Crystal Violet Solution Research Articles

Preparation and Characterization of Lignin‐Based Activated Carbon by Rubidium Chloride Chemical Method

AbstractIn order to prepare carbon adsorbent materials, lignin was used as raw material and rubidium chloride as activator, activated carbon materials were prepared by chemical activation method, and its structure was characterized and its adsorption performance on methylene blue solution was investigated; the adsorption of crystalline violet dye was carried out at different temperatures, and the adsorption thermodynamics was studied. The results showed that: the specific surface area of the activated carbon was 433.32 m2/g, the pore volume was 0.2191 cm3/g, and the average pore size was 2.0222 nm; the adsorption value of methylene blue could reach 172.0 mg/g, and it could quickly and efficiently adsorb methylene blue solution; the adsorption effect on crystal violet solution was good, and the saturated adsorption amount at 40 °C was up to 279 mg/g, and the removal rate reached 93 %, belonging to the spontaneous adsorption thermodynamic reaction. The experiment proved that rubidium chloride can be used as an activator to activate lignin raw materials to prepare activated carbon samples, and can effectively adsorb dyes.

Bifunctional titanium boron-phosphate glass containing Ag nanoparticles for the detection and photocatalysis of organic compounds

This study delves into the structural characterization of a composition comprising Ag-NPs/phosphate plasmonic glass. Additionally, it explores two applications aimed at addressing one of the numerous challenges facing the modern world. The continuous technological progress of society has led to the proliferation of chemicals in natural water sources, posing a significant threat to ecosystems due to their low concentrations, making them difficult to detect and remove. The findings presented herein showcase the potential of Ag-NPs/sodium/titanium-phosphate glasses as a promising solution for detecting and degrading organic pollutants in freshwater. To achieve this, Ag nanoparticles were integrated into the glass surface via the ion exchange method, followed by thermal treatment. Subsequently, the detection of crystal violet solutions, applied dropwise onto the sample surface, was successfully carried out using surface-enhanced Raman spectroscopy, reaching a detection limit as low as 10−6 M. Furthermore, the glass composition demonstrated heterogeneous photocatalytic properties for UV degradation of methylene blue, with enhanced photoactivity attributed to the presence of silver nanoparticles, resulting in a 111 % increase in the kinetic constant compared to unmodified glass. Thus, these newly developed Ag-NPs sodium titanium-phosphate glasses exhibit remarkable bifunctional capabilities, offering improved optical detection and efficient photodegradation of organic molecules.

Role of ZnO/GO nanocomposite in photocatalytic degradation of mixture of organic pollutants and antimicrobial activity

AbstractA number of carcinogenic dyes and microbial infections have negative effects on living being. These also have a detrimental effect on water quality and responsible for major health problems. ZnO/GO nanocomposites (NCs) (10 wt. % GO) is synthesized via one pot ecofriendly route. It is utilized for photocatalytic degradation of aqueous solution of Malachite green (MG), Crystal violet (CV) and first time mixture of pollutants (CV+MG) dyes in 1 : 2 ratio. These synthesized NCs are analyzed by using many techniques such as P‐XRD, FE‐SEM, HR‐TEM, BET and UV‐Vis spectrophotometer. Kinetics and mechanism of photocatalytic degradation is also explored. The photocatalytic degradation followed the order (CV+MG) (1 : 2) binary system > MG > CV dyes. On the other hand, an antibacterial activity is also investigated against Gram positive (+ve) bacteria such as Staphylococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis) as well as Gram negative (−ve) bacteria such as Escherichia coli (E. coli), and Citrobacter sp. The ZnO/GO NCs followed the antibacterial activity order: E. coli > S. aureus ~ Citrobacter sp. > E. faecalis and the inhibition zones diameters are 20, 15, 15 and 10 mm respectively which is comparable with standard drug Gentamycin.

