RESUMO
Photodynamic therapy (PDT) is an effective method for bacterial infection control in root canals of teeth with a broad-spectrum antibacterial activity. However, its application in root canal treatment is limited due to its inefficiency under hypoxic conditions and dentin staining. Triton X-100 (TX) shows great potential in enhancing the efficiency of antimicrobial agents through improving bacterial membrane permeability. The present study employed a combination of toluidine blue O (TB)-mediated PDT with TX to target the Enterococcus faecalis (E. faecalis), a bacterium with strong resistance to various antibacterial agents and mostly detected in infected root canals. PDT combined with TX showed enhanced antibacterial efficiency against both planktonic cells and biofilms of E. faecalis. At the same time, TX enhanced the antibacterial effect in dentinal tubules and reduced the incubation time. Mechanism studies revealed that TX improved reactive oxygen species (ROS) production through increasing the proportion of TB monomers. Additionally, increased membrane permeability and wettability were also observed. The findings demonstrated the PDT combined with TX could be used as a highly effective method for the root canal disinfection of teeth.
Assuntos
Antibacterianos , Biofilmes , Enterococcus faecalis , Octoxinol , Fotoquimioterapia , Espécies Reativas de Oxigênio , Enterococcus faecalis/efeitos dos fármacos , Fotoquimioterapia/métodos , Antibacterianos/farmacologia , Antibacterianos/química , Biofilmes/efeitos dos fármacos , Octoxinol/química , Octoxinol/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Cloreto de Tolônio/farmacologia , Cloreto de Tolônio/química , Humanos , Testes de Sensibilidade Microbiana , Cavidade Pulpar/microbiologia , Cavidade Pulpar/efeitos dos fármacos , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/químicaRESUMO
CA125 (carbohydrate antigen 125) is an important biomarker of ovarian cancer, so developing effective method for its detection is of great significance. In the present work, a novel sandwich-like electrochemical immunosensor (STEM) of CA125 was constructed by preparing nanoribbon-like Ti3C2Tx MXenes (Ti3C2TxNR) to immobilize primary antibody (PAb) of CA125 and UIO-66-NH2 MOFs structure to immobilize second antibody (SAb) and electroactive toluidine blue (Tb) probe. In this designed STEM assay, the as-prepared Ti3C2TxNR nanohybrid offers the advantages in large surface area and conductivity as carrier, and UIO-66-NH2 provided an ideal platform to accommodate SAb and a large number of Tb molecules as signal amplifier. In the presence of CA125, the peak currents of Tb from the formed STEM structure increase with the increase of CA125 level. After optimizing the related control conditions, a wide linear range (0.2-150.0 U mL-1) and a very low detection limit (0.05 U mL-1) of CA125 were achieved. It's thus expected the developed STEM strategy has important applications for the detection of CA125.
Assuntos
Antígeno Ca-125 , Técnicas Eletroquímicas , Cloreto de Tolônio , Antígeno Ca-125/análise , Antígeno Ca-125/sangue , Imunoensaio/métodos , Humanos , Cloreto de Tolônio/química , Titânio/química , Técnicas Biossensoriais , Nanotubos de Carbono/química , Limite de Detecção , Anticorpos Imobilizados/imunologia , Anticorpos Imobilizados/química , Proteínas de MembranaRESUMO
The high level of alpha-fetoprotein (AFP) expression is closely related to hepatocellular carcinoma (HCC). Herein, a dual signal ratiometric electrochemical immunosensor based on chitosan-ferrocenecarboxaldehyde-spindle gold (Chit-Fc-SAu) and Co/Fe metal-organic framework-toluidine blue/polydopamine (Co/Fe MOF-TB/PDA) was proposed for quantitative analysis of AFP. Specifically, Chit-Fc-SAu worked as a substrate to trap more primary antibodies (Ab1) generating the first electrochemical signal from Fc. Thanks to the large specific surface area, the synergistic and electronic effects of Co/Fe MOF nanosheets, and the rich functional groups of PDA, Co/Fe MOF-TB/PDA could load more secondary antibodies (Ab2) and signal molecules (TB) providing another amplified electrochemical signal. In the presence of AFP, Ab1-AFP-Ab2 formed a sandwich structure, and as the AFP concentration increased, the peak current ratio of TB to Fc (ITB/IFc) also increased. The dual signal ratiometric strategy can avoid environmental signal interference and achieve signal self-calibration, thereby improving the accuracy and reproducibility of detection. After a series of exploration, this self-calibrated ratiometric immunosensor exhibited a wide linear range (0.001-200 ng mL-1), a low detection limit (0.34 pg mL-1), and good repeatability. When applied to the assay of clinical serum samples, the detection results of ratiometric sensor were consistent with that of commercial electrochemiluminescence (ECL) immunoassay, significantly superior to that of non-ratiometric sensor. The self-calibrated strategy based on ratiometric sensor helps to improve the accuracy of AFP in clinical diagnosis.
