Bio-Based Waterborne Poly(Vanillin-Butyl Acrylate)/MXene Coatings for Leather with Desired Warmth Retention and Antibacterial Properties

This study presents a solvent-free,facile synthesis of a bio-based green antibacterial agent and aromatic monomer methacrylated vanillin(MV)using vanillin.The resulting MV not only imparted antibacterial properties to coatings layered on leather,but could also be employed as a green alternative to petroleum-based carcinogen styrene(St).Herein,MV was copolymerized with butyl acrylate(BA)to obtain waterborne bio-based P(MV-BA)miniemulsion via miniemulsion polymerization.Subsequently,MXene nanosheets with excellent photothermal conversion performance and antibacterial properties,were introduced into the P(MV-BA)miniemulsion by ultrasonic dispersion.During the gradual solidification of P(MV-BA)/MXene nanocomposite miniemulsion on the leather surface,MXene gradually migrated to the surface of leather coatings due to the cavitation effect of ultrasonication and amphiphilicity of MXene,which prompted its full exposure to light and bacteria,exerting the maximum photothermal conversion efficiency and significant antibacterial efficacy.In particular,when the dosage of MXene nanosheets was 1.4 wt%,the surface temperature of P(MV-BA)/MXene nanocomposite miniemulsioncoated leather(PML)increased by about 15℃ in an outdoor environment during winter,and the antibacterial rate against Escherichia coli and Staphylococcus aureus was nearly 100%under the simulated sunlight treatment for 30 min.Moreover,the introduction of MXene nanosheets increased the air permeability,water vapor permeability,and thermal stability of these coatings.This study provides a new insight into the preparation of novel,green,and waterborne bio-based nanocomposite coatings for leather,with desired warmth retention and antibacterial properties.It can not only realize zerocarbon heating based on sunlight in winter,reducing the use of fossil fuels and greenhouse gas emissions,but also improve ability to fight off invasion by harmful bacteria,viruses,and other microorganisms.

Biological oyster shell waste enhances polyphenylene sulfide composites and endows them with antibacterial properties

To date,there is no research that deals with biological waste as fillers in polyphenylene sulfide(PPS).In this study,oyster shells were recycled and treated to prepare thermally-treated oyster shells(TOS),which were used as PPS fillers to make new bio-based antibacterial composite materials.The effect of varying the content of TOS was studied by means of structure and performance characterization.PPS/TOS composites were demonstrated to have an antibacterial effect on the growth of E coli and S.aureus.Qualitative analysis showed that when the TOS content was≥30%and 40%,the composite materials had an apparent inhibition zone.Quantitative analysis showed that the antibacterial activity increased with the TOS content.Fourier transform infrared spectroscopy indicated the formation of hydrogen bonds between the molecular chains of TOS and PPS and the occurrence of a coordination reaction.At 10%TOS,the composite tensile strength reached a maximum value of 72.5 MPa,which is 9.65%higher than that of pure PPS.The trend of bending properties is the same as that of tensile properties,showing that the maximum property was reached for the composite with 10%TOS.At the same time,the crystallinity and contact angle were the highest,and the permeability coefficient was the lowest.The fatigue test results indicated that for the composite with 10%TOS,the tensile strength was 23%lower than static tensile strength,and the yield strength was 10%lower than the static yield strength.The results of the study showed that TOS not only could reduce the cost of PPS,but also could impart antibacterial properties and enhance the mechanical and,barrier properties,the thermostability,as well as the crystallinity.

Effect of Electrodeposition Methods of Cuprous Oxide on Antibacterial Properties of Concrete

