Preparation and Characterization of Novel Cationic Chitosan Derivatives Bearing Quaternary Ammonium and Phosphonium Salts and Assessment of Their Antifungal Properties

Electrospun nonwoven fabric of poly(ε-caprolactone)/n-phosphonium chitosan for antiviral applications: Fabrication, characterization, and potential efficacy

This work reports the virucidal properties of nonwoven fibers developed via electrospinning with polycaprolactone (PCL) and chitosan quaternized with phosphonium salt (NPCS), emphasizing the influence of NPCS concentration on the structure of fibers and their performance against the MHV-3 coronavirus. The addition of NPCS enhances solutions conductivity and viscosity, leading to fibers containing a finer porous structure with a more hydrophilic and smoother surface, thereby making them a potent barrier against respiratory particles, which is a key factor for protective face masks. In terms of degradation, NPCS paced-up the process, suggesting potential environmental benefits. PCL/NPCS (90/10) fibers exhibit a 99 % coronavirus inhibition within a five-minute exposure without cellular toxicity, while also meeting breathability standards for medical masks. These findings suggest the use of NPCS as a promising strategy to design materials with remarkable virucidal performance and physical characteristics that reinforce their use in the field of biomaterials engineering.

Combatting Fungal Infections: Advances in Antifungal Polymeric Nanomaterials

Fungal pathogens cause over 6.5 million life-threatening systemic infections annually, with mortality rates ranging from 20 to 95%, even with medical intervention. The World Health Organization has recently emphasized the urgent need for new antifungal drugs. However, the range of effective antifungal agents remains limited and resistance is increasing. This Review explores the current landscape of fungal infections and antifungal drugs, focusing on synthetic polymeric nanomaterials like nanoparticles that enhance the physicochemical properties of existing drugs. Additionally, we examine intrinsically antifungal polymers that mimic naturally occurring peptides. Advances in polymer characterization and synthesis now allow precise design and screening for antifungal activity, biocompatibility, and drug interactions. These antifungal polymers represent a promising new class of drugs for combating fungal infections.

Advances of biological macromolecules hemostatic materials: A review

Achieving hemostasis is a necessary intervention to rapidly and effectively control bleeding. Conventional hemostatic materials currently used in clinical practice may aggravate the damage at the bleeding site due to factors such as poor adhesion and poor adaptation. Compared to most traditional hemostatic materials, polymer-based hemostatic materials have better biocompatibility and offer several advantages. They provide a more effective method of stopping bleeding and avoiding additional damage to the body in case of excessive blood loss. Various hemostatic materials with greater functionality have been developed in recent years for different organs using diverse design strategies. This article reviews the latest advances in the development of polymeric hemostatic materials. We introduce the coagulation cascade reaction after bleeding and then discuss the hemostatic mechanisms and advantages and disadvantages of various polymer materials, including natural, synthetic, and composite polymer hemostatic materials. We further focus on the design strategies, properties, and characterization of hemostatic materials, along with their applications in different organs. Finally, challenges and prospects for the application of hemostatic polymeric materials are summarized and discussed. We believe that this review can provide a reference for related research on hemostatic materials, contributing to the further development of polymer hemostatic materials.

Synthesis and characterization of n-phosphonium chitosan and its virucidal activity evaluation against coronavirus

Despite the worldwide vaccination effort against COVID-19, the demand for biocidal materials has increased. One promising solution is the chemical modification of polysaccharides, such as chitosan, which can provide antiviral activity through the insertion of cationic terminals. In this study, chitosan was modified with (4-carboxybutyl) triphenylphosphonium bromide to create N-phosphonium chitosan (NPCS), a quaternized derivative. The resulting NPCS samples with three degrees of substitution (15.6 %, 19.8 % and 24.2 %) were characterized and found to have improved solubility in water and alkaline solutions but reduced thermal stability. The particles zeta potential exhibits positive charges and is directly correlated with the degree of substitution of the derivative. In virucidal assays, all NPCS samples were able to inhibit 99.999 % of the MHV-3 coronavirus within 5 min at low concentrations of 0.1 mg/mL, while maintaining low cytotoxicity to L929 cells. In addition to its potential application against current coronavirus strains, NPCS could also be valuable in combating future pandemics caused by other viral pathogens. The antiviral properties of NPCS make it a promising material for use in coating surface and personal protective equipment to limit the spread of disease-causing viruses.

