Graft Copolymers Of Chitosan Research Articles

The Low-Waste Grafting Copolymerization Modification of Chitosan Is a Promising Approach to Obtaining Materials for Food Applications.

Chitosan takes second place of the most abundant polysaccharides naturally produced by living organisms. Due to its abundance and unique properties, such as its polycationic nature, ability to form strong elastic porous films, and antibacterial potential, it is widely used in the food industry and biomedicine. However, its low solubility in both water and organic solvents makes its application difficult. We have developed an environmentally friendly method for producing water-soluble graft copolymers of chitosan and poly (N-vinylpyrrolidone) with high grafting efficiency and a low yield of by-products. By using AFM, SEM, TGA, DSC, and XRD, it has been demonstrated that the products obtained have changed properties compared to the initial chitosan. They possess a smoother surface and lower thermal stability but are sufficient for practical use. The resulting copolymers have a higher viscosity than the original chitosan, making them a promising thickener and stabilizer for food gels. Moreover, the copolymers exhibit an antibacterial effect, suggesting their potential use as a component in smart food packaging.

Features of Synthesis of Graft Copolymers of Chitosan and Acrylic Acid

Features of Synthesis of Graft Copolymers of Chitosan and Acrylic Acid

Exploring Swelling Behaviour of Chitosan-Based Hydrogels in Diverse Environmental Conditions

Hydrogels, versatile materials with diverse applications in biomedicine and beyond, have garnered significant attention due to their unique properties. Among these, chitosan-based hydrogels have emerged as promising candidates owing to their biocompatibility, biodegradability, and antimicrobial properties. The hydrogels were synthesized through cross-linking of chitosan graft copolymers with N-vinylpyrrolidone and other vinyl monomers, as well as through thermal methods in situ. The impact of cross-linking agent concentration on gel fraction yield and cross-linking efficiency was examined. The results indicate that higher cross-linking densities lead to reduced swelling capacity as a result of a denser network structure. The swelling behaviour of chitosan-based hydrogels under various environmental conditions, including pH, temperature and ionic strength were also investigated. It is found that swelling behaviour varied among different hydrogel formulations, with natural and vinyl graft copolymers exhibiting increased swelling in acidic environments. Semi-synthetic copolymers containing hydrophobic groups showed relatively lower swelling across pH ranges. Additionally, swelling kinetics were studied, revealing equilibrium reached at different time intervals depending on temperature and hydrogel composition. Furthermore, the effect of glucose concentration on swelling behaviour was explored, demonstrating decreased swelling with increasing glucose concentration. Overall, this comprehensive investigation provides valuable insights into the swelling behaviour of chitosan-based hydrogels, essential for optimizing their performance in biomedical applications.

Poly(ε-caprolactone)-grafted-chitosan copolymers: Synthesis and use as tunable and biodegradable coating for water soluble fertilizers

The urgent need for efficient agriculture to increase crop and food has fueled the development of coated fertilizers with a slow-release kinetics, water economy and full degradability to avoid negative environmental impact. In this context, we herein report the synthesis of poly(ε-caprolactone) (PCL) grafted from chitosan (CS) as a new class of biodegradable coating materials. The CS-g-PCL were prepared following a one-pot, two-step strategy, in which the primary amines of CS first react with ε-caprolactone (CL) to form CL-oligomers linked to CS via amide bonds terminated with hydroxyls, which together with the native hydroxyls of CS initiate the ring-opening polymerization of CL after addition of Sn(C ≡ CPh)4 as catalyst. Owing to the great stability of the used catalyst, the high molar mass of PCL grafted onto CS was successfully obtained under trivial open-air conditions. Different copolymers (CS-g-PCL) were prepared by varying the CS content. The structural characterization of CS-g-PCL was carried out using FTIR, 1H NMR, X-ray diffraction, contact angle and size exclusion chromatography (SEC) while the thermal and mechanical characterization of the prepared CS-g-PCL were compared to the neat PCL. Next, using a laboratory rotary drum, CS-g-PCL was implemented to uniformly coat granular diammonium phosphate fertilizer (DAP). Consequently, the kinetic releases of nitrogen and phosphorus were significantly delayed compared to that observed from uncoated DAP (conventional fertilizers). Finally, the degradation of CS-g-PCL was examined under aerobic conditions and showed a significant increase in their biodegradability with respect to neat PCL.