Assuntos
Técnicas Biossensoriais , Carcinoma Hepatocelular , Neoplasias Hepáticas , Nanopartículas Metálicas , Humanos , alfa-Fetoproteínas/análise , Cloreto de Tolônio/química , Técnicas Biossensoriais/métodos , Reprodutibilidade dos Testes , Bases de Schiff , Imunoensaio/métodos , Anticorpos/química , Técnicas Eletroquímicas/métodos , Nanopartículas Metálicas/química , Limite de Detecção , Ouro/químicaRESUMO
This study evaluated the photobiocidal performance of four widely distributed visible-light-activated (VLA) dyes against two bacteria (Staphylococcus epidermidis and Escherichia coli) and two bacteriophages (phages MS2 and phi 6): rose bengal (RB), crystal violet, methylene blue, and toluidine blue O (TBO). The photobiocidal performance of each dye depended on the relationship between the type of dye and microorganism. Gram-negative E. coli and the non-enveloped structure of phage MS2 showed more resistance to the photobiocidal reaction than Gram-positive S. epidermidis and the enveloped structure of phage phi 6. RB had the highest potential to yield reactive oxygen species. However, the photobiocidal performance of RB was dependent on the magnitude of the surface charge of the microorganisms; for example, anionic RB induced a negative surface charge and thus electrical repulsion. On the other hand, the photobiocidal performance of TBO was observed to be less affected by the microorganism type. The comparative results presented in our study have significant implications for selecting photodynamic antimicrobial chemotherapy (PACT) dyes suitable for specific situations and purposes. Furthermore, they contribute to the advancement of PACT-related technologies by enhancing their applicability and scalability.
Assuntos
Anti-Infecciosos , Cloreto de Tolônio , Cloreto de Tolônio/química , Cloreto de Tolônio/farmacologia , Azul de Metileno/química , Rosa Bengala/química , Violeta Genciana , Fármacos Fotossensibilizantes/química , Escherichia coli , CorantesRESUMO
A ratiometric electrochemical sensor for bisphenol A (BPA) detection is developed using a glassy carbon electrode modified with a poly(toluidine blue)/gold nanoparticle composite (PTB/AuNP/GCE). The ratiometric signal, namely, the oxidation peak current ratio of BPA to PTB, increases linearly with BPA concentration in the 0.2-5.0 µM range, with a detection limit of 0.15 µM. The electrochemical mechanism of BPA is studied at the PTB/AuNP/GCE, and the results show that BPA undergoes an electrooxidation process of two electrons and two protons at the PTB/AuNP/GCE. The proposed sensor has high sensitivity, high stability and good selectivity. The application of BPA in water samples is successfully verified using the proposed ratiometric electrochemical sensor.
