Antimicrobial properties of natural dyes against Gram-negative bacteria

There is increasing interest in adding value to textiles by the use of natural products. Many of the plants from which natural dyes are obtained are, for example, also known to have medicinal properties. In the current study, the antimicrobial properties of eleven natural dyes against three types of Gram-negative bacteria were studied experimentally. Seven of the dyes showed activity against one or more of the bacteria. The minimum inhibitory concentration for three selected dyes was determined. The results demonstrate that certain dyes are able to reduce microbial growth almost completely in the case of Escherichia coli and Proteus vulgaris . Selected dyes would therefore be valuable for the dyeing of sheets and gowns for hospital use, and on articles which are less suitable for laundering such as mattresses and upholstery. The dyes examined exhibited good wash fastness and the antibacterial effect is therefore likely to be durable.     

植物染发剂的发展

简单介绍了染发剂产品的市场需求和发展现状；比较了植物染发剂与化学染发剂的功能特点；并阐述了植物染发剂的历史发展趋势以及最新研究进展；综述了色素吸附型植物染发剂和植物活性成分与金属盐络合型植物染发剂的国内外最新研究现状；提出了发展植物型染发剂的重要意义和广阔前景。     

Nanostructured ordering of fluorescent markers and single proteins on substrates

Highly ordered hexagonal nanopatterns of gold clusters on glass substrates were used as anchoring points for the specific attachment of fluorescence dyes and proteins labeled with fluorescence dyes. Thiol- or disulfide-containing linker molecules were used for the binding to the gold dots. In order to ensure specific binding on the gold dots only, the surface area in between the dots was protected against unspecific adsorption. For the attachment of polar low-molecular-weight fluorescence dyes, an octadecyltrichlorosilane self-assembled monolayer was prepared on the surface in between the gold dots, whereas a layer prepared from star-shaped poly(ethylene oxide-stat-propylene oxide) prepolymers was used to prevent unspecific adsorption of proteins between the gold dots. Fluorescence microscopy proved the specific binding of the dyes as well as of the proteins. Scanning force microscopy studies show that each gold dot is only capable of binding one protein at a time.     

Novel anti‐bacterial acid dyes derived from naphthalimide: synthesis,characterisation and evaluation of their technical properties on nylon 6

As an attempt to combine the dyeing and functional finishing steps into one process, two novel anti‐bacterial monoazo acid dyes based on N‐ester‐1,8‐naphthalimide were synthesised. To do this, 4‐amino‐N‐ethyl glycinate‐1,8‐naphthalimide was prepared, diazotised and then coupled to thiosalicylic acid or salicylic acid to produce anti‐bacterial dyes. The synthesised dyes were purified and then fully characterised using Fourier Transform–infrared spectrometry, proton nuclear magnetic resonance spectroscopy and melting point analysis. Dispersion of the dyes was prepared in water and applied to nylon 6 fabrics. The novel dyes offered good build‐up properties on the substrate. The anti‐bacterial efficacy of the synthesised dyes was assessed, with the dyes showing activity against both Gram‐positive and Gram‐negative bacteria.     

Protection against phototendering of wool by metal salts and mordanted dyes

Samples of treated and dyed wool have been irradiated with an artificial UV radiation source with a spectral distribution that matched the summer solar UV spectrum. The extent of phototendering was determined by measuring the loss of tensile strength of strips of wool fabric. Many of the dyes studied accelerated phototendering, although some metal-complex dyes prolonged the lifetime. Significant protection of wool against phototendering could be obtained by treatment with aluminium salts, or related salts, followed by dyeing with classical mordant dyes.     

A novel approach for improving the light fastness of crystal violet lactone

Colour formers are important as functional dyes for imaging and data recording systems. Metal complexes of substituted arylsulphonic acids or arylcarboxylic acids have been synthesised to prolong the life of coloured species derived from crystal violet lactone. The suppressing effect of these compounds towards photofading was investigated on cellulose. It was found that zinc and nickel salts of 2,6-dihydroxybenzoic acid and its derivatives can be applied as effective stabilisers against the fading of crystal violet lactone. The protecting effect of phenyl esters against fading was also examined.     

Cationic azomethine disperse dyes: Synthesis,antifungal activity and tinctorial properties of N-arylideneamino p-substituted pyridinium salts as possible dyes for synthetic fibres

In a four-step synthesis, a series of N-arylideneamino p-substituted pyridinium salt derivatives were prepared for use as cationic azomethine disperse dyes for polyester and polyacrylonitrile fibres. The effect of different substituents, in both of homo- and heterocyclic ring systems, on position of maximum absorbance in UV-vis spectra was used to explain the different hues of the prepared dyes. Besides, showing promising tinctorial properties, the synthesised dyes revealed fungicidal activity against Aspergillus niger. The structure of the hitherto prepared dyes was inferred by elemental and spectral data.     

