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RESUMO O processo da determinação eletroanalítica do fármaco letrozol, assistida pelo compósito VO(OH)-polipirrol, obtido mediante um processo catódico, foi descrito teoricamente. Tanto para a síntese do compósito, como para o processo eletroana-lítico foi sugerido e analisado, mediante a teoria de estabilidade linear e análise de bifurcações, um modelo matemático. Foi mostrado que, ao contrário da eletrossín-tese de polipirrol catódica, iniciada por um composto na solução, o polipirrol resultante tem uma morfologia mais "centrada" aos centros ativos da matriz, dopados pelos cátions VO2+. No entretanto, tanto a síntese do compósito, como o seu desempenho eletroanalítico com o letrozol podem ser considerados eficientes.
SUMMARY The process of the electroanalytical determination of letrozol drug, assisted by the cathodically obtained VO(OH)-Polypyrrole, has been theoretically described. For both the composite synthesis and electroanalytical function a mathematical model has been suggested and analyzed by means of linear stability theory and bifurcation analysis. It was shown that, contrarily to the cathodic polypyrrole electrosynthesis, initiated by a compound in a solution, the resulting cathodic polypyrrole has more "centred" morphology, in the relation to the matrix active centers, doped by VO2+ cations. Nevertheless, either the synthesis of the composite, or its electroanalytical function with letrozole may be considered efficient.
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Objective: The main task of this work consists in an obtaining polarizable, dry mode, of bio-impedance sensors for non-invasiveECG monitoring, that work without any skin preparation or gel use, in two constructive models, based on conductive organicpolymer polypyrrole and polypyrrole with Ag nanoparticles (NP), as sensitive materials. Methods: The polypyrrole wassynthetized by chemical oxidative polymerization using FeCl3 as oxidant agent. For sensors fabrication two technological variantshave been chosen, a first variant realized by photolithographic method consisting in a substrate of Printed Circuit Board (PCB)with interdigitated copper electrode with step of 0.25 mm and over a distance of 12 mm and two pads. The polypyrrole orpolypyrrole with Ag NP dissolved in ethyl alcohol was deposed on the substrate by dipping method. The second model consists ina polypyrrole powder pressed at a hydraulic press at 10 tones/cm2 of force where one site was deposed a layer of Ag ink forconduction. Results: The performance of bio-impedance sensors were accessed by impedance skin-sensor interface withfrequency in the range of 10 - 300 kHz measurements. The influences of technological fabrication as shape and geometry as wellas the sensitive materials that used, in terms of impedance were analyzed. Conclusions: The introduction of Ag NP in polypyrrole,led to a better behavior, in terms of conduction and impedance response. For all tested sensors, the impedance decreases with thefrequency with a good linearity.
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This paper describes the electrodeposition of polyphosphate-doped polypyrrole/nanosilica nano-composite coating on steel wire for direct solid-phase microextraction of bisphenol A and five phthalates. We optimized influencing parameters on the extraction efficiency and morphology of the nanocomposite such as deposition potential, concentration of pyrrole and polyphosphate, deposition time and the nanosilica amount. Under the optimized conditions, characterization of the nanocomposite was inves-tigated by scanning electron microscopy and Fourier transform infra-red spectroscopy. Also, the factors related to the solid-phase microextraction method including desorption temperature and time, extrac-tion temperature and time, ionic strength and pH were studied in detail. Subsequently, the proposed method was validated by gas chromatography-mass spectrometry by thermal desorption and acceptable figures of merit were obtained. The linearity of the calibration curves was between 0.01 and 50 ng/mL with acceptable correlation coefficients (0.9956-0.9987) and limits of detection were in the range 0.002-0.01 ng/mL. Relative standard deviations in terms of intra-day and inter-day by five replicate analyses from aqueous solutions containing 0.1 ng/mL of target analytes were in the range 3.3％-5.4％ and 5％-7.1％, respectively. Fiber-to-fiber reproducibilities were measured for three different fibers prepared in the same conditions and the results were between 7.3％ and 9.8％. Also, extraction recoveries at two different concentrations were ≥96％. Finally, the suitability of the proposed method was demonstrated through its application to the analysis of some eye drops and injection solutions.