Assuntos
Ouro , Nanopartículas Metálicas , Fenóis/análise , Compostos Benzidrílicos/análise , Compostos Benzidrílicos/química , Carbono , Eletrodos , Fenóis/química , Cloreto de Tolônio/químicaRESUMO
In the present work, we evaluated the supramolecular interactions between three photosensitizers, namely toluidine blue O (TBO, positively charged) and two fatty acid conjugates of 6 and 14 carbon atoms chain lengths (TBOC6 and TBOC14), with human serum albumin (HSA) and the macrocycle cucurbit[7]uril (CB[7]), alone or in combination within a biosupramolecular system as potential carriers of photosensitizers for Photodynamic therapy (PDT). Binding studies were carried out using photophysical and calorimetric techniques and accompanied with molecular docking simulations. Amphiphilic photosensitizers, particularly TBOC14, showed stronger binding to HSA and (CB[7]). Comparing the different delivery systems, (CB[7]) had a marginal effect on cell uptake and phototoxicity in HeLa cells, while HSA showed enhanced cell uptake with phototoxicities that depended on the photosensitizer. Despite low cell uptake, the combination of both (CB[7]) and HSA was the most phototoxic, which illustrates the potential of combining these systems for PDT applications.
Assuntos
Hidrocarbonetos Aromáticos com Pontes/química , Imidazóis/química , Fármacos Fotossensibilizantes/química , Albumina Sérica Humana/química , Sítios de Ligação , Hidrocarbonetos Aromáticos com Pontes/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Ácidos Graxos/química , Células HeLa , Humanos , Imidazóis/metabolismo , Simulação de Acoplamento Molecular , Fotoquimioterapia , Fármacos Fotossensibilizantes/metabolismo , Fármacos Fotossensibilizantes/farmacologia , Ligação Proteica , Albumina Sérica Humana/metabolismo , Cloreto de Tolônio/química , Cloreto de Tolônio/metabolismoRESUMO
In this study, an innovative strategy was proposed for the electrocatalytical reduction and enzymatic biosensing of hydrogen peroxide (H2 O2 ) using chronoamperometry technique. For the first time, immobilization of horseradish peroxidase (HRP) in polydopamine-modified magnetic nanoparticles (PDA-MNPs) was successfully performed. Also, poly(l-arginine/toluidine blue) film-modified glassy carbon electrode was constructed through co-electropolymerization of l-arginine and toluidine blue on the surface of GCE using cyclic voltammetry technique. The engineered hybrid thin film provides strong functionalities for efficient grafting of PDA-MNPs which, in turn, enable the covalent immobilization of HRP. The proposed biosensor was used for the detection of H2 O2 in the range of 0.5-30 µM with a low limit of quantification 0.23 µM. It also was successfully applied for the investigation of hydrogen peroxide in human plasma samples.
Assuntos
Técnicas Biossensoriais/métodos , Enzimas Imobilizadas/metabolismo , Compostos Férricos/química , Peroxidase do Rábano Silvestre/metabolismo , Peróxido de Hidrogênio/sangue , Indóis/química , Nanopartículas Metálicas/química , Polímeros/química , Arginina/química , Eletroquímica , Eletrodos , Enzimas Imobilizadas/química , Peroxidase do Rábano Silvestre/química , Humanos , Cloreto de Tolônio/químicaRESUMO
Photodynamic damage to the cell envelope can inactivate microorganisms and may be applied to combat super-resistance phenomenon, empowered by the indiscriminate use of antibiotics. Efficiency in microbial inactivation is dependent on the incorporation of photosensitizers (PS) into the bacterial membranes to trigger oxidation reactions under illumination. Herein, Langmuir monolayers of Escherichia coli lipid extract were built to determine the binding mechanisms and oxidation outcomes induced by eosin decyl ester (EosDEC) and toluidine blue-O (TBO) PSs. Surface-pressure isotherms of the E. coli monolayers were expanded upon EosDEC and TBO, suggesting incorporation of both PSs. Fourier-transform infrared spectroscopy (FTIR) of Langmuir-Schaefer (LS) films reveled that the EosDEC and TBO binding mechanisms are dominated by electrostatic interactions with the anionic polar groups, with limited penetration into the chains. Light-irradiation reduced the relative area of E. coli monolayer on TBO, indicating an increased loss of material to the subphase owing to the chain cleavage, generated by contact-dependent reactions with excited states of TBO. In contrast, the increased relative area of E. coli monolayers containing EosDEC suggests lipid hydroperoxidation, which is PS contact-independent. Even considering a small chain penetration, the saturated EosDEC may have partitioned towards saturated reach domains, avoiding direct contact with membrane unsaturations.