Three types of electrodeposition,DC electrodeposition,low-frequency pulsed electrodeposition and high-frequency pulsed electrodeposition,were used to deposit cuprous oxide on the concrete surface to improve the antibacterial properties of concrete.The effects of pulse deposition frequency on the antibacterial property of concrete were studied using sulfate-reducing bacteria(SRB)and Escherichia coli(E.coli)as model bacteria.The bacterial concentration and the antibacterial rate were measured to evaluate the antibacterial performance of concrete.The effects of different deposition methods on the elemental content of copper and the amount of copper ions exuded were studied.XRD and SEM were used to analyze the microstructure of the deposited layers.The experimental results show that the concrete treated by electrodeposition exhibited good antibacterial properties against SRB and E.coli.The antibacterial effect of cuprous oxide deposited on concrete by pulse method was better than that by direct current(DC)method.The antibacterial rate of concrete was positively correlated with the exudation rate of copper ion.As the pulse frequency increased,the deposits content on the surface was increased with an accompanying improvement in the antibacterial property.Besides,the pulsed current had an indiscernible effect on the composition of the sediments,which were all mainly composed of Cu_(2)O,but the morphology of the Cu_(2)O differed greatly.Cubic octahedral cuprous oxide had better antibacterial properties with the highest copper ion leaching rate compared with cubic and spherical cuprous oxide.

In vitro corrosion and antibacterial properties of layer-by-layer assembled GS/PSS coating on AZ31 magnesium alloys

To enhance the corrosion resistance of magnesium（Mg） alloy and to impart its surface with antibacterial functionality for inhibiting biofilm formation and biocorrosion, Mg（OH）2 films were fabricated on AZ31 magnesium alloy substrates by an in-situ hydrothermal method and well-defined multilayer coatings, consisting of gentamicin sulfate（GS） and poly（sodium 4-styrene sulfonate）（PSS）, were prepared via layer-by-layer（Lb L） assembly. The morphologies, chemical compositions and corrosion resistance of the obtained（PSS/GS）n/Mg sample were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, electrochemical methods and immersion tests. Finally, the bactericidal activity of（PSS/GS）n/Mg samples against Staphylococcus aureus was assessed by the zone of inhibition methods and plate-counting method. The so-synthesized composite coating on the Mg alloy substrates exhibits good corrosion resistance and antibacterial performance, which make them attractive as coatings for medical implanted devices.

Antibacterial properties and corrosion resistance of AISI 420 stainless steels implanted by silver and copper ions

Silver or copper ions are often chosen as antibacterial agents. But a few reports are concerned with these two antibacterial agents for preparation of antibacterial stainless steel （SS）. The antibacterial properties and corrosion resistance of AISI 420 stainless steel implanted by silver and copper ions were investigated. Due to the cooperative antibacterial effect of silver and copper ions, the Ag/Cu implanted SS showed excellent antibacterial activities against both Gram-negative Escherichia coli （E. coli） and Gram-positive Staphylococcus aureus （S. aureus） at a total implantation dose of 2~ 1017 ions/cm2. Electrochemical polarization curves revealed that the corrosion resistance of Ag/Cu implanted SS was slightly enhanced as compared with that of un-implanted SS, The implanted layer was characterized by X-ray photoelec- tron spectroscopy （XPS）. Core level XPS spectra indicate that the implanted silver and copper ions exist in metallic state in the implanted layer.

Long-term Antibacterial Properties and Bond Strength of Experimental Nano Silver-containing Orthodontic Cements

The purpose of this study was to evaluate the long time antibacterial properties and shear bond strength of experimental nano silver-containing cements （NSC）. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at five different weight ratios to obtain a series of nano silver-containing cements, then the antibacterial properties of three orthodontic cement products and five NSC samples were evaluated by the direct contact test （DCT） and the agar diffusion test （ADT）. The DCT, which was based on turbidness determination of bacterial growth in 96-well microtiter plates, was performed in both fresh and aged for 1 day, 1 week, 2 weeks, 3 weeks, 4 weeks, 6 weeks, and 8 weeks tested materials. The shear bond strengthes of three orthodontic cement products and five NSC samples were examined using a universal testing machine. The ADT results indicated that there were no significant differences between NSCs and ORTHO LC fresh specimens. In the DCT experiment, all fresh silver nanoparticles-containing tested samples presented powerful antibacterial properties, but they gradually lost the effective antimicrobial agents with the extension of aging time. Finally, none of the tested materials maintained its antibacterial property after aging for 8 weeks. A gradually decreasing trend of bond strength presented with the increasing incorporation of nano silver base inorganic antibacterial powder into the glass ionomer cement, even though all the tested material specimens reached the ideal bond strength range. We may conclude that NSCs can contribute to decrease the demineralization rate around brackets without compromising bond strength.