Preparation and characterization of cellulose-based activated carbon by cesium chloride chemical method

Carbon adsorbent material with a specific surface area as high as 436 m2/g was prepared by chemical activation method using cellulose as raw material and cesium chloride as activator, and its structure was characterized. Its adsorption performance on methylene blue solution was investigated, and the adsorption thermodynamics of crystalline violet dye at different temperatures was studied. The results showed that the surface of the prepared activated carbon material was smooth with abundant pores. The methylene blue adsorption value was as high as 176 mg/g, and it could adsorb methylene blue solution quickly and efficiently. It had good adsorption effect on crystal violet solution, the saturated adsorption amount reaches 281 mg/g at 40 °C, and the removal reached 92%, which indicated a self-heating adsorption reaction. Thus, CsCl could be used as an activator of wood raw material for the preparation of activated carbon samples.

THE EFFECT OF PARGILINE, SPERMINE AND THEIR COMBINATIONS ON ANDROGEN-DEPENDENT AND ANDROGEN-INDEPENDENT HUMAN PROSTATE CANCER CELLS in vitro

Summary. A series of studies on enhancing the cytotoxic effect of spermine on human prostate cells by affecting the enzymes of its metabolism has been continued. Aim: to investigate effects of pargyline, spermine and their combinations the survival, ζ-potential and surface charge and cytomorphological properties of human prostate cancer cells in culture. Object and methods: studies were conducted on cell cultures: differentiated androgen-dependent LNCaP cell line and low-differentiated androgen-independent DU-145 cell line. Cell survival was determined in the trypan blue assay. The effect of the investigated compounds, both individually and in combination, on the viability and proliferative activity of cells was assessed by the colorimetric method – by staining living cells with a solution of crystal violet in methanol. Biophysical parameters (ζ-potential and surface electric charge density) were determined according to the method cellular microelectrophoresis. Cytomorphological characteristics were studied on preparations of cells grown on coverslips, fixed and stained with hematoxylin and eosin (magnification 1000×). Results: for LNCaP cells, the IC50 of pargyline was 2.2 mM, and the IC50 of spermine was 1.5 mM. For DU-145 cells, the IC50 of pargyline was 2.35 mM, the IC50 of spermine was 5.0 mM. According to biophysical indicators, spermine caused an inversion of the sign of the electric charge in cells of the LNCaP line. Pargyline did not exert such an effect, the charge remained negative, demonstrating an inverse dependence on its concentration. The combination of pargyline and spermine increased the cytotoxic effect of spermine on LNCaP cells, but did not affect the value of their ζ-potential and surface charge density, the positive sign of which, caused by the effect of spermine, was preserved. At the same time, pargyline completely eliminated spermine-induced inversion of the sign of the total surface charge of DU-145 cells, returning it to the normal negative values. Conclusions: it is shown that the differentiated androgen-dependent cells of the LNCaP line with the combined use of pargyline and spermine demonstrated an enhancement of the cytotoxic effect of spermine. At the same time, low-differentiated cells of the DU-145 line, which do not have androgen receptors, were more resistant to the effects of both pargyline and pargyline in combination with spermine. Pargyline also reversed spermine-induced inversion of the sign of the total surface charge of DU-145 cells, returning it to normal negative values. Cytomorphological changes that occurred under the influence of both pargyline alone and in its combination with spermine demonstrate mainly the apoptotic pathway of cell death in the androgen-independent DU-145 line, while in the androgen-dependent LNCaP line, a smaller proportion of cells were in a state of apoptosis.

Microbiological activity of thiamphenicol and thiamphenicol glycinate acetylcysteinate against clinically significant microorganisms and their biofilms