3D-printed hydrogels based on amphiphilic chitosan derivative loaded with levofloxacin for wound healing applications

Skin wounds not only cause physical pain to patients but also pose an economic burden to society. Consequently, effective approaches to promote skin repair remain a challenge. Specifically, chitosan-based hydrogels are ideal candidates to promote wound healing at different stages and while diminishing the factors that impede this process (such as excessive inflammatory and chronic wound infection). Furthermore, the unique biological properties of a chitosan-based hydrogel enable it to serve as both a wound dressing and a drug delivery system (DDS). In the present work, chitosan (CS) graft copolymer with [2-(methacryloyloxy)ethyl] trimethyl ammonium chloride (CS-MTAC), a cationic monomer with promising antibacterial properties, was synthesized. The successful synthesis of the copolymer was confirmed, while it was studied for its swelling ability and water absorption capacity, as well as for its biocompatibility and antibacterial properties. Expecting to improve its printability, the copolymer was blended with elastin (EL), collagen (COL), and increasing concentrations of gelatin (GEL). The hydrogel with 6% w/v CS, 4% w/w EL, 4% w/w COL and 1% w/v GEL was selected for its potential to be 3D-printed and was neutralized with ammonia vapors or ethanol/sodium hydroxide solution and loaded with levofloxacin. The feasibility of CS-MTAC/EL/COL/GEL bioink, loaded with Levo, as a suitable candidate for wound healing and drug delivery applications, has been demonstrated.

Dual stimuli-responsive polymeric nanoparticles combining soluplus and chitosan for enhanced breast cancer targeting.

A dual stimuli-responsive nanocarrier was developed from smart biocompatible chitosan and soluplus graft copolymers. The copolymerization was investigated by differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), and Fourier transform infrared (FTIR). The optimized chitosan-soluplus nanoparticles (CS-SP NPs) were further used for the encapsulation of a poorly water-soluble anticancer drug. Tamoxifen citrate (TC) was used as the model drug and it was loaded in CS-SP NPs. TC CS-SP NPs were characterized in terms of particle size, zeta potential, polydispersity, morphology, encapsulation efficiency, and physical stability. The nanoparticles showed homogenous spherical features with a size around 94 nm, a slightly positive zeta potential, and an encapsulation efficiency around 96.66%. Dynamic light scattering (DLS), in vitro drug release, and cytotoxicity confirmed that the created nano-system is smart and exhibits pH and temperature-responsive behavior. In vitro cellular uptake was evaluated by flow cytometry and confocal microscopy. The nanoparticles revealed a triggered increase in size upon reaching the lower critical solution temperature of SP, with 70% of drug release at acidic pH and 40 °C within the first hour and a 3.5-fold increase in cytotoxicity against MCF7 cells incubated at 40 °C. The cellular uptake study manifested that the prepared nanoparticles succeeded in delivering drug molecules to MCF7 and MDA-MB-231 cells. In summary, the distinctive characteristics provided by these novel CS-SP NPs result in a promising nano-platform for effective drug delivery in cancer treatment.

Glutathione and acid dual-responsive nanomaterials loaded with methotrexate and magnolol for triple-negative breast cancer treatment

ABSTRACT In this study, we designed and synthesised MTX and PEG‒grafted chitosan copolymer nanoparticles (PsCM) to load MAG. We generated MAG@PsCM nanoparticles according to the effective ratio of dual drugs of 1:2.5, achieving 3.73% and 8.95% drug loading for MTX and MAG, respectively. Drug efficiency experiments were conducted on MDA-MB-231 breast cancer cells, and the results showed that when MTX was used alone, the tumour cell survival rate was 43.66 ± 1.77%and when low-dose MAG and MTX were used in combination, the survival rate of tumour cells was significantly reduced to 29.82% ± 2.22%. The nanoparticles enhanced the synergistic tumour therapeutic effect of the two drugs with the cell survival rate was 21.94 ± 1.43%, significantly lower compared with the free drugs. MAG@PsCM nanoparticles were significantly taken up by cells at 3, 6 and 12 h, and the total amount taken up increased significantly with time.

