Preparation and characterization of activated carbon fibers supported with silver metal for antibacterial behavior

In this work, the effect of immersion in silver nitrate solution on activated carbon fibers (ACFs) was investigated in relation to adsorption behavior and antibacterial activity of ACFs supported with silver (ACF/Ag). The pore and surface properties were studied in terms of BET volumetric measurement with nitrogen adsorption, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The antibacterial activities of ACF/Ag were studied in broth dilution tests against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) from a point of view of water purification. As an experimental result, the silver content of ACF/Ag increased with increasing concentration of silver nitrate. It was found that the micropore structure slightly decreased as the silver nitrate concentration increased. Otherwise, it was revealed that the ACF/Ag possessed a strong antibacterial activity and an inhibitory effect for the growing of E. coli and S. aureus, respectively. Silver content on ACF/Ag decreased rapidly because of rough morphology of silver particles in water erosion.     

Synthesis of copolymer brushes endowed with adhesion to stainless steel surfaces and antibacterial properties by controlled nitroxide-mediated radical polymerization

Novel copolymer brushes have been synthesized by a two-step "grafting from" method that consists of the electrografting of poly(2-phenyl-2-(2,2,6,6-tetramethyl-piperidin-1-yloxy)-ethylacrylate) onto stainless steel, followed by the nitroxide-mediated radical polymerization of 2-(dimethylamino ethyl)acrylate and styrene or n-butyl acrylate, initiated from the electrografted polyacrylate chains. The grafted copolymers were quaternized in order to endow them with antibacterial properties. Peeling tests have confirmed the strong adhesion of the grafted copolymer onto the stainless steel substrate. Quartz crystal microbalance experiments have proven that fibrinogen adhesion is lower on the hydrophilic quaternized films compared to the nonionic counterpart. Such quaternized copolymers exhibit significant antibacterial activity against the Gram-positive bacteria S. aureus and the Gram-negative bacteria E. coli.     

Facile preparation of antibacterial polymer coatings via thiol-yne click photopolymerization

Novel antibacterial polymer coatings were prepared by a facile thiol-yne click photopolymerization of 1-propargyl-3-alkyl-1,3-diazanyl-2,4-cyclopentadiene bromide ([PAIM]Br) and tetra(3-mercapto-propionate) pentaerythritol (PETMP) (2:1 molar ratio) using 2,2-dimethoxy-2-phenylacetophenone (DMPA) as initiator. The antibacterial activity of the coatings was tested against Staphylococcus aureus (ATCC 292130) and Escherichia coli (ATCC 25922) by the dynamic shake method. The evaluation results revealed the antibacterial polymer coatings exhibited excellent inhibitory activity against S. aureus and E. coli, especially for S. aureus.     

Study of zwitterionic sulfopropylbetaine containing reactive siloxanes for application in antibacterial materials

Antibacterial agents receive a great deal of attention around the world due to the interesting academic problems of how to combat bacteria and of the beneficial health, social and economic effects of successful agents. Scientists are actively developing new antibacterial agents for biomaterial applications. This paper reports the novel antibacterial agent siloxane sulfopropylbetaine (SSPB), which contains reactive alkoxysilane groups. The structure and properties of SSPB were systematically investigated, with the results showing that SSPB contains both quaternary ammonium compounds and reactive siloxane groups. SSPB has good antibacterial activity against both Escherichia coli (E. coli, 8099) and Staphylococcus aureus (S. aureus, ATCC 6538). The minimal inhibition concentration is 70 μmol/ml SSPB against both E. coli and S. aureus. In addition, the SSPB antibacterial agent can be used in both weak acid and weak alkaline environments, functioning within the wide pH range of 4.0-9.0. The SSPB-modified glass surface killed 99.96% of both S. aureus and E. coli organisms within 24 h. No significant decrease was observed in this antibacterial activity after 20 washes. Moreover, SSPB does not induce a skin reaction and is nontoxic to animals. Thus, SSPB is an ideal candidate for future applications as a safe, environmentally friendly antibacterial agent.     