Objective. To determine the minimum inhibitory concentrations of thiamphenicol and thiamphenicol glycinate acetylcysteinate against clinically significant microorganisms and determine their efficacy against microbial biofilms. Materials and Methods. This study included 48 clinical strains isolated from the sputum of patients with respiratory tract infections (16 S. pneumoniae, K. pneumoniae and S. aureus strains). Antimicrobial susceptibility testing was performed using broth microdilution method. Biofilm formation culturing with antibiotics, N-acetylcysteine and their combinations was assessed in Mueller-Hinton broth and brain heart broth in 96-well plates. Biofilms are fixed with 2,5% glutaraldehyde solution, stained with 0,25% crystal violet solution, which is extracted by 33% acetic acid solution. Results. The MIC of thiamphenicol and thiamphenicol glycinate acetylcysteinate (in terms of thiamphenicol) were the same for 87,5% of strains. Thiamphenicol and thiamphenicol glycinate acetylcysteinate have been confirmed high antimicrobial activity against S. pneumoniae strains (MIC50 0,5 mg/l, MIC90 1-2 mg/l). Cultivation with chloramphenicol, thiamphenicol, thiamphenicol glycinate acetylcysteinate, combination of chloramphenicol and thiamphenicol with N-acetylcysteine contributed to significant reduction in the optical density of S. pneumoniae biofilms. Thiamphenicol increased biofilm formation in some resistant S. aureus and K. pneumoniae. Combination based on N-acetylcysteine neutralized this effect. Conclusions. Potentiation of antibacterial activity of thiamphenicol by N-acetylcysteine against S. pneumoniae biofilms has been shown.

Interfacial and Electronic Modulation of M-Bridged Heterostructures with L-Tryptophan and Transition Metallic Oxides: Enhancing Corrosion Resistance and Photocatalytic Activity.

Despite remarkable advancements in multilayer composite materials, achieving controlled growth on stationary platforms for optimal corrosion protection and photocatalytic capabilities remains a challenge. In this study, we introduce an innovative approach by integrating bifunctional metal-organic frameworks (MOFs) into plasma-electrolyzed layers made on AZ31 Mg alloy. Metallic oxides of Zr, Ti, and W serve as new pivotal centers for MOF formation, while L-tryptophan (Trp) acts as an organic linker. This innovative approach establishes an efficient electron transport system that acts as a functional pathway for creating highly effective and versatile materials. The tunable structure of the MOF/plasma electrolyzed layer enables it to concurrently display electrochemical stability and photocatalytic activity for the photodegradation of organic pollutants. Remarkably, the WOF complex emerges as a standout performer, effectively shielding the substrate from corrosive anion attacks. This sample showcases exceptional photocatalytic efficiency of 99.61% for crystal violet solution, with sustained performance after five cycles and a 72 h corrosion test (96.55% and 98.39% degradation, respectively). Moreover, DFT calculations elucidate the fundamental bonding modes between MOFs and inorganic constituents, delivering comprehensive insights into their structural formation. Our research addresses the critical challenge of achieving controlled growth for enhanced corrosion resistance and photocatalytic activity, demonstrating a novel pathway for creating multifunctional materials with practical applications across various fields.

Fabrication of nanofiltration membranes through the deposition of polyethyleneimine on SMA-polyethersulfone supports under acid catalysis for cationic dye/salt separation

Organic selective nanofiltration membranes, with high organic rejections and salt passages, have attracted extensive research attention, especially for dye/salt separations. In the present work, nanofiltration membranes with lower MWCO were prepared by depositing PEI aqueous on porous supports containing poly (styrene-maleic anhydride) (SMA), under the catalysis of sulfuric acid. The amines in PEI reacted with the anhydrides in SMA through electrophilic protonation–addition, forming a crosslinked dense layer. Under the optimal conditions, a nanofiltration membrane with a permeance of about 24.3 Lm−2h−1bar−1 and a MWCO of about 400 Da was obtained. The membrane was further evaluated by filtrating aqueous solutions of dye and/or salt. The rejections of cationic dyes (crystal violet and methylene blue) were as high as 99.9%. The rejection of Na2SO4 was only 3.6%. During the 24 h filtration process of the crystal violet and Na2SO4 mixed aqueous solution, the separation performance remained stable, indicating the PEI/SMA-PES nanofiltration membrane had excellent organic-water selectivity and organics-salts selectivity. The membrane may have good potential in positively charged dye desalination.

