Crystal Violet Dye Research Articles

Textile Dye Decolorization Potential of Bacillus pumilus and Staphylococcus saprophyticus Isolated From Textile Industry Effluents

Textile dyeing industries are usually chastised for being big polluters due to the poisonous nature of most dyes, which endangers all kinds of life, including people. In this study, dye degrading bacteria were isolated from water and soil samples contaminated with textile dye taken from Batik palli in Narayanganj and the ability of five isolated bacteria including Staphylococcus saprophyticus, Bacillus pumilus, Micrococcus endophyticus, Pseudomonas mendocina, and Acinetobacter baumannii, to decolorize crystal violet (CV) dye was investigated. Among these, Bacillus pumilus decolorized 58% of CV at 250 ppm, while Staphylococcus saprophyticus decolorized 48% of CV, after 3 days of incubation at 37°C. We examined multiple temperature and pH conditions to determine the best parameters for CV dye decolorization. Bacillus pumilus boosted decolorization rates by 65.39% at 37°C and at pH 7.0, while Staphylococcus saprophyticus increased decolorization rates by 58.73%, at 37°C and at pH 5.0. Furthermore, extending the incubation period to 6 days enhanced decolorization rate in both isolates, with Bacillus pumilus increased from 58% to 65% and Staphylococcus saprophyticus increased from 48% to 58%. Nevertheless, the inclusion of co-substrates such glucose and yeast extract further boosting decolorization rate for both isolates, approximately tripling it. As a result, this study discovered indigenous bacteria capable of decolorizing CV dye, implying that they could be employed in the treatment of textile wastewater effluents. Bangladesh J Microbiol, Volume 40, Number 2, December 2023, pp 50-54

Selenium-Doped Biochar for Removal of Anionic Acid Red and Cationic Crystal Violet Dye

The environmental impact of untreated dye effluent is a concern due to potential mutagenic and allergic effects. This study aims to develop a cost-effective selenium-doped biochar as an adsorbent material to remove acid red (AR) and crystal violet (CV) dyes from water. Selenium nanoparticles (SeNPs) were produced using chemical and biological synthesis methods. The SEM, EDX, XRD, FTIR, and BET surface analysis methods were used to characterize the biochar and selenium-doped biochar (Se-AC and BSe-AC) samples. Surface modification with SeNPs resulted in an increase in surface area to 14.560[Formula: see text]m2/g for Se-AC and 85.456[Formula: see text]m2/g for BSe-AC. Different adsorption isotherms (Langmuir, Freundlich, and Temkin) and adsorption kinetic models (pseudo-firstorder, pseudo-secondorder, and intra-particle diffusion kinetics) were investigated to understand the adsorption patterns of biochar, Se-AC, and BSe-AC. The maximum adsorption capacities of biochar, Se-AC, and BSe-AC for AR and CV dye were found to be between 0.48[Formula: see text]mg[Formula: see text]g[Formula: see text] and 7.51[Formula: see text]mg[Formula: see text]g[Formula: see text], 2.31[Formula: see text]mg[Formula: see text]g[Formula: see text] and 7.86[Formula: see text]mg[Formula: see text]g[Formula: see text], and 6.88[Formula: see text]mg[Formula: see text]g[Formula: see text] and 9.09[Formula: see text]mg[Formula: see text]g[Formula: see text], respectively, at 313[Formula: see text]K. The obtained negative [Formula: see text] indicates effective adsorption, while a positive [Formula: see text] suggests an endothermic reaction for both dyes. BSe-AC is an eco-friendly alternative to biochar for removing AR and CV.

