is a water-dispersible molecule with a hydrophobic core that can encapsulate and protect non-polar substances. The functional attributes of β-CD can be further enhanced by chemical modification. In this study, a simple and effective dry-heating process was applied to fabricate succinic acid (SA)-modified β-CD (SACD) through esterification. SACD showed better encapsulation property than non-modified β-CD to guest molecules such as methyl orange (up to 1.41-folds of β-CD) and curcumin (with an encapsulation efficiency of up to 10 mg/g). Meanwhile, higher water solubility (up to 469.30 g per 100 g of H₂O) was achieved for SACD, indicating that a high dose of SACD could be applied in an aqueous food matrix. Such a simple strategy exhibiting low cytotoxicity shows great potential incorporating bioactive compounds into functional foods.

Hydroxypropyl methylcellulose/graphene oxide composite as drug carrier system for5-Fluorouracil

AIM

This study aims to prepare green nanocomposite (HPMC/5-FL@GO) from the most biocompatible materials, hydroxypropyl methylcellulose (HPMC) and graphene oxide (GO), to enhance the drug activity of immobilized 5- Fluorouracil (5-FU) with decreasing the side effect of long-run treatment protocols with highly efficient drug-drug activity.

METHOD AND RESULTS

Different samples were characterized by ATR-FTIR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), Thermogravimetric analysis (TGA), and dynamic light scattering (DLS) along with cytotoxicity and anticancer study. A homogenous and compatible nanocomposite structure with a homogenous drug distribution was confirmed. The results suggested that the prepared nanocomposite has a low cytotoxicity effect against normal Vero cell lines compared with 5-FU. The antitumor activities of the same nanocomposite (20.4 and 74.3 μg/ml on A549 and HepG-2) were lower than that of 5-FU (54.1and 103 μg/ml on A549 and HepG-2).

CONCLUSION AND IMPLICATIONS

According to the attained results, the HPMC/5-FL@GO can be expected to be widely applied in a biomedical application such as cancer therapy with the unique biocompatible to human cells. This article is protected by copyright. All rights reserved.

Nucleophilic Displacement Reaction on Tosyl Cellulose by L-Methionine to the Synthesis of Novel Water-Soluble Cellulose Derivative and Its Antibacterial Activity

A novel ampholytic cellulose derivative, cellulose-L-methionine, has been synthesized by means of an esterification reaction of microcrystalline cellulose with tosyl chloride (p-TsCl) in DMAc/LiCl (8%) at 8°C that was followed by nucleophilic displacement (SN) of the tosyl group by the L-methionine amino acid. The resulting structure of cellulose-L-methionine has been characterized by elemental analysis (CHNSO), Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), and scanning electron microscopy (SEM). The antibacterial activity of the synthesized product was screened against Gram-positive and Gram-negative microbial strains such as Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, by the agar well diffusion method, and compared with commercial antibiotics such as ampicillin and chloramphenicol. It was found that antibacterial experiment revealed excellent antibacterial activity of the cellulose-methionine with respect to a minimal inhibitory concentration (MIC) reference.

Comparative studies on Pb(II) biosorption with three spongy microbe-based biosorbents: High performance, selectivity and application

Lead pollution in industrial-derived water has become an increasingly serious concern. The development of adsorbents with excellent efficiency, selectivity and separability using diverse microorganisms is ideal for treating lead pollution. In this study, gram-negative bacteria Pseudomonas putida I3, gram-positive bacteria Microbacterium sp. OLJ1 and mycelial fungus Talaromyces amestolkiae Pb served as raw materials to facilely synthesize sponge-like biosorbents via a one-step method at room temperature. SEM, EDS, FTIR, ¹³C NMR, XRD and XPS were used for investigating the morphology and surface properties of these three biosorbents. The obtained biosorbents possessed the same three-dimensional porous structure but different productivities and mechanical strengths due to the similar chemical compositions and different cell structures of their microorganisms. Pb(II) adsorption on X-PI3, X-OLJ1 and X-TPb was fast and pH dependent, with maximal adsorption capacities of 345.02, 237.02 and 199.02 mg/g, respectively. The biosorbents had a high selectivity for Pb(II), while Pb(II) remarkably suppressed the adsorption of co-existing heavy metal ions. The analyses indicated that Pb(II) removal was mainly achieved by ion exchange reactions, surface complexation with heteroatom-containing functional groups and microprecipitation. The treatment effects of synthetic and real wastewater revealed that the as-prepared biosorbents are promising for Pb(II) removal.

New approach for immobilization of 3-aminopropyltrimethoxysilane and TiO2 nanoparticles into cellulose for BJ1 skin cells proliferation

In the present study, tosylcellulose (TC) was used as a key intermediate for the selective coupling with 3-aminopropyltrimethoxysilane (APTMS) affording amino-propylsilane-grafted tosylcellulose (TC-Si). Solid state ¹³C NMR and FT-IR analyses confirmed the coupling and self-condensation of APTMS along TC. The changes in the surface morphology of the functionalized cellulose were identified by SEM imaging. The thermal stability of TC-Si was significantly improved as compared to MCC and TC. A new organic/inorganic hybrid cellulosic material was fabricated by embedding TiO₂ nanoparticles into TC-Si network. The new cellulose polymers were investigated for their ability to promote the proliferation of human skin fibroblast (BJ1). The cell cytotoxicity assay showed that both TC and TC-Si possessed moderate toxicity to BJ1 cells by 17% and 23.8%, respectively at 20 μM. Meanwhile, TC-Si/TiO₂ hybrid enhanced the proliferation of BJ1 by 42%. Additionally TC-Si/TiO₂ hybrid demonstrated promising antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans.