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Verticillium wilt (VW) is a soil-borne vascular disease that affects upland cotton and is caused by Verticillium dahliae Kleb. A rapid and user-friendly early diagnostic technique is essential for the preventing and controlling VW disease. In this study, Fourier transform infrared (FTIR) spectroscopy with attenuated total reflectance (ATR) technology was used to detect VW infection in cotton leaves. About 1800 FTIR spectra were obtained from 348 cotton leaves. The cotton leaves were collected from three categories: VW group, infected group and control group (non-infected). The vibrational peak of chitins at 1558 cm-1 was identified through mean and differential analysis of FTIR spectra as a criterion to differentiate the VW or infected group from the control group. Classification models were constructed using various machine learning algorithms. The support vector machines (SVM) model exhibited the highest predictive accuracy (>96 %) in each group and a total accuracy (>97 %) for the three groups. These results provide a new approach for detecting Verticillium infection in cotton leaves and shows a promising potential for the future applications of the method in plant science.
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The weak electron-hole separation ability and the more severe photocorrosion of CdS largely limit its hydrogen precipitation performance. In this study, CoP loading on the surface of CdS was utilized to form a type I heterojunction. The photocurrent density increased from 2 µA cm-2 to 20 µA cm-2. When the loading of CoP was 10%, the best photocatalytic performance reached 4.43 mmolg-1 h-1 under visible light, which was 20.1 times higher than that of CdS (0.22 mmolg-1 h-1). In addition, the loading of CoP solved the problem of CdS photocorrosion. After 5 cycles of simulated solar irradiation, the performance of 10% CoP/CdS remained at 93% of the initial test. This work provides new ideas for the design of low photocorrosion and high-performance catalysts.
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Background: Solute carrier (SLC) proteins play an important role in tumor metabolism. But SLC-associated genes' prognostic significance in hepatocellular carcinoma (HCC) remained elusive. We identified SLC-related factors and developed an SLC-related classifier to predict and improve HCC prognosis and treatment. Methods: From the TCGA database, corresponding clinical data and mRNA expression profiles of 371 HCC patients were acquired, and those of 231 tumor samples were derived from the ICGC database. Genes associated with clinical features were filtered using weighted gene correlation network analysis (WGCNA). Next, univariate LASSO Cox regression studies developed SLC risk profiles, with the ICGC cohort data being used in validation. Result: Univariate Cox regression analysis revealed that 31 SLC genes (P < 0.05) were related to HCC prognosis. 7 (SLC22A25, SLC2A2, SLC41A3, SLC44A1, SLC48A1, SLC4A2, and SLC9A3R1) of these genes were applied in developing a SLC gene prognosis model. Samples were classified into the low-andhigh-risk groups by the prognostic signature, with those in the high-risk group showing a significantly worse prognosis (P < 0.001 in the TCGA cohort and P=0.0068 in the ICGC cohort). ROC analysis validated the signature's prediction power. In addition, functional analyses showed enrichment of immune-related pathways and different immune status between the two risk groups. Conclusion: The 7-SLC-gene prognostic signature established in this study helped predict the prognosis, and was also correlated with the tumor immune status and infiltration of different immune cells in the tumor microenvironment. The current findings may provide important clinical indications for proposing a novel combination therapy consists of targeted anti-SLC therapy and immunotherapy for HCC patients.