Evaluación de un antimicrobiano sobre la adhesión de Candida albicans a materiales de prótesis dentales

Objective: to evaluate the effect of AlphaSan® on C. albicans adhesion to acrylic and polyamide resins. Methods: 2 x 2 mm squares were made with acrylic resin (AR) and polyamide resin (PR). Four study groups (n=12) were established: Group A: AR without AlphaSan®, Group B: AR with AlphaSan®, Group C: RP without AlphaSan®, Group D: RP with AlphaSan®. All groups were incubated in BHI broth with C. albicans ATCC at 36°C for 48 hours. Quantification of fungal adherence was performed by confocal microscopy (CM) and by means of an aqueous solution of crystal violet (CV), measuring the absorbance at 570 nm. Results: In the quantification of C. albicans adherence with CM, a 50% decrease (p =0.03) was observed between the treated groups (B and D) in relation to those not treated with AlphaSan® (A and C). No significant difference in C. albicans adherence was found between groups B and D (p > 0.5). C. albicans adherence, by CV, decreased by 55% (p= 0.01) in AR with AlphaSan® compared to AR without AlphaSan®. On the other hand, it was observed that fungal adherence decreased by 61% (p=0.01) in RP with AlphaSan® compared to RP without AlphaSan®. No significant difference was observed between the samples treated with the antifungal studied (p >0.05). Conclusion: Fungal adherence to the materials treated with AlphaSan® was limited to 50%, this would be due to the fact that the fungus presents a rigid cell wall (glucans and chitin), which provides a physical barrier for the penetration of different compounds. Consequently, it could be assumed that AlphaSan® would act on the cell wall, which would result in 50% of the fungi being able to adhere to the dental materials.

Mechanistic study on the synergy of cold plasma and sulfate radical in the degradation of azo and triarylmethane dyes using density functional theory

The activation of persulfate using cold plasma and the synergy of plasma-generated reactive species and SO4•− in mineralization of organic dyes were assessed. In this regard, solutions of crystal violet (CV) as a triarylmethane dye and methyl orange (MO) as an azo dye, were treated with cold plasma, UV-C-activated sulfate radicals, and their combination. The achieved results showed 95% TOC removal, a synergy factor of 1.3 and an energy yield of 1.68 (g kWh−1) for the combined system. The contribution of oxidant species in CV (SO4•− > O2•- > •OH) and MO (SO4•−> O2•- >1O2) degradation was explored. Moreover, analysis of degradation products and density functional theory (DFT) calculations were adopted to find the degradation mechanism based on the minimum energy pathway. Experimental and DFT results revealed that while radical and nucleophilic pathways were the drivers of CV degradation, the electrophilic attack of oxidants was a more plausible mechanism for MO degradation. Additionally, a comparison of the results of different DFT methods with experimental values showed that the Kohn–Sham DFT yielded more accurate results compared to recommended double hybrid methods. Analysis of a treated real wastewater revealed that the background constituents had negligible effects on MO and CV degradation. The high TOC removal efficiency of the combined system suggests its feasibility for treating wastewater from fertilizer and pharmaceutical production facilities.

Feasibility of microencapsulated phytochemical as disinfectant for inhibition of Candida albicans proliferation on denture base produced by digital light processing.

A proper disinfection of denture is vital to prevent a fungal infection. A study on the feasibility of microencapsulated phytochemical as complementary disinfectant and its interaction with effervescent tablet immersion on denture base resin is lacking. The aim of this study was to examine the feasibility of phytochemical-filled microcapsules as disinfectant for the inhibition of Candida albicans (C. albicans) attachment on the denture base produced by digital light processing (DLP). 54 denture base specimens uniformly mixed with or without 5wt% phytochemical-filled microcapsules were prepared using DLP. Fungal cells were inoculated onto the surfaces of the specimens, which were divided into three different disinfection treatment groups (n = 9): 1) none, 2) sterile tap water immersion for 15 min, and 3) effervescent tablet immersion for 15 min. After each treatment, the biofilm on denture surface was stained with a crystal violet solution to measure the absorbance. The number of fungal colonies was counted as colony-forming units (CFU) per mL. Morphological changes were examined by microscopy. An aligned rank transform analysis of variance was performed to analyze the interaction of presence of microcapsule and disinfection condition, with statistical significance set at P < 0.05. Both for the absorbance and CFU, there was no significant interaction between the presence of microcapsules and disinfection conditions (P = 0.543 and P = 0.077, respectively). The presence of microcapsules was statistically significant (both P < 0.001), while the effect of disinfection condition was not significant (P = 0.165 and P = 0.189, respectively). Morphological changes in fungi were detected in the groups containing microcapsules, whereas undamaged hyphal structures were found in those without microcapsules, irrespective of disinfection treatments. The presence of phytochemical-filled microcapsules significantly reduced the adhesion of C. albicans and inhibited its proliferation on denture surfaces, regardless of disinfection conditions.