Dihydrocaffeic acid grafted chitosan self-assembled nanomicelles with enhanced intestinal transport and antioxidant properties of chicoric acid.

Chicoric acid (CA) plays a crucial role as a functional factor within the realm of foods, showcasing a wide array of bioactivities. Nevertheless, its oral bioavailability is significantly limited. To optimize the intestinal absorption and bolster the antioxidant capacity of CA, a water-soluble dihydrocaffeic acid grafted chitosan copolymer (DA-g-CS) was synthesized using a conventional free radicals system, and subsequently utilized for the encapsulation of CA within self-assembled nanomicelles (DA-g-CS/CA). The average particle size of DA-g-CS/CA was 203.3nm, while the critical micelle concentration was 3.98×10-4 mg/mL. Intestinal transport studies revealed that DA-g-CS/CA penetrated cells via the macropinocytosis pathway, exhibiting the cellular uptake rate 1.64 times higher than that of CA. This substantial enhancement in the intestinal transport of CA underscores the significant improvements achieved through DA-g-CS/CA delivery. The pharmacokinetic results demonstrated that DA-g-CS/CA exhibited a remarkable bioavailability 2.24 times that of CA. Furthermore, the antioxidant assessment demonstrated that DA-g-CS/CA exhibited exceptional antioxidant properties in comparison to CA. It demonstrated enhanced protective and mitigating effects in the H2O2-induced oxidative damage model, while also displaying a stronger emphasis on protective effects rather than attenuating effects. These findings aim to establish a solid theoretical foundation for the advancement of CA in terms of its oral absorption and the development of functional food products.

Cationic chitosan graft flocculants: Synthesis, characterization and applications in kaolin separation

Chitosan is a biodegradable, non-toxic and environmental friendly biopolymer. It is a linear polysaccharide which can be tailored for wide range of applications such as, wound healing, drug delivery, mineral recovery, flocculation etc. In this work, cationic flocculants based on the graft co-polymerization of chitosan (Chi) with cationic monomer namely, 3-acrylamidopropyltrimethylammonium chloride (APTMAC) were synthesized. The grafting ratio was varied to get three different compositions of the graft-co-polymers (Chi: APTMAC 1:3, 1:5 and 1:8 wt% in feed) with different MWs and charge, which are the important parameters for efficient flocculation. The chemical structure of the copolymers was confirmed by 1H and 13C NMR spectroscopy. The molecular weight and zeta potential for all the graft copolymers were determined. The charge on the graft polymer increased as the content of the APTMAC increased from 1:3 to 1:8 wt%. The graft copolymers were used for the flocculation of kaolin and the flocculation performance was correlated to molecular weight and charge on the graft copolymers. The optimum dosages were determined and the driving mechanism for the flocculation was discussed in terms of bridging, charge neutralization and electrostatic patch model. The flocs of kaolin were characterized in terms of moisture content and surface properties by optical microscopy. The efficiency of flocculation was found to be very good with low dosages of the flocculants and show great potential in industrial separations.

Fabrication, characterization and properties of silver nanoparticles using poly (MAA)–chitosan graft copolymer as an ecofriendly non-fibrous textile

PurposeThis study aims to address a comprehensive and integrated investigations pertaining to the preparation of AgNPs with well-defined nano-sized scale using the aforementioned poly (meth acrylic acid [MAA])–chitosan graft copolymer, which is cheap, nontoxic, biodegradable and biocompatible agent as a substitute for the traditionally used toxic reducing agents.Design/methodology/approachAgNPs are prepared under a range of conditions, containing silver nitrate and poly (MAA)–chitosan graft copolymer concentrations, time, temperature and pH of the preparation medium. To classify AgNPs obtained under the various conditions, ultraviolet–visible spectroscopy spectra and transmission electron microscopy images are used for characterization of AgNPs instrumentally in addition to the visual color change throughout the work. The work was further extended to study the application of the so prepared AgNPs on cotton fabric to see their suitability as antibacterial agent as well as their durability after certain washing cycles.FindingsAccording to the current investigation, the optimal conditions for AgNPs formation of nearly 3–15 nm in size are 5 g/l, poly (MAA)–chitosan graft copolymer and 300 ppm AgNO3 in addition to carrying out the reaction at 60°C for 30 min at pH 12. Besides, the application of the so prepared AgNPs on cotton fabric displayed a substantial reduction in antibacterial efficiency against gram-positive and gram-negative bacteria estimated even after 10 washing cycles in comparison with untreated one.Originality/valueTo the best of the authors’ information, no comprehensive study of the synthesis of AgNPs using poly (MAA)–chitosan graft copolymer with a graft yield of 48% has been identified in the literature.