Synergistic effect of Sonophotocatalytic degradation of crystal violet and alizarin red S dyes using Ag-doped ZnSnO3 nanoparticles

This study proposes an environmentally conventional sonophotocatalytic method that uses silver (Ag)-doped ZnSnO3 nanoparticles (NPs) to effectively eliminate industrial dye-polluted wastewater. This study was conducted to investigate the effect of the Ag doping ratio of the synthesized ZnSnO3 NPs on the removal of dye molecules. We used crystal violet (CV) and alizarin red S (AR) dyes as test pollutants to examine the catalytic activity of the synthesized Ag-doped ZnSnO3 NPs in response to the ultrasound and visible light stimulation. The most effective photocatalytic performance was exhibited by 4 % Ag-ZnSnO3 NPs, which degraded 95 % of the CV and 52 % of the AR dye in 100 min. Surprisingly, using sonophotodegradation to combine ultrasound with visible-light irradiation has resulted in almost complete degradation of the CV dye in 100 min, demonstrating a strong beneficial synergy between the sonocatalytic and photocatalytic processes. Additionally, the sonophotocatalytic degradation of the CV and AR dyes was examined at various pH values. It shows to have high stability across several cycles of dye treatment, indicating that this method can be used for industrial effluents. Scavenger tests demonstrated that the primary active species in the dye degradation is O2•−. Ultimately, the prepared Ag-ZnSnO3 NPs and sonophotocatalytic processes may offer a promising path toward a variety of environmental uses, including the remediation of water and the removal of other organic contaminants.

Assessment of Biodegradation and Phytotoxicity of Azo Dyes Methyl Orange and Crystal Violet by Escherichia coli and Bacillus subtilis

Azo dyes are widely used colourants, possess array of colours and are generally recalcitrant to microbial degradation. This study aimed to isolate azo dyes degrading bacteria from soil; treat methyl red and crystal violet dyes using the isolates, and assess the phytotoxicity of the treated and untreated dyes on sorghum. Ten bacteria were isolated from the soil, of which two were identified as efficient azo dyes degrading bacteria by efficiency in dye decolouration. The isolates were identified as Escherichia coli and Bacillus subtilis based on their biochemical characteristics. The isolates were able to degrade methyl orange dye by 16-75 % and crystal violet by 16-78%, depending on the concentration of the dye. The isolates were more efficient at degrading the dyes at a low concentration of 0.00025 mg/ml, as indicated by a higher percentage of decolourization (53-79%). The percentage phytotoxicity of the untreated methyl red ranged from 33-59%, while the toxicity of the untreated crystal violet ranged from 62-91%. The toxicity of the treated methyl red ranged from 9-34%, while the toxicity of the treated crystal violet ranged from 12-32%. The results revealed that the isolates were capable of degrading methyl red and crystal violet dyes, and could be useful in the bioremediation of azo dyes polluted soil.

Impact of Co and Cu co‐doping on the Structural, Electrical, Magnetic and Solar Light Driven Photo‐Catalytic Properties of NiFe2O4 Nano‐crystals for Crystal Violet Dye Removal

