To explore the application of chitosan–gentamicin conjugate (CS-GT) in inhibiting Vibrio parahaemolyticus (V. parahaemolyticus), which is an important pathogen in aquatic animals worldwide, the ...antimicrobial activity of CS-GT and the effects of a CS-GT dose on the intestine histopathology and intestinal flora of V. parahaemolyticus-infected shrimps were explored. The results showed that CS-GT possessed broad-spectrum antibacterial activity, with minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and half inhibitory concentration (IC50) of 20.00 ± 0.01, 75.00 ± 0.02 and 18.72 ± 3.17 μg/mL for V. parahaemolyticus, respectively. Further scanning electron microscope and cell membrane damage analyses displayed that the electrostatic interaction of CS-GT with cell membrane strengthened after CS grafted GT, resulting in leakage of nucleic acid and electrolytes of V. parahaemolyticus. On the other hand, histopathology investigation indicated that high (100 mg/kg) and medium (50 mg/kg) doses of CS-GT could alleviate the injury of a shrimp’s intestine caused by V. parahaemolyticus. Further 16S rRNA gene sequencing analysis found high and medium dose of CS-GT could effectively inhabit V. parahaemolyticus invasion and reduce intestinal dysfunction. In conclusion, CS-GT possesses good antibacterial activity and could protect shrimps from pathogenic bacteria infection.
Most studies on enhanced polymer gels look at modifying the interaction between the polymer matrix and fillers. Here, a new strategy is proposed for the fabrication of a new kind of ...polyacrylamide/Ca(OH)2 nanocomposite organogel with tunable mechanical properties and temperature tolerance. By changing the solvent component, the properties of an organogel can be modulated without adding further reinforcing agent. Two commonly used organic solvents, glycerin (GL) and ethylene glycol (EG), were used in different weight ratios (GL:EG = 100:0, 70:30, 50:50, 30:70, 0:100) to achieve modulation of the organogel properties. At 25 °C the compressive strength could be regulated in the range 18–29 MPa at 95% strain, and it could be kept in the range 12–46 MPa within the temperature range −25 °C–110 °C. Increasing the proportion of GL, which has a high boiling point, the high and low temperature tolerance of the organogel was strengthened significantly. The EG served as a lubricant and enhanced the tensile recoverability from 77% to 84%. Overall, the properties of the organogel were the best when the GL:EG ratio was 70:30. The solvent-switchable organogel fabricated in this study is a good candidate for extending the field of application of gel materials.
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•A novel polyacrylamide/Ca(OH)2 nanocomposite organogel with two-component solvent was created via in-situ polymerization.•Through a solvent exchange, the performances of the organogel can be modulated.•This organogel can be used under extreme temperature ranging from 110 °C to −25 °C and keep a high elasticity .•Glycerin intensifies temperature tolerance and ethylene glycol strengthens tensile recoverability of the organogel.•This novel alterable organogel can solve the problem that smart gel materials need to fulfill the varying demands.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Marine microalgae can be used as sustainable protein sources in many fields with positive effects on human and animal health. DAPTMGY is a heptapeptide isolated from
which is a microalga. In this ...study, we evaluated its anti-photoaging properties and mechanism of action in human immortalized keratinocytes cells (HaCaT). The results showed that DAPTMGY scavenged reactive oxygen species (ROS) and increase the level of endogenous antioxidants. In addition, through the exploration of its mechanism, it was determined that DAPIMGY exerted anti-photoaging effects. Specifically, the heptapeptide inhibits UVB-induced apoptosis through down-regulation of p53, caspase-8, caspase-3 and Bax and up-regulation of Bcl-2. Thus, DAPTMGY, isolated from
, exhibits protective effects against UVB-induced damage.