Preparation and antibacterial properties of polycaprolactone/quaternized chitosan blends

This article is a preliminary study on antibacterial blends of polycaprolactone,chitosan and quaternized chitosan by melt processing.Blends were characterized,mechanical test and antibacterial evaluation against Escherichia coli and Staphylococcus aureus,were conducted.Results showed that the antibacterial potential of chitosan was limited in blends and polycaprolactone/chitosan did not show significant antibacterial effect compared with neat polycaprolactone(PCL).Inhibition rates of polycaprolactone/quaternized chitosan were 39.2%99.9%against Escherichia coli,while inhibition rate was 40.9%99.9%against Staphylococcus aureus.When quaternized chitosan(QCTS)content was up to 20%,blends exhibited 99.9%inhibition rates against both two types of bacteria.

Antibacterial Properties of Cerium-Bearing Stainless Steel Bearing Cerium

In this study, the nominal 00Cr18Ni9 type alloys containing 0 to 5% Ce were melted in a inductive furnace in an atmosphere of argon, the distribution and content of cerium in these Ce-bearing stainless steels were analyzed, the composition of cerium precipitation phase was analyzed with X-ray diffraction method, the antibacterial performance of Ce-bearing stainless steels against Escherichia coli ATCC 8099 and Staphytococcus aureus ATCC 6538 were investigated with film attachment method. It is found that the stainless steels containing Ce have excellent antibacterial property, especially, not as the Cu-bearing antibacterial stainless steels, a special aging treatment is not required for Ce-bearing antibacterial stainless steels, which makes their application easy and cheap. The antibacterial mechanism of Ce-bearing stainless steels was also discussed.

Antibacterial Properties of TiO_2 Ceramic Pellets Prepared Using Nano TiO_2 Powder

Titanium dioxide （TiO2） porous ceramic pellets with three dimension nano-structure were prepared using nano TiO2 powder. The TiO2 porous ceramic pellets were composed of TiO2 nanoparticles with 14-16 nm in diameter and had porosity of 74.85%. The mean pore size of the TiO2 porous ceramic pellets was 20.73 nm and the main pore size ranged from 3 to 16 nm. The mass loss of the TiO2 ceramic pellets was less than 5% after 20 d immersion in water. The antibacterial properties of the TiO2 pellets were studied. The sterilization rate of Colibacillus （hospital polluted water with bacterium） can reach 99% after 3 h photocatalytic process and these TiO2 pellets are easy to be re-activated and cyclically be used. The shaping mechanism and photocatalysis sterilization mechanism of the TiO2 pellets were discussed.

Two Novel Coordination Polymers of Schiff Base Ligands:Synthesis,Crystal Structures and Antibacterial Properties Studies

Two novel complexes [Ag L1（NO3）H2O]n（1） and [Pb L2（NO3）2]n（2） were synthesized by the evaporation reaction with metal salts and Schiff base ligands. They were characterized by elemental analyses, IR spectra and X-ray single-crystal diffraction. 1 crystallizes in monoclinic, space group P21/c with a = 18.358（3）, b = 10.0395（15）, c = 13.4643（16） A, β = 91.749（12）o, V = 2480.4（6） ？3, Dc = 1.597 g/cm3, Mr = 596.35, F（000） = 1208, Z = 4, R = 0.0772 and w R = 0.0927. 2 crystallizes in monoclinic space group C2/c with a = 15.8549（10）, b = 21.1988（17）, c = 17.7198（12） A, β = 105.829（8）o, V = 5729.9（7） A3, Dc = 1.645 g/cm3, Mr = 709.63, F（000） = 2736, Z = 8, R = 0.0541 and w R = 0.1175. X-ray single-crystal diffraction experiments of 1 and 2 display that extensive π×××π stacking interactions and hydrogen bonds construct into a 2D rectangular network and a 3D supramolecular framework. The antibacterial properties of L1, L2, 1 and 2 were also studied.

