Good Antimicrobial Properties Research Articles

Low-cost bacterial cellulose production from agricultural waste for antibacterial applications

Various carbon sources can be utilized for the biosynthesis of bacterial cellulose (BC), with agricultural wastes being explored as sustainable options. In this study, glucose was extracted from bamboo dust via mild acid hydrolysis to prepare a modified medium combining extracted glucose with Hestrin-Schramm (HS) medium for BC biosynthesis using Acetobacter xylinus NCIM 2526. Chitosan, a biopolymer, was incorporated into the BC synthesis medium at concentrations of 0.2%, 0.6%, and 1% (w/v) after 2 days of shaking incubation, producing chitosan-incorporated BC membranes through in situ synthesis. Fourier transform infrared (FTIR) spectroscopy confirmed cellulose in the BC produced from the modified medium and chitosan in BC membranes with 0.2% and 0.6% (w/v) chitosan. Changes in physical and crystalline morphology were further characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The purity of cellulose was validated through chemical solubility tests, while energy-dispersive X-ray (EDX) analysis confirmed the presence of chitosan in the BC membranes. The average yields were 5.8 ± 0.21 g/l for pure BC, 5.2 ± 0.21 g/l for BC with 0.2% (w/v) chitosan, and 4.6 ± 0.21 g/l for BC with 0.6% (w/v) chitosan after 7 days. The medium with 1% (w/v) chitosan did not produce BC membranes. BC synthesized with 0.2% chitosan exhibited similar physical and chemical properties to pure BC and demonstrated good antimicrobial properties, suggesting its potential use in bandages and wound dressings.

Interferometric analysis of the opto‐mechanical properties for polyamide‐6 antimicrobial fibers

AbstractPolyamide‐6 fibers were modified for use as antimicrobial fibers using two complementary methods: grafting with polyacrylic acid and silver nanoparticle treatment. The grafted samples exhibited different grafting yields of 7%, 8.8%, 10%, and 20.7%. Subsequently, two grafted samples (7% and 20.7% yields) were treated with silver nanoparticles (Ag NPs). The grafting process and the silver nanotreament were successfully confirmed using FTIR spectroscopy and SEM microscopy. Shake‐ flask method was used to study the cell viability of nanotreated samples. A two‐beam Mach–Zehnder interferometer was used to characterize the opto‐mechnaical and structural properties of the modified samples. For this purpose, a mechanical drawing device was equipped with the interferometer. The results indicated that with increasing grafting yield, optical properties decreased in both directions of light vibration. A fitting method was employed to calculate intrinsic optical properties that help to determine structural properties. Mechanical properties, including tensile strength and elongation at break, were also examined. Treatment of the grafted samples with silver nanoparticles improved their optical, mechanical, and antimicrobial properties. These findings confirmed that the PA‐6‐g‐PAA 20.7%‐t‐Ag NPs sample is suitable for various medical applications. Figures and tables are provided for illustration.Highlights PA‐6 fiber has been modified for medical applications by complementary processes. Grafting process introduced additional functional groups and enhanced ductility. Ag nano‐treatment gives the grafted PA‐6 fiber good antimicrobial activity. Interferometry precisely characterizes structural and opto‐mechanical properties. PA‐6‐g‐PAA20.7%‐t‐Ag NPs sample has good mechanical and antimicrobial properties.

Cu2O/H2Ti3O7/Cellulose biohybrid film with efficient photocatalytic and antibacterial activities in solar-driven environmental decontamination

Increasing efforts have been devoted to cellulose-based multifunctional biomaterials for environmental applications. In this study, solvothermal method combined with impregnation reduction process of Cu2+ has been developed to create versatile Cu2O/H2Ti3O7/CP (cellulose paper) biocomposite films that demonstrates efficacy in treating wastewater from organic compounds, disinfecting it from microbes and also purifying the air from volatile organic compounds (VOCs). H2Ti3O7 nanosheets decorated with Cu2O nanoparticles exhibit an excellent visible-light responsibility. Furthermore, the Cu2O/H2Ti3O7/CP biocomposite film demonstrated enhanced efficacy in removing aniline in the liquid phase and 1-propanol in the gaseous phase compared to the H2Ti3O7/CP. This enhanced photocatalytic activity is primarily due to the synergistic effect between Cu2O and H2Ti3O7, which suppresses the recombination of charge carriers and improves their mobility. Reuse tests confirm the stability of the prepared hybrid photocatalyst. Moreover, the biocomposite exhibits good antimicrobial properties, which contributed to the effective inactivation of Escherichia coli. This proves its versatility as a photocatalyst for a broad range of biological and environmental applications.