AbstractHerein, we have synthesised cobalt (Co) and copper (Cu) co‐doped Ni‐ferrite Ni1‐xCoxFe2‐yCuyO4 nanocrystals (NCs) via the facile micro‐emulsion method. The materials were analysed for various physio‐chemical characterizations to investigate the co‐doping (Co and Cu) effects on magnetic, structural, electrical, photo‐catalytic properties. The structural analysis via Fourier Transform Infrared spectroscopy (FTIR) and X‐rays diffraction (XRD) showed the successful fabrication of Co and Cu co‐doped materials with cubic spinel geometry having a single phase, the crystallite size was observed in 15 to 24 nm range. The electrical response measured using current‐voltage (I–V) analysis showed good electrical features, the electrical resistivity declined from 6.85×107 Ohm.cm for un‐doped materials to 0.04×107 Ohm.cm for co‐doped materials, which was accredited due to the synergistic effects of Co and Cu metal cations in co‐doped Ni‐based ferrite structures. Magnetic investigation using VSM analysis showed increased saturation magnetization (Ms 31.32 to 50.75 emu/g) and coercivity (218.76 to 406.82 Oe) because of the higher magnetic responses of Co2+ions in the co‐doped spinel ferrite NCs. BET surface‐area analysis showed good porosity for co‐doped materials with an increased surface area of 52 to 104 m2/g on co‐doping. The Tauc's plot described the decline of band‐gap energies value (Egs) (1.99 eV) in co‐doped (x=y=0.56) materials as compared to (2.16 eV) of the un‐doped NiFe2O4 materials, which is due to more electrical responses of Co and Cu co‐dopant cations that possess higher energy levels, which can stabilize the charge carrier‘s species. Furthermore, the photo‐degradation using solar light showed good removal of crystal violet (CV) dye, which was almost 94.14 % by co‐doped material; however, by un‐doped material, it was 38.044 %. The scavenger experiment shows that the (OH⋅) hydroxyl radicals and (e−/h+) species play a prime role in the degradation of CV dye. Recycling and recoverability tests for five cycles’ exhibited outstanding stability of the photocatalyst with only 1.7 % losses in activity. Overall, our results showed that co‐doped Ni1‐xCoxFe2‐yCuyO4 NCs materials exhibited enhancement in the magnetic, electrical, photo‐catalytic properties and a decline in band‐gap energy values as compared to un‐doped NiFe2O4, which might have potential use in magnetic and electrical devices as well as solar‐driven photo‐catalyst materials for the remediation of environmental pollution.

A smart L‐alanine modified Cd‐NDI metal‐organic framework crystalline material: Photochromic properties and photocatalytic degradation dye applications

1, 4, 5, 8‐naphthalene diimide (NDI)‐based MOFs, due to their tunable structures and properties, have shown promising applications in photochromism, photocatalysis, electrocatalysis, photothermal therapy, etc. Herein, using an L‐alanine modified NDI ligand, i.e. N, N′‐bis(L‐alanine)naphthalenediimide (AlaNDI), a novel Cd‐NDI Cd (AlaNDI)(H2O)]·DMF·H2O (complex 1) was constructed under solvothermal conditions, which has an obvious different structure with the previously reported ones. Structural analysis shows that the packing structure of complex 1 consists of two adjacent Cd atoms sharing two AlaNDI ligands, forming a dimetallic building block [Cd2O8]. Each building block connects a total of four AlaNDI ligands, where two Cd atoms are bridged by two ligands. The building blocks are interconnected by ligands to form a two‐dimensional layered structure. Based on the features of the NDI skeleton, it was found that complex 1 possesses multiple stimulus responses involving sensitivity to light: a reversible photochromism property and good photocatalytic degradation activity against various dyes, especially against cationic dyes crystal violet (CV), methyl violet (MV), and Janus green B (JGB). In addition, the stimulus‐response mechanism was investigated by control experiments. It is revealed that the photocatalytic active species may be related to h+ and •OH.

Crystal violet removal using algae-based activated carbon and its composites with bimetallic Fe0-Cu

