Crystal Violet Research Articles

Metal-organic frameworks (MOFs) are an emerging class of porous materials with remarkable surface area, tunable pore structures, and diverse chemical functionalities. In this study, we reported the green synthesis and comprehensive characterization of a novel modified NH2-MIL-101 (Cu) derived from 2-aminoterephthalic acid, followed by post-synthetic modification with terephthalaldehyde to improve its adsorption capabilities. The synthesized Cu-MOF exhibited a very high specific surface area (2037.65m2·g-1, BET), a total pore volume of 0.7465cm2·g-1 and mesoporosity with an average pore diameter of 29.06nm. SEM and TEM images showed uniform polyhedral particles with an average particle size of ≈ 85 ± 10nm, while XRD patterns displayed well-defined diffraction peaks with the most intense reflection at ~ 2θ = 28-29°, confirming high crystallinity and preservation of the MIL-101 topology after modification. Under optimized conditions (10mg adsorbent, 10 mL solution, room temperature and appropriate pH), the material exhibited high adsorption capacities of 230.1, 165.2, and 187.4mg·g-1 for crystal violet, methyl orange, and rhodamine B, respectively, attributable to its large porosity and functional surface groups. A plausible mechanism involving electrostatic interaction, π-π stacking, and coordination bonding is proposed for adsorption of dyes onto the modified MOF. The Cu-MOF maintained excellent structural stability and reusability, retaining over 92% of its initial adsorption capacity after five consecutive adsorption-desorption cycles, as confirmed by XRD patterns showing no noticeable framework collapse. This highlights its robustness and potential for sustainable wastewater remediation. In addition to dye removal, the material demonstrated antimicrobial activity, with MIC values of 4, 8, 32 and 128µg/mL for P. aeruginosa, C. albicans, E. coli, and A. fumigatus, respectively, while no inhibition was observed against Gram-positive strains at concentrations up to 4096µg/mL. The antimicrobial effect is likely attributed to Cu2+ ion release and electrostatic interactions leading to membrane disruption and ROS generation. These results highlight the potential of the synthesized Cu-MOF as a multifunctional and eco-friendly candidate for both wastewater treatment and biomedical applications.

To discover new probiotics that can protect mammary glands from mastitis, 40 Lactobacillus (Ligilactobacillus) spp. isolates from bovine milk were subjected to a preliminary series of in vitro subtractive analyses. Antibiotic susceptibility testing was performed according to the ISO norm 10932. Many lactobacilli had elevated MIC values for kanamycin (35%), but fewer were resistant to chloramphenicol (15%), streptomycin (7.5%) and tetracycline (5%). The enzymic activities of lactobacilli were tested using an API ZYM system. Nearly 27% exhibited undesirable activities (β-glucuronidase, β-glucosidase and N-acetyl-β-glucosaminidase). The safe strains were monitored for antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, and Bacillus cereus using microtiter plates and for their ability to form biofilms using the crystal violet assay. The antimicrobial activity of lactobacilli against indicator bacteria ranged from 29 to 89% and the isolates exhibited moderate-to-high biofilm formation. Suitable strains were selected for whole-genome sequencing analysis. Antibiotic-resistance genes and putative virulence genes were not predicted in the genomic analysis. Moreover, the isolate Ligilactobacillus salivarius 48 carries genetic information responsible for bacteriocin production that is similar to that encoding salivaricin CRL1328. Our study demonstrates the safety of the above mentioned isolate, which has potential to be used as a probiotic, exerting health benefits through production of antimicrobial substances.

Mesenchymal Stem Cells Conditioned Media-Chitosan Nanoparticles against Clinical Carbapenem-Resistant Acinetobacter Baumannii: In-Vitro Study.