Antibacterial Properties of Nano Silver-containing Orthodontic Cements in the Rat Caries Disease Model

The purpose of this study was to evaluate the antibacterial properties of experimental nano silver-containing cements（NSCs） using rat caries disease model. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at three different weight ratios to obtain a series of nano silver-containing cements, then two orthodontic cement products and three NSC samples were implanted into rat caries disease model, and their antibacterial properties were evaluated by the scanning electron microscope（SEM）. Moreover, the rat caries disease model were established by inoculating cariogenic bacteria S mutans into antibiotics treated rat mouths and feeding with cariogenic diet. The tested materials were bonded on the surface of the buccal half crowns of the upper fi rst premolar, and then fi xed under the rats＇ front teeth lingual side to acquire enough retention. The SEM results indicated that the growth of streptococcus mutans was very active in group of Transbond XT. One month later, S mutans scattered on the GC Fuji ORTHO LC surface, and then the number signifi cantly increased and arranged in chains after three months. In groups of NSC2, NSC3 and NSC4, the number of S mutans presented the downward trend and tended to disperse individually with the increase of silver nanoparticle content. We may conclude that the incorporation of silver nanoparticle enhanced GC Fuji ORTHO LC the adhesion restrain and killing effect to S mutans.

Isolation and Screening of Lactic Acid Bacterial Strains with Antibacterial Properties from the Vaginas of Healthy Cows

In the present study, eight strains were isolated from 20 cow vagina samples and identified using phenotype, biochemical analysis, sugar fermentation tests, and 16S rRNA sequence analysis. Among eight strains, only SQ0048 was identified as Lactobacillus johnsonii based on a series of biochemical testing (including the adhesion test, catalase test, bacteriocin production test, antibacterial test, and pH value), suggesting that its biological activity was superior to the other seven strains. Furthermore, SQ0048 had the lowest pH value (4.32) and the shortest fermentation time (8 h) compared with the other strains. The adhesion rate of SQ0048 was significantly higher than that of Lactobacillus delbrueckii, with an average adhesion number of 304 ± 2.67. The hydrogen peroxide production testing in SQ0048 was positive;in addition, bacteriocin gene of SQ0048, encoding an approximately 10-kDa product, was successfully cloned, expressed, and detected using the SDS-PAGE method. Meanwhile, SQ0048 had a weak inhibitory effect on Staphylococcus aureus and Escherichia coli. However, the expression products of the bacteriocin gene of SQ0048 had a very strong inhibitory effect on S. aureus and E. coli, with inhibition zone sizes of 18 ± 0.45 mm and 15 ± 0.60 mm, respectively. These data showed that SQ0048 has excellent antibacterial properties compared with other isolated strains and is a potential probiotic candidate to improve the health of the vaginas of cows by inhibiting pathogenic microorganisms.

Synthesis, characterization and antibacterial properties of multifunctional hindered amine light stabilizers

A series of novel hindered amine light stabilizers containing an N-halamine moiety were designed and synthesized. Their structures were characterized by FT-IR, 1H NMR, and MS. The compounds were tested for antibacterial activity against Candida albicans, Staphylococcus aureus, and Escherichia coll. At a concentration of 0.5 mmol/L, these compounds all exhibited satisfactory antibacterial activity against all the three types of bacteria.

Ag-doped CNT/HAP nanohybrids in a PLLA bone scaffold show significant antibacterial activity

Bacterial infection is a major problem following bone implant surgery.Moreover,poly-l-lactic acid/carbon nanotube/hydroxyapatite(PLLA/CNT/HAP)bone scaffolds possess enhanced mechanical properties and show good bioactiv-ityregardingbonedefectregeneration.Inthisstudy,wesynthesizedsilver(Ag)-dopedCNT/HAP(CNT/Ag-HAP)nanohybrids via the partial replacing of calcium ions(Ca2+)in the HAP lattice with silver ions(Ag+)using an ion doping technique under hydrothermal conditions.Specifically,the doping process was induced using the special lattice structure of HAP and the abundant surface oxygenic functional groups of CNT,and involved the partial replacement of Ca2+in the HAP lattice by doped Ag+as well as the in situ synthesis of Ag-HAP nanoparticles on CNT in a hydrothermal environment.The result-ing CNT/Ag-HAP nanohybrids were then introduced into a PLLA matrix via laser-based powder bed fusion(PBF-LB)to fabricate PLLA/CNT/Ag-HAP scaffolds that showed sustained antibacterial activity.We then found that Ag+,which pos-sesses broad-spectrum antibacterial activity,endowed PLLA/CNT/Ag-HAP scaffolds with this activity,with an antibacterial effectiveness of 92.65%.This antibacterial effect is due to the powerful effect of Ag+against bacterial structure and genetic material,as well as the physical destruction of bacterial structures due to the sharp edge structure of CNT.In addition,the scaffold possessed enhanced mechanical properties,showing tensile and compressive strengths of 8.49 MPa and 19.72 MPa,respectively.Finally,the scaffold also exhibited good bioactivity and cytocompatibility,including the ability to form apatite layers and to promote the adhesion and proliferation of human osteoblast-like cells(MG63 cells).