Quantitative PEEM and Raman Study of Nanorough Au SERS-Active Substrates for Molecular Sensing Applications

Surface-enhanced Raman scattering (SERS) is a well-established surface-sensitive technique for detecting trace amounts of molecular analytes. While the impact of surface singularities on plasmonic materials has been widely studied, the fabrication of cost-effective, efficient SERS substrates remains a challenge. In this paper, we present the study of large-area nanorough Au SERS-active substrates, elaborated by thermal evaporation deposition by photoemission electron microscopy (PEEM), a high-resolution near-field mapping technique, to access the statistical properties of the hot-spot distribution. We experimentally demonstrate that the near-field PEEM and far-field Raman statistical signatures of nanorough Au surfaces are quantitatively correlated when used for molecular sensing. The maximum of the SERS signal of thiophenol (TP) molecules diluted to 10–6 M is observed near the film percolation threshold for which the hot-spot density is maximum. Finally, SERS measurements from solutions of TP, crystal violet, and rhodamine B molecules at 10–8 M demonstrated the sensitivity of our substrates for molecular sensing.

Preparation of La2O3-modified BaSn Composite Nanorods and Photocatalytic Properties toward Crystal Violet

Background: The separation efficiency of the electron and hole pairs of the BaSn composite nanorods is limited due to a wide band gap energy restricting the photocatalytic treatment ability of the composite nanorods. It is an efficient route to improve the photocatalytic properties of the semiconductor photocatalysts by La2O3 modification. Objective: This study aims to synthesize La2O3-modified BaSn composite nanorods through a simple method and research the photocatalytic performance of the La2O3-modified BaSn composite nanorods for crystal violet degradation. Methods: La2O3 modified BaSn composite nanorods were synthesized by a facile method using lanthanum acetate as the lanthanum raw material and evaluated by electron microscopy, solid diffuse reflectance spectra, X-ray diffraction, photoluminescence and photocatalytic measurement for crystal violet degradation under ultraviolet light irradiation. Results: BaSn composite nanorods consist of orthorhombic SnO2, monoclinic BaSn(OH)6, and monoclinic Ba(OH)2. La2O3 suppresses the growth of the monoclinic BaSn(OH)6, and orthorhombic SnO2. The La2O3-modified BaSn composite nanorods possess coarse surface covered with the La2O3 nanoscale particles with an average size of about 50 nm. The absorption edge red-shifts to 373 nm and the band gap energy reaches 3.32 eV of the La2O3 modified BaSn composite nanorods compared with the BaSn composite nanorods. 20 mL 10 mg·L-1 crystal violet solution can be entirely removed by 20 mg composite nanorods with 15wt.% La2O3 content under ultraviolet light irradiated for 120 min. The reaction rate constant is 2.4 times higher than that of the non-modified composite nanorods. Hydroxyl radicals and holes are the reaction active substances for crystal violet degradation in the composite nanorod reaction system. Conclusion: La2O3 modification decreases the band gap energy, enhances the light absorption ability, and suppresses the recombination of the electron and hole pairs of the composite nanorods.

Heat-treated Pediococcus acidilactici LM1013-mediated inhibition of biofilm formation by Cutibacterium acnes and its application in acne vulgaris: A single-arm clinical trial.