Gamma radiation dosimetry is vital for applications in medicine, industry, and the environment. Conventional dosimeters are limited by sensitivity, stability, and real-time detection. We report a novel gamma-ray dosimeter based on one-dimensional topological photonic crystals (1D TPCs) incorporating topologically protected edge states (TESs) as highly sensitive spectral markers. The device comprises two interfaced photonic crystal configurations built from nanoporous silicon layers infiltrated with a polyvinyl alcohol (PVA) polymer doped with crystal violet (CV) and carbol fuchsine (CF). Upon exposure to gamma radiation (0–70 Gy), the refractive index of the doped polymer changes, inducing a measurable redshift in the TES resonance peak by ∼14 nm, from 496 nm to 510 nm. The sensor demonstrates a high sensitivity of 0.22 nm/Gy, a quality factor (QF) of 9734, a detection limit (DL) of 0.013 Gy, and a spectral resolution (SR) of 0.003 nm, significantly surpassing conventional photonic and fiber-optic dosimeters. Structural tuning, via layer thickness, periodicity, and incidence angle, enables optimized photonic bandgap engineering and robust TES confinement. The real-time optical readout, high signal-to-noise ratio, and radiation dose tunability highlight the sensor’s potential for integration into advanced monitoring systems for clinical radiotherapy, nuclear safety, and aerospace applications.

The genus Eugenia has a long history of use in traditional medicine for treating various conditions, including infectious diseases, gastrointestinal disorders, and skin problems. Essential oils derived from Eugenia species are known for their medicinal properties and have been studied for their antimicrobial and bioactive potential. This study aimed to evaluate, through in vitro tests, the antibacterial, antibiofilm, and antibiotic-modulating effects of Eugenia brejoensis essential oil (EOEb) against multidrug-resistant (MDR) clinical isolates of Acinetobacter baumannii and Pseudomonas aeruginosa from COVID-19 patients. In addition, we sought to analyze its toxicity and survival rates through in vivo tests in an invertebrate model using Tenebrio molitor. The EOEb was extracted via hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS) and flame ionization detector (FID). Clinical isolates of A. baumannii and P. aeruginosa were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and their resistance profiles were determined using the Vitek 2 system. The in vitro tests were conducted using the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using microdilution and plating methods. Biofilm formation and inhibition assays were performed using crystal violet staining. Synergistic effects of EOEb with ciprofloxacin and gentamicin were evaluated using the checkerboard assay. The antibacterial effect of EOEb was tested in vivo using the T. molitor (mealworm) larvae model to assess toxicity and survival rates. The major constituents of EOEb were rosifoliol (16.47%), guaiol (12.69%), and (E)-caryophyllene (11.97%). All bacteria exhibited an MDR profile. EOEb showed significant antibacterial activity against MDR strains, with MIC and MBC values ranging from 0.512 to 4.096mg/mL. It also effectively inhibited biofilm formation at concentrations between 0.512 and 4.096mg/mL. EOEb exhibited synergistic effects with ciprofloxacin against A. baumannii and with gentamicin against P. aeruginosa, as indicated by fractional inhibitory concentration (FIC) indices close to 0.5. The EOEb demonstrated low toxicity in the T. molitor model, with a survival rate of approximately 70%. The EOEb exhibits notable antimicrobial and biofilm-inhibiting properties against MDR pathogens. Its low toxicity and synergistic effects with conventional antibiotics suggest its potential as a therapeutic alternative for combating antibiotic-resistant infections.

Objective: Multidrug-resistant bacteria create an urgent need for new materials and treatment combinations. This study aims to identify effective antibiofilm agents derived from nanomaterials, either alone or in combination with antibiotics or essential plant oils, and to evaluate their potential in preventing biofilm formation. Methods: Four bacterial pathogens were selected for their resistance to more than two classes of antibiotics: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. Biofilm formation was assessed using the Crystal violet staining method, with the highest biofilm producer selected for further analysis. The biofilm formation and bacterial Exopolysaccharide (EPS) content were measured and compared after treatment with Ag nanoparticles, whether used alone or combined with Amoxicillin or the essential oil extracted from Cymbopogon schoenanthus. Results: All treatments effectively inhibited both bacterial growth and biofilm formation. The most significant activity was observed with the combination of AgNPs and plant oil, followed by the combination of AgNPs and Amoxicillin, and then nanoparticles alone. All treatments demonstrated significant inhibitory effects compared to the control group (which did not receive any inhibitory substances). The addition of Amoxicillin or plant oil also reduced the minimal inhibitory concentrations (MIC) for K. pneumoniae, which were determined to be 6.0 µg/ml for nanoparticles alone, 4.5 µg/ml for nanoparticles combined with the antibiotic, and 3 µg/ml for nanoparticles combined with plant oil. Furthermore, the toxicity of nanoparticles against Artemia salina, a test organism, was assessed. Treatment with AgNPs also decreased EPS production by K. pneumoniae by 39.6%, with further reductions of 54% and 80% observed in the presence of the antibiotic or plant oil, respectively. The effectiveness of the plant oil is attributed to the numerous secondary metabolites it contains. Conclusion: This research highlights the promising potential of using AgNPs with either Amoxicillin or C. schoenanthus oil to fight against antibiotic-resistant bacterial infections.