Optimization of mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy by heat treatment

Previous study has shown that Ti-3Cu alloy shows good antibacterial properties(>90%antibacterial rate),but the mechanical properties still need to be improved.In this paper,a series of heat-treatment processes were selected to adjust the microstructure in order to optimize the properties of Ti-3Cu alloy.Microstructure,mechanical properties,biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy at different conditions was systematically investigated by X-ray diffraction,optical microscope,scanning electron microscope,transmission electron microscopy,electrochemical measurements,tensile test,fatigue test and antibacterial test.Heat treatment could significantly improve the mechanical properties,corrosion resistance and antibacterial rate due to the redistribution of copper elements and precipitation of Ti2Cu phase.Solid solution treatment increased the yield strength from 400 to 740MPa and improved the antibacterial rate from 33%to 65.2%while aging treatment enhanced the yield strength to 800e850MPa and antibacterial rate(>91.32%).It was demonstrated that homogeneous distribution and fine Ti2Cu phase plays a very important role in mechanical properties,corrosion resistance and antibacterial properties.

Wear Resistance, Cytotoxicity and Antibacterial Properties of Polyetheretherketone Composite Modified by Carbon Fiber and Black Phosphorus

High wear resistance,low cytotoxicity and excellent antibacterial properties are the basis for osseointegration of implant materials.Polyetheretherketone(PEEK)has been considered as a potential implant material due to its excellent biocompatibility,natural radiolucency and mechanical properties.In this work,to improve the wear resistance,cytotoxicity and antibacterial properties of PEEK,carbon fiber(CFR)and Black Phosphorus(BP)were used to synergistically modify PEEK by two methods,deposition of BP coating on CFR-PEEK and BP/CFR-PEEK coating on Ti6Al4V(TC4)through electrostatic spraying.After CFR and BP synergistically modified PEEK,the friction coefficient of BP coating on CFR-PEEK and BP/CFR-PEEK coating were 0.14±0.01 and 0.09±0.02,respectively.The wear volume of BP coating on CFR-PEEK(30.54±1.32)was higher than that of BP/CFR-PEEK coating(9.46±1.32),which indicated that BP/CFR-PEEK coating showed high wear resistance.The difference in wear resistance may be caused by the fact that BP was not easily oxidized in BP/CFR-PEEK coating.In addition,BP coating on CFR-PEEK and BP/CFR-PEEK coating showed no obvious cytotoxicity to L929 cell and presented excellent antibacterial efficiency(up to 94.5%±2.8%and 96.0%±3.8%,respectively)against Staphylococcus aureus(S.aureus).It was concluded that BP/CFR-PEEK coating exhibited high wear resistance,low cytotoxicity and excellent antibacterial properties against S.aureus,which might provide a foundation for osseointegration of implants.

Study on the barrier properties and antibacterial properties of cellulose-based multilayer coated paperboard used for fast food packaging