Nanocellulose‐polypropylene composites with novel antimicrobial complex salt

AbstractPolypropylene composites with different contents of zinc‐ammonium salts (3, 5 and 7 wt%) and nanocellulose (1 wt%) after enzymatic bioconversion were characterized by structural, dispersion‐morphological, thermal, antimicrobial and mechanical analysis. It was shown that the use of a newly synthesized salt significantly affected the formation of the supermolecular structure of the polymer matrix and increased the nucleation activity, thermostability and flexibility of the composite materials. Moreover, the addition of the inorganic filler allowed to obtain composites with very good antimicrobial properties against Staphylococcus aureus, Escherichia coli and Candida albicans. An interesting relationship between the degree of filler dispersion in the polymer matrix and the formation of polymorphic varieties was elucidated in the study, which contributes to the improvement of final performance characteristics of composite materials. It is noteworthy that a hybrid filler in the form of nanometric cellulose and a biocidal additive containing zinc‐ammonium complex salt was used for the first time. Research has shown that such polymer composites can find application during the manufacture of smart packaging materials with enhanced barrier properties against oxygen and water vapor as well as improved biocidal characteristics, which will notably extend food storage time. At the same time, the presented process of obtaining the innovative composite materials is an excellent example of sustainable technologies for the design of antimicrobial treatments, while guaranteeing the possibility of further processing of these composite materials through material recycling.Highlights Zinc‐ammonium complex with antimicrobial properties was obtained The strength properties and thermal stability of the composites were improved Degree of filler dispersion in polymer affects formation of polymorphic varieties The composites can be applied in the production of smart packaging materials

Multifunctional injectable oxidized sodium alginate/carboxymethyl chitosan hydrogel for rapid hemostasis

Uncontrolled bleeding from incompressible or irregularly shaped wounds is a major factor in the death of people in the battlefield or surgery process. Ideal rapid hemostatic materials should have the performance of rapid hemostasis and at the same time can be applied to a variety of complex wound trauma types, in addition, excellent antimicrobial properties, adhesion, biocompatibility, degradation, and the non-toxicity of degradation products are also necessary, but there are fewer hemostatic materials that meet these requirements. Herein, we prepared an injectable hemostatic hydrogel based on the natural products sodium alginate (SA) and carboxymethyl chitosan (CMC). Oxidized sodium alginate (OSA) was prepared by the oxidation reaction of NaIO4 with SA, and OSA with aldehyde group was mixed with CMC with amino group to rapidly form an in situ injectable hemostatic hydrogel (OSA/CMC) by the Schiff base reaction. OSA/CMC hydrogel exhibited excellent antimicrobial and adhesion properties by the Schiff base reaction. In addition, OSA/CMC hydrogel directly activate the endogenous coagulation pathway through the synergistic effect of OSA, CMC to enhance the hemostatic effect. The results of in vivo hemostasis study showed that OSA/CMC hydrogel significantly accelerated hemostasis and reduced blood loss in liver hemorrhage model and tail amputation model. Therefore, OSA/CMC hydrogel is expected to be a potential material in the direction of rapid clinical hemostasis due to its good adhesion properties, antimicrobial properties, biocompatibility, blood compatibility, and efficient rapid hemostasis.

Enhanced osseointegration and antimicrobial properties of 3D-Printed porous titanium alloys with copper-strontium doped calcium silicate coatings.