Fading of Phenylazo–β–naphthol Dyes on Polypropylene*

The fading of a series of phenylazo–β–naphthol dyes on polypropylene by exposure to either long– or short–wavelength ultraviolet radiation and under nitrogen and oxygen atmospheres, respectively, is reported. The half–lives and relative rates of fading of the dyes were calculated at the wavelength of maximum absorption of the hydrazone band and the hydrazone–azo ratios of the dyes were determined on polypropylene and in ethanol. The relative rates of fading were plotted against the appropriate Hammett constants for the substituents. In general, a linear relation was observed. The graphs had positive slopes, but negative slopes were also obtained with the dyes bearing electropositive groups. Graphs of relative rates of fading against hydrazone?azo ratio were also drawn. The results were generally similar to those obtained with the plots of Hammett constants, but correlation was better. The results indicate that, on polypropylene, the most important fading mechanism for the hydrazone form of the dye is reductive, although there is evidence that oxidation may occur, especially in the presence of oxygen.     

近红外吸收菁染料光氧化反应机理的研究

本文选择了三种分子结构相同而母核杂原子不同的近红外吸收菁染料，对它们的光谱性能特征及光氧化稳定性能进行了研究。结果表明，具有三各步同母核杂原子的菁染料，其光氧化稳定怀顺序为：苯并恶唑〉苯并噻唑〉苯并硒唑，通过猝灭实验给出，在三咱菁染料的光氧化反应机制中，具有反应活性的单线态氧和超氧负离子同时存在，其中单线态氧是导致菁染褪色的主要因素。     

Relationship between the solubility of disperse dyes and the equilibrium dye adsorption in supercritical fluid dyeing

In order to understand the dyeing behaviour of synthetic fibres in supercritical carbon dioxide, the solubility of some disperse dyes in supercritical fluid, as well as the rate of dyeing and the equilibrium adsorption of these dyes, have been studied. Dye solubility was measured by a dynamic analytic method at a range of pressure (7.5–25 MPa) and temperature (50–145 °C). The apparent rate of dyeing was measured and the dyeing isotherm was obtained by plotting the equilibrium dye adsorption against the equilibrium dyebath concentration. Linear isotherms were obtained when poly(ethylene terephthalate) samples were dyed with the disperse dyes. The mechanism of dyeing using supercritical carbon dioxide was discussed by considering the solubility, the dyeing rate and the dyeing isotherm.     

One‐bath union dyeing of wool/polytrimethylene terephthalate blends†

The one‐bath dyeing of blends of polytrimethylene terephthalate (PTT) staple and wool has been investigated. The exhaustion of selected Terasil disperse dyes on PTT fibre and Lanasol reactive dyes on wool was measured as a function of temperature, together with the cross‐staining of the Terasil dyes on the wool component and the Lanasol dyes on PTT component. Most Terasil disperse dyes achieved satisfactory dye uptake on PTT at 110 °C, whereas on conventional polyester (polyethylene terephthalate) temperatures of up to 130 °C are required. An optimised union‐dyeing technique for wool/PTT blends was developed which minimised the staining of Terasil disperse dyes on wool and produced dyed goods with high levels of wet colour fastness. Carriers were not required to enhance the dyeability of PTT at low temperatures. The wool component appeared to be protected against damage at 110 °C by the reactive dyes. The results indicate the potential for blending PTT fibre and wool to produce fabrics that are easier to dye at lower temperatures than conventional wool/polyester blends.     

The biocidal properties of anthraquininoid dyes

A modified minimum inhibitory concentration test method was employed to determine the antimicrobial properties against both Gram-positive and Gram-negative bacteria of two series of cationic anthraquininoid dyes. The antimicrobial strength of the colorants increased with increasing carbon chain length up to C16; the activities of the colorants were improved by the use of elevated temperature as well as either high or low pH. However, the colorants were deactivated in the presence of both anionic surfactants and divalent cations.     

Synthesis, spectral characterisation and anti-bacterial activity of various 1,3,4-oxadiazine cyanine dyes

A number of new styryl, aza-styryl, acyclic mero, cyclic mero and mixed cyanine dyes with a benzo[2,3- e ; 2',3'- e ']bis-1,3,4-oxadiazine nucleus were synthesised. The absorption spectra in the visible region of all the synthesised cyanine dyes in 95% ethanol solution were examined and studied in detail. Anti-bacterial activity for a number of selected dyes was evaluated against various bacterial strains. The structural determination was carried out using elemental and spectroscopic analysis.     