Some petroleum-based packaging materials have a series of safety issues,and as a result,people are more inclined to use biodegradable and nontoxic packaging materials for foods.However,biodegradable alternatives often need to be modified to overcome their own shortcomings.In this paper,carboxymethyl chitosan(CMCS)/carboxymethyl cellulose sodium(CMC)+polylactic acid(PLA)nano zinc oxide(ZnO)nanoparticles(CMCS/CMC+PLA/ZnO NPs)multilayer coated paperboard was prepared to explore its potential use in food package applications.The multilayer CMCS/CMC+PLA coating reduced the oxygen transmission rate by 99%and doubled the barrier properties for soybean oil penetration and water vapor compared with a single PLA coating layer in a 23℃/50 RH environment.The oil resistance time of the multilayer CMCS/CMC+PLA coating also increased 28 times,and the water vapor barrier properties increased twofold compared to a single CMCS/CMC coating layer.The water vapor barrier properties increased by a factor of 3 even at 38℃/90 RH.Compared with the CMCS/CMC+PLA coating without nanoparticles,the barrier performance of the CMCS/CMC+PLA/ZnO NPs coating was further improved.The oxygen,water vapor,and heptane vapor barrier properties all doubled,and the oil resistance time reached 235 h.While a corona treatment reduced the polar component content in the CMCS/CMC coating and led to a slight decrease in the barrier properties of the coating to heptane,it was still a good oil-repellent coating overall.The antibacterial activity(A)toward Escherichia coli and Staphylococcus aureus exceeded 2,which meant that the multilayer coating with 1.5%added ZnO NPs reduced the growth of bacteria by more than 99%.The multilayer coated paperboard created here with the blended and modified materials significantly improved the barrier and antibacterial properties,suggesting that multilayer coatings prepared from degradable materials have good commercial prospects as fast food packaging.

Antibacterial properties of copper-substituted cobalt ferrite nanoparticles synthesized by co-precipitation method

Controlled growth and careful characterization of cobalt ferrite nanoparticles for antibacterial applica- tions are challenging. Copper-substituted cobalt ferrite nanoparticles （CuxCo1-xFe2O4）, where x = 0.0, 0.3, 0.5, 0.7 and 1.0, were synthesized using an economical and simple co-precipitation technique. The crys- tal structure and antibacterial properties of the samples as a function of Cu-substituted content were systematically studied. With increasing Cu concentration, the nanopartide size decreased from ~30 to ~20 nm. The Fourier transform infra-red spectra exhibit two prominent fundamental absorption bands, at ~595 and 419 cm^-1. These bands correspond to intrinsic stretching vibrations of metals at tetrahedral and octahedral sites, respectively. The Raman scattering results reveal that increasing the Cu content enhances the local disorder at both tetrahedral and octahedral sub lattices. The results indicate that the substitution of Co with Cu in cobalt ferrite nanoparticles strongly influences the microstructure, crystal structure, and oarticle diameter, and also improves the antibacterial properties.

Synthesis, Spectral Properties, Antibacterial and Antitumor Activity of Salinomycin Complexes with the Transition Metal Ions Co（ll）, Ni（ll）, Cu（ll） and Zn（ll）

SalNa （sodium salinomycin） reacts with divalent transition metal ions of Co（II）, Ni（II）, Cu（II） and Zn（II） to produce novel compounds characterized by various spectroscopic methods. The interaction of metal （II） ions with SalNa results in the formation of mononuclear complexes of a general composition of [M（Sal）2·（H2O）2] nH2O （n = 0 or 2） where the divalent cations replace Na~ ions from the cavity of initial compound. The new compounds （disalinomycinates） possess an enhanced antibacterial activity against Gram-positive microorganisms as compared to both SalNa and SalH （salinomycinic acid）, respectively. The metal （II） complexes manifest strong concentration dependent cytotoxic effect in experiments using human leukemia cell lines. The complexes of Co0I） and Cu（lI） proved to exert superior activity as compared to the Ni（II） and Zn（II） analogues and are much more cytotoxic than SalNa and SalH. Further studies should be conducted to determine the therapeutic indexes of the new compounds.

Mechanical and Antibacterial Properties of Injection Molded Polypropylene/TiO_2 Nano-Composites:Effects of Surface Modification

Polypropylene （PP）/titanium dioxide （TiO2） nano-composites were prepared by melt compounding with a twin screw extruder. Nanoparticles were modified prior to melt mixing with maleic anhydride grafted styreneethylene-butylene-styrene （SEBS-g-MA） and silane. The composites were injection molded and mechanical tests were applied to obtain tensile strength, elastic modulus and impact strength. Antibacterial efficiency test was applied on the injection molded composite plaques by viable cell counting technique. The results showed that the composites including SEBS-g-MA and silane coated TiO2 gave better mechanical properties than the composites without SEBS-g-MA. Antibacterial efficiency of the composites varied according to the dispersion and the concentration of the particles and it was observed that composites at low content of TiO2 showed higher antibacterial property due to the better photocatalytic activity of the particles during UV exposure.