Triphenylmethane Dyes Research Articles

One-Factor-at-a-Time (OFAT) Optimization of Victoria Blue R Dye Biodegradation by Pineapple Waste Garbage Enzymes

Victoria blue R is a cationic triphenylmethane dye usually released from textile industries and reported to exhibit mutagenic and carcinogenic effects on aquatic organisms and humans. Hence, the objective of this study is to investigate the capability of pineapple waste garbage enzymes to biodegrade the Victoria blue R dye using One-Factor-At-a-Time (OFAT) optimization under the effect of Victoria blue R dye concentration (0.02 to 0.10 mg/mL), pH (1 to 7), and temperature (25°C to 49°C) via Design Expert 7.0 software. The results show that pineapple waste garbage enzymes gave the highest decolorization efficiency at a concentration of 0.07 mg/mL of Victoria blue R dye, pH 4.74, and 40.4°C. The ANOVA analysis suggests all models are quadratic, and the R-Squared values for the factors are 0.92, 0.95 and 0.92 for the concentration of Victoria blue R dye, pH and temperature, respectively. This work proposed that pineapple waste garbage enzymes can effectively remove Victoria blue R dye in wastewater applications.

Solvent Media on Nonlinear Optical Properties of Triarylmethane Dye via Facile Z-Scan Method.

Solvent environment on third-order nonlinear optical (TNLO) features of triarylmethane dye namely, basic blue 7 in different solvents is reported herein using 650nm diode laser with continuous wave mode. The basic blue 7 dye is dissolved in different solvent media including ethanol, methanol, dimethyl formamide (DMF) and dimethyl sulfoxide (DMSO). The influence of solvent characteristics such as solvent polarizability and dipole moment on solute molecule is discussed. TNLO characteristics such as nonlinear optical index of refraction, nonlinear optical coefficient of absorption, real and imaginary components of the TNLO susceptibility are measured to be the order of 10‒7 cm2/W, 10‒3cm/W, 10‒6 esu and 10‒7 esu, respectively. The dye exhibits large TNLO susceptibility by dissolving in DMSO. The TNLO susceptibility of basic blue 7 dye is measured to be the order of 10‒6 esu. The overall results revealed that the basic blue 7 dye is suitable material for optoelectronics applications.

Crystal violet degradation in the ozone/persulfate/ferroferric oxide system: A heterogeneous catalytic process for simultaneous catalysis of ozone and persulfate

Crystal violet (CV) is a widely used cationic triphenylmethane dye, mostly from textile, leather and other industrial manufacturing companies. The carcinogenicity, teratogenicity and mutagenicity of crystalline violet have received widespread attention, but due to the toxicity of crystalline violet itself, the It is difficult to degrade crystal violet by conventional wastewater biological treatment system. In this study, Fe3O4 was used to activate ozone and persulfate to degrade crystal violet in water. The results showed that the degradation of crystal violet followed a pseudo-second-order kinetic model and logistic model in the O3/PDS/Fe3O4 system, there was an obvious synergistic effect among ozone, persulfate, and Fe3O4. The effect of chelating agents and background components in aqueous solution on the degradation of crystalline violet in the O3/PDS/Fe3O4 system was investigated. The Radical quenching experiments and electron spin resonance spectra show that the generation of SO4•-, •OH, and 1O2 is the main cause of crystal violet degradation. After eight reuses of ferroferric oxide, the catalytic activity of Fe3O4 slightly decreased, but it still showed a high removal effect on crystal violet. The catalysis of Fe3O4 in O3/PDS/Fe3O4 system is mainly carried out by heterogeneous catalytic process, including electron transfer in Fe(Ⅱ)/Fe(Ⅲ) redox and lattice oxygen, catalytic ozonation process of surface hydroxyl groups. The O3/PDS/Fe3O4 system has an EE/O of 139.23 kWh·m−3 per order, indicating a higher energy efficiency compared to the other process. Intermediate products of CV degradation were identified by ultraviolet absorption spectrometry and liquid chromatography-mass spectrometry (LC-MS), and the degradation pathways of CV were determined.