Assuntos
Misturas Complexas/química , Amarelo de Eosina-(YS)/química , Escherichia coli/química , Lipídeos/química , Fármacos Fotossensibilizantes/química , Cloreto de Tolônio/química , Membrana Celular , Membranas Artificiais , Oxirredução , Permeabilidade , Processos Fotoquímicos , Eletricidade Estática , Relação Estrutura-AtividadeRESUMO
In this study, a novel biosensor based on molecular imprinting polymer (MIP) methodology was fabricated toward recognition of carcinoembryonic antigen (CEA). For this purpose, poly (toluidine blue) (PTB) was electropolymerized on the surface of gold electrode in the absence and presence of CEA. So, the target molecules were entrapped into the imprinted specific cavities of MIP. Obtained results show that, the binding affinity of the MIP system was significantly higher than that of revealed for the nonimprinted polymer (NIP) system, MIP-based biosensor revealed linear response from (0.005 to 75 µg/L) and low limit of quantification of (0.005 µg/L) by using chronoamperometry technique, leading to CEA monitoring in real and clinical samples. Thus, a novel technique for rapid, simple, sensitive and affordable monitoring of CEA (LLOQ = 0.005 µg/L) has provided through developed biosensor. From a future perspective, moreover, this method can be considered as an applicable candidate in biomedical and clinical analysis for point-of-care usages.
Assuntos
Técnicas Biossensoriais/métodos , Antígeno Carcinoembrionário/sangue , Polímeros Molecularmente Impressos , Cloreto de Tolônio/química , Eletrodos , Ouro , Humanos , Limite de Detecção , Plasma/química , Cloreto de Tolônio/análogos & derivadosRESUMO
Infectious disease outbreaks within healthcare facilities can exacerbate patient illness and, in some cases, can be fatal. Contaminated surfaces and medical devices can act as a reservoir for transmission of pathogens and have been linked to the rising incidence of healthcare-acquired infections. Antimicrobial surfaces can reduce microbial contamination and transmission and have emerged as a crucial component in healthcare infection control in recent years. The aim of this study was to manufacture antimicrobial polymer surfaces containing the photosensitiser, toluidine blue O (TBO), using hot-melt extrusion (HME). Several concentrations of TBO were combined with a range of medically relevant polymers via HME. TBO-polymer extrudates displayed no significant differences in thermal properties and surface wettability relative to non-loaded polymers. Minimal leaching of TBO from the surface was confirmed through in vitro release studies. Antibacterial activity was observed to vary according to the polymer and concentration of incorporated TBO, with PEBAX® polymers modified with 0.1% w/w TBO demonstrating promising reductions of >99.9% in viable bacterial adherence of a range of common nosocomial pathogens, including Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter baumannii and Escherichia coli. This study demonstrates the use of HME as a facile alternative method to common encapsulation strategies for the production of light-activated antimicrobial polymer surfaces. This method can be easily translated to large-scale manufacture and, in addition, the polymers constitute promising antimicrobial base materials for the rapidly growing additive manufacturing industries.