Development of novel and versatile approaches to engineer composites with light density, broad effective bandwidth and high microwave absorption (MA) capacity is of great importance. Here, ...co-continuous natural rubber/epoxidized natural rubber (NR/ENR) blends with a selective distribution of conductive carbon black nanoparticles (CCBs), have been fabricated by tow-roll mixing. ENR with abundant epoxide groups shows inferior wettability to CCB than NR, which is responsible for the preferential location of CCB in the NR/ENR blend. Increasing the epoxidation level of ENR promotes the preferential location of CCB and creates stronger dielectric loss, thus enhancing the MA properties of CCB/NR/ENR composites. When the epoxidation level increases to 40 mol%, the MA capacity of the composite has been significantly enhanced by 40%. Meanwhile, the qualified frequency bandwidth (RL < −10 dB) of composites with ENR is 85% broader than that of CCB/NR composites. Such a novel approach of compatibility-tuned nanoparticles distribution in co-continuous rubber blends will significantly promote the multi-functional use of rubber and carbonaceous resources.
Carbon black incorporated natural rubber/epoxidized natural rubber composites with enhanced microwave absorption capacity have been designed by a novel approach of compatibility-tuned nanoparticles distribution in co-continuous rubber blends.
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IJS, KILJ, NUK, UL, UM, UPUK
The oyster shell powder/natural rubber composites were successfully prepared by blending the modified oyster shell powder with natural rubber (NR). The oyster shell powder with a particle size of 209 ...nm were well distributed within the rubber matrix. The characteristic Fourier transform infrared spectroscopy (FTIR) absorption bands of both oyster shell powder and natural rubber were observed in the FTIR spectra of NR/oyster shell powder composites. The C-O absorption bands in carbonates of composites exhibit a shift from 1425 cm−1 to 1446 cm−1 which suggests the bonds formed among oyster shell powder, earth coupling agent and NR. The tensile strength and stress at 500% elongation increased with rising of the earth coupling agent. Composites with 1.5 parts per hundred rubber (phr) coupling agent achieved the highest mechanical properties, where an increase of 13.4% in tensile strength was found. The tensile strength and tear strength increased along with an increment of oyster shell powder. When the content of oyster shell powder attained 25–30 phr, the composites exhibited the best mechanical properties. In particular, the tensile strength and tear strength increased by 27.9% and 17.2% when compared with those of the control samples. Furthermore, the addition of the oyster shell powder leads to the improvement of thermal stability which is evidenced by an increase of 8 °C in the initial degradation temperature. The improvement of the mechanical properties and thermal stability of the composites have demonstrated that the oyster shell powder can be used as potential fillers for natural rubber.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
As a natural antibacterial agent with pleasant fragrance, citral possesses low aqueous solubility. To improve citral loading in hydrophilic nanofiber, Pickering emulsion electrospinning strategy was ...proposed for anti-infection dressing development. The in-situ aggerated β-cyclodextrin-citral inclusion complex particles (βCPs) were used as emulsion stabilizers, while citral and carboxymethyl chitosan (CMCS)/polyvinyl alcohol (PVA) mixed solutions were used as the inner “dispersed oil phase” and outer “continuous water phase”, respectively. The results of electronic microscope investigation shown βCPs possessed regular cube appearances with a size of 5.5 ± 2.2 μm, which might improve the emulsion storage stability based on visual investigation. Moreover, randomly oriented and bead-on-string nanofibers with βCPs uniformly distributed could be obtained under optimized compositions and electrospinning parameters. Despite volatilization during electrospinning, nanofibers with high citral loading possessed good antibacterial performance against Staphylococcus aureus and Escherichia coli. In vitro hemolysis test indicated that nanofibers were hemocompatible. In addition, both fiber matrix and citral could promote the proliferation of mouse fibroblast cells. And the permeability of the fibers was adjustable. Thus, CMCS/PVA/βCPs/citral nanofibers could potentially protect wound from infection. In summary, CMCS/PVA/βCPs/citral nanofibers seemed to be promising alternatives to conventional wound dressings.