DEVELOPMENT OF APPROACHES TO THE ANALYSIS OF ELEMENTAL IMPURITIES IN TITANIUM DIOXIDE (ANTIMONY DEFINITION)

Reltvance. Due to its properties, substance of titanium dioxide is still widely used in the pharmaceutical industry as a drug excipient. However, from the point of view of the safe use of any component of drugs, one of the most important factors is the determination of its content of elemental impuri-ties (PE). The pharmacopoeic requirements for titanium dioxide to contain elemental impurities are not harmonized today. It was therefore advisable to develop approaches to defining them under the strictest of standards. Research objective. This work is devoted to the development of approaches to the analysis and further validation of the method of determination of antimony in the substance titanium dioxide at the level of 2 ppm. Material and Methods. The method used in this paper is based on the extraction into the organic phase of ionic associates, in which the halogen complex SbCl6-antimony acts as an anion and interacts with the triphenylmethane dye - diamond green. All the reagents and materials used were pharmacopoeic. A sample of titanium dioxide, produced by Venator Germany GmbH, Germany, was used as the research object. The validation of the methodology was carried out in accordance with the requirements of the SP RF on the following characteristics: specificity, linearity, LOQ, correctness, repeatability, intralaboratory precision and range of methods. Results. The article shows applicability of the method of determination of antimony in the substance titanium dioxide, at the level of 2 ppm, using as a reagent diamond green. At the same time, the validation evaluation of the methodology showed that the obtained results met the criteria of accepta-bility for all the studied characteristics. Conclusions. Control of PE is an important aspect of the safe use of any component of the drug. Due to the wide variety of pharmacopeic requirements for PE content in the substance TiO2, this study shows the possibility of using the extraction and photometric method with the use of a triphenylmethane dye (diamond green) to determine Sb at the most stringent standards (2 ppm). At the same time, the validation of the methodology on such characteristics as specificity, linearity, LOQ, correctness, repeatability, intralaboratory precision and range confirmed the possibility of quantitative estimation of Sb content in the substance TiO2 in the range of 50% (LOQ) up to 150% of the specification level.

Genomic Insights into the Microbial Agent Streptomyces albidoflavus MGMM6 for Various Biotechnology Applications.

Microbial biotechnology plays a crucial role in improving industrial processes, particularly in the production of compounds with diverse applications. In this study, we used bioinformatic approaches to analyze the genomic architecture of Streptomyces albidoflavus MGMM6 and identify genes involved in various metabolic pathways that have significant biotechnological potential. Genome mining revealed that MGMM6 consists of a linear chromosome of 6,932,303 bp, with a high G+C content of 73.5%, lacking any plasmid contigs. Among the annotated genes, several are predicted to encode enzymes such as dye peroxidase, aromatic ring-opening dioxygenase, multicopper oxidase, cytochrome P450 monooxygenase, and aromatic ring hydroxylating dioxygenases which are responsible for the biodegradation of numerous endogenous and xenobiotic pollutants. In addition, we identified genes associated with heavy metal resistance, such as arsenic, cadmium, mercury, chromium, tellurium, antimony, and bismuth, suggesting the potential of MGMM6 for environmental remediation purposes. The analysis of secondary metabolites revealed the presence of multiple biosynthesis gene clusters responsible for producing compounds with potent antimicrobial and metal-chelating activities. Furthermore, laboratory tests conducted under controlled conditions demonstrated the effectiveness of MGMM6 in inhibiting phytopathogenic microbes, decolorizing and degrading aromatic triphenylmethane dyes, particularly Blue Brilliant G250, from wastewater by up to 98 ± 0.15%. Overall, the results of our study highlight the promising biotechnological potential of S. albidoflavus MGMM6.

Ultrasonic-assisted synthesis of highly efficient and robust metal oxide QDs immobilized-MOF-5/Ni-Co-LDH photocatalyst for sunlight-mediated degradation of multiple toxic dyes

Concerns regarding the supply of clean and safe water are key issues that demand a suitable solution for improved wastewater treatment. Developing an efficient photocatalytic material for environmental applications is a growing research area in the present day. The present work emphasizes the natural sunlight-mediated photodegradation of toxic thiazine, xanthene, and triarylmethane dyes, employing a heterogenous advanced oxidation process. A novel heterogenous MOF-5/Ni-Co-LDH composite loaded with metal-oxide quantum dots (ZNCQD) was synthesized via ultrasonication. The polyhedral-shaped MOF-5 composite exhibited excellent photo-activity in a sunlight-driven, H2O2-assisted advanced oxidation process towards the degradation of Methylene Blue (MB), Rose Bengal (RB), and Malachite Green (MG). The experimental results indicated maximum degradation of Malachite Green. The maximum percentage degradation of MB, RB, and MG was 96.2%, 95.8%, and 99.6%, respectively. In addition, the photocatalyst demonstrated good stability for up to six consecutive cycles. The photodegradation was governed by a pseudo-first-order reaction kinetics, with MG having the highest rate constant (0.105 min−1) of all the dyes. The increased photocatalytic effectiveness could be attributed to the improved light absorption capacity by the metal quantum dots deposited on the composite surface. A detailed degradation mechanism and pathways have been proposed using various analysis techniques. Such an efficient photocatalyst with excellent activity towards both cationic and anionic dyes from aqueous medium unveils opportunities to employ MOF/LDH composites for efficient wastewater treatment and environmental remediation.

Combined application of plant extracts (tannic acid and baicalin) with acid dyes in the simultaneous dyeing and finishing of tussah silk for enhanced antioxidant, antibacterial and UV protective properties

The one-step dyeing and finishing of tussah fiber have advantages of short process, high efficiency, and energy and water saving. Additionally, to upgrade the functionalities of tussah silk fiber using natural chemicals with environmental benefits can increase its applicability. In this work, the combined application of plant extracts and acid dyes was presented for simultaneously imparting colorful shades, antioxidant activity, antibacterial activity, and UV protection capability to tussah silk. The stability of tannic acid, baicalin, and their mixtures with acid dyes was first discussed, and the colors and functionalities of dyed and finished tussah silk were evaluated. Tannic acid had less effect on the colors of dyed tussah silk. C.I. Acid Blue 113 was not stable in hot baicalin solution, and its pre-heated mixture with baicalin dyed tussah silk to dull red hue rather than blue hue. The bright blue and green colors of tussah silk were obtained by dyeing with anthraquinone and triarylmethane dyes, but their hues were affected by baicalin due to the light yellow color of baicalin and the matching of colors. Tannic acid exhibited better antibacterial property than baicalin on tussah silk, while baicalin had better antioxidant and UV protection capability than tannic acid. This work demonstrates that the one-step dyeing and finishing of tussah silk with acid dyes and plant extracts are feasible. However, special attention should be paid to the color changes of individual dyes for pale dyeing.

Fabrication of polyaniline based calcium ferrite nanocomposite and its application in sequestration of Victoria blue dye from wastewater

Fabrication of a novel nanocomposite named calcium ferrite/polyaniline (CaFe2O4-PANI) was reported and its potential for adsorption of toxic cationic dye named Victoria blue (VB) was studied in this work. The CaFe2O4-PANI has showcased improved adsorptive potential for VB dye with approximately 95.35 (±1.48)% of removal efficiency at solution pH 8.0, CaFe2O4-PANI dose of 0.5 g/L, contact time of 20 min and initial VB dye concentration of 50 mg/L. The adsorption process follows pseudo-second-order kinetic model and Freundlich isotherm model with a maximum uptake capacity of 266.67 mg/g. The adsorbent was also tested against surface and ground water sample loaded with VB dye and in presence of several ions. It was found that surface water has caused less interference (∼2 (±0.85)% reduction in VB dye removal efficiency) followed by ground water (∼4 (±0.91)% reduction) and wastewater (∼8 (±1.24)% reduction) and also the removal efficiencies are affected the most by bicarbonate ions (∼12 (±1.39)%–14 (±1.62)% reduction in VB dye removal efficiency). The experimental process was optimized utilizing a five level, three factor based response surface methodology (RSM) approach and the experimental parameters were optimized to CaFe2O4-PANI dosage = 0.5 g/L, contact time = 65 min and initial VB dye conc. = 60 mg/L, using the developed quadratic model to achieve a maximum VB removal efficiency of 98.63 (±2.13)%. Regeneration study suggests that the fabricated adsorbent can be reused up to five cycles with ∼10 (±1.13)% decrease in the VB dye removal efficiency.

Fungal decolorization of toxic Triphenylmethane dye by newly isolated Ganoderma fungi: Growth, enzyme activity, kinetics

White-rot fungi have proven their ability to release ligninolytic enzymes for degrading textile dyes. In the present study, ten new strains of the Ganoderma fungi (6001 to 6010) isolated from Hyrcanian forests in Iran were employed to decolorize Malachite Green (MG) as a toxic textile dye. Two isolates, 6009 and 6007, showed the fastest growth and dye decolorization for solid and liquid media, respectively. The strain 6009, identified as Ganoderma resinaceum, completely degraded MG (> 99 %) within two weeks. The results showed that only the laccase enzyme was present in the media, where its activity in the absence and presence of the MG was 2186 and 1787 U/L, respectively. The second-order model was best fitted to the kinetics of the MG dye decolorization. The performance of G. resinaceum in this study showed that this strain could be successfully used for the fungal degradation of MG dye.

Structural, optical, thermal, mechanical, SHG and antibacterial properties of organic dyes doped glycine potassium dihydrogen orthophosphate single crystals

The advanced electro-optical materials are highly demanded because of their various uses in recent years. Glycine potassium dihydrogen orthophosphate single crystals are grown using a slow solvent evaporation technique in order to investigate the effects of the organic dyes crystal violet, malachite green, chrysoidine y, alizarin red, and victoria blue on the structural, optical, mechanical, thermal, SHG, and antibacterial properties. The powder XRD study validates the 14-2d space group tetragonal crystal structure. The higher optical bandgap energy and increased optical transparency of the crystal violet and victoria blue dye doped crystals indicate that there are less defects in their crystal lattice. The elemental analysis confirmed the presence of different organic dyes in the GKDP crystal lattice. The dye doping has enhanced the mechanical and optical characteristics of the formed crystals, and are categorised as soft materials. It is found that all dye-doped crystals have improved thermal stability. Malachite green and crystal violet doped GKDP crystals have higher SHG efficiency.

Gamma‐sterilized cow‐dung for confiscation of triphenylmethane dyes from water bodies

AbstractThe purpose of this work was to adsorb the triphenylmethane dyes crystal violet (CV), brilliant green (BG), and malachite green (MG) from an aqueous solution using cowdung (CD) that has been gamma‐sterilized. FTIR, SEM, EDX, and TGA‐DTA advanced techniques were used to characterize CD. The material had a pHPZC of 6, and it was shown that the maximal monolayer adsorption capacities for CV (at pH 4.83), BG (at pH 4.53), and MG (at pH 3.75) were, respectively, 179.39, 172.28, and 111.62 mg g−1. The equilibrium results were completely described by the pseudo‐second order model and Langmuir isotherm. Using the van't Hoff and Arrhenius equations, thermodynamic parameters like ΔG, ΔS, and ΔH were computed. The exothermic nature of the process change is indicated by the fact that the adsorption of CV and BG increased with lowering temperature whereas the adsorption of MG increased with increasing temperature, as the process was endothermic. Curiously, the values of the adsorption capacity acquired using the column adsorption approach is very similar to those obtained using batch adsorption trials illustrating the CD's capacity for dyes adsorption.