Assuntos
Anti-Infecciosos/química , Portadores de Fármacos/química , Infecções/terapia , Fármacos Fotossensibilizantes/química , Polímeros/química , Cloreto de Tolônio/química , Anti-Infecciosos/farmacologia , Ácidos Borônicos/química , Liberação Controlada de Fármacos , Humanos , Nylons/química , Fotoquimioterapia , Polímeros/farmacologia , Exposição à Radiação , Propriedades de Superfície , Temperatura de TransiçãoRESUMO
We studied the effect of bone marrow autotransplantation on the morphofunctional properties and numerical population of mast cells. The experiments were performed on 4-monthold male mice. The animals received an injection of a suspension of bone marrow obtained from the femoral epiphyses of these animals into the caudal vein. In 40 min and 2 h after autotransplantation, the number of tryptase-positive mast cells increased by 1.1 times. The formation of groups of mast cells near erythroid-neutrophil islets and near blood vessels was observed. The proportion of metachromatic mast cells significantly increased. By the degree of mast cells degranulation, we detected non-degranulated up to 48.0±1.4% (vs 55.2±1.2% in intact mice) and moderately degranulated mast cells 22.0±1.2% (vs 18.2±0.9% in intact mice); the percentage of actively degranulated cells was 10.0±0.8% (vs 3.6±0.9% in intact mice; p<0.05). Morphometric parameters of mast cells were changed, with a slight increase in their diameter and distance between the cells. The number of histamine-containing mast cells increased significantly (by 3.2 times in 40 min and by 5.9 times in 2 h) and histamine content in these cells also increased. Thus, bone marrow autotransplantation led to intensification of degranulation and sulfation of mast cells and the release of histamine from them.
Assuntos
Células da Medula Óssea/metabolismo , Heparina/química , Histamina/metabolismo , Mastócitos/metabolismo , Transplante Autólogo/métodos , Triptases/metabolismo , Animais , Medula Óssea/metabolismo , Diferenciação Celular , Proliferação de Células , Heparina/metabolismo , Masculino , Camundongos , Fatores de Tempo , Cloreto de Tolônio/químicaRESUMO
BACKGROUND: When the resected specimen is sent for intraoperative margin assessment, all margins are grossly checked, and selected margins undergo a frozen section (FS) examination. Therefore, there is a possibility of sampling error. This study evaluated the effectiveness of using toluidine blue (TB) as an intraoperative triage screening tool to detect positive mucosal margins of the resected specimens of oral squamous cell carcinoma (OSCC) and serve as a guide for FS sampling. METHODS: Surgical samples of 30 consecutive patients with biopsy-proven OSCC were included in the study. A total of 140 mucosal margins were analyzed intraoperatively by TB and FS, the results were compared with the final histopathology. RESULTS: Of the 140 examined mucosal tumor margins, 14 stained positives with TB, six were true-positives, eight were false-positives, and there were no false-negatives, as confirmed by final histopathology of the same margins. The diagnostic performance measures were sensitivity 100.0%; specificity 94.0%; positive predictive value (PPV) 42.9%; negative predictive value (NPV) 100.0%; and accuracy 94.3% (95% CI: 89.0-97.5%). For FS, there were three true-positives, three false-negatives, and no false-positives. The diagnostic performance measures were sensitivity 50.0%; specificity 100.0%; PPV 100.0%; NPV 97.8%; and accuracy 97.9% (95% CI: 93.9-99.6%). CONCLUSION: TB is less specific but more sensitive than FS for detecting positive mucosal margins of resected OSCC. Screening the tumor mucosal margins with TB before FS sampling may help identify more tumor-bearing margins. TRIAL REGISTRATION: This trial was registered at ClinicalTrials.gov. Registration number: NCT03554967 . Registration date: June 13, 2018.