The 3D printing of porous titanium scaffolds reduces the elastic modulus of titanium alloys and promotes osteogenic integration. However, due to the biological inertness of titanium alloy materials, the implant-bone tissue interface is weakly bonded. A calcium silicate (CS) coating doped with polymetallic ions can impart various biological properties to titanium alloy materials. In this study, CuO and SrO binary-doped CS coatings were prepared on the surface of 3D-printed porous titanium alloy scaffolds using atmospheric plasma spraying and characterized by SEM, EDS, and XRD. Both CuO and SrO were successfully incorporated into the CS coating. The in vivo osseointegration evaluation of the composite coating-modified 3D-printed porous titanium alloy scaffolds was conducted using a rabbit bone defect model, showing that the in vivo osseointegration of 2% CuO-10% SrO-CS-modified 3D-printed porous titanium alloy was improved. The in vitro antimicrobial properties of the 2% CuO-10% SrO-CS-modified 3D-printed porous titanium alloy were evaluated through bacterial platform coating, co-culture liquid absorbance detection, and crystal violet staining experiments, demonstrating that the composite coating exhibited good antimicrobial properties. In conclusion, the composite scaffold possesses both osteointegration-promoting and antimicrobial properties, indicating a broad potential for clinical applications.

High mechanical performance and multifunctional degraded fucoidan-derived bioink for 3D bioprinting

While 3D bioprinting serves as a powerful tool in the field of tissue engineering, there is still a lack of natural biomaterial inks that simultaneously combine high mechanical performance with multiple biofunctionalities. Here, a single-component natural bioink with high strength and multi-biofunctionality was developed through the simple degradation and methacrylation of natural fucoidan. Hydrothermal degradation significantly decreased the natural fucoidan solution's viscosity by 99.9 %, meeting the necessary viscosity for Digital Light Processing (DLP) 3D printing. Meanwhile, various biofunctionalities of low molecular weight fucoidan obtained through degradation, such as antimicrobial and antioxidant properties, were developed. The resulting bioink exhibited good mechanical performance (compression modulus of 311 kPa), antimicrobial properties (antibacterial rates of 95.5 % and 97.9 % against E. coli and S. aureus, respectively), and antioxidant properties (intracellular ROS inhibition rates of 94.7 %). Using DLP 3D bioprinting, all printed products showed high shape fidelity with exceptional viability and activity of the encapsulated cells. Due to the unique sulfate structure resembling the natural components of chondroitin sulfate, the in vivo tests revealed its efficacy in promoting cartilage defect repair. In conclusion, the novel bioink blending high mechanical performance with multiple biofunctionalities, shows great potential in the 3D printing of tissue and organ regeneration.

Comparative antioxidant and antimicrobial activities of Nigella sativa flower, leaf, stem, and seed derived silver nanoparticles

This study was aimed to synthesize biogenic silver nanoparticles (AgNPs) using Nigella sativa (N. sativa) plant extracts as bio-reductant. The fabricated nanoparticles were characterized by UV–visible, FTIR, and XRD. The extracts and AgNPs were then evaluated for their antioxidant and antimicrobial potentials using DPPH (2, 2-diphenyl-1-picrylhydrazyl) assay and agar well diffusion assay correspondingly. The color change from pale yellow to tan brownish confirmed the fabrication of nanoparticles. The broad peak from 420 to 430 in the UV–Visible spectrum also confirmed AgNPs formation. In XRD spectrum the peaks indices (111), (200), (220), and (311) belonging to 2θ values of 38.101, 44.370, 64.179, and 77.549 indicated the presence of silver crystals (JCPDS file no. 00-001-1167). The presence of organic functional groups in the FTIR spectra confirmed the involvement of plant phytochemicals in fabrication of nanoparticles. Comparatively strong antioxidant potential was recorded for silver nanoparticles in comparison to parental extract. The lowest IC50 recorded was in the case flower based AgNPs was 70 µl where it corresponding crude extract resulted in IC50 of 910 µl. Highest IC50 was recorded for stem extract based NPs (100 µl). The antifungal potential of AgNPs from flower was high (24 mm) and that of the stem extract-based NPs was low (19 mm) whereas the antibacterial potential of the stem and seed extract-based extract was comparable however, the leaf and flower-based extract-based NPs were also, substantial. It was concluded from the results that all the whole Nigella sativa plant contained the reductant phytochemicals which be effectively used to fabricate NPs of the desired sizes. The fabricated NPs also exhibited good antioxidant and antimicrobial properties and can be considered as alternative drugs subjected to further verifications of the results in animal model.