An invasive plant Ageratum houstonianum L. as an adsorbent for the removal of triphenylmethane dye (malachite green): isotherm, kinetics, and thermodynamic studies

An invasive plant Ageratum houstonianum L. as an adsorbent for the removal of triphenylmethane dye (malachite green): isotherm, kinetics, and thermodynamic studies

Application of Raman spectroscopy in relative blue ballpoint pen ink dating for forensic document analysis – a case report

In this case report, blue ballpoint ink on a questioned document was investigated using a newly developed Raman model devoted for dating of documents via writing inks. The majority of blue ballpoint pen inks contain crystal violet - a triarylmethane dye which displays a typical “molecular fingerprint” type of Raman spectrum, of which most intense peaks at 749 cm−1 and 1542 cm−1 (under 785 nm laser excitation) represents the least and the most stable bonds of crystal violet molecules, respectively. The ratios of peak intensities at above mentioned Raman shifts are utilized to estimate the relative dating of the questioned blue ballpoint pen ink in practice, results of which agreed with estimations using other traditional relative dating methods.
 ® 2023 Journal of Science and Technology - NTTU

Theranostic approach to specifically targeting the interloop region of BCL2 i-motif DNA by crystal violet

Ligands that recognise specific i-motif DNAs are helpful in cancer diagnostics and therapeutics, as i-motif formation can cause cancer. Although the loop regions of i-motifs are promising targets for ligands, the interaction between a ligand and the loop regions based on sequence information remains unexplored. Herein, we investigated the loop regions of various i-motif DNAs to determine whether these regions specifically interact with fluorescent ligands. Crystal violet (CV), a triphenylmethane dye, exhibited strong fluorescence with the i-motif derived from the promoter region of the human BCL2 gene in a sequence- and structure-specific manner. Our systematic sequence analysis indicated that CV was bound to the site formed by the first and third loops through inter-loop interactions between the guanine bases present in these loops. As the structural stability of the BCL2 i-motif was unaffected by CV, the local stabilisation of the loops by CV could inhibit the interaction of transcription factors with these loops, repressing the BCL2 expression of MCF-7 cells. Our finding suggests that the loops of the i-motif can act as a novel platform for the specific binding of small molecules; thus, they could be utilised for the theranostics of diseases associated with i-motif DNAs.

Preparation of graphene oxide/cobalt trimesinate composites and study of their adsorption properties

A nanocomposite based on graphene oxide and cobalt trimesinate was obtained by in situ method and employed in solid-phase extraction of organic pollutants using the triphenylmethane dye, brilliant green, as an example. The maximum adsorption reaches 385.2 mg g–1.

Azophenyl Calix[4]arene Porous Organic Polymer for Extraction and Analysis of Triphenylmethane Dyes from Seafood.