Chitosan Graft Copolymers with N-Vinylimidazole as Promising Matrices for Immobilization of Bromelain, Ficin, and Papain.

This work aims to synthesize graft copolymers of chitosan and N-vinylimidazole (VI) with different compositions to be used as matrices for the immobilization of cysteine proteases—bromelain, ficin, and papain. The copolymers are synthesized by free radical solution copolymerization with a potassium persulfate-sodium metabisulfite blend initiator. The copolymers have a relatively high frequency of grafting and yields. All the synthesized graft copolymers are water-soluble, and their solutions are characterized by DLS and laser Doppler microelectrophoresis. The copolymers are self-assembled in aqueous solutions, and they have a cationic nature and pH-sensitivity correlating to the VI content. The FTIR data demonstrate that synthesized graft copolymers conjugate cysteine proteases. The synthesized copolymer adsorbs more enzyme macromolecules compared to non-modified chitosan with the same molecular weight. The proteolytic activity of the immobilized enzymes is increased up to 100% compared to native ones. The immobilized ficin retains up to 97% of the initial activity after a one-day incubation, the immobilized bromelain retains 69% of activity after a 3-day incubation, and the immobilized papain retains 57% of the initial activity after a 7-day incubation. Therefore, the synthesized copolymers can be used as matrices for the immobilization of bromelain, ficin, and papain.

Polylactide microparticles stabilized by chitosan graft-copolymer as building blocks for scaffold fabrication via surface-selective laser sintering

Polylactide microparticles stabilized by chitosan graft-copolymer as building blocks for scaffold fabrication via surface-selective laser sintering

PREPARATION OF CHITOSAN GRAFT COPOLYMERS AND STUDY OF THEIR WATER-SWELLING PROPERTIES

In this work, graft copolymers of chitosan with trimethylmethacryloxyethylammonium methyl sulfate were synthesized by the method of controlled radical polymerization, and it was found that replacing the dimethylformamide aprotic solvent with water increases the degree of grafting. With the aim of the possible use of chitosan copolymers as a functional component for regulating the water-swelling properties of elastomers, the kinetics of swelling of the samples was investigated. An increase in the degree of swelling of the copolymers in comparison with the initial chitosan was revealed, and the influence of the molecular weight and the conditions of their synthesis was established.

Synthesis of chitosan and N-vinylimidazole graft-copolymers and the properties of their aqueous solutions

The aim of this work is to synthesise chitosan and N-vinylimidazole graft-copolymers of various compositions and to study the properties of their aqueous solutions.Chitosan and N-vinylimidazole graft-copolymers were obtained by solution polymerisation in the presence of a ceric ammonium nitrate redox initiator. The synthesised graft copolymers were characterised by FTIR to determine their compositions and the grafted side chains of poly-N-vinylimidazole were characterised by gel permeation chromatography to determine their molecular wights and polydispersity indices. It was established that the obtained products are characterised by high values of yield and grafting efficiency and low values of the polydispersity index. It was found that when the content of the N-vinylimidazole links is above 57 wt%, the synthesised graft copolymers are water-soluble. Aqueous solutions of the obtained copolymers were characterised using dynamic light scattering, transmission electron microscopy, and laserDoppler microelectrophoresis. The study showed that macromolecules of graft copolymers in aqueous solutions have stimuli-sensitive properties with respect to the medium reaction and at a concentration above 10–2 wt% are characterised by a tendency to self-association forming core-crown aggregates, the geometry of which depends on the molecular masses of the grafted chains. Associates of macromolecules in solutions are characterised by positive values of the electrokinetic potential, the values of which also depend on the medium reaction. Thus, it was found that the ceric ammonium nitrate initiator allows obtaining chitosan and N-vinylimidazole graft-copolymers showing stimuli-sensitive properties in aqueous solutions and prone to self-association at concentrations above 10–2 wt%.