Synthesis and antibacterial properties of new 8-nitrofluoroquinolone derivatives

The objective of this research was the preparation of new 8-nitrofluoroquinolone models and investigation of their antibacterial properties. The work initially involved large scale preparation of the synthon 7-chloro-1-cyclopropyl-6-fluoro-8-nitro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (3), followed by introduction of substituted primary amine appendages at the C-7 position to give derivatives 9a-g, in which the amino group is appended to substituted benzenes or aromatic heterocycles, is part of a primary alpha-amino acid or just a simple primary aliphatic amine. This nucleophilic aromatic substitution step was a very simple procedure since the 8-nitro group of the above synthon facilitated the addition of weak nucleophiles at C-7. All compounds prepared were fully identified and characterized using NMR, IR, EA and MS, and were consistent with expected structures. The prepared targets and the intermediates have shown interesting antibacterial activity against gram positive and/or gram negative strains. In particular, the p-toluidine, p-chloroaniline and aniline derivatives showed good activity against S. aureus with MIC range approximately 2-5 microg/mL. In conclusion, more lipophilic groups seem to enhance activity against gram positive strains.     

Preparation and Characterization of Antibacterial Polyacrylonitrile-based Activated Carbon Fiber Supporting Nano-ZnO

Polyacrylonitrile(PAN)-based activated carbon fiber(PACF) supporting nano-ZnO(PACF /nano-ZnO) was prepared by spin, pretreatment, carbonization, and KOH chemical activation at an activation temperature of 950 ℃ for 40 min. Nano-ZnO content, distribution and antibacterial properties of the PACF/nano-ZnO were studied. The pore structure and surface properties of the PACF/nano-ZnO were studied by Brunauer-Emmett-Teller(BET), N₂/77 K isothermal adsorption. The specific surface area increased markedly after the activation process and it was several hundred times greater than that before the process. The PACF/nano-ZnO shows a strong adsorption for Staphylococcus aureus(S. aureus) and Escherichia coli(E. coli) and antibacterial activity against them. As an experimental result, antibacterial properties of PACF/nano-ZnO increased with increasing the concentration of nano-ZnO particles, which suggests it is a promising antibacterial material.     

动态多孔海绵结构多层膜负载溶菌酶用于抗菌涂层的研究

以聚丙烯酸(PAA)和聚乙烯亚胺(PEI)为构筑单元,运用层层自组装技术制备了聚电解质多层膜.该多层膜具有独特的动态特点——经酸处理后膜内部形成海绵状通孔结构,该海绵结构在饱和水蒸气的处理下,多孔结构能够闭合,重新回到致密的膜结构.借助该种动态多层膜平台,能够简单有效地通过毛细作用力将溶菌酶负载并固定于多层膜中,为制备基于抗菌蛋白的抗菌涂层提供了新的方法.扫描电镜表征了多层膜动态变化过程,激光共聚焦显微镜表征了溶菌酶在膜内的分布情况,并测定了溶菌酶载入量及其释放动力学.进一步的抗菌测试表明该种抗菌涂层在溶菌酶和PEI的共同作用下可以有效地抑制金黄色葡萄球菌.将多层膜同时负载溶菌酶和乳铁蛋白,提升了涂层对大肠杆菌的杀菌效果.     

CuCl2 heterogenized on metformine‐modified polystyrene resin as an antibacterial agent and recyclable nanocatalyst for Ullmann‐type C‐N coupling reactions

Merrifield Resin was functionalized with metformine and applied as a solid support to immobilize the CuCl₂. The Ps‐Met/CuCl₂ was characterized by several techniques including Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), energy‐dispersive X‐ray spectroscopy (EDX), wavelength‐dispersive X‐ray spectroscopy (WDX) and inductively coupled plasma (ICP). The Ps‐Met/CuCl₂ was used as an efficient recyclable solid nanocatalyst for N‐arylation of indole and aniline through coupling reactions of Ullmann‐type C‐N. The advantages of this method are easy workup, improved yields, and simple recovery via filtration. Ultimately, the Ps‐Met/CuCl₂ antibacterial property was examined against two bacteria (Staphylococcus aureus (Staph. aureus) and Escherichia coli (E. coli)) and indicated its antibacterial performance against gram negative (E. coli) bacteria and gram positive (Staph. aureus).     

