Modification Of Pigments Research Articles

Prussian Blue Encapsulated with Brush-like Polyorganosiloxane Nanospheres with Tunable Functionality

Faced with higher demands of pigments in various applications, the performance of pigments in a specific system is in urgent need of optimization and improvement. Polyorganosiloxane (POS) stands out among various encapsulating polymeric materials for pigment modification due to its superior thermal stability and alkali resistance. However, the inherent hydrophobicity of POS causes poor stability in aqueous systems, which is usually applied in environmentally friendly applications. Grafting hydrophilic polymer chains on the surface of POS could improve water dispersity. In addition, the encapsulated pigment can also be endowed with various functionalities by selecting or combining grafted polymers. Herein, we reported a strategy to encapsulate Prussian blue (PB27) with POS grafted with poly(acrylic acid) (PAA) or poly(N-(2-hydroxyethyl) acrylamide) (PHEAA) to allow better stability and functionality of the composite pigment particles, denoted as PB27@POS@PAA or PB27@POS@PHEAA, respectively. The effect of the number of monomers and the amount of initiator potassium persulfate (KPS) on the brush thickness of the grafted polymers was studied, along with various performance properties and the functionality of PB27@POS@PAA and PB27@POS@PHEAA. The dispersity, alkali resistance, and high-temperature stability are studied. The brush-like composite pigment performs better after centrifugation (5000 rpm, 30 min) or treatment under 90 °C when the dosage of grafting monomer AA or HEAA reaches 400 wt%. Optimal alkali resistance was obtained for PB27@POS@PAA (AA, 200 wt%) with a particle size variation of only 31 nm after 8 h. Comparably, PB27@POS@PHEAA behaved worse under similar conditions. Moreover, PB27@POS grafted with PAA was responsive to pH and that with PHEAA showed excellent antifouling properties, which could also be replaced by other functional monomers if needed.

Future of dermal fillers

AbstractThe advancement of dermal fillers has progressed from animal collagen extraction to a spectrum of recombinant DNA, nanotechnology, and biostimulation. Consumers now have a variety of fillers to choose from, including organic fillers composed of hyaluronic acid and calcium hydroxyapatite, as well as synthetic fillers made from poly‐l‐lactic acid and polymethylmethacrylate. This piece serves to add to the open dialogue discussing the prognosis, prospects, and potential pitfalls of dermal fillers. Expansion of product indications and technical alterations are currently changing the dermal fillers' landscape. The potential for new approaches to side effect mitigation or adjunct pigment modification is still exploratory. Furthermore, with social implications increasingly coming into frame, healthcare providers and companies seem geared toward developing effective, safe, and equitable products while maintaining a process of rigorous review and quality control processes. As such, future developments of this medical tool appear promising; fillers seem poised to imbue a role as dynamic as the tissues they were conceived to restore.

The chromogenic mechanism of natural pigments and the methods and techniques to improve their stability: A systematic review

Pigments have become a very important part of food research, not only adding sensory properties to food, but also providing functional properties to the food system. In this paper, we review the source, structure, modification, encapsulation and current status of the three main types of natural pigments that have been studied in recent years: polyphenolic flavonoids, tetraterpenoids and betaines. By examining the modification of pigment, the improvement of their stability and the impact of new food processing methods on the pigments, a deeper understanding of the properties and applications of the three pigments is gained, the paper reviews the research status of pigments in order to promote their further research and provide new innovations and ideas for future research in this field.

He–Ne Laser Priming Enhances Drought Tolerance in Wheat through Differential Modification of Photosynthetic Pigments and Antioxidative Enzymes

Water stress seriously impacts agro-systems worldwide, severely affecting plant growth and crop productivity. Radio-priming agents such as lasers can induce stress tolerance in plants due to their physiological roles in growth and development. The potential protective role of He–Ne laser pretreatment (i.e., one, two and five min at 630 nm) was evaluated in germination and growth of two wheat varieties, FSD-2008 and Anaj-2017, under water-stressed (50% field capacity) environments. Drought and laser priming significantly affected the growth (shoot and shoot fresh and dry weight and lengths), grain yield (number of total and fertile tillers and 100-grain weight), biochemical attributes (total soluble proteins and total free amino acids), and ionic concentration of both tested wheat varieties. In this study, the 2 min laser priming treatments were most effective for protecting wheat plants from drought stress. While the prolonged treatment duration significantly inhibited growth. We conclude that laser pretreatment assisted wheat plants in sustaining biomass assimilation, growth and yield formation by protecting their pigments and key metabolites from drought-induced oxidative injury. This study suggested that 2 min of laser priming had a much better result than other time duration, i.e., 1 and 5 min of laser priming.