Pickering emulsion fabrication and electrospinning. Display omitted
•β-Cyclodextrin inclusion complex particle was used as a novel emulsion stabilizer.•Uniform nanofibers were fabricated via Pickering emulsion electrospinning.•Nanofibers with high loading of citral possessed excellent antibacterial activity.•Nanofibers have shown good hemocompatibility and cytocompatibility.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Photothermal material is indispensable for the fabrication of solar steam generation with easy-manufacture, cost-effective, and high-performance. Here, Ti2O3/polyacrylamide/polyurethane foams ...(Ti2O3/PU/PAM) were rationally designed, applying the synergetic effects from ball-milled Ti2O3, hydrophilic PAM, and heat-retaining structure of PU foam. With virtues of reduced evaporation enthalpy, abundant water transport pathways, and effective thermal insulation, the resulting Ti2O3/PU/PAM photothermal foam exhibits a high evaporation rate of 2.15 kg m−2 h−1 and a water evaporation efficiency of 140.42 % under 1 sun (1 kW m−2). In addition, the results of this study can serve as a reference for highly efficient, green, and recyclable seawater desalination. It is envisioned that the results of this study provided a strategy to fabricate novel photothermal materials for highly efficient, clean, and long-term solar steam generation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Bacterial infections have always been a major threat to public health, and the development of effective antibacterial substances from natural polymers is crucial. 2-Aminoisonicotinic acid (AN) was ...grafted onto chitosan by 1-ethyl-(3-dimethylaminopropyl)carbodiimide-mediated coupling reactions, and then modified chitosan‑iodine (CSAN-I) complexes were prepared by solvent-assisted grinding. The samples were characterized using ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, proton nuclear magnetic resonance spectroscopy, and X-ray diffraction, confirming that CSAN-I complexes had been successfully prepared. Thermogravimetric (TG) analysis indicated that the chemical modification of chitosan and iodine complexation reduced the thermal stability; X-ray photoelectron spectroscopy (XPS) analysis revealed that 81 % of the iodine in CSAN-I complex was in the form of triiodide ions. The iodine contents of three CSAN-I complexes (CSAN-I-1, CSAN-I-2 and CSAN-I-3) were 1.59 ± 0.22 %, 3.18 ± 0.26 %, and 5.56 ± 0.41 %, respectively. The antibacterial effects were evaluated in vitro, and the results indicated that CSAN-I complexes had strong antibacterial activities against both E. coli and S. aureus. In particular, CSAN-I-3 exhibited the best antibacterial effect. In addition, CSAN-I-3 was nontoxic to L929 cells with good cytocompatibility. Therefore, CSAN-I complexes can be considered as promising candidates for wound management in clinical applications.
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•Modified chitosan-iodine (CSAN-I) complex was prepared by solvent-assisted grinding.•CSAN-I complex was characterized and its structure was validated.•CSAN-I complex showed strong antibacterial activities and good cell compatibility.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
As a natural antibacterial agent, Tea tree oil (TTO) possesses low aqueous solubility. To load TTO in hydrophilic hydroxyethyl chitosan/polyvinyl alcohol nanofiber matrix, Pickering emulsion ...electrospinning strategy using ZnO/Ag nano composite (ZA) as stabilizer was proposed for anti-infection dressing development. Under the stabilizing assistance of ZA particles in the size range of 53 and 59 nm, Pickering emulsions with homogenously distributed TTO droplets show good stability, which can be further elctrospun into continuously bead-on-string nanofibers under optimized processing conditions. In spite of the volatilization of TTO during electrospinning, the nanofibers possess good and long-term antibacterial activity against both gram-positive and gram-negative bacteria. In vitro experiments indicated that the nanofibers possess superior hemocompatibility and cytocompatibility. Particularly, it can promote the cell proliferation and migration when its concentration is 800 μg/mL or less. In conclusions, Pickering emulsion electrospinning is a feasible strategy for the fabrication of nanofibers loaded with hydrophobic TTO and the as-obtained nanofibers can be potentially applied in infected wounds.
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•ZnO/Ag nano composite can stabilize tea tree oil (TTO) Pickering emulsions effectively.•TTO can be encapsulated into homogenous nanofibers via Pickering emulsion electrospinning.•Nanofibers possess superior hemocompatibility and cytocompatibility.•Nanofibers show good and long-term antibacterial activity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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