Effect of the structure of chitosan quaternary phosphonium salt and chitosan quaternary ammonium salt on the antibacterial and antibiofilm activity

N-(4-N', N', N'-trimethylphosphonium chloride) benzoyl chitosan (TMPCS), N-(4-N', N', N'-triphenylphosphonium chloride) benzoyl chitosan (TPPCS), and N-(4-N', N', N'-trimethylmethanaminium chloride) benzoyl chitosan (TMACS) were synthesized. The structures of the products were characterized by Fourier transform infrared spectroscopy, Nuclear magnetic resonance spectroscopy and ultraviolet-visible spectroscopy. Their antibacterial activities against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were investigated in vitro using the antibacterial rate, minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), the antibiofilm activity was investigated by crystal violet assay. The antibacterial assessment revealed that the chitosan quaternary phosphonium salts of similar structure had superior antibacterial activity than chitosan quaternary ammonium salt. The antibacterial rate of CS, TMPCS, TPPCS and TMACS against E. coli at 0.5 mg/mL was 10.4 %, 42.0 %, 58.5 % and 21.6 % respectively. At the same concentration, the antibacterial rate of TMPCS, TPPCS and TMACS against S.aureus was all up to 100 %. The biofilm inhibition rate of CS, TMPCS, TPPCS and TMACS at a half of MIC against E.coli was 28.4 %, 33.9 %, 56.6 % and 57.6 % respectively, and against S.aureus was 30.8 %, 53.8 %, 62.2 % and 58.5 % respectively. The biofilm removal rate of CS, TMPCS, TPPCS, TMACS against E.coli at 2.5 mg/mL was 20.6 %, 46.4 %, 48.9 % and 41.6 % respectively, and against S.aureus at 2.5 mg/mL was 41.5 %, 60.4 %, 69.9 % and 59.01 % respectively.

Efficiency of Neat and Quaternized-Cellulose Nanofibril Fillers in Chitosan Membranes for Direct Ethanol Fuel Cells

In this work, fully polysaccharide based membranes were presented as self-standing, solid polyelectrolytes for application in anion exchange membrane fuel cells (AEMFCs). For this purpose, cellulose nanofibrils (CNFs) were modified successfully with an organosilane reagent, resulting in quaternized CNFs (CNF (D)), as shown by Fourier Transform Infrared Spectroscopy (FTIR), Carbon-13 (C13) nuclear magnetic resonance (¹³C NMR), Thermogravimetric Analysis (TGA)/Differential Scanning Calorimetry (DSC), and ζ-potential measurements. Both the neat (CNF) and CNF(D) particles were incorporated in situ into the chitosan (CS) membrane during the solvent casting process, resulting in composite membranes that were studied extensively for morphology, potassium hydroxide (KOH) uptake and swelling ratio, ethanol (EtOH) permeability, mechanical properties, ionic conductivity, and cell performance. The results showed higher Young's modulus (119%), tensile strength (91%), ion exchange capacity (177%), and ionic conductivity (33%) of the CS-based membranes compared to the commercial Fumatech membrane. The addition of CNF filler improved the thermal stability of the CS membranes and reduced the overall mass loss. The CNF (D) filler provided the lowest (4.23 × 10^-5 cm² s^-1) EtOH permeability of the respective membrane, which is in the same range as that of the commercial membrane (3.47 × 10^-5 cm²s^-1). The most significant improvement (~78%) in power density at 80 °C was observed for the CS membrane with neat CNF compared to the commercial Fumatech membrane (62.4 mW cm^-2 vs. 35.1 mW cm^-2). Fuel cell tests showed that all CS-based anion exchange membranes (AEMs) exhibited higher maximum power densities than the commercial AEMs at 25 °C and 60 °C with humidified or non-humidified oxygen, demonstrating their potential for low-temperature direct ethanol fuel cell (DEFC) applications.

Nanoparticle-mediated therapeutic management in cholangiocarcinoma drug targeting: Current progress and future prospects

Patients with cholangiocarcinoma (CCA) often have an unfavorable prognosis because of its insidious nature, low resectability rate, and poor response to anticancer drugs and radiotherapy, which makes early detection and treatment difficult. At present, CCA has a five-year overall survival rate (OS) of only 5%, despite advances in therapies. New an increasing number of evidence suggests that nanoplatforms may play a crucial role in enhancing the pharmacological effects and in reducing both short- and long-term side effects of cancer treatment. This document reviews the advantages and shortcomings of nanoparticles such as liposomes, polymeric nanoparticle，inorganic nanoparticle, nano-metals and nano-alloys, carbon dots, nano-micelles, dendrimer, nano-capsule, bio-Nanomaterials in the diagnosis and treatment of CCA and discuss the current challenges in of nanoplatforms for CCA.