Alumina nanocoating assisted dispersion stability of permanent violet pigments via atomic layer deposition

Permanent violet is an organic pigment that is extensively applied in the colourant industry, wherein excellent dispersion ability and stability of organic pigments in a solution is required. Therefore, surface modification of organic pigments significantly impacts their application performance. Herein, a few-nanometres-thick inorganic film coating layer via atomic layer deposition (ALD) method has been prepared for surface modification of permanent violet pigments, which enhances the pigments’ dispersion stability. Uniform coatings comprising individual particles (rather than agglomerates) are confirmed by morphology, specific surface area and particle size distribution characterizations. The UV–Vis absorbance results indicate 20 cycles of Al2O3 coated permanent violet pigments exhibit excellent stability when dispersed in ethanol solvent, which is attributed to the electrostatic stabilization of Al2O3 coatings. The ultrathin film coating provides an effective method of improving the dispersion stability of organic pigments, which can promote the applications in electronic colouration industry.

Modification and performance analysis of pigment red 122 by fumed silica

In order to improve the properties of pigment red 122 (P.R.122), fumed silica was used as the adsorption carrier of pigment modification, and pigment red 122 was modified by precipitation-adsorption modification method, and a number of performance tests and characterization analysis of the pigments before and after modification were carried out. The effects of fumed silica modification on the color light, coloring power, dispersibility and hiding power of pigment red 122 were studied, and the structure and properties of pigment before and after modification were analyzed by means of particle size distribution analysis, scanning electron microscope (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TG-DTG). The results show that: when the addition of fumed silica is 10%, the properties of the modified pigments are enhanced to a certain extent; when the addition of fumed silica reached 20%, the crystal form of the modified pigment did not change significantly, and the color light, coloring power, water dispersibility, hiding power and heat resistance of the modified pigment were significantly enhanced. It is obvious that the performance of pigment red 122 modified by fumed silica is more excellent, which has a certain guiding significance for the research and development of new varieties and high-quality pigment red.

Natural pigment: Preparation of brown pigment from lignin biomass for coloring application

Nanopigment based coatings have attracted considerable interest due to their high surface area, enhanced covering strength, resistance to scratch and abrasion properties. The preparation of nano pigments from industrial waste is challenging and can potentially be used in various industrial applications. As per environmental concerns, utilization of insoluble residues such as black liquor separated from paper and pulp industry waste as value added products is essential for industrial waste management. Tailoring of nanosized pigment colorants with improved surface covering properties from the industrial waste black liquor has been proposed. The acidified and precipitated insoluble organic part of black liquor was used for pigment preparation. Surface modification of pigment with silica coating, through sol-gel method, using synthesized Gemini surfactant, was adopted for size reduction. The prepared nanopigments were characterised through Fourier Transform Infrared Spectroscopy (FT-IR), Reflectance measurement and Transmission Electron Microscope (TEM). The results for optical studies of the prepared pigment confirms the suitability of this surface modified pigment as a brown coloring agent. From the DLS measurements, the dispersion property of prepared pigment was found to be monodispersed with a narrow size distribution of approximately 50–200 nm. The industrial applicability of such nano pigment was analysed by utilizing it as colorant for the leather surface coating as well as in plastics. Commercial viability of nano-pigments as coloring agents, adds value to the paper and pulp industry waste in a sustainable way.