The textile industry is considered a source of pollution because of the discharge of dye wastewater. The dye wastewater effluent has a significant impact on the aquatic environment. According to the World Bank, textile dyeing, and treatment contribute 17 to 20% of the pollution of water. This paper aims to prepare the bimetallic nano zero-valent iron-copper (Fe0-Cu), algae-activated carbon, and their composites (AC-Fe0-Cu), which are employed as adsorbents. In this paper, Synthetic adsorbents are prepared and examined for the adsorption and removal of soluble cationic crystal violet (CV) dye. The influence of synthetic adsorbents on the adsorption and removal of soluble cationic crystal violet (CV) dye is investigated using UV-V spectroscopy at different pH (3–10), time intervals (15–180) min, and initial dye concentrations (50–500 ppm). Raw algae exhibit an impressive 96.64% removal efficiency under the following conditions: pH 7, contact time of 180 min, rotational speed of 120 rpm, temperature range of 25 °C–30 °C, concentration of 300 ppm in the CV dye solution, and a dose of 4 g l−1 of raw algae adsorbent. The best removal efficiencies of Raw algae Fe0-Cu, and H3PO4 chemical AC-Fe0-Cu are 97.61 % and 97.46 %, respectively, at pH = 7, contact time = 150 min, rotational speed = 120 rpm, T = (25–30) °C, concentration = 75 ppm of CV dye solution, and 1.5 g l−1 doses of raw algae F e0-Cu adsorbent and 1 g l−1 dose of H3PO4 chemical AC-Fe0-Cu adsorbent. The maximum amounts (q max) of Bi-RA and RA adsorbed for the adsorption process of CV are 85.92 mg g−1 and 1388 mg g−1, respectively. The Bi-H3A-AC model, optimized using PSO, demonstrates superior performance, with the highest adsorption capacity estimated at 83.51 mg g−1. However, the Langmuir model predicts a maximum adsorption capacity (q e ) of 275.6 mg g−1 for the CV adsorption process when utilizing Bi-H3A-AC. Kinetic and isothermal models are used to fit the data of time and concentration experiments. DLS, zeta potential, FT-IR, XRD, and SEM are used to characterize the prepared materials. Response surface methodology (RSM) is used to model the removal efficiency and then turned into a numerical optimization approach to determine the ideal conditions for improving removal efficiency. An artificial neural network (ANN) is also used to model the removal efficiency.

Exploring the multi-faceted potential: Synthesized ZnO nanostructure – Characterization, photocatalysis, and crucial biomedical applications

This research describes the methodology for synthesizing zinc oxide nanoparticles (ZnO-NPs). It demonstrates a unique, cost-effective, and non-toxic chemical technique for producing ZnO-NPs using the precipitation method with NaOH as reducing and capping agents. The formed nanoparticles have been characterized and analyzed using numerous techniques such as; Fluorescence emission spectroscopy (FL), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray Spectroscopy (EDX), ultraviolet–visible optical absorption (UV–Vis), Fourier transform infrared spectroscopy (FTIR), and Thermal gravimetric analysis (TGA). Also, the analytical technique X-ray diffraction studies has been used which showed that the ZnO-NPs had a Wurtzite hexagonal crystal structure with an average crystallite size of 34.27 nm. The form and the size of the synthesized ZnO-NPs have been seen in SEM and TEM photographs. Using J-image, particle size has been obtained at 13.33 nm, and the grain boundaries were all approximately spherical. Peaks in the FT-IR spectrum of the NPs indicate the presence of carboxylate (COO) and hydroxyl (O–H) functional groups. According to these findings, Zn interstitial defects are responsible for the 380 nm emission peak. Since EDX could not identify any impurities below the detection threshold, we may be sure that Zn and O are the principal components of the synthesized sample. ZnO-NPs cause an absorption band at 350.34 nm in the UV–Vis spectrum and a band gap of 3.24 eV. The catalytic activity of the synthesized ZnO nanoparticles (NPs) was evaluated by investigating their effectiveness in degrading crystal violet (CV) and methylene blue (MB) dyes, along with assessing the degradation rates. The results demonstrated a high degradation efficiency, with ZnO NPs achieving approximately 96.72 % degradation for CV and 97.169 % for MB dyes, underscoring their remarkable efficacy in the degradation process. As for antimicrobial activity assessment, the results revealed that the ZnO-NPs had negligible impact on Gram-negative bacteria, whereas they exhibited a discernible effect on Gram-positive bacteria. Additionally, it showed anti-cancer potential against colon (SW480), breast (MDA-231), and cervix (HELA) lines cells as seen by (MTT) assay. Hence, due to its simplified processes and cheaper chemicals, our synthesis technique may use in industrial settings for various applications.