Recent advances in the medical applications of hemostatic materials

Bleeding caused by trauma or surgery is a serious health problem, and uncontrollable bleeding can result in death. Therefore, developing safe, effective, and convenient hemostatic materials is important. Active hemostatic agents currently used to investigate the field of hemostasis are divided into four broad categories: natural polymers, synthetic polymers, inorganic materials, and metal-containing materials. Hemostatic materials are prepared in various forms for wound care applications based on the active ingredients used. These materials include nanofibers, gels, sponges, and nanoparticles. Hemostatic materials find their applications in the field of wound care, and they are also used for hemostasis during malignant tumor surgery. Prompt and effective hemostasis can reduce the possibility of the spread of tumor cells with blood. This review discusses the outcomes of current research conducted in the field and the problems persisting in the field of developing hemostatic materials. The review also presents a platform for the further development of hemostatic materials. Bleeding caused by trauma or surgery is a serious health problem, and uncontrollable bleeding can result in death. Therefore, developing safe, effective, and convenient hemostatic materials is important. Active hemostatic agents currently used to investigate the field of hemostasis are divided into four broad categories: natural polymers, synthetic polymers, inorganic materials, and metal-containing materials. Hemostatic materials are prepared in various forms for wound care applications based on the active ingredients used. These materials include nanofibers, gels, sponges, and nanoparticles. Hemostatic materials find their applications in the field of wound care, and they are also used for hemostasis during malignant tumor surgery. Prompt and effective hemostasis can reduce the possibility of the spread of tumor cells with blood. This review discusses the outcomes of current research conducted in the field and the problems persisting in the field of developing hemostatic materials. The review also presents a platform for the further development of hemostatic materials.

Synthesis, characterization, and biological activities of new conjugates of Guanosine grafted on polyvinyl alcohol, carbohydrate chitosan, and cellulose

Guanosine (GU) is a purine nucleoside that has different biological applications. This study aimed to synthesize, characterize, and enhance the biological activities of GU through its covalently grafting on polyvinyl alcohol (PVA), chitosan (CS), and cellulose (CL). In this regard, the conjugation was constructed by different linkers such as chloroacetyl chloride, 2-bromopropionyl bromide, and epichlorohydrin (EPCH). The resulted novel conjugates were characterized by FT-IR, 1H-NMR, GPC, and TGA techniques. FT-IR spectra revealed the main characteristic groups, O–H, N–H, C=O and C=N of GU moieties. Furthermore, 1H-NMR spectra showed the aromatic C–H, O–H, and N–H protons of the grafted GU moieties. Two decomposition stages of grated polymers with high thermal stability are illustrated by TGA. GU showed no antifungal activity against Aspergillus fumigatus and Candida albicans. However, its conjugates: P-1A, P-1B, P-2A, P-2B, P-3A, and P-3B displayed significant antifungal effect with inhibitory zones in the range 8–11 mm. As compared to GU group, most of GU-polymer conjugates showed significant in vivo antitumor activity against EAC-bearing mice via the reduction in total tumor volume. In summary, these conjugates are biologically active macromolecules and may act as candidate carrier systems for other applications such as drug delivery.

Novel Chitosan Derivatives and Their Multifaceted Biological Applications

Chitosan is a rather attractive material, especially because of its bio-origins as well as generation from exoskeletal waste. As the mantle has been effectively transferred from chitin to chitosan, so has it been extrapolated to in-house synthesized novel chitosan derivatives. This review comprehensively lists the available novel chitosan derivatives (ChDs) and summarizes their biological applications. The fact that chitosan derivatives do comprise multifaceted biological applications is attested by the voluminous reports on their varied contributions. However, this review points out to the fact that there has been selective focus on bio functions such as antifungal, antioxidant, antibacterial, whereas other biomedical applications and antiviral applications remain relatively less explored. With their current functionality record, there is definitely no doubt that the plethora of synthesized ChDs will have a profound impact on the unexplored biological aspects. This review points out this lacuna as room for future exploration.