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Objective To prepare a mesoporous silica-coated polypyrrole nanoparticles loaded with honokiol (PPy@MSN-HK) and evaluate their in vitro release behavior. Methods In this study, PPy@MSN-HK was obtained in three steps: First, prepared polypyrrole nanoparticles; Second, coated mesoporous silica shell on its surface; Third, absorbed honokiol. The TEM, particle size, zeta potential, drug loading, infrared spectroscopy, in vitro photothermal properties, and in vitro release characteristics were chosen as indexes to investigate its potential as antitumor nanocarries. The release profiles were analyzed by simulating factor (f2), and the dissolution profiles were fitted by a variety of commonly used mathematical models. Results The results showed that the prepared nanoparticles had uniform particle size and uniform size distribution. The average particle size was (220.4 ± 4.2) nm, polydispersity coefficient was 0.042 ± 0.010, zeta potential was (-21.1 ± 0.8) mV, drug loading was (2.58 ± 0.53)%, and entrapment efficiency was (75.04 ± 0.95)%, respectively. The results of in vitro photothermal experiments showed that with the constant laser power density, the temperature change value of nanoparticles suspension increased with the increase of nanoparticles concentration. This showed that PPy@MSN have a good photothermal effect. In vitro release test revealed that the two release curves were not similar, and fitting best with Ritger-Peppas eqution and Logistic eqution respectively. Conclusion The water solution method could be used to prepare PPy@MSN, which may provide a promising drug delivery strategy for tumor treatment.
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Objective: To prepare nano polypyrrole (PPy)/chitin composite membrane and observe their biocompatibility. Methods: The nano PPy was synthesized by microemulsion polymerization, blended with chitosan and then formed membranes. The membranes were then modified by acetylation to get the experimental membranes (nano PPy/chitin composite membranes, group A). The chitosan membranes (group B) and chitin ones (group C) modified by acetylation acted as control. Scanning electron microscopy and FT-IR spectra were used to identify the nano PPy and the membranes of each group. And the conductivity of membranes of each group was measured. Schwann cells were co-cultured in vitro with each group membranes to observe the biocompatibility by inverted microscope observing, living cell staining, cell counting, and immunofluorescence staining. The lysozyme solution was used to evaluate the degradation of the membranes in vitro. Results: The FT-IR spectra showed that the characteristic vibrational absorption peaks of C=C from nano PPy appeared at 1 543.4 cm -1 and 1 458.4 cm -1. Scanning electron microscopy observation revealed that the size of nano PPy particles was about 100-200 nm. The nano PPy particles were synthesized. It was successful to turn chitosan to chitin by the acetylation, which was investigated by FT-IR analysis of membranes in groups A and C. The characteristic peaks of the amide Ⅱ band around 1 562 cm -1 appeared after acetylated modification. Conductivity test showed that the conductivity of membranes in group A was about (1.259 2±0.005 7)×10 -3 S/cm, while the conductivity of the membranes in groups B and C was not detected. The nano PPy particles uniformly distributed on the surface of membranes in group A were observed by scanning electron microscope; the membranes in control groups were smooth. As a result, the nano PPy/chitin composite membranes with electrical conductivity were obtained. The cultured Schwann cells were found to survive with good function by fluorescein diacetate live cell staining, soluble protein-100 immunofluorescence staining, and inverted microscope observing. The cell counting showed that the proliferation of Schwann cells after 2 days and 4 days of group A was more than that of the two control groups, and the differences were significant ( P<0.05). It indicated that the nano PPy/chitin composite membranes had better ability of adhesion and proliferation than those of chitosan and chitin membranes. The degradation of membranes in vitro showed that the degradation rates of membranes in groups A and C were significantly higher than those in group B at all time points ( P<0.05). In a word, the degradation performance of the membranes modified by acetylation was better than that of chitosan membranes under the same condition. Conclusion: The nano PPy and chitosan can be blended and modified by acetylation successfully. Nano PPy/chitin composite membranes had electrical conductivity, degradability, and good biocompatibility in vitro.
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p-Hydroxybenzoic acid can be oxidized by hydroxyl radicals ( · OH) to produce electroactive 3,4-dihydroxybenzoic acid (3,4-DHBA). Therefore, it can be used as a probe to detect ·OH. In this work, 3,4-DHBA/ PPy / TiO2 molecularly imprinted polymer film was prepared for indirect determination of ·OH based on its recognition ability for 3,4-DHBA. The sensor was constructed by using pyrrole as the functional monomer and 3, 4-DHBA as the template molecule. The sensor was characterized by scanning electron microscope and different electrochemical methods. The preparation and determination conditions, such as the electropolymerization cycle number, pH value in the electropolymerization process, and elution time, were optimized. Under the optimal conditions, a linear range of 1. 0×10-8-1. 0×10-6 mol/ L was obtained for 3,4-DHBA and the detection limit was down to 4. 2×10-9 mol/ L (S / N = 3). This new approach was of low cost and convenience, and was successfully applied to measure the concentration of ·OH in the atmosphere.