Injectable Salecan/hyaluronic acid-based hydrogels with antibacterial, rapid self-healing, pH-responsive and controllable drug release capability for infected wound repair

Designing materials for wound dressings with superior therapeutic benefits, self-healing and injectable characteristics is important in clinical practice. Herein, a new self-healing injectable hydrogel was prepared via thermal treatment and dynamic Schiff base reaction by mixing oxidized hyaluronic acid (OHA) and hydrazided Salecan (Sal-ADH). The versatility of the wound dressing was confirmed by studying the inherent rheological properties, high swelling rate, sustained-release behavior of the drug, pH/hyaluronidase-dependent biodegradation, in vitro antimicrobial as well as in vivo wound healing performance. The presence of the antimicrobial drug polyhexamethylene biguanide (PHMB) conferred good antimicrobial properties to the Sal-ADH/OHA/PHMB (SOP) hydrogel, which could effectively prevent wound infection (the width of the inhibition circle of SOP-0.20 hydrogel was 4.97 mm, 5.93 mm for Staphylococcus aureus and Escherichia coli, respectively). The findings suggested that SOP hydrogel exhibited remarkable self-healing and injectability properties, as well as excellent hemostasis and biocompatibility. In vivo experiments indicated that the application of SOP hydrogels would obviously accelerate wound healing and attenuate the inflammatory response while increasing collagen deposition and angiogenesis. Altogether, antibacterial SOP hydrogels with moderate mechanical properties, pH-responsive release, excellent injectability, exceptional self-healing ability and anti-inflammatory effects could expand potential applications of injectable hydrogels in the biomedical field.

Novel Synthesis and Biophysical Characterization of Zinc Oxide Nanoparticles Using Virgin Coconut Oil.

One of the primary concerns in the field of green synthesis of nanoparticles (NPs) utilizing plant materials is the scarcity of high purity, challenges in achieving large-scale production, and limited global accessibility. Hygienic preparation and safe storage of plant extracts are also considerable challenges in this field. So, an investigation was started to overcome these limitations. Virgin coconut oil (VCO) in its purest form is available commercially all over the world. Also, it has high medicinal value with excellent biomedical applications. Very limited work has been reported on oils as bio reducers and stabilizers. In those reports, they used a few chemicals as mediators in the processes of synthesis and cleaning. So, to the best of our knowledge, for the first time, zinc oxide (ZnO) NPs were synthesized using VCO as a reducing and capping agent with zero chemical mediators. A comprehensive investigation of the structural, microstructural, and optical properties was reported. X-ray diffraction confirms the formation of VCO-ZnO NPs with an average crystallite size of 32.81 nm in a hexagonal structure. UV characteristics confirm quantum confinement through a well-defined SPR near 223 nm with fwhm of 67 nm and a direct band gap at 3.96 eV. FTIR reveals the capping of VCO through carboxylic functional groups, particularly the -COO- group of coconut oil at 1770 cm-1 with a shift of about 30 cm-1 compared to plain VCO. TEM confirms the polycrystalline nature with nearly spherical and 10-22 nm particle size. The zeta potential of -15.4 ± 5.0 mV signifies the stability and antiagglomeration properties. FESEM with EDS results confirms morphological excellence, the purity level of synthesized NPs (99.5%), and the prominent scalability of NPs (84.38% yield). Finally, as-synthesized VCO-ZnO NPs showed very good antioxidant (IC50 78.991, 51.464, and 4.677 μg/mL in DPPH, ABTS, and FRAP assays, respectively), anti-inflammatory (IC50 22.42 μg/mL in protein denaturation), antimicrobial (MIC 0.156 mg/mL for Pseudomonas and 0.316 mg/mL for S. aureus), and antidiabetic properties (IC50 88.45 and 147.67 μg/mL for α-amylase and α-glucosidase assays, respectively).

Enhancing the porosity of chitosan sponges with CBD by adding antimicrobial violacein

Given the growing interest in non-toxic materials with good anti-inflammatory and antimicrobial mechanical properties, this work focuses on preparing chitosan sponges with violacein and cannabis oil crosslinked with dialdehyde chitosan. The sponge was tested for its physicochemical and biological properties, presenting a high swelling rate, good thermal stability, and satisfactory mechanical properties. The obtained sponge's water vapor transmission rate was 2101 g/m2/day and is within the recommended values for ideal wound dressings. Notably, adding violacein favorably affected the material's porosity, which is essential for dressing materials. In addition, studies have shown that the designed material interacts with human serum albumin and exhibits good antioxidant and anti-inflammatory properties. The antibacterial properties of the prepared biomaterial were assessed using the Microtox test against A. fisherii (Gram-negative bacterium) and S. aureus (Gram-positive bacterium). The investigated material provides potential therapeutic benefits due to the synergistic action of chitosan, violacein, and cannabis oil so that it could be used as a dressing material. The natural origin of the substances could provide an attractive and sustainable alternative to traditional commercially available dressings.