A hazardous triphenylmethane dye, Crystal Violet, was effectively removed from its aqueous solution using a waste material—Hen Feather—as biosorbent. The Crystal Violet-Hen Feather adsorption system gives promising results and has not been studied previously. By removing a highly toxic dye, using a ubiquitous biowaste material this research provides dual advantages. The influence of contact time, adsorbent dosage, dye concentration, and solution pH on the uptake of Crystal Violet by Hen Feathers was systematically investigated. Six adsorption isotherm models, namely the Freundlich, Langmuir, Temkin, Dubinin–Radushkevich, Halsey, and Jovanovic models, were studied for the adsorption of Crystal Violet over Hen Feather and various physicochemical parameters were derived. Langmuir isotherm data were exploited to obtain thermodynamic variables. Negative values for ΔH° were recorded as −15.15 to −17.01 kJ·mol−1, and negative ΔG° values of −23.34 to 25.94 kJ·mol−1 confirmed the adsorption process was exothermic and spontaneous. It was determined that a pseudo-second-order kinetic model is applicable to the present adsorption system at all three tested temperatures. It was established that Hen Feather possesses a very strong affinity for Crystal Violet and works as an excellent scavenger through physisorption.

Aim Periprosthetic infection (PPI) continues to be a problem in orthopedic surgery with a frequency of around 3%-5% and the main causative etiology is Staphylococcus spp. Once infection is established, the ability of multiple bacteria and fungi to generate biofilm on the prosthesis and surrounding tissues makes it difficult to eradicate the infection due to their ability to resist antibiotics and the immune response, which is a challenge in clinical practice. The ability of Staphylococcus spp. to form suspended aggregates on fluids, and not on surfaces, has recently been described (1-5). Therefore, in our study we aim to explore the frequency of this phenomenon of Staphylococcal “biofilm-like” suspended aggregates in joint fluid samples. Method During 1 year patients suspected of knee and hip PPI and who have signed the informed consent form prior to surgery were enrolled and joint fluids were cultured. In case of positivity with isolation of Staphylococci we tested bacterial aggregation by inoculating a 24h-mature biofilm suspension of each strain with 50% fetal bovine serum followed by an incubation of 1h at 22ºC under orbital shaking to observe the macroscopic formation of floating aggregates. We classify aggregation production from 1 to 5. We also quantify biomass and metabolic activity of the biofilm by crystal violet and XTT staining techniques, respectively. Clinical-microbiological data were also collected and patients were classified based on the Philadelphia consensus criteria 2018 into proven PPI (a major criterion or >6 points in minor criteria), possible PPI (2-5 points in minor criteria) or unlikely PPI (<2 points). Results We included 11 positive cultures from 10 patients (5 with Staphylococcus aureus and 6 with coagulase-negative Staphylococci). Floating aggregates were formed in 63.6% of the strains, being most of them of grade 2. We did not find statistically significant differences in the level of aggregates’ production according to species. We also observed that CoNS showed higher biomass production. All PPI were proven and 27.3% occurred at an early stage (≥1 month) being these not associated to aggregates’ production (p=0.721). Conclusions We observed that staphylococcal biofilm floating aggregates commonly occurred in strains from joint fluids, being mainly of low intensity. It is needed to further assess its role in the pathogenesis of PPI.

