This work was supported by the New Professor Research Foundation Program, funded by Gyeongsang National University (Grant Number 2015-04-020).

1. Preparation of Plant Phenol-derived Polymeric Dyes
<ol>
	<li>Dissolve catechol (0.1 g) and (+)-catechin hydrate (0.1 g) in 32 ml of 100 mM sodium acetate buffer (pH 5.0) and 8 ml of absolute ethanol.</li>
	<li>Add 10 mg of T. versicolor laccase to the catechol- and catechin-containing buffer. Mix vigorously and pour the solution into a square Petri dish. Incubate the dish at room temperature in a shaking incubator (25 rpm) for 24 hr. Dramatic color change of the solution from transparent to dark black can be observed with the naked eye after laccase-induced coupling reactions.</li>
	<li>Centrifuge the solution for 10 min at 20,000 x g in order to spin down insoluble polymeric particles. Use the deep black supernatant for further desalting.</li>
	<li>Desalt the reaction solution with a 5 kDa ultrafiltration disc. After concentrating the reaction volume to 20 ml through ultrafiltration, exchange the reaction buffer by adding 300 ml of distilled water. Finally, using filtration, concentrate the volume of the solution to 25 ml.</li>
</ol>
2. Dyeing Solutions for Gray Keratin Hair
<ol>
	<li>Prepare the following six polymeric solutions: polymeric dyes, polymeric dyes/FeSO4, polymeric dyes/FeSO4 in pH 3 water, polymeric dyes/FeSO4 in pH 11 water, polymeric dyes/FeSO4 with acetic acid, and polymeric dyes/FeSO4 with ammonia.
	<ol>
		<li>For the polymeric dye, mix 5 ml of distilled water with 1 ml of the desalted polymeric dyes (1.4).</li>
		<li>For the mordant solutions, add 0.33 g of FeSO4 to the mixture from step 2.1.1. Vigorously vortex to dissolve the FeSO4 completely.</li>
		<li>For the pH 3 or 11 water solution, adjust the pH of 5 ml distilled water using 1 N HCl or 1 N NaOH. Then add 1 ml of the desalted polymeric dyes (1.4) and 0.33 g of FeSO4.</li>
		<li>For acetic acid- or ammonia-treated solution, mix 1.0 ml of glacial acetic acid or 1.0 ml of ammonia water with 5 ml of distilled water. Then add 1 ml of the desalted polymeric dyes (1.4) and 0.33 g of FeSO4.</li>
	</ol>
	</li>
	<li>For the plant monomers, mix catechol (0.1 g) and (+)-catechin hydrate (0.1 g) in 6 ml of distilled water, with or without 0.33 g of FeSO4, to soak the hair in.</li>
	<li>As soon as the dyeing solutions from step 2.1 and 2.2 are prepared, completely soak 5-cm long gray human hair tresses (0.2 g) in the solutions. Incubate the hair tresses at 32 &#176;C in a shaking incubator (160 rpm) for 2.5 hr.</li>
	<li>Afterwards, take out the hair tresses and rinse them with running water. Use an electronic hair drier to remove the moisture. Color change caused by the polymeric dyes can be visualized with the naked eye.
	<ol>
		<li>To obtain the color parameters (i.e., L*, a*, and b*), employ a conventional colorimeter according to the manufacturer&#39;s protocol. Crumple the hair tresses into a ball, thus allowing them to be measured with the lens of a colorimeter. Repeat this process on a different region of the hair with the colorimeter lens.</li>
		<li>Measure the color parameters of each dyed tress seven times. Calculate averages and standard deviations of the parameters. Calculate &#916;E using the formula: [(100 - L*)2 + (a*)2 + (b*)2]1/2.</li>
	</ol>
	</li>
</ol>
3. Color Durability Tests
<ol>
	<li>Dissolve 200 mg of sodium dodecyl sulfate (SDS) in 40 ml of distilled water. Soak the dyed hair completely in the SDS-containing water for 5 min at room temperature. Take out the hair tresses and then rinse them with enough running water to remove the detergents. Use an electronic hair drier to remove the moisture.</li>
	<li>To obtain the color parameters (i.e., L*, a*, and b*), employ a conventional colorimeter according to the manufacturer&#39;s protocol. Repeat the soaking described in step 3.1 once more with the same dyed hair and then measure the parameters again.</li>
	<li>Dissolve 800 mg of SDS in 40 ml of distilled water. As described in step 3.1, repeat the soaking twice more with the same dyed hair. Overall, treat each dyed hair tress with the SDS solution a total of four times.</li>
</ol>