Development of magnesium hydroxide-doped nanofibrous spheres for repairing infected skin wounds

The healing of skin wounds is a continuous and coordinated process, typically accompanied by microbial colonization and growth. This may result in wound infection and subsequent delay in wound healing. Therefore, it is of particular importance to inhibit the growth of microorganisms in the wound environment. In this study, magnesium hydroxide-doped polycaprolactone (PCL/MH) nanofibrous spheres were fabricated by electrospinning and electrospray techniques to investigate their effects on infected wound healing. The prepared PCL/MH nanofibrous spheres had good porous structure and biocompatibility, providing a favorable environment for the delivery and proliferation of adipose stem cells. The incorporation of MH significantly enhanced the antimicrobial properties of the spheres, in particular, the inhibition of the growth of S. aureus and E. coli. We showed that such PCL/MH nanofibrous spheres had good antimicrobial properties and effectively promoted the regeneration of infected wound tissues, which provided a new idea for the clinical treatment of infected wounds.

A cleaner and eco-friendly approach to simultaneous extraction and characterization of essential oil and pectin from Assam lemon peel and its application for energy generation through TENG devices

Scientists have been working on developing a green bio-TENG for portable remote devices, including wearables in the biomedical sector. The process involves obtaining pectin, a green material with anti-microbial properties, as a Triboelectric material. This study focuses on the extraction of essential oil (EO) and pectin from Assam lemon peel simultaneously. A single-step strategy was optimized using a central composite design-based response surface approach. The extracted pectin yielded 4.19 ± 0.31 % and 11.53 ± 0.11 %, respectively. GC-MS analysis revealed 52 volatile components in the Assam lemon EOs, with limonin being 94.47 % and β-Bisabolene being 1.26 %. Only khusilal was found in the EOs, a rare discovery in the scientific domain. The extracted pectin showed good purity and antimicrobial properties. The in vitro activities of the citrus EO against microbial cultures revealed its activity in controlling and eradicating bacterial and fungal growth. Hydro distillation followed by enzyme treatment is a promising approach that combines two separate extraction procedures. The produced biopolymer showed the generation of electrical signals under minimal pressure and stretching and prevented microbial degeneration when applied to a nanogenerator.

Multibiofunctional Self-healing Adhesive Injectable Nanocomposite Polysaccharide Hydrogel.

Injectable hydrogels with good antimicrobial and antioxidant properties, self-healing characteristics, suitable mechanical properties, and therapeutic effects have great practical significance for developing treatments for pressing healthcare challenges. Herein, we have designed a novel, self-healing injectable hydrogel composite incorporating cross-linked biofunctional nanomaterials by mixing alginate aldehyde (Ox-Alg), quaternized chitosan (QCS), adipic acid dihydrazide (ADH), and copper oxide nanosheets surface functionalized with folic acid as the bioligand (F-CuO). Gelation was achieved under physiological conditions via the dynamic Schiff base cross-linking mechanism. The developed nanocomposite injectable hydrogel demonstrated the fast self-healing ability essential to bear deformation and outstanding antibacterial properties along with ROS scavenging ability. Furthermore, the optimized formulation of our F-CuO-embedded injectable hydrogel exhibited excellent cytocompatibility, blood compatibility, and in vitro wound healing performance. Taken together, the F-CuO nanosheet cross-linked injectable hydrogel composite presented herein offers a promising candidate biomaterial with multifunctional properties to develop solutions for addressing clinical challenges.