Acne vulgaris is a common skin disease accompanied by chronic inflammation in the pilosebaceous follicles, resulting from excessive Cutibacterium acnes. This study aimed to investigate the inhibition of biofilm formation by C. acnes ATCC 6919 using heat-treated Pediococcus acidilactici LM1013 (HT-LM1013), previously isolated from the Korean traditional fermented alcoholic beverage-makgeolli, and its application as a leave-on-type product for patients with acne vulgaris. HT-LM1013 was prepared by Lactomason and homogenized using a high-pressure homogenizer. The minimum inhibitory concentration (MIC), tricarboxylic acid (TCA) cycle, and lipase activity were evaluated for C. acnes inhibition. Inhibition of biofilm formation was demonstrated using a crystal violet solution. Damaged C. acnes was observed using field-emission scanning electron microscopy (FE-SEM). Clinical trials were performed using a leave-on-type product containing HT-LM1013. HT-LM1013 inhibited the TCA cycle (36.80%) and lipase activity using palmitate (31.89%), stearate (36.91%), and oleate (30.86%) as substrates at 1 × MIC (p < 0.01). After treatment with HT-LM1013, concave and elongated shapes of C. acnes were observed by FE-SEM. In addition, HT-LM1013 inhibited biofilm formation by 71.75% at 1 × MIC (p < 0.001) and removed 73.35% of mature biofilms (p < 0.01). In the clinical trial, the leave-on-type product decreased the number of closed comedones from 14.04 to 10.22, open comedones from 7.22 to 4.39%, and sebum content to 76.23% at week 4 (p < 0.01). The satisfaction score of the participants was recorded 3.83 on a five-point scale. HT-LM1013 is potent for the treatment of acne vulgaris.

Ti–N–C Bonded Close‐Coupled TiO2/g‐C3N4 for Rapid Degradation of Cationic Dyes from a Multi‐Dye System by Persulfate Activation

AbstractA novel Z‐Scheme photocatalyst (TCN) was prepared with TiO2 and graphitic carbon nitride (GCN) and utilized to study the degradation efficiency of a binary dye mixture consisting of 5 ppm Rhodamine B (RhB) and 5 ppm Crystal Violet (CV) solutions by persulfate activation. Derivative spectrometric analysis was adopted to find the degradation efficiencies of the individual dyes in the mixture. The results indicate that in the presence of persulfate ions 0.6 TCN gives 100 % degradation in 60 min and 30 min for Rh B and CV, respectively. Hydroxyl radicals, superoxide radicals, and sulfate radicals were found to be the active species involved in photocatalytic degradation. From the results of radical scavenging experiments and band potentials of the semiconductors, a plausible mechanism of photocatalytic degradation of the model pollutants is proposed.

Gastrointestinal: Real-time observation of rectal malignant lymphoma using endocytoscopy for differentiation from adenocarcinoma.

A 25-year-old man was suspected of having advanced rectal cancer by his previous physician and was referred to our hospital for surgery. Colonoscopy was repeated in our hospital before surgery. White-light imaging revealed a semi-circumferential ulcerative lesion in the rectum (Fig. 1a). The lesion was stained with 1% methylene blue and 0.05% crystal violet solution and evaluated using endocytoscopy. Proliferation of swollen, irregular-shaped nuclei with the formation of glandular duct structures was observed (Fig. 1b). Tissue biopsies were taken for flow cytometry and histological assessment. Histopathological examination after hematoxylin and eosin staining revealed infiltration and proliferation of enlarged dysplastic cells, without formation of glandular ducts (Fig. 1c). Immunohistochemistry was performed in response to the flow cytometry results, and was positive for CD20, CD79a, bcl2, and bcl6, but negative for CD3, CD10, multiple myeloma oncogene 1, and Epstein–Barr-virus-encoded small RNA in situ hybridization. Ki-67 index was 90%. The lesion was diagnosed as diffuse large B-cell lymphoma (DLBCL), germinal center B-cell-like type. Malignant lymphomas of the colon account for 0.1%–0.7% of all colorectal malignancies. In the colon, DLBCL is the second most common tumor after mucosa-associated lymphoid tissue lymphoma. DLBCL is often ulcerated and resembles ulcerated colorectal cancer by white-light endoscopic imaging (Fig. 2a). However, differentiation is required for treatment decision-making. Tissue sampling for flow cytometry can be used to quantify expression of proteins associated with prognosis and to detect multidrug resistance, which makes it useful for measuring prognostic indicators in lymphoid neoplasia. Hence, it is important to make a diagnosis of lymphoma on-site to prevent multiple repeat colonoscopies. Endocytoscopy allows real-time, in vivo visualization of atypical cells on the tumor surface and tissue details, including nuclei and glandular lumens, resulting in high diagnostic accuracy for adenocarcinoma or adenomatous lesions. However, there are few reports of the endocytoscopic findings of lymphomas in the gastrointestinal tract. In this case, endocytoscopy (520×, H290ECI; Olympus, Tokyo, Japan) showed a significant difference between DLBCL and adenocarcinoma, with irregular and rough lumens and agglomeration of distorted nuclei strongly stained with methylene blue (Fig. 2b,c).