Application of Chitosan and Its Derivative Polymers in Clinical Medicine and Agriculture

Chitosan is a biodegradable natural polymer derived from the exoskeleton of crustaceans. Because of its biocompatibility and non-biotoxicity, chitosan is widely used in the fields of medicine and agriculture. With the latest technology and technological progress, different active functional groups can be connected by modification, surface modification, or other configurations with various physical, chemical, and biological properties. These changes can significantly expand the application range and efficacy of chitosan polymers. This paper reviews the different uses of chitosan, such as catheter bridging to repair nerve broken ends, making wound auxiliaries, as tissue engineering repair materials for bone or cartilage, or as carriers for a variety of drugs to expand the volume or slow-release and even show potential in the fight against COVID-19. In addition, it is also discussed that chitosan in agriculture can improve the growth of crops and can be used as an antioxidant coating because its natural antibacterial properties are used alone or in conjunction with a variety of endophytic bacteria and metal ions. Generally speaking, chitosan is a kind of polymer material with excellent development prospects in medicine and agriculture.

Recent advances of emerging green chitosan-based biomaterials with potential biomedical applications: A review

Chitosan is the most abundant natural biopolymer, after cellulose. It is mainly derived from the fungi, shrimp's shells, and exoskeleton of crustaceans, through the deacetylation of chitin. The ecological sustainability associated with its exercise and the flexibility of chitosan owing to its active functional hydroxyl and amino groups makes it a promising candidate for a wide range of applications through a variety of modifications. The biodegradability and biocompatibility of chitosan and its derivatives along with their various chemical functionalities make them promising carriers for pharmaceutical, nutritional, medicinal, environmental, agriculture, drug delivery, and biotechnology applications. The present work aims to provide a detailed and organized description of modified chitosan and its derivatives-based nanomaterials for biomedical applications. We addressed the biological and physicochemical benefits of nanocomposite materials made up of chitosan and its derivatives in various formulations, including improved physicochemical stability and cells/tissue interaction, controlled drug release, and increased bioavailability and efficacy in clinical practice. Moreover, several modification techniques and their effective utilization are also reviewed and collected in this review.

Does polysaccharide quaternization improve biological activity?

The natural polysaccharides, due to their structural diversity, commonly present very distinct solubility and physical chemical properties and additionally have intrinsic biological activities that, gene-rally, reveal themselves in a light way. The chemical modification of the molecular structure can improve these parameters. In this review, original articles that approached the quaternization of polysaccharides for purposes of biological application were selected, without limitation of year of publication, in the databases Scopus, Web of Science and PubMed. The results obtained from the bibliographic survey indicate that the increase in positive charges caused by quaternization improves the interaction between modified polysaccharides and structures that have negative charges on their surface, such as the cell wall of microorganisms and some cells in the human body, such as the DNA. This greater interaction is reflected as an increase in the biological activity of all polysaccharides broached in this study. Another important data obtained was the fact that the chemical changes did not affect or irrelevantly affect the toxicity of almost all of the polysaccharides that were quaternized. Therefore, polysaccharide quaternization is a safe and effective way to obtain improvements in the biological behavior of these macromolecules.

Corrosion mitigation performance of disodium EDTA functionalized chitosan biomacromolecule - Experimental and theoretical approach

Disodium ethylenediaminetetraacetate salt is known for its excellent coordinating properties with the metal ions. The present study deals with the investigation of the prepared Disodium EDTA functionalized chitosan in corrosion inhibition for mild steel in 1 M HCl. The modified chitosan was characterized by spectral studies, thermal analysis, and Zeta potential studies. The corrosion inhibition efficiency (%) was evaluated using the gravimetric method and electrochemical studies. The electrochemical studies included potentiodynamic polarization, linear polarization resistance, and electrochemical impedance methods. The modified chitosan polymer showed an inhibition efficiency of 96.63% for 500 ppm at 303 K. Adsorption process obeyed Langmuir isotherm. Experimental results and theoretical calculations endorsed initial physisorption followed by a chemisorption process. Surface characterization studies supported the formation of a protective film that enabled the inhibition process. Density functional theory, Monte Carlo studies, and molecular dynamics simulation studies show a good agreement with the experimental results. Two-way Analysis of Variance was performed to test the influence of immersion period and inhibitor concentration on the corrosion rate using the statistical software IBM SPSS 20.0. A quartic model was generated as the best fit with the highest R2 value of 0.973. Design Expert software was employed for statistical modeling fit.