Respiratory infections remain a leading cause of morbidity and mortality, necessitating new therapeutic strategies. This study evaluated the antiviral and antibacterial activities of harmine, harmaline, and harmalacidine hydrochloride against H1N1 influenza virus and Staphylococcus aureus, key respiratory pathogens. The in vitro antiviral activity of the tested compounds against the H1N1 virus was evaluated using a plaque assay. Harmalacidine hydrochloride demonstrated notable activity, with an IC50 of 68.2 ± 0.8 µg/mL, while harmine and harmaline showed no significant effects at non-cytotoxic concentrations. The potential antibacterial action of the tested compounds was initially investigated by agar well diffusion method, which revealed clear zones of inhibition around the wells. Subsequently, their minimum inhibitory concentrations (MICs) were recorded using the broth microdilution method. Harmalacidine hydrochloride exhibited the highest antibacterial action with MICs from 16 to 128 µg/mL. Based on these findings, further investigations were conducted to assess the effect of harmalacidine hydrochloride on membrane integrity and permeability, cellular morphology, and biofilm formation. A noticeable reduction (p < 0.05) in the membrane integrity and a distinct escalation (p < 0.05) in the permeability were noticed in 46.15% and 53.85% of the tested isolates, respectively. Moreover, scanning electron microscopy revealed pronounced distortion in cellular morphology following harmalacidine hydrochloride treatment. The compound also exhibited antibiofilm activity, as demonstrated by the crystal violet assay, alongside a downregulation of biofilm-associated gene expression. Molecular docking revealed that harmalacidinium ion binds strongly to the Accessory Gene Regulator A (AgrA) of S. aureus, suggesting antibacterial activity through inhibition of quorum sensing-mediated virulence. It also showed high affinity for H1N1 neuraminidase and polymerase basic protein 2 (PB2), indicating potential antiviral activity. However, experimental enzyme assays and in vivo studies are required to confirm the proposed antiviral and antibacterial mechanisms.

Iron oxide nanoparticles (IONPs) have attracted great attention for different environmental applications, mainly due to their magnetic, enzymatic and adsorption properties. In this study, IONPs functionalized with Betula pendula extract (FIONPs) were synthesized by a simple and green method and fully characterized using FE-SEM, EDS, XRD, TGA, DLS, VSM, and FTIR. The monodisperse and colloidal FIONPs represented a crystal structure and spherical shape, an average hydrodynamic size of 118.4 nm with PDI of 0.52 and zeta potential value of -28.4, and also high saturation magnetization value of 45.3 emu g−1. The in vitro studies revealed high biocompatibility of FIONPs on the human cell lines and their potent antibacterial effects on S. aureus and E. coli. FIONPs also displayed high peroxidase-like activity with a specific activity of 0.50 mmol min−1 mg−1. UV-Vis spectroscopy showed more than 99% removal of crystal violet and methylene blue in the batch experiments in the presence of FIONPs, while HPLC analysis revealed more than 98% degradation of antibiotic cefixime and chlorpyrifos pesticide. Degradation mechanism of chlorpyrifos was further studied by LC-MS analysis and biocompatibility of degradation products was evaluated in vitro. The overall results indicated high potential of FIONPs for pollutant removal from water.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-22455-8.