<ol>
	<li>Jeon, J. R., Chang, Y. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laccase-mediated+oxidation+of+small+organics:+bifunctional+roles+for+versatile+applications.">Laccase-mediated oxidation of small organics: bifunctional roles for versatile applications.</a> Trends Biotechnol. 31, 335-341 (2013).</li><li>Kudanga, T., Nyanhongo, G. S., Guebitz, G. M., Burton, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potential+applications+of+laccase-mediated+coupling+and+grafting+reactions:+a+review.">Potential applications of laccase-mediated coupling and grafting reactions: a review.</a> Enzyme Microb Technol. 48, 195-208 (2011).</li><li>Jeon, J. R., Le, T. T., Chang, Y. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dihydroxynaphthalene-based+mimicry+of+fungal+melanogenesis+for+multifunctional+coatings.">Dihydroxynaphthalene-based mimicry of fungal melanogenesis for multifunctional coatings.</a> Microb. Biotechnol. 9, 305-315 (2016).</li><li>Jeon, J. R., Baldrian, P., Murugesan, K., Chang, Y. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laccase-catalyzed+oxidations+of+naturally+occurring+phenols:+From+in+vivo+biosynthetic+pathways+to+green+synthetic+application.">Laccase-catalyzed oxidations of naturally occurring phenols: From in vivo biosynthetic pathways to green synthetic application.</a> Microb. Biotechnol. 5, 318-332 (2012).</li><li>Chung, K. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutagenicity+and+toxicity+studies+of+p-phenylenediamine+and+its+derivatives.">Mutagenicity and toxicity studies of p-phenylenediamine and its derivatives.</a> Toxicol. Lett. 81, 23-32 (1995).</li><li>Bai, Y. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=p-aminophenol+and+p-phenylenediamine+induce+injury+and+apoptosis+of+human+HK-2+proximal+tubular+epithelial+cells.">p-aminophenol and p-phenylenediamine induce injury and apoptosis of human HK-2 proximal tubular epithelial cells.</a> J. Nephrol. 25, 481-489 (2012).</li><li>Jeon, J. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laccase-catalyzed+polymeric+dye+synthesis+from+plant-derived+phenols+for+potential+application+in+hair+dyeing:+Enzymatic+colorations+driven+by+homo-+or+hetero-polymer+synthesis.">Laccase-catalyzed polymeric dye synthesis from plant-derived phenols for potential application in hair dyeing: Enzymatic colorations driven by homo- or hetero-polymer synthesis.</a> Microb. Biotechnol. 3, 324-335 (2010).</li><li>Franca, S. A., Dario, M. F., Esteves, V. B., Baby, A. R., Velasco, M. V. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Types+of+hair+dye+and+their+mechanisms+of+action.">Types of hair dye and their mechanisms of action.</a> Cosmetics. 2, 110-126 (2015).</li><li>Ball, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deposition+mechanism+and+properties+of+thin+polydopamine+films+for+high+added+value+applications+in+surface+science+at+the+nanoscale.">Deposition mechanism and properties of thin polydopamine films for high added value applications in surface science at the nanoscale.</a> BioNanoSci. 2, 16-34 (2012).</li><li>Barrett, D. G., Sileika, T. S., Messersmith, P. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+diversity+in+phenolic+and+polyphenolic+precursors+of+tannin-inspired+nanocoatings.">Molecular diversity in phenolic and polyphenolic precursors of tannin-inspired nanocoatings.</a> Chem. Commun. 50, 7265-7268 (2014).</li><li>Sileika, T. S., Barrett, D. G., Zhang, R., Lau, K. H. A., Messersmith, P. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Colorless+multifunctional+coatings+inspired+by+polyphenols+found+in+tea,+chocolate,+and+wine.">Colorless multifunctional coatings inspired by polyphenols found in tea, chocolate, and wine.</a> Agnew. Chem. 52, 10766-10770 (2013).</li><li>Boonsong, P., Laohakunjit, N., Kerdchoechuen, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+pigments+from+six+species+of+Thai+plants+extracted+by+water+for+hair+dyeing+product+application.">Natural pigments from six species of Thai plants extracted by water for hair dyeing product application.</a> J. Clean. Prod. 37, 93-106 (2012).</li><li>Bechtold, T., Turcanu, A., Ganglberger, E., Geissler, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+dyes+in+modern+textile+dyehouses+-+how+to+combine+experiences+of+two+centuries+to+meet+the+demands+of+the+future.">Natural dyes in modern textile dyehouses - how to combine experiences of two centuries to meet the demands of the future.</a> J. Clean. Prod. 5, 499-509 (2003).</li><li>Zheng, H., Gao, C., Peng, B., Shu, M., Che, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=pH-responsive+drug+delivery+system+based+on+coordination+bonding+in+a+mesostructured+surfactant/silica+hybrid.">pH-responsive drug delivery system based on coordination bonding in a mesostructured surfactant/silica hybrid.</a> J. Phys. Chem. C. 115, 7230-7237 (2011).</li><li>Robbins, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Chemical and physical behavior of human hair. , 105-176 (2011).</li></ol>