Imminent antimicrobial bioink deploying cellulose, alginate, EPS and synthetic polymers for 3D bioprinting of tissue constructs

3D printing, one of its kinds has been a recent technological trend to fabricate complex and patterned biomaterial with controlled precision. With the conventional kick-start of printing metals and plastics, advancements in printing viable cells, polysaccharides or microbes themselves have been achieved. The additive antimicrobial properties in bioinks sourced from organic and inorganic materials have profound implications in tissue engineering. Cellulose, alginate, exopolysaccharides, ceramics and synthetic polymers are integrated as a viable component in inks and used for bio-printing. To date, bacterial infection and immunogenicity pose a potential health risk during a tissue implant or bone substitution. In order to mitigate microbial infection, antimicrobial bioinks with significant antimicrobial potential have been the much sought after strategies. This approach could be an effective frontline defense against microbial interference in tissue engineering and biomedical applications. An overview on the antimicrobial potential of polysaccharides as bioinks for 3D bioprinting has been critically reviewed.

An Overview of Current Knowledge on the Properties, Synthesis and Applications of Quaternary Chitosan Derivatives

Chitosan, a chitin-derivative polysaccharide, known for its non-toxicity, biocompatibility and biodegradability, presents limited applications due to its low solubility in neutral or basic pH medium. Quaternization stands out as an alternative to modify this natural polymer, aiming to improve its solubility over a wide pH range and, consequently, expand its range of applications. Quaternization occurs by introducing a quaternary ammonium moiety onto or outside the chitosan backbone, via chemical reactions with primary amino and hydroxyl groups, under vast experimental conditions. The oldest and most common forms of quaternized chitosan involve N,N,N-trimethyl chitosan (TMC) and N-[(2-hydroxy-3-trimethyl ammonium) propyl] chitosan (HTCC) and, more recently, quaternized chitosan by insertion of pyridinium or phosphonium salts. By modifying chitosan through the insertion of a quaternary moiety, permanent cationic charges on the polysaccharide backbone are achieved and properties such as water solubility, antimicrobial activity, mucoadhesiveness and permeability are significantly improved, enabling the application mainly in the biomedical and pharmaceutical areas. In this review, the main quaternized chitosan compounds are addressed in terms of their structure, properties, synthesis routes and applications. In addition, other less explored compounds are also presented, involving the main findings and future prospects regarding the field of quaternized chitosans.

A facile route to transfer Cu nanoparticles to organic medium for better stabilization and improved photocatalytic activity towards N-formylation reaction

Cu nanoparticles were prepared in an aqueous phase by means of a simple reduction-route using sodium borohydride as the reducing agent in the presence of ascorbic acid and polyvinylpyrrolidone (PVP). The hydrosol of the Cu nanoparticles deteriorated within a day. It compelled to initiate a scheme to stabilize the nanoparticles for a long period of time. Phase transfer to organic solvents using Benzyldimethylstearylammonium chloride (BDSAC) as a phase transfer agent was found to be an effective path in this respect. BDSAC performed the dual role of dragging the Cu nanoparticles from water to organic solvent and also acted as a capping agent along with PVP for better stabilization of Cu nanoparticles. The organosol of the Cu nanoparticles exhibited excellent stability and promising catalytic activity towards N-formylation reactions on a number of amine substrates in presence of visible green LED light. The yield and reusability of the catalyst were promising. All the samples were thoroughly characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, energy dispersive analysis of x-rays, x-ray photoelectron spectroscopy and thermo gravimetric analysis.

Controlled Release of Spirotetramat Using Starch-Chitosan-Alginate-Encapsulation

This study was intended to develop an environment-friendly controlled release system for spirotetramat in an alginate matrix. Four formulations, starch-chitosan-calcium alginate (SCCA), starch-calcium alginate (SCA), chitosan-calcium alginate (CCA), and calcium alginate (CA) complex gel beads, were prepared by the extrusion-exogenous gelation method. The properties of the formulations were studied. The results showed that the release behaviors of the formulations in water could be well described by the logistic model, and the release occurred through Fickian diffusion. Among the four formulations, SCCA showed the highest entrapment efficiency, drug loading and the slowest release rate. Degradation studies revealed that the SCCA formulation exhibited an obvious slower degradation rate of spirotetramat in soils than the commercially available formulation. The estimated half-life of the SCCA formulation was 2.31, 3.25, and 4.51 days in waterloggogenic paddy soil, purplish soil, and montmorillonite, respectively, when the soils were moistened to 60% of its dry weight. This study provided a possible approach to prolong the duration of spirotetramat and to reduce environmental contamination.