Assuntos
Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/cirurgia , Secções Congeladas/métodos , Neoplasias Bucais/patologia , Neoplasias Bucais/cirurgia , Cloreto de Tolônio/química , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Margens de Excisão , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Adulto JovemRESUMO
A surface-enhanced Raman scattering (SERS) method is proposed for the assay of microRNA 122 based on configuration change of DNA tetrahedron. Firstly, a DNA tetrahedron was self-assembled with one vertex labeled with toluidine blue (TB). Then, it was immobilized on the porous Ni/SiO2@PEI@Au as a SERS platform, which was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). At this time, the DNA tetrahedron was contracted; so, the TB is close to AuNPs and the Raman signal is high. When target microRNA 122 existed, with the nicking enzyme amplification strategy, a great deal of DNA signal chains (S5) was obtained, which can extend the contracted DNA tetrahedron and change it into a three-dimensional DNA tetrahedron. In this case, the TB was far from AuNPs, resulting in a lower Raman signal. Due to the configuration change of DNA tetrahedron, the Raman signal at 1624 cm-1 (with the excitation wavelength of 633 nm) has a linear relationship with the logarithm concentration of microRNA 122. This SERS assay has high sensitivity for microRNA 122 with a determination range from 0.01 aM to 10 fM and a detection limit of 0.009 aM. The recoveries from spiked samples were in the range 95 to 109%. This SERS strategy is designed based on the target-triggered configuration change of DNA tetrahedron, which can give new insight for DNA structures in bioanalysis. Graphical abstract A sensitive surface-enhanced Raman scattering (SERS) biosensor was developed to detect microRNA 122 using the configuration change of DNA tetrahedron to indirectly control the position of TB and hot spot.
Assuntos
DNA/química , MicroRNAs/sangue , Análise Espectral Raman/métodos , Desoxirribonuclease I/química , Ouro/química , Humanos , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Nanopartículas Metálicas/química , Níquel/química , Conformação de Ácido Nucleico , Polietilenoimina/química , Dióxido de Silício/química , Cloreto de Tolônio/químicaRESUMO
AIM: The study was aimed to investigate the impact of superassociation of hydrophobic ion pairs (HIPs) on membrane permeability. METHODS: Toluidine blue O (TBO) as a cationic model compound was complexed with anionic counter ions having different physiochemical properties namely dodecanoate (DD), oleate (OL), deoxycholate (DC), docusate (DO) and dodecyl sulfate (DS). TBO HIPs were characterized regarding log P, zeta potential and stability over 8 h at pH 7.4. Association and dissociation constants (Ka and Kd) were calculated by applying quasi-equilibrium equation to the double reciprocal plots of log P versus counter ion concentrations. Permeation studies of free TBO, superassociated TBO HIPs and HIPs applied as entirely dissociated form were carried out across human colorectal adenocarcinoma-derived cell line (Caco-2) and freshly excised rat intestinal mucosa. RESULTS: TBO HIPs of increasing lipophilicity ranging from log P 0.59 to 2.35 were obtained as a result of ion pairing with anionic counter ions. Zeta potential of TBO shifted from positive to negative due to ion pairing. HIPs with DO and DS showed highest stability at pH 7.4. Association constant (Ka) values for TBO HIPs were found in the following rank order; DS > DO > OL > DC > DD. Due to superassociation of HIPs, permeation of TBO was efficiently improved up to 3.1-fold across Caco-2 cells and up to 2.5-fold across rat intestinal mucosa. CONCLUSION: Superassociated HIPs showed generally a significantly higher membrane permeability than free TBO and entirely dissociated HIPs.