Study on silica coated chrome oxide green pigment and its performance

AbstractIn this study, sodium silicate (Na2SiO3) was used as the precursor of SiO2 to prepare Cr2O3/SiO2 composite pigments. First, using cetyltrimethylammonium bromide to surface modification of the chromium oxide green pigment to make the surface of the particles positively charged. The negatively charged SiO2 sol coats the surface of the pigment particles through electrostatic attraction. Then use HCl solution acid to precipitate SiO2, and finally get Cr2O3/SiO2 composite pigment. The structure of the modified pigment was analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), particle size distribution analysis, and X‐ray diffraction (XRD) characterization. The influence of silica coating on the tinting strength, dispersibility of pigment in water, and hiding power of the chromium oxide green pigment were further investigated. The results demonstrate that SEM, TEM, and particle size analysis shows that this experimental method can obtain a good silica coating. When the coating quantity is 30%, the full coating of chromium oxide green by silica is achieved. According to the XRD analysis before and after the chromium oxide green coating, as the reaction temperature increases, the intensity of the SiO2 diffraction peak becomes larger and the crystallization effect becomes better. In the test of pigment performance, it can be concluded that the coloring power, hiding power, and dispersibility of Cr2O3/SiO2 composite pigments are better than those of uncoated chromium oxide green pigments.

Sulfonation of Monascus pigments to produce water-soluble yellow pigments

Red Yeast Rice, a kind of Monascus pigments produced by fermentation of Monascus species on rice, is a traditional Chinese medicine and food colorant. Chemical modification of natural pigments is a common strategy to diversify the pigments to meet various demands. Herein, native Monascus pigments as well as some of their derivates were prepared. Sulfonation of Monascus pigments with conjugated double bonds adjacent to a carbonyl group was carried out to produce novel water-soluble yellow pigments (WSYPs). The chemical structure of novel WSYPs, i.e., an addition of H2SO3 to the double bond at the side-chain of Monascus pigments, was elucidated by MS and NMR analysis. The introduction of H2SO3 into Monascus pigments makes WSYPs exhibit yellow color and high water solubility. The yellow color, high water solubility, as well as relatively high stability in a wide pH range contribute the novel WSYPs as a potential food colorant.

Characteristics of pigments, modification, and their functionalities

AbstractNovel treatments of pigments with inorganic materials have tremendous industrial and commercial prospects. Specific treatment of pigment has a marked effect on its behavior during application. The treatment allows a broad modification of the surface characteristics of pigment particles which leads to improved functionalities. Surface modification of pigments is achieved via coating, polymerization with modifying reagent, treatment with derivatives or polymers, which alter either the optical, conductivity or dispersibility during processing and application. These and many other distinguishing factors that affect the characteristics of pigments such as the class, crystal structure, particle morphology, particle size, hiding power, pigment volume concentration, surface character, and surface treatment have been reviewed. Various organic pigments such as those from fungus and bacteria, and the various families of pigment types such as metallic pigment, light interference, and diffractive pigments which presents decorative quality such as leafing, nonleafing, pearlscent, and Fabry‐Perot effects on substrates have also been reviewed in addition to those from inorganic sources with emphasis on the structure and physiochemical modifications using metal and nonmetal Ions.

Behavioural changes controlled by catecholaminergic systems explain recurrent loss of pigmentation in cavefish.

Multiple cave populations of the teleost Astyanax mexicanus have repeatedly reduced or lost eye and body pigmentation during adaptation to dark caves. Albinism, the complete absence of melanin pigmentation, is controlled by loss-of-function mutations in the oca2 gene. The mutation is accompanied by an increase in the melanin synthesis precursor l-tyrosine, which is also a precursor for catecholamine synthesis. In this study, we show a relationship between pigmentation loss, enhanced catecholamine synthesis and responsiveness to anaesthesia, determined as a proxy for catecholamine-related behaviours. We demonstrate that anaesthesia resistance (AR) is enhanced in multiple depigmented and albino cavefish (CF), inversely proportional to the degree of pigmentation loss, controlled by the oca2 gene, and can be modulated by experimental manipulations of l-tyrosine or the catecholamine norepinephrine (NE). Moreover, NE is increased in the brains of multiple albino and depigmented CF relative to surface fish. The results provide new insights into the evolution of pigment modification because NE controls a suite of adaptive behaviours similar to AR that may represent a target of natural selection. Thus, understanding the relationship between loss of pigmentation and AR may provide insight into the role of natural selection in the evolution of albinism via a melanin-catecholamine trade-off.