The authors declare that they have no competing financial interests.

Interestingly, our method reduced the time it took to dye keratin hair with oxidant-induced polymerizations of natural phenolics. It also induced diverse colors in the hair through simple manipulations of the polymeric dyes, such as changing the pH and applying mordant.
In situ incubation of keratin hair with laccase-catalyzed oxidation of plant phenols requires overly long incubation times to attain effective dyeing7. Such slow dyeing kinetics may be due to the poor bindin...

Laccases are oxidases that are active towards phenolic and polyphenolic compounds. They have been identified in various living organisms, including plants, fungi, insects, and bacteria. Their enzymatic actions contribute to several morphogenetic phenomena1. The enzymes catalyze single-electron oxidation of the substrates, resulting in the formation of radicals that are further coupled to small organics and to solid surfaces. Such coupling processes lead to syntheses of oligomers and polymers and to surface functionalizations2, 3. When laccase substrates are from natural sources, such as plant phenolics, the enzymatic reactions are of great interest with respect to green chemistry. Here, both reactants and catalysts are from natural sources. In addition, the resulting products are similar to the natural products, since the overall reactions mimic the in vivo syntheses of natural phenolic polymers-including plant lignin, poly(flavonoid), and humus-wherein small plant phenolic compounds are highly cross-linked by oxidase-induced radical coupling4.
Products derived from laccase-catalyzed coupling reactions of plant-derived phenols can be used to dye gray hair through in situ incubation and can be developed as alternatives to commercially available dyes1. Such alternatives are important, since commercial hair-dyeing agents are based on p-phenylenediamine (PPD), PPD-related diamine compounds, and hydrogen peroxide, which have been shown to be toxic, carcinogenic, and allergenic to humans5, 6. In the laccase-catalyzed coupling reactions, the laccases and plant phenols functionally replace hydrogen peroxide and p-phenylenediamine, respectively7. However, the dyeing speed of the laccase-based systems is much slower than that of the commercial one. In general, the PPD-based dyeing agents require less than one hour to achieve effective color change in keratin hair, while the laccase-based reactions require an overnight incubation7. The slow dyeing kinetics could be explained by two possible phenomena. First, the use of a low-pH buffer (e.g., pH 5) to maximize laccase activity has been observed to decrease the degree of swelling in the keratin matrices, thus inhibiting deep penetration of dyes into the matrices. Indeed, agents allowing the dyeing reactions to proceed in high-pH conditions have been shown to be integral to commercial hair-dyeing products8. Second, the number of possible chromophore molecules exhibiting strong adsorption to keratinous surfaces during the polymerization reaction has been shown to be proportional to the incubation time (i.e., the extent of polymerization). For example, the transformation of dopamine to polydopamine was shown to induce a strong adhesion to many surfaces that was concomitant with the formation of a black color9.
In the current work, pre-synthesized polymeric products obtained from T. versicolor laccase-catalyzed oxidation of catechin and catechol were used to treat keratin hair for dyeing. We hypothesized that the adsorption ability of the polymers would be much stronger than that of the monomeric plant phenols and that they would initially form low-molecular-weight oligomers. Results demonstrated that, when using the pre-synthesized polymers, the enzymatic oxidation power was no longer necessary. This indicates that the pH can be controlled and that metal ions can be used in hair-dyeing treatments, regardless of enzyme activity. This protocol provides a simple and fast method to dye keratin hair in various shades of color while using eco-friendly and renewable plant-derived phenolics (Figure 1).