Essential oil analysis and antibacterial activity of Rosmarinus tournefortii from Algeria

The volatile compounds obtained by hydrodistillation of the aerial parts of Rosmarinus tournefortii De Noé. growing wild in the occidental region of Algeria were analyzed by GC/MS. Thirty-six compounds were characterized representing 95.6% of the essential oil, with camphor (37.6%), 1,8-cineole (10.0%), p-cymene-7-ol (7.8%), and borneol (5.4%) as the major components. The antimicrobial activity was evaluated against three pathogenic bacteria: Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus). The minimum inhibitory concentration (MIC; mg/mL) was determined by sub-culture on Muller Hinton agar plates. The essential oil exhibited strong antibacterial activity against E. coli and P. aeruginosa, and was also active against Staphylococcus aureus.     

Structural modification of sanguinarine and chelerythrine and their antibacterial activity

In this study, five derivatives of sanguinarine (1) and chelerythrine (2) were prepared, with 1 and 2 as starting materials, by reduction, oxidation and nucleophilic addition to the iminium bond C=N+. The structures of all compounds were elucidated on account of their MS, 1H-NMR and 13C-NMR data. The antibacterial activities of all compounds were screened, using Staphylococcus aureus, Escherichia coli, Aeromonas hydrophila and Pasteurella multocida as test bacteria. The minimum bacteriostatic concentration and minimum bactericidal concentration of the active compounds were determined by the turbidity method. The structure-activity relationships of 1 and 2 were discussed. The results showed that 1, 2 and their pseudoalcoholates were found to be potent inhibitors to S. aureus, E. coli and A. hydrophila, while the other derivatives were found to be inactive. The pseudoalcoholates might be the prodrugs of 1 and 2. The iminium bond in the molecules of 1 or 2 was the determinant for antibacterial activity, and the substituents at the 7 and 8 positions influenced the antibacterial activities of 1 and 2 against different bacteria.     

Inherent antibacterial activity of a peptide-based beta-hairpin hydrogel

Among several important considerations for implantation of a biomaterial, a main concern is the introduction of infection. We have designed a hydrogel scaffold from the self-assembling peptide, MAX1, for tissue regeneration applications whose surface exhibits inherent antibacterial activity. In experiments where MAX1 gels are challenged with bacterial solutions ranging in concentrations from 2 x 10(3) colony forming units (CFUs)/dm2 to 2 x 10(9) CFUs/dm2, gel surfaces exhibit broad-spectrum antibacterial activity. Results show that the hydrogel surface is active against Gram-positive (Staphylococcus epidermidis, Staphylococcus aureus, and Streptococcus pyogenes) and Gram-negative (Klebsiella pneumoniae and Escherichia coli) bacteria, all prevalent in hospital settings. Live-dead assays employing laser scanning confocal microscopy show that bacteria are killed when they engage the surface. In addition, the surface of MAX1 hydrogels was shown to cause inner and outer membrane disruption in experiments that monitor the release of beta-galactosidase from the cytoplasm of lactose permease-deficient E. coli ML-35. These data suggest a mechanism of antibacterial action that involves membrane disruption that leads to cell death upon cellular contact with the gel surface. Although the hydrogel surface exhibits bactericidal activity, co-culture experiments indicate hydrogel surfaces show selective toxicity to bacterial versus mammalian cells. Additionally, gel surfaces are nonhemolytic toward human erythrocytes, which maintain healthy morphologies when in contact with the surface. These material attributes make MAX1 gels attractive candidates for use in tissue regeneration, even in nonsterile environments.     