染料在聚合法制备静电复印色粉中的应用及对荷电性能的影响

介绍一种采用悬浮聚合法制备彩色静电复印粉的新工艺,染料和其它添加剂是在聚合反应之前加入。测试和讨论了几种染料对色粉荷电性能的影响,并且根据FTIR测试结果分析了染料与聚合物树脂之间的相互作用情况。     

Synthesis and properties of acid dye derivatives of arylsulphonanilides

Thirty-five acid dyes suitable for dyeing wool and polyamide fibres were synthesized, using derivatives of arylsulphonanilides prepared from o-nitrotoluene or chloronitrotoluene. As coupling components, derivatives of 1-phenyl-3-methylpyrazolone-5 and 2-naphthol were used. Fastness and colour properties of the prepared dyes were determined. It was found that some of the prepared dyes on polyamide fibres show batho- and hypso-chromic effects as well as hypo- and hyper-chromic effects during testing of their fastness to washing and to acid and alkaline perspiration. Spectroscopic examinations and determination of pK_a of the sulphonamide and hydroxyl groups of the dyes showed that the observed changes are associated with aggregation or disaggregation of the dyes on fibres or with a change in the azo-hydrazone equilibrium. Some of the prepared dyes are characterized by very good dyeing and fastness properties.     

染发剂的毒性及安全监管

分别对持久性或氧化型染发剂、半持久性染发剂和暂时性染发剂等常用染发剂的毒性进行了分析,包括致敏性、致癌性及重金属物质的毒性;重点对染发剂的安全监管进行了分析,涉及我国及欧盟对染发剂监管的措施,并针对我国在染发剂监管方面存在的问题,提出了相关对策,如完善化妆品卫生规范,增加禁用物质种类,对限用物质的限量要求更加严格或进行调整,提升染发剂安全性检测的技术水平,加强对染发剂标签警示用语的管理等。     

Effect of uv absorbers containing singlet oxygen quenching groups on the photochemical stability of crystal violet lactone and related colours

The photofading behaviour of Crystal Violet Lactone was investigated in solution. The contribution of singlet oxygen to that fading was suggested. UV absorbers containing nickel sulphonate quenching groups were prepared and the protecting effect of these compounds towards the photofading of colour materials derived from colour formers was examined in solution and in solid state. It was proposed that nickel salts of 2,2′-dihydroxy-4,4′-dimethoxybenzophenone-5-sulphonic acid and its derivative can be applied as effective stabilisers against the photofading of indicator dyes in pressure (or heat) sensitive recording systems.     

Photoreactivity of Wool Dyed with Reactive Dyes

Presented at the 13th Congress of the International Federation of Associations of Textile Chemists and Colourists in London on 20 September 1984. Processes induced by two kinds of illumination (ultra-violet and Xenotest) in wool dyed with reactive dyes ha ve been investigated as a function of time. The fading of dyed fibres has been determined in terms of the conditions of illumination. The degradation of wool was followed on the basis of changes in alkali solubility and tensile characteristics. Moreo ver the colour change of the dyed fibres was also determined. Correlation was found between the chemical structure of the dye, the extent of fading and the photodegradation undergone by the wool. On the basis of amino acid analysis conclusions were drawn on the photodegradation mechanism of wool, both uncoloured and dyed with reactive dyes. Reactive dyes protect wool against photodegradation, and at the same time the light fastness of reactive dyes on wool is 1–1.5 units higher than on cotton, both under ultra-violet (u.v.) and Xenotest irradiation.     

Influence of dichloro-s-triazinyl reactive dyes on the fibrillation propensity of lyocell fibres

Four dichloro- s -triazinyl dyes and 2,4-dichloro-6- p -sulphoanilino-1,3,5-triazine have been applied by exhaustion methods to dried lyocell fibres. The method of application, of both dyes and agent, influenced the cross-linking performance and, in turn, the wet abrasion resistance of the treated fibre. However, dyeing alone, with any of the MX dyes used in this study, was insufficient to protect the fibre from wet abrasion problems during laundering. A comparison between one of the MX dyes, Chloranyl Orange MX-2R, and 2,4-dichloro-6- p -sulphoanilino-1,3,5-triazine on a mol-for-mol fixed basis, showed 2,4-dichloro-6- p -sulphoanilino-1,3,5-triazine to be greatly superior at protecting lyocell against wet abrasion.     

Recent Development of Photothermal Agents (PTAs) Based on Small Organic Molecular Dyes

Photothermal therapy (PTT) has attracted great attention due to its noninvasive and effective use against cancer. Various photothermal agents (PTAs) including organic and inorganic PTAs have been developed in the last decades. Organic PTAs based on small-molecule dyes exhibit great potential for future clinical applications considering their good biocompatibility and easy chemical modification or functionalization. In this review, we discuss the recent progress of organic PTAs based on small-molecule dyes for enhanced PTT. We summarize the strategies to improve the light penetration of PTAs, methods to enhance their photothermal conversion efficiency, how to optimize PTAs’ delivery into deep tumors, and how to resist photobleaching under repeated laser irradiation. We hope that this review can rouse the interest of researchers in the field of PTAs based on small-molecule dyes and help them to fabricate next-generation PTAs for noninvasive cancer therapy.