Porous organic polymers (POPs) based on calix[4]arene with a hydrophobic π-rich cavity and host-guest recognition properties exhibit a wide application range of molecular extraction and separation. However, it is still a challenge to improve the extraction and separation selectivity by exploring and seeking appropriate building blocks for the functionalization and pore size adjustment of calix[4]arene. Herein, an azophenyl calix[4]arene porous organic polymer (AC-POP) was proposed. By introducing an electron-rich cavity and adjusting the pore sizes of calix[4]arene, the AC-POP showed high selectivity extraction performance in triphenylmethane (TPM) dyes. The extraction mechanism was explored by adsorption thermodynamics study, density functional theory (DFT) calculation, and reduced density gradient (RDG) and electrostatic potential (ESP) analyses, which suggested that the selectivity adsorption of TPM dyes based on AC-POP was mainly the result of entropy driven by the hydrophobic effect. In addition, the noncovalent interactions including π-π stacking, van der Waals force, and electrostatic interaction were also important factors affecting the adsorption capacity of TPM dyes. Under optimal extraction conditions, the AC-POP possessed a maximum extraction amount of 95.3 mg·g-1 for Rhodamine B (RB), high enrichment factor of about 100, and excellent reusability more than 10 times. Then, an analytical method of TPM dyes with AC-POP as a solid-phase extractant combined with high-performance liquid chromatography-ultraviolet (HPLC-UV) was established, which displayed excellent sensitivity with the limits of detection (LODs) and limits of quantitation (LOQs) in the ranges of 0.004-0.35 and 0.016-1.16, respectively. The mean recoveries for TPM dyes ranged from 85.0 to 109.4% with an RSD of 0.48-9.45%. The proposed method was successfully applied to the analysis of the five TPM dyes in seafood matrix samples.

IDENTIFICATION OF TRIARYLMETHANE, PHTHALOCYANINE AND XANTHENE IN A MIXTURE OF DYES BY ELECTRON ABSORPTION SPECTROSCOPY

In the work, the qualitative composition and differentiation of 43 samples of ballpoint pen pastes of different colors was investigated (blue-violet – 29 samples, pink-violet – 3 samples, blue – 3 samples, black – 5 samples, green – 1 sample and red –2 samples) by the method of electronic absorption spectroscopy. The results of the study showed that each paste can be distinguished by studying the nature of their absorption spectra, which arises due to the presence of different functional groups. It was established that most of the analyzed paste samples contain pigments based on triarylmethane, phthalocyanine, xanthene dyes or their mixture. Certain absorption maxima correspond to each type of dyes. The broad and most intense band at λ~590 nm, which was detected for all samples, corresponds to triarylmethane dyes. The band at λ~670 nm corresponds to phthalocyanine dyes. The presence of absorption bands in the green range (λ~520–560 nm) indicates the presence of xanthene dyes in the composition of the pastes. Using the method of photoluminescence spectroscopy upon exci­tation of IR luminescence in the green region of the spectrum (λ=530 nm) it is shown that 11 blue-violet, 5 black and one red pastes exhibit bright luminescence due to the presence of crystal violet and some other triarylmethane dyes in their composition. Weak luminescence was detected for three blue pastes. No luminescence response was observed for the other tes­ted pastes, which is due to the presence of phthalocyanine dyes in these pastes, the absorption of which overlaps with the luminescence spectra of triarylmethane dyes. The obtained data can be used to create a reference base for identifying and differentiating the composition of ballpoint pen pastes of modern manufacturers and establishing their classification and identification differences.

One-Pot Synthesis of Silver Nanoparticles from Garcinia gummi-gutta: Characterisation, Antimicrobial, Antioxidant, Anti-Cancerous and Photocatalytic Applications.

Methods like the bio-synthesis of silver nanoparticles (Ag NPs) using plant extracts have become promising due to their eco-friendly approach. The study aimed to examine the utilization of Garcinia gummi-gutta fruit phytochemicals as agents in the biosynthesis of Ag NPs, evaluation of the antimicrobial, antioxidant, and anti-cancerous properties, as well as the photocatalytic ability of bio-synthesized Ag NPs against Crystal Violet (CV), a triphenylmethane dye. The characterization of the physical properties of the Ag NPs synthesized via the green route was done using UV-Vis spectrophotometry (UV-Vis), X-ray Diffraction (XRD), Fourier Transform Infrared Spectrophotometry (FTIR), Scanning Electron Microscopy (SEM), Zeta potential analysis, and Transmission Electron Microscopy (TEM). The dye degradation efficiency of CV was determined using synthesized Ag NPs under UV light by analyzing the absorption maximum at 579 nm. The antimicrobial efficacy of Ag NPs against E. coli, S. aureus, Candida tropicalis, and Candida albicans was examined using the broth dilution method. The antioxidant and anti-cancer properties of the synthesized Ag NPs were assessed using the DPPH and MTT assays. The UV analysis revealed that the peak of synthesized Ag NPs was 442 nm. Data from FTIR, XRD, Zeta potential, SEM, and TEM analysis confirmed the formation of nanoparticles. The SEM and TEM analysis identified the presence of spherical nanoparticles with an average size of 29.12 nm and 24.18 nm, respectively. Maximum dye degradation efficiency of CV was observed at 90.08% after 320 min without any silver leaching, confirming the photocatalytic activity of Ag NPs. The bio-efficiency of the treatment was assessed using the Allium cepa root growth inhibition test, toxicity analysis on Vigna radiata, and Brine shrimp lethality assay. The findings revealed the environmentally friendly nature of green Ag NPs over physical/chemically synthesized Ag NPs. The synthesized Ag NPs can effectively be used in biomedical and photocatalytic applications.