羧甲基香菇多糖表面修饰的聚乳酸材料的表面性能研究

制备了香菇多糖羧甲基衍生物,再通过化学接枝方法利用共价键将羧甲基香菇多糖固定在氨基化聚乳酸基材表面,得到羧甲基香菇多糖化学接枝修饰的聚乳酸材料.此外,通过在氨基化聚乳酸基材表面进行羧甲基香菇多糖与壳聚糖的层层自组装,得到生物多糖层层自组装修饰的聚乳酸材料.采用扫描电子显微镜、水接触角测量仪、抗菌活性测试、溶血试验和血栓试验等方法对被修饰聚乳酸材料的表面性能和生物性能进行了分析和比较.结果表明采用2种表面修饰方法得到的羧甲基香菇多糖修饰的聚乳酸材料的亲水性、血液相容性以及对大肠杆菌抗菌活性得到改善.与化学接枝方法相比,经过羧甲基香菇多糖与壳聚糖层层自组装修饰的聚乳酸材料具有更好的亲水性、血液相容性和抗菌活性.     

铜树枝晶的水热合成以及结构表征和抗菌性能评价(英文)

在乙醇胺-水混合溶液中采用水热处理硫酸铜的方法制备了多结构的铜树枝晶;采用X射线粉末衍射仪、扫描电子显微镜、透射电子显微镜分析了所得样品的结构和形貌;采用牛津杯法评价了其对金黄葡萄球菌、枯草芽孢杆菌、大肠杆菌和绿脓杆菌的抗菌性能.结果表明,铜树枝晶由一个长的一级中心主干和许多高度对称分布在主干两侧的二级分支结构构成,且形貌均匀;反应温度、反应时间以及溶剂组成对铜树枝晶的形貌有很大影响.与此同时,铜树枝晶表现出选择性的抗菌行为,对金黄葡萄球菌、枯草芽孢杆菌和绿脓杆菌更有效.     

Anti-bacterial treatment of polyethylene by cold plasma for medical purposes

Polyethylene (PE) is one of the most widely used polymers in many industrial applications. Biomedical uses seem to be attractive, with increasing interest. However, PE it prone to infections and its additional surface treatment is indispensable. An increase in resistance to infections can be achieved by treating PE surfaces with substances containing antibacterial groups such as triclosan (5-Chloro-2-(2,4-dichlorophenoxy)phenol) and chlorhexidine (1,1'-Hexamethylenebis[5-(4-chlorophenyl)biguanide]). This work has examined the impact of selected antibacterial substances immobilized on low-density polyethylene (LDPE) via polyacrylic acid (PAA) grafted on LDPE by low-temperature barrier discharge plasma. This LDPE surface treatment led to inhibition of Escherichia coli and Staphylococcus aureus adhesion; the first causes intestinal disease, peritonitis, mastitis, pneumonia, septicemia, the latter is the reason for wound and urinary tract infections.     

Improving the Antibacterial Property of Polyethylene Terephthalate by Cold Plasma Treatment

Many studies suggest strong hydrophilicity of plasma treated polyester surfaces. However, no studies have been reported on the influence of plasma on the antibacterial activity of polyethylene terephthalate. First samples were padded with triclosan as antibacterial agent with different concentrations. Second samples were treated by oxygen plasma with different operating frequency and treating time, respectively. Afterwards, plasma treated samples were padded with triclosan in same conditions. The results revealed that the antibacterial activity slighlty increased after treating with triclosan. SEM images and FTIR spectra showed that horizontal channels were brought about on the fiber surface and then better surface roughness and wettability were obtained by plasma. Fibers were fully coated with triclosan after plasma and the antibacterial activity increased with increasing operating frequency and reaction time. Finally, the samples treated with triclosan after plasma gave acceptable results and showed the best antibacterial activity for Staphylococcus aureus and Escherichia coli.     

石墨烯/锌铁氧体复合物的制备及抗菌性能

用氧化还原法和化学共沉淀法分别制备了石墨烯(GE)和石墨烯/锌铁氧体(GE/ZnFe2O4)复合物,通过现代测试技术表征了样品的物相结构、组成和微观形貌.以大肠杆菌、金黄色葡萄球菌和白色念珠菌为测试菌种,分别对样品的抗菌性能进行了研究.结果表明,样品的抗菌活性受GE/ZnFe2O4复合物中GE和ZnFe2O4质量比(mG/Z)以及菌种的影响,其中mG/Z=0.4的复合物对三种菌均有较好的抗菌效果,其最小抑菌浓度分别为25、25和12.5μg/mL;复合物对白色念珠菌的抗菌效果最好,这与菌种的结构有关.此外,对样品的抗菌机理进行了详细研究.     