Synthesis of magnetic nanocomposite for the ultrasound-assisted removal of antibiotic and dye from aqueous solution: Characterization, modeling, and optimization

In this study, the efficiency of the nickel ferrite/magnesium oxide magnetic nanocomposite (NiFe2O4@MgO) was investigated for the removal of amoxicillin (AMX) antibiotic and crystal violet (CV) dye from aqueous media in a discontinuous system. The required experiments and result analysis were predicted using response surface methodology (RSM). The effects of pH (3–11), concentration (10–50 mg/L), and the amount of NiFe2O4@MgO (0.01–0.03 g) at various time intervals (10–50 min) during the removal process were examined. The central composite design (CCD) predicted the optimal conditions for AMX and CV removal using the NiFe2O4@MgO nanocomposite, showing excellent agreement between the predicted model response and the experimental results. According to the CCD experimental design analysis, the highest removal of AMX and CV was achieved at a pH of 8, a concentration of 24 mg/L, and 0.019 g of NiFe2O4@MgO for 35 min. Under optimal conditions, the removal efficiency for AMX and CV was 96.12 % and 93.30 %, respectively. Eluent determination results indicated that ammonia exhibited the best efficiency for the desorption of AMX and CV. Additionally, recovery studies demonstrated that the NiFe2O4@MgO adsorbent had the capability for multiple reuses in AMX and CV removal. The application of this method in real sample analysis showed successful removal of AMX and CV from various water samples.

Increased photodegradation of crystal violet dye using Ni and Zn codoped cadmium oxide nanoparticles

Increased photodegradation of crystal violet dye using Ni and Zn codoped cadmium oxide nanoparticles

Non-cytotoxic 3-Acetylcoumarin as an Attractive Target for Human Monoamine Oxidase (HMAO) Enzymes.

Coumarins are a broad class of naturally occurring oxygen-heterocyclic compounds found in plants with diverse biological properties, making them attractive for evaluation as novel therapeutic agents. We herein report the in vitro cytotoxic and monoamine oxidase (MAO) inhibitory activities of 3-acetylcoumarins (6a-e). The cytotoxic activity was evaluated using crystal violet dye binding assay, and those compounds unable to induce cytotoxicity were further tested for the monoamine oxidase (MAO) activity using the MAO-GloTM kit. The 3-acetylcoumarins (6a-e) were non-cytotoxic (inactive) against MDA MB-231 (estrogen receptor-negative, ER-, highly invasive) and MCF-7 (estrogen receptor-positive, ER+, weakly invasive) breast cancer cell lines, but showed interesting MAOs inhibition activities. Among the synthesized compounds, 3-acetylcoumarin bearing dichloro (-diCl) (6d; IC50=0.31±0.04 μM) at Carbon-7, 8 positions showed higher inhibition, MAO B/A non-selectivity (selectivity index, SI=3.10), reversible inhibition against the hMAO-B enzyme, and neuroprotection against H2O2-treated human neuroblastoma (N2a) cells. Compound (6d) can be considered a promising scaffold for further investigation in developing hMAO-B inhibitors (MAOIs).

Synthesis of Dy-doped calcium hexaferrite (CaDyxF12-xO19) nanoparticles and their ferroelectric, dielectric, magnetic and photocatalytic properties under solar light irradiation

Calcium hexaferrite (CaDyxFe12-xO19) was synthesized using the microemulsion method, incorporating Dy as a dopant at varying levels (x = 0.00, 0.1, 0.15, 0.20, 0.25, and 0.30). The effects of Dy-doping on the structural, magnetic, ferroelectric, dielectric and photocatalytic properties of CFO (CaDyxFe12-xO19) was evaluated. X-ray diffractometer, scanning electron microscopy, Fourier transform infrared spectroscopy, and UV–vis spectroscopy were employed for the characterization of the prepared samples. A single-phase hexagonal structure with space group P63/mmc was verified by the XRD analysis and the crystallite size was in the 31.74 nm to 38.77 nm range. The ferroelectric properties were examined using a hysteresis loop (P-E), revealing that higher dopant concentrations led to decreased saturation polarization (Ps) and retentivity (Pr). Electrical studies, including I-V measurements, aligned with semiconductor behavior, as evidenced by Curie temperature and activation energy values. Magnetic assessments demonstrated increased saturation magnetization (0.028–0.049 emu/g) and remanence (0.0046–0.0144 emu/g) upon Dy-doping. Photocatalytic experiments exhibited promising crystal violet dye degradation under visible light irradiation, with highly doped catalyst showing 85 % degradation within 100 minutes, surpassing the 42 % degradation with pristine CaFe12O19. The synthesized nanoparticles demonstrated promising stability and reusability in recycling experiments. Investigation of scavenger effects highlighted the crucial role of reactive •OH in dye degradation, surpassing the contributions of e- or h+ species. The CaDyxFe12-xO19 holds significant potential for efficient photocatalytic application in the removal of dyes from effluents under visible light irradiation.