Assuntos
Permeabilidade da Membrana Celular/efeitos dos fármacos , Íons/química , Íons/metabolismo , Animais , Células CACO-2 , Linhagem Celular Tumoral , Ácido Desoxicólico/química , Ácido Dioctil Sulfossuccínico/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Mucosa Intestinal/metabolismo , Lauratos/química , Masculino , Ácido Oleico/química , Ratos , Ratos Sprague-Dawley , Dodecilsulfato de Sódio/química , Cloreto de Tolônio/químicaRESUMO
No-wash detection of small molecules in real samples has been attracting attention in the field of sensors including electroanalytical biosensors. Based on the direct electrochemical oxidation of fluorene-9-bisphenol (BHPF) on a CoN nanoarray electrode, we developed a ratiometric molecularly imprinted polymeric electrochemical (MIP-EC) sensor to realize no-wash detection of BHPF in serum and tap water. The CoN nanoarray in situ grown on carbon cloth (CC) served as the working electrode, which could load the electroactive toluidine blue (TB) and be modified by the MIPs. As the MIP concentration on the modified electrode surface was increased, the amount of BHPF exposed on the electrode surface increased and the amount of exposed TB decreased. Thus, the values of ΔITB and ΔIBHPF decreased and increased, respectively, with an increasing amount of BHPF. Therefore, a ratiometric strategy was established by using the value of ΔITB/ΔIBHPF as the instruction response to realize detection of BHPF with high sensitivity and reliability. The developed ratiometric MIP-EC sensor showed strong anti-interference ability, good detection reproducibility and stability towards no-wash detection of BHPF as shown from tests with real samples. This work can further provide theoretical and practical guidance for the detection of other familiar small molecules.
Assuntos
Compostos Benzidrílicos/análise , Cobalto/química , Técnicas Eletroquímicas/métodos , Nanopartículas Metálicas/química , Polímeros Molecularmente Impressos/química , Fenóis/análise , Compostos Benzidrílicos/sangue , Carbono/química , Eletrodos , Água Doce/análise , Humanos , Fenóis/sangue , Reprodutibilidade dos Testes , Cloreto de Tolônio/químicaRESUMO
This article presents 20 combinations of histochemical stainings for the determination of mast cell co-localization with the fibrous component of the connective tissue in the fibrillogenesis course. Best results were obtained using metachromatic detection of mast cells in combination with silver or picro-fuchsin impregnation, staining with brilliant green using van Gieson staining, and a combination of aniline blue staining with neutral red. Proposed variants of histochemical protocols open up new opportunities to analyze the participation of mast cells in extracellular matrix remodeling of the tissue microenvironment in the course of adaptive and pathological processes. Results obtained expand the current theoretical views of the process of fibrillogenesis in the extracellular matrix. They also shed new light on the participation of mast cell secretion components in the molecular mechanisms of fiber formation.
Assuntos
Colágeno/química , Matriz Extracelular/química , Mastócitos/química , Músculos do Pescoço/química , Animais , Corantes/química , Mastócitos/citologia , Ratos , Ratos Wistar , Prata/química , Coloração e Rotulagem , Cloreto de Tolônio/químicaRESUMO
In this work, a label-free electrochemical immunosensor was developed for the detection of procalcitonin (PCT), using toluidine blue functionalized NiFe Prussian-blue analog nanocubes (NiFe PBA nanocubes@TB) as a signal amplifier. NiFe PBA nanocubes was synthesized by a simple and efficient self-templating method in this work. NiFe PBA nanocubes with open-framework construction not only provides a larger specific area to load a mass of antibodies but produces an excellent signal without adding extra reaction reagent. Besides, the electrochemical performance of NiFe PBA nanocubes can be enhanced after functionalized with TB. The developed immunosensor exhibited favorable performance for PCT detection with a linear range from 0.001 to 25â¯ngâ¯mL-1 and a detection limit of 3â¯×â¯10-4â¯ngâ¯mL-1. Moreover, the immunosensor with acceptable reproducibility, selectivity, and stability may provide a new strategy in the clinical detection of PCT.