原子转移自由基聚合法改性壳聚糖及其抑菌性研究

合成了大分子引发剂(CS-Br)———壳聚糖(CS)接枝2-溴丙酰溴,然后以溴化亚铜与五甲基二乙烯三胺(PMDETA)为催化体系,氯甲基化甲基丙烯酸二甲氨乙酯季铵盐(DMC)为单体,利用原子转移自由基聚合法制备了新材料P(CS-Br-DMC)。重点研究了该材料对白色念珠菌、金黄色葡萄球菌和大肠杆菌的最低抑菌浓度(MIC)、抑菌圈直径及溶血性。同时考察了其在不同时间对三种菌种生长的影响,并且与壳聚糖本身的抑菌性进行了对比。结果表明,该材料比壳聚糖具有更好的水溶性和抑菌性,其对金黄色葡萄球菌的抑菌效果最佳。     

通过柠檬酸改性提高载银活性炭的抗菌性能

通过负载柠檬酸对活性炭进行改性,用N2吸附法测定活性炭的比表面积,用AAS、SEM、XRD测试技术分析了银在活性炭上的吸附和分布,并研究了载银活性炭的抗菌性能。结果表明,负载柠檬酸使活性炭的比表面积下降约24%,但载银后活性炭的比表面积增大。柠檬酸改性为[Ag(NH3)2] 的还原吸附提供更多的活性点,使银的吸附速率加快,吸附量提高约25%,表面的银颗粒变得非常密集,粒径减小,且颗粒均匀,因此抗菌性能显著增强,其中对金黄色葡萄球菌的杀灭效果明显优于对大肠杆菌的,同时对于高分散Ag/C催化剂的制备及银的回收也具有重要的价值。     

Synthesis, biological and computational study of new Schiff base hydrazones bearing 3-(4-pyridine)-5-mercapto-1,2,4-triazole moiety

A series of new Schiff base hydrazones (compounds 1-16) were synthesized by condensation reaction of 4-amino-3-(4-pyridine)-5-mercapto-1,2,4-triazole with various aldehydes and/or dialdehydes. The structure of the prepared compounds was confirmed by means of 1H NMR, 13C NMR, UV-vis, IR and elemental analyses. The all prepared compounds were assayed for antibacterial (Escherichia coli and Staphylococcus aureus) and antifungal (Candida albicans) activities by disc diffusion method. The results indicate that all tested compounds did not show any antibacterial activity against E. coli, as gram negative bacteria, and antifungal activity against C. albicans. But the compounds 2, 3, 4, 6 and 8 containing 4-Cl, 4-Me, 4-MeO, 2,4-di-Cl and 2-OH substituted phenyl moiety, respectively, showed good inhibition against S. aureus as compare to standard drugs. The structure of all biologically active compounds has also been theoretically studied by ab initio Hartree-Fock (HF) methods.     

Preparation and antibacterial activities of polyaniline/Cu0.05Zn0.95O nanocomposites

Polyaniline/Cu(0.05)Zn(0.95)O (PANI/CZO) nanocomposites were prepared by in situ inverse microemulsion method. Based on the characterization of the crystal structure, chemical composition, and morphology of the samples, it was confirmed that CZO nanoparticles were incorporated into the polyaniline matrix. Studies of the antimicrobial activities of the samples against Staphylococcus aureus, Escherichia coli and Candida albicans were carried out using powder inhibition zone, minimum inhibitory concentration and minimal bactericidal concentrations methods. The results showed clearly that, as an antibacterial agent, PANI/CZO nanocomposites exhibited excellent antibacterial activity against the growth of microorganisms. Furthermore, the antibacterial mechanism of the samples was also deduced in this paper.