Layer-by-layer films of polysaccharides modified with poly(N-vinylpyrrolidone) and poly(vinyl alcohol)

N-grafted copolymers of chitosan (460 kDa) with poly(N-vinylpyrrolidone) (2.4 kDa) or poly(vinyl alcohol) (2.0 ​kDa) as side chains were synthesized. Depending on the polymer-to-chitosan mass ratio the degree of amino group substitution with side chains in chitosan backbone was varied in the range of 0.01–0.33. Layer-by-layer films consisted of copolymers and dextran sulfate as polyanion were obtained. Thickness, hydrophilicity, and morphology of the films were investigated using QCM, UV-vis spectrophotometry, AFM, and contact angle measurements. The obtained films show enhanced protein-repellent properties in fetal bovine serum medium. The mass of adsorbed proteins on LbL films based on copolymer with a degree of substitution of 0.2 decreases by 50 ​% compared to unmodified chitosan. Protein-repellent properties of copolymer-based films are common for LbL films of grafted chitosan copolymers and depend on hydrophilic side chain density on the surface.

Materials Based on Chitosan and Polylactide: From Biodegradable Plastics to Tissue Engineering Constructions

The transition to green chemistry and biodegradable polymers is a logical stage in the development of modern chemical science and technology. In the framework of this review, the advantages, disadvantages, and potential of biodegradable polymers of synthetic and natural origin are compared using the example of polylactide and chitosan as traditional representatives of these classes of polymers, and the possibilities of their combination via obtaining composite materials or copolymers are assessed. The mechanochemical approach to the synthesis of graft copolymers of chitosan with oligolactides/polylactides is considered in more detail.

Synthesis and Evaluation of Performance Characteristics Green Composites from Sustainable Fatty Chitosan Graft Copolymer with Acrylic Acid for Wastewater Treatment

Many chitosan adsorbent derivatives for metal ion adsorption have been developed by grafting novel functional groups on the chitosan chain, and these functional groups are combined with chitosan to improve sorption capability. The chemical structure of chitosan was characterized by the spectroscopy of Fourier Transform Infrared (FT-IR). The degree of N-deacetylation (DDA) was also calculated from FT-IR data. The use of bio sorbent chitosan-fatty acid derivatives makes it possible to extract both heavy metals and organic compounds. In this analysis, the grafting copolymer of fatty chitosan derivatives with acrylic acid polymer was synthesized using ceric ammonium nitrate, the redox nitric acid method under UV irradiation. Synthesized copolymers have been subjected to various analytical techniques such as X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTA) to confirm the formation of copolymers and to research their thermal stability. The findings show the formation and strong chemical interaction between fatty chitosan derivatives and acrylic acid. Fatty Chitosan derivatives and prepared grafting copolymers have been treated with copper and chromium-containing metal solutions and the results have shown that fatty chitosan derivatives and prepared copolymers are excellent in the removal of heavy metals such as copper and chromium. Prepared compounds could therefore open the way for industrial wastewater treatment.

Physical and Mechanical Properties of Films Based on Graft Copolymers of Chitosan with N, N-Dimethylaminoethyl Methacrylate

The graft-polymerization of N, N-dimethylaminoethylmethacrylate (DMAEMA) on chitosan (CTS) was performed in the presence of ammonium persulfate (PSA) at a temperature of 323K. The effect of the DMAEM concentration in the reaction mixture on the copolymer yield, the degree and effectiveness of grafting, as well as on the physical-mechanical properties of films obtained on the basis of synthesized copolymers was studied. The copolymers formation was prooven by gravimetric method, extraction, and IR spectroscopy. Chitosan-graft-DMAEM copolymers of various compositions were obtained. The grafing degree reached ~ 350 wt. % with the ratio [DMAEMA]/[CTS] = 5 (mol/(base-mol), the grafting effectiveness was ~ 86 wt. % with the ratio [DMAEMA]/[CTS] = 1 (mol/(base-mol). It was established that the changing the copolymers composition lead to variation of tencile strength and deformation characteristics of films widely from 1.4 MPa to 25.7 MPa and from 34% to 413%, correspondingly.