<table><tbody><tr><td>Sodium dodecyl Sulfate</td><td>Promega</td><td>H5114</td><td></td></tr><tr><td>Laccase from Trametes versicolor</td><td>Sigma</td><td>38429-1G</td><td>Enzyme activity is denoted as 0.53 U/mg</td></tr><tr><td>(+)-catechin hydrate</td><td>Sigma</td><td>C1251-5G</td><td></td></tr><tr><td>1,2-dihydroxybenzene (catechol)</td><td>Sigma</td><td>135011-5G</td><td></td></tr><tr><td>Ammonia water&amp;nbsp;</td><td>Duksan</td><td>701</td><td>Ammonia contents is denoted as 25 ~ 30%</td></tr><tr><td>Acetic acid, glacial</td><td>Duksan</td><td>448</td><td></td></tr><tr><td>Iron(II) sulfate heptahydrate</td><td>JUNSEI</td><td>83380-1250</td><td></td></tr><tr><td>Ultracell 5 kDa</td><td>Amicon</td><td>PLCC06210</td><td></td></tr><tr><td>Stirred ultrafiltration cells</td><td>Millipore</td><td>Model 8200</td><td></td></tr><tr><td>Human gray hair</td><td>PheonixKorea</td><td>Not available</td><td></td></tr><tr><td>Colorimeter</td><td>SPEC</td><td>JCS-10</td><td></td></tr><tr><td>Square dish</td><td>SPL</td><td>10125</td><td>125 * 125 * 20 (mm)</td></tr></tbody></table>

synthesis of plant phenol-derived polymeric dyes for direct or mordant-based hair dyeing

Effective hair dyeing through in situ incubation of keratin hair with the products of fungal laccase-catalyzed polymerization of plant phenols has been previously demonstrated. However, the dyeing process takes a long time to complete compared to commercial hair-dyeing products. To overcome this bottleneck, pre-synthesized polymeric products of the oxidative reaction of Trametes versicolor laccase on catechin and catechol, either with or without mordant agents (e.g., FeSO4), were here employed to achieve permanent keratin hair dyeing in various colors and shades. The laccase action in acidic sodium acetate buffer led to a deep black coloration after coupling reactions between the plant phenols. The colored dye products were then desalted and concentrated with ultrafiltration. The dyes, with or without mordant agents, caused a significant increase in &#916;E values (i.e., color difference value) in gray human hair within 2.5 hours. In addition, different keratin colors and shades were induced depending upon the mordanting and pH changes. The dyed hair also exhibited a strong resistance to detergent treatments, indicating that our methods can give rise to permanent hair dyeing.&#160;Overall, our work has provided novel insight into developing eco-friendly hair-dyeing methods as alternatives to commercial toxic diamine-based dyes.

First, the dyeing ability of polymeric dyes was compared to that of plant-derived monomers (i.e., catechin and catechol). The polymeric dyes induced a significant change in the color of gray keratin hair (Figure 2A and Figure 3), while the innate gray color of the hair remained very stable with plant monomers (data not shown). The effects of mordanting agents on the dyeing abilities of polymeric products were then evaluated. As s...