Facile fabrication of bifunctional ternary nanocomposite (FCPTNC) as an efficient catalyst for 4-nitrophenol reduction and crystal violet photodegradation

The synthesis of a ternary nanocomposite Fe3O4/CuO-Ppy (FCPTNC) was effectively achieved via hydrothermal and in-situ chemical oxidative polymerisation techniques. FCPTNC was used as a catalyst for reducing the toxic compound 4-nitrophenol to the non-toxic compound 4-aminophenol. Additionally, it was utilised for the visible-light-induced degradation of the crystal violet (CV) dye. FCPTNC underwent characterisation using various techniques, namely X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), ultraviolet–visible diffuse reflectance spectroscopy (UV-DRS), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). The successful preparation of the nanocomposite was validated through analysis of its structural properties. Moreover, examining its optical properties indicated that the nanocomposite can effectively operate through visible light irradiation. The catalyst demonstrated exceptional catalytic efficacy in eliminating the targeted organic pollutants, namely 4-nitrophenol (4-NP) and crystal violet (CV). The catalyst exhibited a degradation efficiency of 97 % for CV dye within60 min. It achievedthecomplete conversion of 4-nitrophenol into its corresponding amino derivative within15 min. The calculated first-order rate constants for the reduction of 4-NP and photodegradation of CV dye were found to be in the range of 0.53–11.6 × 10−2 min−1 and 3.2–5.6 × 10−2 min−1, respectively. The magnetic catalyst exhibited efficient separation from the reaction media and was successfully recycled for up to fiveconsecutive cycles with negligible loss of catalytic activity. The work demonstrates that the FCPTNC nanocomposite has favourable characteristics, such as facilesynthesis, efficient catalytic activity, and reusability. These findings suggest that the nanocomposite possesses desirable efficiency and durability, rendering it a promising catalyst for environmental applications.

Crystal violet degradation by visible light-driven AgNP/TiO2 hybrid photocatalyst tracked by SERRS spectroscopy

Dyes are important concerns regarding aquatic environmental contamination given their extensive industrial use and the occurrence of highly toxic and carcinogenic effects on the biota. In this work, photodegradation processes of the organic dye crystal violet (CV) by a hybrid plasmonic photocatalyst involving titanium dioxide (TiO2) and silver nanoparticles (AgNP), through irradiation with low-power visible light were studied, and the experiments were tracked by ultraviolet-visible absorption (UV–VIS) and surface-enhanced resonance Raman scattering (SERRS) spectroscopies. Enhanced photocatalytic activity was observed, reaching about 71, 80 and 87 % of CV removal with only 100 minutes of irradiation, depending on the Ag loading used. The high photocatalytic efficiency is further highlighted by the low energy consumption in the process, requiring only ca. 1.46 kW h L-1 in the best reaction condition. Quantum-mechanical calculations were used to the assignment of electronic spectra, as well as to the prediction of frontier molecular orbitals and atomic charges, aiming to propose mechanisms for radical attacks. Such results allow suggesting degradation processes involved mainly N-demethylation and bond breaking of central carbon. The presence of CV protonated species was also supported through Density Functional Theory (DFT) investigation. The integration of theoretical and experimental results allows proposing the formation of pararosaniline, phenol and benzophenone derivatives, which may have highest ecotoxicity than the original contaminant, outstanding the remarkable relevance of SERRS spectroscopy in monitoring such recalcitrant substances.