Bioinspired water-soluble two-photon fluorophores

The structural modification of plant pigments allows the development of new functional dyes with tailored photophysical properties. Two-photon excitation fluorescence microscopy has emerged as an important technique, but requires the use of fluorophores having large two-photon absorption cross-sections in water. This feature is rarely found in natural or artificial dyes, but betalains, the main pigments of beetroots and some species of fluorescent flowers, can be modified to produce water-soluble two-photon fluorophores. Herein we describe the semisynthesis and photophysical characterization of two water-soluble artificial coumarinic betalains. The excitation of these compounds in the near-infrared results in yellow fluorescence with two-photon cross-sections in water of 323 GM and 179 GM.

Modification of Merck's effect pigment yields special automotive clear coat

Modification of Merck's effect pigment yields special automotive clear coat

Population-level coordination of pigment response in individual cyanobacterial cells under altered nitrogen levels

Cyanobacterial phycobilisome (PBS) pigment-protein complexes harvest light and transfer the energy to reaction centers. Previous ensemble studies have shown that cyanobacteria respond to changes in nutrient availability by modifying the structure of PBS complexes, but this process has not been visualized for individual pigments at the single-cell level due to spectral overlap. We characterized the response of four key photosynthetic pigments to nitrogen depletion and repletion at the subcellular level in individual, live Synechocystis sp. PCC 6803 cells using hyperspectral confocal fluorescence microscopy and multivariate image analysis. Our results revealed that PBS degradation and re-synthesis comprise a rapid response to nitrogen fluctuations, with coordinated populations of cells undergoing pigment modifications. Chlorophyll fluorescence originating from photosystem I and II decreased during nitrogen starvation, but no alteration in subcellular chlorophyll localization was found. We observed differential rod and core pigment responses to nitrogen deprivation, suggesting that PBS complexes undergo a stepwise degradation process.

FRET-Mediated Long-Range Wavelength Transformation by Photoconvertible Fluorescent Proteins as an Efficient Mechanism to Generate Orange-Red Light in Symbiotic Deep Water Corals.

Photoconvertible fluorescent proteins (pcRFPs) are a group of fluorophores that undergo an irreversible green-to-red shift in emission colour upon irradiation with near-ultraviolet (near-UV) light. Despite their wide application in biotechnology, the high-level expression of pcRFPs in mesophotic and depth-generalist coral species currently lacks a biological explanation. Additionally, reduced penetration of near-UV wavelengths in water poses the question whether light-driven photoconversion is relevant in the mesophotic zone, or whether a different mechanism is involved in the post-translational pigment modification in vivo. Here, we show in a long-term mesocosm experiment that photoconversion in vivo is entirely dependent on near-UV wavelengths. However, a near-UV intensity equivalent to the mesophotic underwater light field at 80 m depth is sufficient to drive the process in vitro, suggesting that photoconversion can occur near the lower distribution limits of these corals. Furthermore, live coral colonies showed evidence of efficient Förster Resonance Energy Transfer (FRET). Our simulated mesophotic light field maintained the pcRFP pool in a partially photoconverted state in vivo, maximising intra-tetrameric FRET and creating a long-range wavelength conversion system with higher quantum yield than other native RFPs. We hypothesise that efficient conversion of blue wavelengths, abundant at depth, into orange-red light could constitute an adaptation of corals to life in light-limited environments.

Loss of anthocyanins and modification of the anthocyanin profiles in grape berries of Malbec and Bonarda grown under high temperature conditions