Watch this Scientific Journal Video about Synthesis of Plant Phenol-derived Polymeric Dyes for Direct or Mordant-based Hair Dyeing at JoVE.com

Synthesis of Plant Phenol-derived Polymeric Dyes for Direct or Mordant-based Hair Dyeing

Here, we present a protocol to use pre-synthesized polymeric products derived from fungal laccase-catalyzed polymerization of plant phenols, either with or without mordant agents (e.g., FeSO4), to induce detergent-resistant keratin hair dyeing within 2.5 hours.

Effective hair dyeing through in situ incubation of keratin hair with the products of fungal laccase-catalyzed polymerization of plant phenols has been ...

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9.2K Views.  Gyeongsang National University. Here, we present a protocol to use pre-synthesized polymeric products derived from fungal laccase-catalyzed polymerization of plant phenols, either with or without mordant agents (e.g., FeSO4), to induce detergent-resistant keratin hair dyeing within 2.5 hours.

Video: Synthesis of Plant Phenol-derived Polymeric Dyes for Direct or Mordant-based Hair Dyeing

Microwave-assisted Intramolecular Dehydrogenative Diels-Alder Reactions for the Synthesis of Functionalized Naphthalenes/Solvatochromic Dyes

Functionalized naphthalenes have applications in a variety of research fields ranging from the synthesis of natural or biologically active molecules to the preparation of new organic dyes. Although numerous strategies have been reported to access naphthalene scaffolds, many procedures still present limitations in terms of incorporating functionality, which in turn narrows the range of available substrates. The development of versatile methods for direct access to substituted naphthalenes is therefore highly desirable.
The Diels-Alder (DA) cycloaddition reaction is a powerful and attractive method for the formation of saturated and unsaturated ring systems from readily available starting materials. A new microwave-assisted intramolecular dehydrogenative DA reaction of styrenyl derivatives described herein generates a variety of functionalized cyclopenta[b]naphthalenes that could not be prepared using existing synthetic methods. When compared to conventional heating, microwave irradiation accelerates reaction rates, enhances yields, and limits the formation of undesired byproducts.
The utility of this protocol is further demonstrated by the conversion of a DA cycloadduct into a novel solvatochromic fluorescent dye via a Buchwald-Hartwig palladium-catalyzed cross-coupling reaction. Fluorescence spectroscopy, as an informative and sensitive analytical technique, plays a key role in research fields including environmental science, medicine, pharmacology, and cellular biology. Access to a variety of new organic fluorophores provided by the microwave-assisted dehydrogenative DA reaction allows for further advancement in these fields.

Microwave-assisted intramolecular dehydrogenative Diels-Alder (DA) reactions provide concise access to functionalized cyclopenta[b]naphthalene building blocks. The utility of this methodology is demonstrated by one-step conversion of the dehydrogenative DA cycloadducts into novel solvatochromic fluorescent dyes via Buchwald-Hartwig palladium-catalyzed cross-coupling reactions.

Functionalized naphthalenes have applications in a variety of research fields ranging from the synthesis of natural or biologically active molecules to ...

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel &#945;-diimine ethylene polymerization catalyst. Initial polymerizations with the catalyst lead to optimized reaction conditions, including catalyst concentration, ethylene pressure and reaction time. Using gas-uptake data for these reactions, a procedure to calculate the initial rate of propagation (kp) is presented. Using the optimized conditions, the ability of the nickel &#945;-diimine polymerization catalyst to undergo chain transfer with diethylzinc (ZnEt2) during ethylene polymerization was investigated. A procedure to assess the ability of the catalyst to undergo chain transfer (from molecular weight and 13C NMR data), calculate the degree of chain transfer, and calculate chain transfer rates (ke) is presented.

A protocol for the high-throughput analysis of polymerization catalyst, chain transfer polymerizations, polyethylene characterization, and reaction kinetic analysis is presented.

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel ...