Innovative insights into the preparation of tamarind gum base film loaded with pomelo essential oil via a low-energy emulsion method combined with melatonin: Maximizing the dual functions of tamarind gum

Pomelo essential oil has good antioxidant and antimicrobial properties. The objective of this study was to modify the active packaging loaded with essential oil through low-energy emulsification, in order to achieve both film-forming and emulsifying properties of tamarind gum, and to investigate the surface activity of melatonin in the emulsion. When α:β mixing ratio of 60:40, the resulting film solution exhibited favorable apparent viscosity and reduced emulsion flocculation and precipitation phenomena. Particle size distribution analysis and optical microscopy results demonstrated that the obtained emulsion was uniformly dispersed at an α:β mixing ratio of 60:40, with droplet diameters mainly concentrated within the range of 1–100 μm. After undergoing film-forming treatment, E-3-F (α:β mixing ratio of 60:40) exhibited a smoother and more compact microstructure, leading to significant improvements in mechanical properties and barrier performance. Laser confocal microscopy imaging revealed that the addition of melatonin further reduced interfacial tension between oil and water, while simultaneously weakening hydrophobic interaction forces among oil droplets, thereby effectively inhibiting droplet aggregation behavior. Moreover, incorporation of melatonin also enhanced material compactness and imparted excellent antioxidant effects to the packaging material. Consequently, this study ultimately unveils potential for low-energy emulsification combined with melatonin application in bio-based packaging field while providing novel insights into developing multifunctional bio-based packaging.

Design Synthesis and Spectral Characterization of Novel Morpholine ring fused with Substituted Pyrazoline Derivatives as Promising Anticancer, Antimicrobial Activity of in vitro and in silico studies

A search for new anticancer agents has prompted the design and synthesis of new novel morpholine ring fused with substituted pyrazoline derivatives MCP 1-4 as potent anticancer agents. MCP compounds were synthesized and the compounds structures were elucidated using elemental analysis and spectroscopic techniques like FT-IR, 1H NMR and 13C NMR. MCP derivatives binding affinities values were predicted by Auto Dock version, which shows the MCP derivatives as good anticancer 1OQA protein and antimicrobial properties, bacterial protein 1UAG and 5KEE with good binding affinity values from -6.2 to -6.5 kcal/mole and -7.6 to -8.9 kcal/ mole respectively. Among the four MCP compounds, the compounds MCP-1,3 and 4 have the similar binding interaction values of 6.5 kcal/mole. The MCP derivatives have good virus inhibition activity and these compounds are docked with SARS COVID 19 CORONA virus protein 6LU7 to have the docking score values -7.4 to 7-7.6 kcal/ mole. In silico ADME predictions were carried for the synthesized MCP 1-4 derivatives by online tool Swissadme. MCP derivatives have the good log p value of <5. MCP derivatives were also evaluated by antimicrobial activity, the compound MCP-3 showed zone of inhibition values on all the sixteen bacterial cell lines. The compound MCP-3 was subjected to anticancer screening on MCF-7 cell line, the compound showed the good IC50 value.

Preparation of Green Silver Nanoparticles and Eco-Friendly Polymer-AgNPs Nanocomposites: A Study of Toxic Properties across Multiple Organisms.

This article focuses on the eco-friendly (green) synthesis of silver nanoparticles (AgNPs) and their incorporation into a polymer matrix. For AgNPs synthesis, Lavandula angustifolia (lavender) leaf extract was used as a reducing and stabilizing agent, and as a silver precursor, AgNO3 solution with different concentrations of silver (50, 100, 250, and 500 mg/L) was used. Prepared AgNPs colloids were characterized using UV-vis spectrophotometry, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The spherical morphology of AgNPs with an average size of 20 nm was confirmed across all samples. Further, the antimicrobial properties of the AgNPs were evaluated using the disk diffusion method on algae (Chlorella kessleri) and the well diffusion method on bacteria (Staphylococcus chromogenes, Staphylococcus aureus, and Streptococcus uberis), along with root growth inhibition tests on white mustard (Sinapis alba). Polymer composite (PVA-AgNPs) was prepared by incorporation of AgNPs into the polymer matrix. Subsequently, non-woven textiles and thin foils were prepared. The distribution of AgNPs within the nanocomposites was observed by scanning electron microscopy (SEM). Antibacterial properties of PVA-AgNPs composites were analyzed on bacteria Streptococcus uberis. It was found that not only AgNPs showed good antimicrobial properties, but toxic properties were also transferred to the PVA-AgNPs nanocomposite.