Malbec and Bonarda are the two most widely cultivated grape varieties in Argentina, and their derived red wines are recognized worldwide, being their intense color a major quality trait. The temperature during fruit ripening conditions berries color intensity. In the main viticulture region of Malbec and Bonarda a 2–3°C increase in temperature has been predicted for the upcoming years as consequence of the global climate change. In the present study, this predicted temperature raise was simulated under field-crop conditions, and its effect on anthocyanin pigmentation in berries of Malbec and Bonarda was monitored by HPLC analysis throughout the ripening process, in two growing seasons. Additionally, expression levels of regulatory (MYBA1 and MYB4) and structural (UFGT and Vv3AT) anthocyanin genes were monitored in Malbec berry skins. Although cultivar-dependent time-course variation was observed for total anthocyanin content, in general, the berries of both cultivars grown under high temperature (HT) conditions had significantly lower total anthocyanins (∼28–41% reduction), and a higher proportion of acylated anthocyanins, than their respective controls. Expression of MYBA1 and UFGT, but not MYB4, was correlated with anthocyanin pigmentation at half ripening and harvest, whereas overexpression of the acyltransferase gene Vv3AT was associated with higher anthocyanin acylation in HT berries. These results suggest that color development and pigment modifications in Malbec berries under HT are regulated at transcriptional level by MYBA1, UFGT, and Vv3AT genes. These data contribute to the general understanding on the effect of high temperatures on anthocyanin biochemistry and genetic regulation, and may have direct implications in the production of high-quality wines from Malbec and Bonarda.

Elucidating variable traits of flower pigments in clivian plants’ species

Elucidating Variable Traits of Flower Pigments in Clivian Plants' Species Colour patterns of flowers are vital commercial characteristics that influence floricultural plants and industries around the globe because of the multiple colour pigmentation produced by flowering plants. Flower colour patterns comprising different sets of colour can be found in many plant species and their cultivars. The varieties of an ornamental cultivated flowering plant like Clivia have also improved significantly in the floricultural industry worldwide. Clivias were recently subjected to a notable deal of retail market among conventional breeders to enhance varieties of variable flower colour traits, thus allowing the idea to understand and explore the origin and development new plant varieties. However, these ideas will be more credible if innovative studies are done on flower modification of pigments. Nonetheless, the review was focused on Clivia biology, flavonoid pigments, and factors affecting anthocyanins accumulation and colour in flowers, anthocyanin biosynthetic structural genes and CHS and ANS gene expression in flowering plants. In addition, the review concentrated on known important species of clivia, specifically on Clivia miniata, and the general studies of flavonoid biosynthetic genes from other plants in regards to flower pigmentation....

Creation of Coatings by Temperature-Controlled Polymer Deposition

In this paper, the results of the recent studies on application of lower critical solution temperature (LCST) phenomena of polymer solutions to the surface modification of flat and spherical substrates are reported. It was found that a controlled polymer deposition can be achieved upon prevailing of the LCST, a peculiar surface topology of polymer coating and particles those remarkably effective in stabilizing pigment dispersiions. Second, the finding is that the temperature induces polymer deposition as the coprecipitation of a finely dispersed component on the substrate surface. That goes along with the polymer deposition after exceeding of the LCST which in turn allows for the tailored surface modification of pigments in that particulate additiives can be incorporated into the surface modifying coating.

Modification and spectral properties research of cobalt blue pigments

In this paper, we produced spinel structure nanometre cobalt blue powder pigment by chemical coprecipitation. We also modified it through element doping and analysed the spinel structure and colouring mechanism of the pigment. We discussed the process conditions of coprecipitation reaction, the influence of doping element and its content on the properties of cobalt blue pigments spectral reflection effect. The morphology and particle size of powders were characterised through scanning electron microscopy and energy dispersive spectroscopy. The doping element type and content have great influence on the spectral curve of the cobalt pigment. High temperature in sintering contributes to the performance of the products. The sample produced at 1250°C sintering possesses good reflection characteristics, which is similar to chlorophyll.

Preparation of Composite Powder and Properties by Surface Modification of Inorganic Pigments for Papermaking

In this study, functional composite-pigment was prepared by a dry impact-blending method, using the inorganic materials used for coating of titanium dioxide, GCC, clay, and talc. After considering the particle size of inorganic pigment, the selected core powder and fine powder were mixed at a suitable mixing ratio. When powder was electrified, their fine particles could adhere by static electricity on the larger ones termed ‘core particles’, and then form an ordered mixture. During the surface modification of pigments, the energy caused by fine powder adhering to core particles was measured, and utilized in examining the efficiency of the change of particle size surface modification. Afterward, these were susceptible to being composited by impact force, resulting from very high-speed air circulation. After putting these surface modified pigments in water, their static electricity properties were measured by particle charge detector and Zeta potential tester. From these results, it was revealed that the elemental powder properties of papermaking inorganic pigment could be improved.