Electroactive Polymer Nanoparticles Exhibiting Photothermal Properties

A method for the synthesis of electroactive polymers is demonstrated, starting with the synthesis of extended conjugation monomers using a three-step process that finishes with Negishi coupling. Negishi coupling is a cross-coupling process in which a chemical precursor is first lithiated, followed by transmetallation with ZnCl2. The resultant organozinc compound can be coupled to a dibrominated aromatic precursor to give the conjugated monomer. Polymer films can be prepared via electropolymerization of the monomer and characterized using cyclic voltammetry and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. Nanoparticles (NPs) are prepared via emulsion polymerization of the monomer using a two-surfactant system to yield an aqueous dispersion of the polymer NPs. The NPs are characterized using dynamic light scattering, electron microscopy, and UV-Vis-NIR-spectroscopy. Cytocompatibility of NPs is investigated using the cell viability assay. Finally, the NP suspensions are irradiated with a NIR laser to determine their effectiveness as potential materials for photothermal therapy (PTT).

A protocol is presented for the synthesis and preparation of nanoparticles consisting of electroactive polymers.

A method for the synthesis of electroactive polymers is demonstrated, starting with the synthesis of extended conjugation monomers using a three-step ...

Engineering

Genetic Incorporation of Biosynthesized L-dihydroxyphenylalanine (DOPA) and Its Application to Protein Conjugation

L-dihydroxyphenylalanine (DOPA) is an amino acid found in the biosynthesis of catecholamines in animals and plants. Because of its particular biochemical properties, the amino acid has multiple uses in biochemical applications. This report describes a protocol for the genetic incorporation of biosynthesized DOPA and its application to protein conjugation. DOPA is biosynthesized by a tyrosine phenol-lyase (TPL) from catechol, pyruvate, and ammonia, and the amino acid is directly incorporated into proteins by the genetic incorporation method using an evolved aminoacyl-tRNA and aminoacyl-tRNA synthetase pair. This direct incorporation system efficiently incorporates DOPA with little incorporation of other natural amino acids and with better protein yield than the previous genetic incorporation system for DOPA. Protein conjugation with DOPA-containing proteins is efficient and site-specific and shows its usefulness for various applications. This protocol provides protein scientists with detailed procedures for the efficient biosynthesis of mutant proteins containing DOPA at desired sites and their conjugation for industrial and pharmaceutical applications.

Genetic Incorporation of Biosynthesized L-dihydroxyphenylalanine DOPA and Its Application to Protein Conjugation

Here, we present a protocol for the genetic incorporation of L-dihydroxyphenylalanine biosynthesized from simple starting materials and its application to protein conjugation.

L-dihydroxyphenylalanine (DOPA) is an amino acid found in the biosynthesis of catecholamines in animals and plants. Because of its particular biochemical ...

Biochemistry

Scale-up Chemical Synthesis of Thermally-activated Delayed Fluorescence Emitters Based on the Dibenzothiophene-S,S-Dioxide Core

We report a procedure to linearly scale-up the synthesis of 2,8-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)dibenzothiophene-S,S-dioxide (compound 4) and 2,8-bis(10H-phenothiazin-10-yl)dibenzothiophene-S,S-dioxide (compound 5) using Buchwald-Hartwig cross-coupling reaction conditions. In addition, we demonstrate a scaled-up synthesis of all non-commercially available starting materials that are required for the amination cross-coupling reaction. In the present article, we provide the detailed synthetic procedures for all of the described compounds, alongside their spectral characterization. This work shows the possibility to produce organic molecules for optoelectronic applications on a large scale, which facilitates their implementation into real world devices.

Scale-up synthesis of highly efficient thermally activated delayed fluorescence emitters is described in the presented article.

We report a procedure to linearly scale-up the synthesis of 2,8-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)dibenzothiophene-S,S-dioxide (compound 4) and ...

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

Cyclic voltammetry (CV) is a technique used in the analysis of organic compounds. When this technique is combined with electron paramagnetic resonance (EPR) or ultraviolet-visible and near-infrared (UV-Vis-NIR) spectroscopies, we obtain useful information such as electron affinity, ionization potential, band-gap energies, the type of charge carriers, and degradation information that can be used to synthesize stable organic electronic devices. In this study, we present electrochemical and spectroelectrochemical methods to analyze the processes occurring in active layers of an organic device as well as the generated charge carriers.