Design of folic acid decorated virus-mimicking nanoparticles for enhanced oral insulin delivery

Mucus penetration and intestinal cells targeting are two main strategies to improve insulin oral delivery efficiency. However, few studies are available regarding the effectiveness of combining these two strategies into one nano-delivery system. For this objective, the folic acid (FA) decorated virus-mimicking nanoparticles were designed and influence of FA graft ratio on the in vitro and in vivo properties of insulin loaded nanoparticles was studied systemically. Firstly, using folic acid as active ligand, different folic acid grafted chitosan copolymers (FA-CS) were synthesized and characterized. Thereafter, using insulin-loaded poly(n-butylcyanoacrylate) nanoparticles as the core, virus-mimicking nanoparticles were fabricated by coating of positively charged FA-CS copolymer and negatively charged hyaluronic acid. Irrespective of the FA graft ratio, all the nanoparticles showed good stability, similar insulin release in the gastrointestinal fluid, excellent and similar penetration in mucus. The nanoparticles permeability in intestine was FA graft ratio and segment dependent, with FA graft ratio at/over 12.51% presenting better effect in the order of duodenum > jejunum ≈ ileum. Both mechanism studies and confocal microscopy observation demonstrated FA-mediated process was involved in the transport of FA decorated nanoparticles. In vivo studies revealed hypoglycemic effect of the nanoparticles was FA graft ratio dependent, a saturation phenomenon was observed when FA graft ratio was at/over 12.51%. In conclusion, folic acid decorated virus-mimicking nanoparticles presented improved insulin absorption, implying combining mucus penetration and active transcellular transport is an effective way to promote oral insulin absorption, while the modification ratio of active ligand needs optimization.

Alternative microwave curing approach for imparting ease and care characteristics and antimicrobial activity to viscose fabric

PurposeThis study aims to use multi-functional viscose fabric that was facilely developed with with respect to ease and care characteristics, reinforcement effect and antibacterial activity by using novel echo friendly antibacterial finish based on citric acid/sodium hypophosphite and the authors’ previously tailor-made poly meth acrylic acid (MAA)-chitosan graft copolymer via alternative microwave curing approach instead of traditional high-temperature cure one.Design/methodology/approachViscose fabric was paddled twice in the cross-linking formulations containing different concentrations of citric acid, poly (MAA)-chitosan graft copolymer and sodium hypophosphite to 90 % wet pick up and dried at 100°C for 3 min in an electric oven. Then, the treated fabrics were placed on the disk spinner of the microwave oven and cured at different power (100–800 Watt) for various durations (60–180 s). The fabric was then water-rinsed and dried at ambient condition before use.FindingsResults revealed that the above echo friendly method for finished viscose fabrics was found to achieve relatively high dry wrinkle recovery angle and maintain the loss in tensile strength within the acceptable range, as well as antibacterial activity against Escherichia coli and Staphylococcus aureus as a gram-negative and gram-positive bacteria, respectively; in addition to durability up to ten washing cycles. Furthermore, scanning electron microscope images, nitrogen content and add on % of the finished fabric confirmed the penetration of grafted chitosan inside the fabric structure. The tentative mechanism for these reactions is advocated.Originality/valueThe novelty addressed here is undertaken with the advantages of using citric acid as a nonformaldehyde, safe and cheap poly carboxylic acid as a crosslinking agent and sodium hypophosphite as a potential catalyst, in addition to the authors’ noncitable multifunctional echo friendly tailor-made poly (MAA)-chitosan graft copolymer for imparting reinforcement and antibacterial characteristics to viscose fabric that uses the pad-dry/cure microwave fixation for progressively persuaded heat within the fabric during curing.Research limitations/implicationsThis was done to see the impact of microwave as green and efficient tool with respect to reduction in organic solvents, chemicals and exposer time as well as fixation temperature on the finishing reaction in comparison with traditional pad-dry-cure method.Practical implicationsPoly (MAA)-chitosan graft copolymer as amphoteric biopolymer was expected to impart multifunctional properties to viscose fabrics especially with comparable dry wrinkle recovery angle and minimize the loss in tensile strength in addition to antibacterial properties in comparison with untreated one.