The antioxidant and antifungal activity of chitosan derivatives bearing Schiff bases and quaternary ammonium salts

In order to improve the antioxidant and antifungal activity of chitosan, eight chitosan derivatives containing Schiff bases and quaternary ammonium salts were synthesized via an intermediate 6-O-chloroacetyl-2-N,N,N-trimethyl quaternary ammonium salt chitosan. Detailed structural characterization was carried out using FTIR and ¹H NMR spectroscopy, and elemental analysis. The antifungal activity against F. oxysporum f. sp. cucumerium, B. cinerea, and F. oxysporum f. sp. niveum was evaluated using a mycelium growth rate test. The results indicated that the chitosan derivatives exhibited enhanced antifungal activity when compared to chitosan, especially at 1.0 mg/mL. 6-[4-(2,3-dihydroxyl-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (2.3HBPATC), 6-[4-(2,3,4-trihydroxyl-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (2.3.4HBPATC), 6-[4-(2-fluorine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (FBPATC), 6-[4-(2-chlorine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (CBPATC), 6-[4-(2-bromine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (BBPATC), and 6-[4-(2-hydroxyl-4-chlorine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (HCBPATC) showed inhibitory indices >90.0% at 1.0 mg/mL against F. oxysporum f. sp. cucumerium and B. cinerea. Furthermore, the chitosan derivatives showed stronger antioxidant activity than chitosan, especially 2.3HBPATC and 2.3.4HBPATC with inhibitory indices of 100.0% at 1.6 mg/mL against DPPH and superoxide radicals. Based on these data, it is reasonable to suggest that the introduction of phenolic hydroxyl and halogen groups enhances the antifungal and antioxidant activity of chitosan.

Inhibition of naphthalene leaching from municipal carbonaceous waste by a magnetic organophilic clay

Municipal solid waste conversion into biofuels via gasification is one of the latest technologies to divert waste from landfills. The byproduct of the process is a carbonaceous material, which is often tainted with polycyclic aromatic hydrocarbons (PAH) such as naphthalene that can leach into the environment and have toxic effects on aquatic organisms. In this paper, we present a novel method to address the issue of leachable naphthalene in a carbonaceous waste produced from a gasification process, using a magnetic sorbent. The sorbent was fabricated by the coprecipitation of iron oxide nanoparticles on an organophilic clay under atmospheric conditions. The characterization results show that the intercalated nanoparticles are predominantly magnetite with a diameter of 15-20 nm, and increase the clay specific surface area from 0.4 to 17 m² g^-1. Toxicity characteristic leaching procedure results indicate that the magnetic composite has a high naphthalene inhibition efficiency comparable to that of the original clay. As opposed to the clay alone, the magnetic hybrid can be separated from the carbonaceous waste with a magnet, regenerated by heat treatment, and reused without compromising its naphthalene removal efficiency. Thus, these composites may provide a cost-effective method to curtail leaching of PAH from contaminated carbonaceous waste.

Antibacterial activity of PEO nanofibers incorporating polysaccharide from dandelion and its derivative

A water-soluble antibacterial polysaccharide from dandelions (PD) was chemically modified to obtain its carboxymethylated derivative (CPD). The degree of substitution of CPD was 0.455. Fourier transform infrared (FTIR) spectra analysis, zeta potential, particle size and rheological test verified the carboxymethylation of PD, accompanying with the change of physicochemical properties. Moreover, Listeria monocytogenes treated with 10 mg/mL PD and CPD achieved 1.96 and 3.29 log CFU/mL reduction in population, respectively. Subsequently, PD and CPD were incorporated into polyethylene oxide (PEO) nanofiber matrix to fabricate antimicrobial nanofibers. The prepared nanofibers were characterized by scanning electron microscope, atomic force microscope and FTIR. Finally, both PD/PEO and CPD/PEO nanofibers exhibited favourable antibacterial effect on L. monocytogenes, with an improved antibacterial activity of CPD/PEO nanofibers than PD/PEO nanofibers. In conclusion, this study demonstrated PD and CPD could be applied to the fabrication of antibacterial food packaging.