In this article, we describe electrochemical, electron paramagnetic resonance, and ultraviolet-visible and near-infrared spectroelectrochemical methods to analyze organic compounds for application in organic electronics.

Cyclic voltammetry (CV) is a technique used in the analysis of organic compounds. When this technique is combined with electron paramagnetic resonance ...

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach

Methine-bridged conjugated bicyclic aromatic compounds are common constituents of a range of biologically relevant molecules such as porphyrins, dipyrrinones, and pharmaceuticals. Additionally, restricted rotation of these systems often results in highly to moderately fluorescent systems as observed in 3H,5H-dipyrrolo[1,2-c:2',1'-f]pyrimidin-3-ones, xanthoglows, pyrroloindolizinedione analogs, BODIPY analogs, and the phenolic and imidazolinone ring systems of Green Fluorescent Protein (GFP). This manuscript describes an inexpensive and operationally simple method of performing a Claisen-Schmidt condensation to generate a series of fluorescent pH dependent pyrazole/imidazole/isoindolone dipyrrinone analogs. While the methodology illustrates the synthesis of dipyrrinone analogs, it can be translated to produce a wide range of conjugated bicyclic aromatic compounds. The Claisen-Schmidt condensation reaction utilized in this method is limited in scope to nucleophiles and electrophiles that are enolizable under basic conditions (nucleophile component) and non-enolizable aldehydes (electrophile component). Additionally, both the nucleophilic and electrophilic reactants must contain functional groups that will not inadvertently react with hydroxide. Despite these limitations, this methodology offers access to completely novel systems that can be employed as biological or molecular probes.

The Claisen-Schmidt condensation reaction is an important methodology for the generation of methine-bridged conjugated bicyclic aromatic compounds. Through utilizing a base-mediated variant of the aldol reaction, a range of fluorescent and/or biologically relevant molecules can be accessed through a generally inexpensive and operationally simple synthetic approach.

Methine-bridged conjugated bicyclic aromatic compounds are common constituents of a range of biologically relevant molecules such as porphyrins, ...

Quantitative 31P NMR Analysis of Lignins and Tannins

The development of sustainable biorefinery products is confronted, among others, with the challenge of lignin and tannin valorization. These abundant, renewable aromatic biopolymers have not been widely exploited due to their inherent structural complexity and high degrees of variability and species diversity. The lack of a defined primary structure for these polyphenols is further compounded with complex chemical alterations induced during processing, eventually imparting a large variety of structural features of extreme significance for any further utilization efforts.
Consequently, a protocol for the rapid, simple, and unequivocal identification and quantification of the various functional groups present in natural polyphenols, is a fundamental prerequisite for understanding and accordingly tailor their reactivity and eventual utility.
Quantitative 31P NMR offers the opportunity to rapidly and reliably identify unsubstituted, o-mono substituted, and o-disubstituted phenols, aliphatic OHs, and carboxylic acid moieties in lignins and tannins with broad application potential.
The methodology consists of an in situ quantitative lignin or tannin labeling procedure using a suitable 31P containing probe, followed by the acquisition of a quantitative 31P NMR spectrum in the presence of an internal standard. The high natural abundance of the 31P nucleus allows for small amounts of the sample (~30 mg) and short NMR acquisition times (~30-120 min) with well-resolved 31P signals that are highly dependent on the surrounding chemical environment of the labeled OH groups.

Quantitative 31P NMR Analysis of Lignins and Tannins

31P NMR is a powerful tool for the structural elucidation of polyphenols. This fast, easy, precise, quantitative, and highly reproducible analytical procedure, that allows for the quantification and differentiation of the different types of hydroxy, phenolic, and carboxylic groups in lignins and tannins has now become a routine analytical tool.

The development of sustainable biorefinery products is confronted, among others, with the challenge of lignin and tannin valorization. These abundant, ...