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Abstract An artificial liver support system is based on the functional hepatocytes being cultured inside a bioreactor; this technique has being used as an effective therapy for treating chronic liver diseases in recent times. This work evaluates different parameters such as cell viability and metabolic function of the hepatocytes when cultured on a hybrid scaffold. The scaffold was built using a polypyrrole plasma coated polymer layer seeded with endothelial matrix for efficient three-dimensional hepatocyte growth within a radial flow bioreactor. The flow rate inside the bioreactor was 7 ml / min. The parts for the bioreactor where either built using food-grade steel and/or glass or the scaffolds comprise a Poly (L-lactic acid)-coated polypyrrole iodine layer or not for HepG2 culture. The results show that the Poly (L-lactic acid)-coated scaffolds increased cell proliferation by 30%, protein production by 16% and albumin secretion by 40% compared with the non-coated scaffold. All experiments were performed thrice and data was analysed by ANOVA and Tukey statistic models with a p<0.05. The obtained results demonstrated that radial flow bioreactors in conjunction with hybrid scaffolds improve hepatocytes' physiological and functional properties and could be used as an alternative therapy for patients with liver diseases.
Resumen Un sistema de soporte hepático artificial se basa en utilizar hepatocitos funcionales cultivados en un biorreactor; esta técnica ha demostrado que se puede utilizar como una terapia eficaz para el tratamiento de enfermedades crónicas del hígado en los últimos tiempos. Este trabajo evalúa diferentes parámetros tales como la viabilidad celular y la función metabólica de los hepatocitos cuando se cultivan en un andamio híbrido. El andamio fue construido usando una capa de polímero recubierto de polipirrol plasma, se sembró con un cultivo tridimensional de células endoteliales y de hepatocitos dentro de un biorreactor de flujo radial. La velocidad de flujo en el interior del biorreactor fue de 7 ml / min. Las piezas para el biorreactor fueron construidas con acero de calidad alimentaria y / o vidrio. Los andamios control fueron de ácido L-poliláctico y a estos se les agrego un revestimiento de polipirrol-yodo para el cultivo de HepG2. Los resultados muestran que el ácido L-poliláctico recubierto, aumento la proliferación celular en un 30%, la producción de proteínas en un 16% y la secreción de albúmina por 40% en comparación con el andamio no recubierto. Todos los experimentos se llevaron a cabo tres veces y los datos se analizaron mediante modelos estadísticos ANOVA y Tukey con una p <0.05. Los resultados obtenidos demostraron que los biorreactores de flujo radial conjuntamente con andamios híbridos mejoran las propiedades fisiológicas y funcionales hepatocitos y podrían utilizarse como una terapia alternativa para los pacientes con enfermedades hepáticas crónicas.
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Objective:To study the effects of cells ’ and bacteria ’s adhesion and proliferation on different fiber diameters of polypyrrole coating with electricity.Methods:Titanium coated with polypyr-role was divided into no electrical stimulation and stimulation groups,each group had 30-60 nm,70-1 00 nm,1 30-1 70 nm diameters of the fiber.MC3 T3 cells and Staphylococcus aureus (S.aureus)were inoculated on different fiber diameters of polypyrrole coating with and without electric stimulation .We gave the electrical stimulation group 1 00 mV for 1 h and every 24 hours gave it 1 h stimulation,and no e-lectrical stimulation group was not managed.We used scanning electron microscope (SEM)to observe the cells’and bacteria’s morphology.The cells were given 20 mL CCK-8 solutions after 1 ,3,7 days’ cultivation,then incubated for 2 h,the solution was transferred to 96-well plate,we measured the cells’ CCK-8 of the 30-60 nm,70-1 00 nm,and 1 30-1 70 nm groups by Elisa.The cells on different fiber diameters were also stained by live-dead cell staining kit,TritonX-1 00 and DAPI.We used PBS to wash and glycerin to seal them.The live-dead situation and morphology were tested by co focal microscope. The bacterial were stained by Live/dead baclight bacterial viability kits,we detect the suspension’s D of the 30-60 nm,70-1 00 nm,and 1 30-1 70 nm groups,and also observed the bacteria’s survival situa-tion by co focal microscope.Results:The CCK-8 of the cells with direct current stimulation was higher than that of the unpowered group (F=1 2.248,P=0.006).The smaller the fiber diameter,the better was the cell’s adhesion and proliferation (F=9.261 ,P=0.005).The bacterial suspension’s D of the electric group was lower than that of the unpowered group,and the fiber diameter had no significant effect on the bacteria’s growth(F=9.641 ,P=0.036).Conclusion:Polypyrrole coating with electricity can promote the cell’s proliferation and inhibit the bacteria’s proliferation,and the cell growth on small fiber diameter coating is better.There is no difference in the bacterial growth of different fiber diameter coatings.