Alleviating Luminescence and Quenching toward Discrimination of Ballpoint Pen Inks Using Spectroscopy and Chromatography Techniques

The phenomenon of luminescence and quenching is widely applied in the forensic examination of various ink materials. Here, we introduce a hybrid spectroscopic and chromatography approach to gain insights into the underlying cause of infrared luminescence (IRL) in blue ballpoint (BP) pen inks. A total of thirty BP pen ink samples from the Egyptian market were employed in this study. Insights into the origin of luminescence and quenching in the studied samples were gained based on video spectral comparator (VSC), thin layer chromatography (TLC), ultraviolet–visible (UV–Vis) spectrophotometry, and photoluminescence (PL) spectroscopy. Results showed that some of the studied inks possessed IRL due to the presence of crystal violet and some other triaryl methane dyes. Nevertheless, some ink samples did not possess IRL, despite the presence of the dyes responsible for IRL in their matrix. Interestingly, the inclusion of phthalocyanine dye in those non-luminescent ink matrices resulted in luminescence quenching, mainly due to the overlap between the absorption of phthalocyanine dye and the luminescence of the triarylmethane dyes. The IRL behavior of the ink sample under the first illumination wave band (400–485 nm) exerted control over the IRL activity across subsequent illumination wavebands, and the most effective differentiation was achieved by utilizing the first and second preset filters in VSC. The results revealed the luminescent components present in studied inks and unraveled their distinct luminescence behavior present within the ink matrix. The combination of optical spectroscopy and chromatography techniques could provide a distinctive tool to reveal the luminescence and quenching behaviors of ink dyes for the successful forensic discrimination of several BP writing pens.

Comprehensive insights into the binding of crystal violet and pepsin: Spectroscopic analysis, molecular model and biochemical method

As a well-known triphenylmethane dye, crystal violet (CV) has received extensive concerns owing to its harmful influence on human health. Pepsin is a digestive enzyme in the stomach that plays a crucial part in several physiological and pathological process. This research aimed to use spectroscopic experiments, computer simulation and enzyme activity assays to investigate the influence of CV on the functions and structure of pepsin from the perspective of binding. Fluorescence and UV–vis spectra confirmed the complex formation between CV and pepsin. Ka was in the order of 104 M−1, implying a moderate affinity between CV and pepsin. Multi non-covalent interactions played a crucial part in this binding process. The conformational alterations of pepsin caused by CV were reflected in β-sheet content reducing, and the presence of CV caused an activation of pepsin. The outcomes of molecular docking indicated that the interaction of Tyr75/Tyr189 with CV is the major cause for the fluorescence quenching phenomenon of pepsin. For molecular dynamics (MD) simulation, the CV-pepsin and free pepsin systems reached equilibrium in 40 ns. In addition, the compactness of pepsin changed after interacting with CV, which was in line with the results of solvent experiment. From the above results, CV has effects on the properties of pepsin, which may provide novel insights into the toxicological study of CV.