Use of Chitosan to Enhance Photoluminescence of Curcumin for Textile Authentication

Enhanced Photoluminescence of Curcuma longa Extracts via Chitosan-Mediated Energy Transfer for Textile Authentication Applications

Dyes for security markings play a pivotal role in safeguarding the integrity of products across various fields, such as textiles, pharmaceuticals, food, and manufacturing among others. However, most commercial dyes used as security markings are costly and may contain toxic and harmful substances that pose a risk to human health. Curcumin, a natural phenolic compound found in turmeric, possesses distinct photoluminescent properties alongside its vibrant yellow color, making it a potential candidate material for authentication applications. This study demonstrates a cost-effective and eco-friendly approach to develop enhanced photoluminescent emissions from curcumin dyes for textile authentication. Curcumin was extracted from C. longa using sonication-assisted-solvent extraction method. The extract was dip-coated and dyed into the textile substrates. Chitosan was introduced as a post-mordanting agent to stabilize the curcumin and as a co-sensitizer. Co-sensitization of curcumin with chitosan triggers energy transfer to enhance its luminescent intensity. The UV-visible absorption peak at 424 nm is associated with the characteristic absorption of curcumin. The photoluminescence measurements showed a broad emission peaking at 545 nm with significant enhancement attributed to the energy transfer induced by chitosan, thus showing great potential as a naturally derived photoluminescent dye for authentication applications.

Author Spotlight: Eco-friendly Photoluminescent Textile Authentication with Curcumin

Photoluminescence is one of the most effective authentication mechanisms being used today. Utilizing and enhancing naturally sourced materials with inherent photoluminescent properties and incorporating them into fabric substrates can lead to development of green, sustainable, and functional textiles for smart applications.

Dyes for security markings play a pivotal role in safeguarding the integrity of products across various fields, such as textiles, pharmaceuticals, food, ...

Polyol-Based Microwave-Assisted Extraction for Phenolic and Antioxidant Yields

Microwave-Assisted Extraction of Phenolic Compounds and Antioxidants for Cosmetic Applications Using Polyol-Based Technology

The utilization of polyols as green solvents for extracting bioactive compounds from plant materials has gained attention due to their safety and inert behavior with plant bioactive chemicals. This study explores the sustainable extraction of phenolic compounds and natural antioxidants from coffee silverskin using the microwave-assisted extraction (MAE) method with polyol-based solvents: glycerin, propylene glycol (PG), butylene glycol (BG), methylpropanediol (MPD), isopentyldiol (IPD), pentylene glycol, 1,2-hexanediol, and hexylene glycol (HG). A comparative analysis was conducted on conventional and non-conventional solvent extractions, focusing on their impact on the bioactive compounds of MAE, encompassing parameters such as total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities like the 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay (DPPH), the 2,2&#8242;-azino-bis(-3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging assay (ABTS), and the ferric reducing antioxidant power assay (FRAP). The highest values were observed for TPC with aqueous-1,2-hexanediol extraction (52.0 &#177; 3.0 mg GAE/g sample), TFC with aqueous-1,2-hexanediol extraction (20.0 &#177; 1.7 mg QE/g sample), DPPH with aqueous-HG&#160;extraction (13.6 &#177; 0.3 mg TE/g sample), ABTS with aqueous-pentylene glycol extraction (8.2 &#177; 0.1 mg TE/g sample), and FRAP with aqueous-HG extraction (21.1 &#177; 1.3 mg Fe (II) E/g sample). This research aims to advance eco-friendly extraction technology through natural plant components, promoting sustainability by minimizing hazardous chemical use while reducing time and energy consumption, with potential applications in cosmetics.

Author Spotlight: Eco-Friendly Extraction of Bioactive Compounds Using Polyol-Based Microwave-Assisted Techniques

This protocol details the utilization of a polyol-based microwave-assisted extraction method for extracting phenolic compounds and natural antioxidants, representing a practical and environmentally sustainable approach to the development of ready-to-use extracts.

The utilization of polyols as green solvents for extracting bioactive compounds from plant materials has gained attention due to their safety and inert ...

Synthesis of Plant Phenol-derived Polymeric Dyes for Direct or Mordant-based Hair Dyeing

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