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Polypyrrole (PPy)-bile salt composite was used for sensing ethanol vapor. PPy was synthesized by interface polymerization for subsequent fabrication of thin film of its composite with bile salt, by in-situ co-dispersion method and then exposed to ethanol vapour. Sensing was visualized through changes in morphological, structural and optical characterizations. The ethanol exposed film showed larger agglomeration as revealed in its surface morphology on scanning electron microscope (SEM) and greater crystallinity as seen through X-Ray diffraction (XRD). Fourier transform infra red (FTIR) and nuclear magnetic resonance spectroscopy (NMR) of the ethanol incorporated film also gave signature of the presence of bile salt and alcohol. Alcohol incorporation pattern resulted in increase in electrical conductance from 7.08539 × 10-5 mA/V to 8.0356 × 10-5 mA/V, as determined from current voltage characterizations. Average molecular weight (Mn) obtained from gel permeation chromatography changed from 6160 to 10300 on ethanol intake. Photoluminescence (PL) intensity was quenched and the PL peak shifted from 430 to 409 on ethanol exposure. Changes in morphological, structural, optical and electrical properties of the composite on ethanol exposure showed its prospective application for sensing ethanol.
Subject(s)
Bile Acids and Salts/diagnosis , Chromatography , Ethanol/analysis , Polymers/analogs & derivatives , Polymers/diagnosis , Pyrroles/analogs & derivatives , Pyrroles/diagnosisABSTRACT
The aim of this work is to implement a biological model of neuromuscular junctions to study the mechanisms involved in intra and inter cellular processes using cell co-cultures. To optimize growth and development of the neuromuscular junction, cells were seeded on plasma polymerized pyrrole which has proven suitable for other types of cell cultures. The cell lines used were motor neuron NG108-15 and skeletal muscle C2C12. Cells were evaluated according to their morphology and electrophysiological characteristics. To observe the expression of specific proteins of the nerve synapse, immunocytochemical techniques were applied using dying antibodies. Proteins localized in nerve terminals were dyed and imaged by fluorescence microscopy. Images of cell co-cultures showed the formation of neuromuscular junctions. The preparation of neuromuscular junctions described in this work will allow the study of the mechanisms involved in their functions.
El objetivo de este trabajo es implementar un modelo biológico de unión neuromuscular para el estudio de los mecanismos involucrados en los procesos intra e intercelulares empleando co-cultivos celulares. Con el fin de optimizar el crecimiento y desarrollo de las uniones neuromusculares, las células se cultivaron sobre superficies de polipirrol obtenidas mediante polimerización por plasma que han mostrado ser adecuadas en otros tipos de cultivos celulares. Las líneas celulares que se emplearon fueron los modelos de motoneurona NG108-15 y muscular C2C12. Las células se evaluaron de acuerdo a su morfología y características electrofisiológicas. Para observar la expresión de proteínas clave de la sinapsis, se aplicaron técnicas inmunocitoquímicas utilizando anticuerpos específicos para la marcación de proteínas localizadas en las terminales nerviosas adquiriendo imágenes con microscopía de fluorescencia. Las imágenes de los co-cultivos celulares mostraron la formación de uniones neuromusculares. El método de preparación de uniones neuromusculares que se describe en este trabajo permitirá estudiar los mecanismos involucrados en sus funciones.
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Objective: To study the potential of growth and mineralization of cultured osteoblasts on the indium tin oxide conductive(ITO) glass disk coated with polypyrrole film (Ppy) . Methods: Osteoblasts were seeded onto ITO glass or ITO glass coated with polypyrrole film of implant materials. The cells were stained by HE and Von Kossa, observed by light microscope and scanning electron microscope (SEM) on day 3, 7, 14 and 28 after seeding respectively. Results: The osteoblast cells attached well to both ITO surfaces and Ppy films, mineralized nodules was observed on Ppy film. Conclusion: The polypyrrole films have good bone biocompatibility and it can be used as the biomaterials for dental implant.
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In recent studies there have been various attempts at replacing a damaged retina with an artificial one. This paper outlines the assembly of an artificial retina membrane by incorporating a photorective protein bacteriorhodopsin into an electrochemically syntheszed conducting polymer polypyrrole. An electrophysiologic test was conducted to evaluate the photoresponsiveness of the bacteriorhodopsin and rabbit eyes were used to examine the biocompatibility of the artificial retina. The electrophysiologic test analyzed both wave forms and amplitudes obtained by photostimulating the artificial retina membrane with various light intensites(0.2, 2, 20J). In the biocompatibility test, the artificial membrane was inserted into the anterior chambers(4 eyes) and vitreous cavities(8 eyes) of rabbits. The condition of the eyes was then observed for one month. At the end of the first moonth, the eyes were enucleated and a histological examination was carried out. The electrophysiologic study displayed negative reflection waves, which are characteristic in rhodpsin, and their amplitudes showed a correspondign increase with stronger light intensities. The results of the biocompatibility test demonstrated that inflammatory reactions were not prominent in either the anterior chambers or the vitreous cavities during the first month and the histological examinations revealed no specific findings. In conclusion, a membrane assembled utilizing an electroactive polymer and a phocial retina.