Constructing the synergistic effects of chitosan and ionic liquid on SPEEK polymer for efficient adsorption of crystal violet dye

In the study, a novel chitosan biopolymer and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid (IL)-incorporated sulfonated poly (ether ether ketone) (SPEEK) composite (Ch-IL@SPEEK) was prepared for adsorption of cationic crystal violet (CV) dye. The proposed composite was well characterized by several techniques. CV adsorption performance was examined via batch studies by varying various variables involving adsorbent dosage, contact time pH and temperature. The isotherm results were demonstrated the adsorption characters of the processes were Langmuirian. The maximum adsorption capacity was determined as 77.66 mg g−1 for the composite which was significantly higher than SPEEK (qmax = 45.36 mg g−1). The determined equilibrium time of the operated system was 360 min and the kinetic model was assessed as Elovich. At low pHs the protonated surface groups repelled the positively charged CV and the adsorption rate increased with increasing pH. The process is spontaneous and favorable as it proceeds via endothermic interactions. Furthermore, even at the end of 5 successful adsorption cycles, 77.86 % CV removal was obtained. Remarkable efficiencies were also achieved in the removal performance of different organic pollutants. Based on the reported results, Ch-IL@SPEEK composite were exhibited as an impressive adsorbent material for adsorption processes.

A Wettability Contrast SERS Droplet Assay for Multiplexed Analyte Detection.

Droplet assay platforms have emerged as a significant methodology, providing distinct advantages such as sample compartmentalization, high throughput, and minimal analyte consumption. However, inherent complexities, especially in multiplexed detection, remain a challenge. We demonstrate a novel strategy to fabricate a plasmonic droplet assay platform (PDAP) for multiplexed analyte detection, enabling surface-enhanced Raman spectroscopy (SERS). PDAP efficiently splits a microliter droplet into submicroliter to nanoliter droplets under gravity-driven flow by wettability contrast between two distinct regions. The desired hydrophobicity and adhesive contrast between the silicone oil-grafted nonadhesive hydrophilic zone with gold nanoparticles is attained through (3-aminopropyl) triethoxysilane (APTES) functionalization of gold nanoparticles (AuNPs) using a scotch-tape mask. The wettability contrast surface facilitates the splitting of aqueous droplets with various surface tensions (ranging from 39.08 to 72 mN/m) into ultralow volumes of nanoliters. The developed PDAP was used for the multiplexed detection of Rhodamine 6G (Rh6G) and Crystal Violet (CV) dyes. The limit of detection for 120 nL droplet using PDAP was found to be 134 pM and 10.1 nM for Rh6G and CV, respectively. These results align with those from previously reported platforms, highlighting the comparable sensitivity of the developed PDAP. We have also demonstrated the competence of PDAP by testing adulterant spiked milk and obtained very good sensitivity. Thus, PDAP has the potential to be used for the multiplexed screening of food adulterants.

Crystal Violet Selectively Detects Aβ Oligomers but Not Fibrils In Vitro and in Alzheimer's Disease Brain Tissue.