Assuntos
Ferrocianetos/química , Imunoensaio , Ferro/química , Nanocompostos/química , Níquel/química , Pró-Calcitonina/análise , Cloreto de Tolônio/química , Técnicas Biossensoriais , Técnicas Eletroquímicas , Humanos , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
A new choline oxidase (ChO) and toluidine blue O (TBO) based amperometric choline biosensor was reported in this article. An amperometric choline biosensor with immobilization of TBO (as a mediator), ChO onto polypyrrole-polyvinylsulphonate (PPy-PVS) film was accomplished on the surface of a platinum electrode. ChO was immobilized on PPy-PVS film by cross-linking with glutaraldehyde (GA). TBO was used as the mediator. Choline is oxidized to betaine and hydrogen peroxide in an oxygenated environment by ChO. Mediator reduced by reaction with hydrogen peroxide. The amperometric response was based upon the electrocatalytic properties of TBO. Optimum pH and temperature values were 7.0 and 30 °C, respectively. There was linearity between 1.0 × 10-8 and 2.0 × 10-8 M (R2 = 0.9805). The detection limit of the biosensor was 1.0 × 10-9 M and response time of the biosensor was 200 s. The storage stability and reproducibility of the biosensor were also investigated. Interfering effect of several interferants such as ascorbic acid, uric acid, alanine, dopamine, paracetamol, cysteine, and glucose on the choline biosensor was examined. The developed biosensor was tested in determinations of content in a synthetic blood sample.
Assuntos
Oxirredutases do Álcool/química , Técnicas Biossensoriais , Colina/isolamento & purificação , Cloreto de Tolônio/química , Colina/química , Humanos , Polímeros/química , Polivinil/química , Pirróis/química , Ácidos Sulfônicos/químicaRESUMO
Oxidation of phenolic compounds is an urgent need in textile industry, biological refinements, pulp and paper production. In present study, a laccase was purified from symbiotic bacterium of Bacillus sp. CF96 existing in termite digestive system. The extracellular laccase was purified via amnion sulfate precipitation, membrane dialysis, and ion exchange chromatography. The results showed that the Bacillus CF96 laccase possesses a molecular mass of 63 kDa, an optimal pH and temperature of 8.0 and 60 °C. Results showed that Zn2+, Mn2+ and Fe2+ were considered as the activator ions, while SDS was the main inhibitor. Using syringaldazine (SGZ) as substrate, the half-life of laccase at optimal temperature was 148 min; Km and Vmax were 0.737 µM and 100.5 U/mg. In addition, the enzyme showed a high effect on indigo dye with 90% bleaching capacity compared to control. In conclusion, the laccase has potential applications in industries under the provided optimal conditions.
Assuntos
Bacillus/química , Proteínas de Bactérias/química , Corantes/química , Isópteros/microbiologia , Lacase/química , Corante Amaranto/química , Animais , Bacillus/enzimologia , Proteínas de Bactérias/isolamento & purificação , Biodegradação Ambiental , Vermelho Congo/química , Estabilidade Enzimática , Microbioma Gastrointestinal/fisiologia , Concentração de Íons de Hidrogênio , Hidrólise , Índigo Carmim/química , Lacase/isolamento & purificação , Peso Molecular , Oxirredução , Especificidade por Substrato , Simbiose/fisiologia , Temperatura , Indústria Têxtil , Cloreto de Tolônio/químicaRESUMO
A low cost, sensitive and selective electrochemical imprinted biosensor for horseradish peroxidase-conjugated prostate-specific antigen (PSA) was designed and prepared based on the combination of Toluidine blue (TB) and self-assembly surface molecular imprinting technique. Poly toluidine blue [P(TB)] provided high surface area for dense loading of HRP-PSA antibody on GCE surface. P(TB), as supporting material, could effectively enhance imprinting efficiency and the electrode conductivity and facilitate electron transfer. The imprinted biosensor was characterized through Field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDX) and electrochemical methods. The proposed biosensor indicates very highly electrocatalytical activity for the reduction of hydrogen peroxide (H2O2). Also, engineered biosensor was used for determination of H2O2 by different electrochemical techniques including differential pulse voltammetry, square wave voltammetry and chronoamperometry. Under the optimized conditions, the proposed bio-imprinted polymer exhibit excellent electrocatalytical activity toward the reduction of H2O2 with wide linear range of 0.001 to 40 mM and a low limit of quantification (LLOQ) of 1 µM.