BackgroundAmoxicillin is among the most frequently prescribed antibiotics globally, either as monotherapy or in combination with clavulanic acid as amoxicillin-clavulanic acid (AMC). However, the prolonged use of AMC and other antibiotics has intensified selection pressure, accelerating the emergence of AMC-resistant and multidrug-resistant (MDR) strains. Klebsiella, a member of the ESKAPE pathogens, employs diverse resistance mechanisms against multiple classes of antibiotics. This study was aimed to identify environmental Klebsiella isolates resistant to AMC with MDR phenotype and to investigate the underlying genetic determinants contributing to their resistance and virulence.MethodologyWater samples were collected from 14 sites, encompassing both wastewater and natural aquatic environments, and screened for AMC resistance on AMC supplemented Klebsiella-Selective agar base media. Antibiotic profiling of AMC resistant isolates was done by Kirby-Bauer’s disc diffusion test. Phenotypically positive MDR isolates were identified by MALDI-ToF MS. Furthermore, Klebsiella pneumoniae isolates were selected for PCR based detection of antibiotic resistance and virulence factor associated genes using plasmid and genomic DNA as a template respectively. Horizontal gene transfer experiment was carried out using K. pneumoniae isolates as donor and plasmid-free and antibiotic sensitive Escherichia coli J53R strain as a recipient. Biofilm formation was detected by crystal violet assay and visualised in SEM. The hypermucoviscosity of K. pneumoniae (hmvKp) was confirmed by string test.ResultsOf the total 178 AMC resistant bacterial isolates, 119 displayed MDR phenotype. Among 63 putative AMC-resistant, MDR isolates exhibiting a non-metallic sheen on EMB agar, MALDI-TOF MS-based identification confirmed 33 to be Klebsiella pneumoniae. PCR based screening for resistance determinants revealed the presence of blaTEM (100%), blaSHV (75.75%), blaCTX−M (54.54%), blaNDM (27.27%), blaOXA−48 (39.39%), blaCMY (48.48%), qnrA (6.06%), qnrB (87.87%), qnrS (93.93%), tetA (81.81%), and tetB (27.27%), alongside sul1 (90.90%) and dfrA12 (9.09%) genes. Additionally, virulence-associated genes viz., fimH (33.33%), mrkD (78.78%), ecpA (54.54%), iucC (54.54%), and rmpA (6.06%) were also detected. Furthermore, biofilm formation assay demonstrated that 24 (72.72%) isolates were strong biofilm-formers, indicating their potential for pathogenicity.ConclusionOccurrence of hypervirulent, AMC resistant and MDR Klebsiella pneumoniae in aquatic environment is a concern and further studies are required to explore their potential threat in dissemination of resistance and clinical implications.Graphical abstractSupplementary InformationThe online version contains supplementary material available at 10.1186/s12879-025-11806-5.

Pulmonary mucormycosis (PM), a life-threatening infection caused by Mucorales, exhibits high mortality. Comprehensive data integrating clinical profiling, antifungal susceptibility, and biofilm formation ability are limited. This retrospective study characterized 26 adult PM patients at a Beijing tertiary-care hospital. Data on demographics, underlying diseases, co-infections, and outcomes were collected. Clinical Mucorales isolates underwent molecular identification via 18 S rRNA gene sequencing and phylogenetic analysis. In vitro susceptibility against nine antifungals (amphotericin B, fluconazole, voriconazole, itraconazole, posaconazole, caspofungin, micafungin, anidulafungin, 5-flucytosine) was determined using Sensititre YeastOne YO10 panels. Biofilm biomass was assessed (24 h, 48 h, 72 h) via the crystal violet staining assay. Patients were predominantly older males (median age 66 years, 65.4% male) with high comorbidity burden (92.3%). All-cause in-hospital mortality was 38.5%. Strikingly, 80.8% had co-infections. Temporal analysis revealed that viral (77.8%) and fungal (62.5%) co-infections often preceded the detection of Mucorales. Molecular identification confirmed Rhizopus spp. (54%) predominated, followed by Rhizomucor spp. (19%), Mucor spp. (19%), and Lichtheimia spp. (8%). Antifungal testing showed amphotericin B possessed the most consistent activity (MIC50/MIC90: 1/2 µg/mL). Posaconazole was the most potent azole (MIC50/MIC90: 0.25/1 µg/mL), but profound genus-level heterogeneity was observed. Biofilm assessment at the 48-h peak revealed biofilm formation in 84.6% (22/26) of isolates. This study highlights the high prevalence of antecedent viral/fungal co-infections preceding Mucorales detection and significant mortality, despite in vitro susceptibility to amphotericin B/posaconazol. In addition, most of the strains demonstrated biofilm formation ability, with evident genus-level heterogeneity. These findings emphasize the imperative of species-level identification and consideration of genus-specific traits to guide effective management of this life-threatening infection.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12866-025-04472-9.