Deposition of extracellular Amyloid Beta (Aβ) and intracellular tau fibrils in post-mortem brains remains the only way to conclusively confirm cases of Alzheimer's Disease (AD). Substantial evidence, though, implicates small globular oligomers instead of fibrils as relevant biomarkers of, and critical contributors to, the clinical symptoms of AD. Efforts to verify and utilize amyloid oligomers as AD biomarkers in vivo have been limited by the near-exclusive dependence on conformation-selective antibodies for oligomer detection. While antibodies have yielded critical evidence for the role of both Aβ and tau oligomers in AD, they are not suitable for imaging amyloid oligomers in vivo. Therefore, it would be desirable to identify a set of oligomer-selective small molecules for subsequent development into Positron Emission Tomography (PET) probes. Using a kinetics-based screening assay, we confirm that the triarylmethane dye Crystal Violet (CV) is oligomer-selective for Aβ42 oligomers (AβOs) grown under near-physiological solution conditions in vitro. In postmortem brains of an AD mouse model and human AD patients, we demonstrate that A11 antibody-positive oligomers but not Thioflavin S (ThioS)-positive fibrils colocalize with CV staining, confirming in vitro results. Therefore, our kinetic screen represents a robust approach for identifying new classes of small molecules as candidates for oligomer-selective dyes (OSDs). Such OSDs, in turn, provide promising starting points for the development of PET probes for pre-mortem imaging of oligomer deposits in humans.

Efficient removal of crystal violet dye from water using zinc ferrite-polyaniline nanocomposites.

Nanomaterials are widely employed in wastewater treatment, among which nanoferrites and their composites hold significant prominence. This study adopts a green approach to synthesize zinc ferrite nanoparticles, subsequently integrating them with polyaniline (PANI) to fabricate the ZnFe2O4-PANI nanocomposite. Characterization of the prepared ZnFe2O4-PANI nanocomposite was conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopic (SEM) techniques. Using Scherrer's equation, the crystallite size of the synthesized zinc ferrite nanoparticles was found to be 17.67nm. SEM micrographs of the ZnFe2O4-PANI nanocomposite revealed that in situ polymerization of ZnFe2O4 with polyaniline transforms the amorphous surface morphology of the polymer into a homogeneous nanoparticle structure. The adsorption of crystal violet (CV) dye onto the surface of the ZnFe2O4-PANI nanocomposite depends on pH, adsorbent dosage, temperature, concentration levels and duration. The Langmuir adsorption model fitted the data well, indicating adherence to a pseudo-second-order kinetic pattern. Thermodynamic values ΔG°, ΔH° and ΔS° indicated that the adsorption process occurred spontaneously. Advantages and disadvantages of the technique have also been highlighted. Mechanism of adsorption is discussed. From the obtained results, it is evident that the ZnFe2O4-PANI nanocomposite holds promise as a sorbent for the removal of dye from wastewater.

Impact of Ag-NiO nanoparticles loaded on g-C3N4 nanosheets for cleaning contaminated water

Congo red (CR) is a synthetic azo dye commonly used in the textile and printing industries. However, CR is also a known pollutant that can cause environmental and health problems. This study investigates the use of Ag-NiO@g-C3N4 nanocomposite as an adsorbent for the removal of CR from aqueous solutions. The Ag-NiO@g-C3N4 nanocomposite was synthesized via a facile ultrasonication method followed by thermal annealing. The synthesized nanocomposite was characterized by TEM, EDX, XPS, BET, XRD and an FT-IR spectrometer. The synthesized nanocomposite exhibited a high surface area of 94.705 m2/g. The adsorption performance of the Ag-NiO@g-C3N4 nanocomposite towards CR dye was investigated under various operational parameters, including pH, initial CR dye concentration, and contact time. Comparative studies with other dyes, namely basic fuchsin (BF), crystal violet (CV), Methylene blue (MB), Rhodamine 6G (RG), and other mixed dyes were also conducted. The adsorption of CR dye onto the Ag-NiO@g-C3N4 nanocomposite was found to follow the pseudo-second-order kinetic model and the Langmuir isotherm, suggesting monolayer adsorption with a finite number of binding sites. The maximum adsorption capacity of the Ag-NiO@g-C3N4 nanocomposite for CR dye was 229.48 mg/g. The results of this study demonstrate the potential of the Ag-NiO@g-C3N4 nanocomposite as an effective adsorbent for CR dye removal from wastewater.

Enhanced degradation of crystal violet dye under solar light by zirconium phosphate-decorated graphitic carbon nitride

Enhanced degradation of crystal violet dye under solar light by zirconium phosphate-decorated graphitic carbon nitride