Microstructure Evolution of Ag/Ta Nanostructured Films for Surface-Enhanced Raman Scattering Substrates

Surface-enhanced Raman scattering (SERS), a nondestructive, ultrasensitive detection method, has a wide range of potential applications. However, its application is limited due to the weak Raman scattering signals. Therefore, it is urgent to explore a simple physical method to prepare SERS substrates with high detection limits and excellent reproducibility. In this work, Ta–Ag alloy films were prepared by magnetron sputtering at room temperature, and a large number of Ag nanoparticles were self-formed on the alloy films’ surface by adjusting the deposition time, Ag content, and annealing temperature. Further research reveals that this is because the amorphous Ta in the alloy films prevents the growth of Ag grains inside Ta–Ag alloy films, resulting in the diffusion of Ag atoms to the alloy film’s surface to form Ag nanoparticles. The results demonstrate that Ag nanoparticles/Ta 55.5 at % Ag alloy films used as SERS substrates have excellent reproducibility and high sensitivity to detect 5 × 10–16 mol L–1 rhodamine 6G (R6G) solution and 5 × 10–12 mol L–1 crystal violet (CV) solution. This method provides a simple approach to developing high-performance SERS substrates.

Plasmonic Ag/ZnO Nanoscale Villi in Microstructure Fibers for Sensitive and Reusable Surface-Enhanced Raman Scattering Sensing

Microstructure fibers, integrating microfluidic channels and light guidance in one fiber, enable three-dimensional surface-enhanced Raman scattering (SERS) detection for large signal accumulation. However, the available fiber SERS probes are complicated to prepare and they are not reusable. In addition, light interacts with analytes in a form of an evanescent field, which is very weak. In this paper, we developed a SERS platform based on suspended-core photonic crystal fibers decorated with Ag/ZnO nanocomposites on the inner surface for direct, ultrasensitive, and reusable analyte detection. The unique configuration not only transfers a core-localized field to the liquid interface to greatly enhance the light–analyte interaction but also facilitates charge transfer to further improve the SERS detection sensitivity and degradation efficiency. The detection limit of crystal violet solution is 10–13 M, and the enhancement factor reaches 1011. The relative standard deviation is as low as 5.4%, ensuring the reproducibility of SERS detection. The probe has good photocatalytic performance and can degrade molecules under ultraviolet-light illumination within 20 min. This ultrasensitive and reusable SERS probe shows great application potential in rapid and in situ liquid detection.

Electrically controllable self-assembly of gold nanorods into a plasmonic nanostructure for highly efficiency SERS.

In this Letter, a method for the rapid and efficient preparation of ultrasensitive detection substrates by assembling gold nanorod suspensions with the application of an alternating current (AC) field is proposed, and it is found that frequency and voltage are the effective means of regulation. A sandwich structure (parallel SiO2 plate) not only effectively slows down the evaporation rate, but also visually reveals the changes in the assembly process. Under the optimal assembly conditions, the sensitivity and uniformity of the substrate to different probe molecules are tested. The Raman detection results experimentally show that the detection limits of Rhodamine 6G (Rh6G), crystal violet (CV), and Aspartame (APM) molecular solutions are 10-14 M, 10-10 M, and 62.5 mg/L, respectively, and the mixed dye molecular solutions can also be effectively distinguished. Furthermore, Rh6G and CV characteristic peaks at 1647 cm-1 and 1619 cm-1 were measured at randomly selected positions, and their relative standard deviations (RSDs) were 5.63% and 8.45%, respectively, indicating that the substrate has good uniformity. The effective regulation of the self-assembly results of nanoparticles will further enhance the practical application effect of surface-enhanced Raman technology and expand the application prospects of this technology.