ObjectivesThis study aimed to assess bacterial contamination on sports mouthguards and their storage cases used by children under 12, and to determine how surface deterioration and poor handling practices influence bacterial attachment and biofilm formation.Materials and methodsMouthguards and cases were collected from junior football players. Culturable bacterial isolates were identified using 16S rRNA sequencing. Biofilm formation was assessed using crystal violet assays. Surface roughness was measured via 3D profilometry, and scanning electron microscopy (SEM) was used to visualise bacterial colonisation. Cleaning efficacy was tested using mechanical brushing with toothpaste and simple water rinses.ResultsThirty-eight culturable bacterial isolates representing 13 genera were identified, with Pseudomonas putida being most prevalent. Most isolates were of environmental origin, indicating contamination through improper handling and storage. Used mouthguards exhibited significantly increased surface roughness (Ra = 173.88 μm) compared to new ones (Ra = 0.713 μm), correlating with enhanced bacterial adhesion. SEM revealed approximately eightfold higher bacterial colonisation on deteriorated surfaces. Mechanical cleaning with a toothbrush and toothpaste achieved 98% bacterial removal, whereas water rinsing removed only 60–70%.ConclusionsMouthguard use leads to surface wear that promotes bacterial colonisation, particularly when coupled with poor storage and cleaning practices.Clinical relevanceChildren’s sports mouthguards require regular mechanical cleaning and hygienic storage to prevent microbial accumulation and reduce oral health risks.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12903-025-07016-9.

The photocatalytic degradation of Crystal Violet (CV) using ZnO-based nanomaterials presents a promising solution for addressing water pollution caused by synthetic dyes. This review highlights the exceptional efficiency of ZnO and its modified forms—such as doped, composite, and heterostructured variants—in degrading CV under both ultraviolet (UV) and solar irradiation. Key advancements include strategic bandgap engineering through doping (e.g., Cd, Mn, Co), innovative heterojunction designs (e.g., n-ZnO/p-Cu2O, g-C3N4/ZnO), and composite formations with graphene oxide, which collectively enhance visible-light absorption and minimize charge recombination. The degradation mechanism, primarily driven by hydroxyl and superoxide radicals, leads to the complete mineralization of CV into non-toxic byproducts. Furthermore, this review emphasizes the emerging role of Artificial Neural Networks (ANNs) as superior tools for optimizing degradation parameters, demonstrating higher predictive accuracy and scalability compared to traditional methods like Response Surface Methodology (RSM). Potential operational challenges and future directions—including machine learning-driven optimization, real-effluent testing potential, and the development of solar-active catalysts—are further discussed. This work not only consolidates recent breakthroughs in ZnO-based photocatalysis but also provides a forward-looking perspective on sustainable wastewater treatment strategies.

Development of an innovative method of Salmonella Typhi biofilm quantification using tetrahydrofuran and response surface methodology.

Biomass and metabolic activity staining biofilm techniques are not reliable enough to be used in microbiology laboratories.

Quantitative immunoassay of prostate-specific antigen dependent on SERS substrate of polymer-silver nanocubes modified with 4-mercaptobenzoic acid: The crucial effect of thiol molecule as internal standard.

The main goal of this study is to address the problem of environmental water pollution caused by organic dyes through waste valorization by synthesizing geopolymer-based adsorbents. In this work, geopolymers were synthesized using fly ash modified with chitosan and polyvinyl alcohol as a starting material. The obtained materials were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and determination of the point of zero charge. We examined the adsorption potential for organic dye (methylene blue, brilliant green, crystal violet) removal through the influence of contact time, initial pH and concentration of adsorbate solution, and temperature on adsorption. The obtained results were analyzed using theoretical kinetics and isotherm models. Interpretation of the obtained results was performed using the Box–Behnken design and chemometric methods of multivariate analysis. The findings showed that modification with chitosan significantly enhanced the adsorption efficiency of the synthesized materials up to 95.9% for methylene blue adsorption. The parameters identified as having the greatest influence on the adsorption process were contact time, pH-value, initial dye concentration, and the type of dye being adsorbed.

Tailoring aggregation of silver nanoparticles via crystal violet: A surface-enhanced Raman scattering perspective

Reusable and self-calibrating SERS platform with Ag-incorporated Prussian blue for efficient detection and degradation of organic pollutants.