Antimicrobial ion-imprinted chitosan-derived hydrogel with quaternary ammonium and thermoresponsive components for UO22+ adsorption

Uranium recovery from wastewater or seawater is important for both pollution control and uranium supply. Due to the complexity of the water body, it requires that the adsorbent should not only be highly efficient for selective adsorption but also have good antimicrobial properties. In this study, an antimicrobial thermosensitive hydrogel (UITAC) for uranium adsorption was prepared by one-step ion-imprinted polymerization using chitosan as a substrate and allyl trimethylammonium chloride as the antimicrobial modifier. UITAC showed excellent antibacterial rate against Escherichia coli and Staphylococcus aureus, being 98.8 % and 89.1 %, respectively. Endothermic and exothermic peaks respectively showed up at 36.3–38.5 °C and 30.5–34.1 °C in the DSC curves. UITAC quickly achieved its adsorption equilibrium in 30.0 min at 50 °C, pH 5.0 in the 0.8 mg/mL UO22+ solution, with an adsorption capacity of 81.2 mg/g. The adsorption capacity could remain at 80 % after 5 cycles of repeated use. UITAC showed better adsorption selectivity to UO22+ than vanadium and other metal ions, with selectivity coefficients α(UO22+/Mn+) being 1.4–10.3. The pseudo-second-order kinetics and Langmuir adsorption model had a better fit for UO22+ adsorption by UITAC. The adsorption was a spontaneous process. The Gibbs Free Energy change, enthalpy change, and entropy change at 323.2 K were − 16.0 kJ/mol, 64.3 kJ/mol, and 248.4 J/mol·K, respectively. UITAC showed high potential in practical application environment.

Construction of multifunctional coating for polyester/cotton fabrics using layer-by-layer assembly of biomaterials and spraying of fluorine-free polydimethylsiloxane

Polyester/cotton (T/C) fabric has the excellent properties of both cotton and polyester, and is widely used in the textile field. However, the fabric is highly flammable. Further, the facile growth of bacteria on the fabric surface may lead to contamination that precludes application in some areas. Multifunctional T/C fabrics with flame retardancy, superhydrophobicity and antibacterial property have been prepared by construction a surface coating of phytic acid, chitosan, ferric ion and polydimethylsiloxane via a finishing method. The coated T/C fabric exhibits excellent flame retardancy with a LOI value of 30.2 % and a char length of 10.0 cm for combustion. The coated T/C fabrics also display superhydrophobicity with a water contact angle (WCA) greater than 150°. The multifunctional coated T/C fabrics exhibit good antibacterial properties with inhibition of bacterial growth for E. coli and S. aureus of over 98 %. Thermogravimetry and scanning electron microscopy suggest that the multifunctional coating on T/C fabrics produces an intumescent flame retardant effect involving both the promotion of char formation in the condensed phase and the evolution inert species to the gas phase to dilute the fuel load in the combustion zone. A new strategy for the preparation of textile fabrics with good flame retardancy, superhydrophobicity and antimicrobial properties by application of a multifunctional surface coating has been developed.

Esterification modified corn starch composite with chitosan and PVP for enhanced mechanical properties and antimicrobial freshness preservation of starch-based films

Traditional plastic packaging films may bring convenience to people, but may also bring fossil energy shortage and pollution problems. Thus, it is of great research significance to use renewable resources to develop biodegradable green packaging materials instead of traditional petroleum-based film materials. In this study, aryl esterified starch was prepared by graft modification of corn starch using acryloyl esterification. Then ES/CS/PVP composite film materials were prepared by introducing chitosan and polyvinylpyrrolidone (PVP) from esterified starch. Chitosan and PVP were introduced to greatly improve the antimicrobial and mechanical properties of the composite film. And the chemical structure and microscopic morphology of ES/CS/PVP were characterised by FT-IR, XRD, SEM and XPS. The results showed that the ES/CS/PVP composite film had excellent tensile properties and good antimicrobial freshness preservation properties. The maximum tensile strength reached 51.69 MPa and the water vapour permeability was 4.76 × 10−5 g/mm∙d. The results of antimicrobial freshness preservation experiments show that the composite film has excellent antimicrobial freshness preservation performance, enough to keep cherries with good freshness in 6 days.