Anti-Herpes Simplex Virus Type-1 Activity of Kyllinga nemoralis Roots Aqueous Extract

Human Herpesvirus 1 known as herpes simplex virus type 1 (HSV-1) is belonged to the Herpesviridae family, Alphaherpesvirinae subfamily, and Simplexvirus genus. Kyllinga nemoralis, known as whitehead spike sedge, white kyllinga, white globose spike, or poverty grass, is a monocotyledonous flowering graminoid similar to grasses and rushes. Acyclovir (ACV) did not eradicate HSV-1 infection as the drug only focuses on inhibiting the production of new viral genomes by interfering with viral DNA synthesis. This study aimed to identify the cytotoxic concentration (CC50) of K. nemoralis roots aqueous extract and evaluate its antiviral activities against HSV-1. &#x0D; &#x0D; Cytotoxicity assay involved the incubation of Vero cells with 10 concentrations of extract ranging between 0.002 mg/mL and 1.000 mg/mL. MTT solution was added and absorbance was measured at 540 nm [1]. The CC50 of extract was determined from the graph of cell viability (%) against extract concentrations. Antiviral assays of post-treatment, pre-treatment and virucidal tests determined the mode of antiviral activity. The 50 % effective concentration (EC50) of extract was derived from the graph of plaque inhibition (%) against concentrations. Selectivity index (SI) was evaluated as the ratio of CC50 to EC50 [2]. &#x0D; &#x0D; &#x0D; Post-treatment assay: Cells were inoculated with HSV-1 for 2 hours. Extract with (2% DMEM and 1% MCS) was added into cells and incubated for 48 hours. &#x0D; Pre-treatment assay: Cells were treated with extract in 5% DMEM for 24 hours and inoculated with HSV-1 for 1 hour 30 minutes. Then, cells were overlaid with (2% DMEM and 1% MCS) and incubated for 48 hours. &#x0D; Virucidal assay: HSV-1 was incubated with extract for 30 minutes. Then, virus-extract suspension was inoculated into cells and overlaid with 2% DMEM and 1% MCS for 48 hours. &#x0D; &#x0D; &#x0D; After 48 hours incubation, cells were stained with crystal violet solution and incubated at room temperature for 30 minutes. The plaques were counted and percentage of plaque inhibition (%) was calculated. &#x0D; The CC50 revealed aqueous extract concentration was able to kill at 50% of cell population. Post-treatment assay showed that 0.062 mg/mL of the extract inhibited intracellular viral replication. Pre-treatment study indicated that 0.02 mg/mL of extract produced protective effects towards cells. Finally, virucidal assay demonstrated that 0.222 mg/mL of extract initiated extracellular interaction with virus in inhibiting infection [3] as shown in Table 1. &#x0D; The cytotoxicity study showed that CC50, 0.72 mg/mL was toxic on cells. Therefore, lower concentrations between 0.016 mg/mL to 0.5 mg/mL, that were least or non-toxic to the cells were utilized in the subsequent antiviral screenings [4]. The extract showed good inhibition of intracellular virus replication with an EC50 of 0.062 mg/mL and SI more than 10 which is 11.61. Similarly, in pre-treatment investigation, the extract produced excellent antiviral activity with an EC50 of 0.02 mg/mL and corresponding SI of 36.00. This finding highlight that the extract is most effective when administered as pre-treatment. Antiviral activity exhibited by roots extract probably results from the inhibition of host cell glycoprotein receptors or due to prevention of binding between HSV-1 virions and host cells [5]. Virucidal assay revealed a weak extracellular interaction between HSV-1 and extract. It was supported by the low SI, 3.24 as shown in Figure 1.1. The finding suggests that 30 minutes of virus-extract exposure could be insufficient for roots extract to show an effective inhibition of virus [2]. In conclusion, the present study revealed that K. nemoralis roots aqueous extract inhibits in-vitro productive HSV-1 infection through three different modes that are effective prevention of intracellular viral replication, excellent interaction with host cell surface to inhibit HSV-1 infection and moderate direct destruction the virus particles.