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To further advance the application of flexible piezoelectric materials in wearable/implantable devices and robot electronic skin, it is necessary to endow them with a new function of antibacterial properties and with higher piezoelectric performance. Introducing a specially designated nanomaterial based on the nanocomposite effect is a feasible strategy to improve material properties and achieve multifunctionalization of composites. In this paper, carbon dots (CDs) were sensitized onto the surface of ZnO to form ZnO@CDs nanoparticles, which were then incorporated into polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) to obtain a multifunctional composite. On the one hand, the antibacterial property of ZnO was improved because CDs had good optical absorption of visible light and their surface functional groups were favorable for electrostatic adsorption with bacteria. Therefore, ZnO@CDs endowed the composite with an outstanding antibacterial rate of 69.1% for Staphylococcus aureus. On the other hand, CDs played a bridging role between ZnO and PVDF-HFP, reducing the negative effect of ZnO aggregation and interface incompatibility with PVDF-HFP. As a result, ZnO@CDs induced ß-phase formation of 80.4% in PVDF-HFP with a d33 value of 33.8 pC N-1. The multifunctional device exhibited excellent piezoelectric and antibacterial performance in the application of energy harvesters and self-powered pressure sensors.
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Nanocompuestos , Nanopartículas , Óxido de Zinc , Antibacterianos/farmacología , CarbonoRESUMEN
The development of high efficiency and low-cost electrocatalysts for the oxygen reduction reaction (ORR) is urgently desired for many energy storage and conversion systems. Nitrogen-doped carbon xerogels (NCXs) which have been successfully applied as effective electrocatalysts for the ORR have continued to attract attention due to their competitive price and tunable surface chemistry. A new dual N-doped NCX (NCoNC) electrocatalyst is fabricated as a carbon based catalyst though a facile impregnation of peptone in a precursor and ammonia etching pyrolysis method. XPS analysis demonstrates that the NCoNC electrocatalyst not only has a high N doping amount, but also has an optimized chemical state composition of N doping, which play an important role in improving the microstructure and catalytic performance of the catalysts. XRD and HRTEM results show that the doped metal nano-particles are coated with a double carbon layer of graphene carbon (inner layer) and amorphous carbon (outer layer) forming serrated edges that facilitate the ORR process. The as-obtained NCoNC catalyst exhibits good electrocatalytic performance and excellent stability for the ORR in both acidic and alkaline environments. In particular, in alkaline electrolyte, the decrements of both the limiting current density and the half-wave potential of the NCoNC catalyst were significantly lower than those of a commercial Pt/C catalyst during accelerated aging tests. When serving as an air electrode in Zn-air batteries, the catalyst also exhibits superior catalytic performance with a peak power density of 78.2 mW cm-2 and a stable open-circuit voltage of 1.37-1.43 V. This work presents a novel tactic to regulate the microstructure and composition of carbon-based electrocatalysts by the facile and scalable dual-effect nitrogen doping method which may be conducive to promoting and developing highly efficient and promising electrocatalysts for the ORR.
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Microsatellite stable /microsatellite instable-low is the most common colorectal cancer genotype, counting for approximately 85% of common colorectal cancer patients. Treatment of advanced microsatellite stable/microsatellite instable-low colorectal cancer is difficult and successful pharmacological treatment options are currently lacking. Here, we report a case of a 37-year-old man with advanced colorectal cancer genotyping microsatellite stable/microsatellite instable-low with a Kirsten rat sarcoma viral oncogene (G12V) mutation. Following palliative surgery, the patient did not response to the common recommended chemotherapy FOLFIRI regimen and other chemotherapy options. Finally, the patient was successfully treated using a unique combinational immunotherapy, using nivolumab plus ipilimumab combined with regorafenib and irinotecan. Significant improvement in the Karnofsky Performance Status scores, liver function and well-being, reduction in serum tumor biomarkers, and reduction in the size of multiple liver metastatic tumors was evident. This report provides a rare case in which a unique and effective combinational immunotherapy for refractory advanced colon cancer patients is discussed. It encourages further research into combined immunotherapy for immuno-insensitive colon cancer patients.
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Coating with FePO4 with the size of 20-30 nm on the surface of a LiNi0.8Co0.10Mn0.1O2 (NCM811) cathode produces an LFP3@NCM811 cathode via a sol-gel method, which markedly reduces secondary crystal cracking. A stable particle structure greatly improves the cycling stability of the LFP3@NCM811cathode, which retains 97% of its initial discharge capacity compared to NCM811 (78%) after 100 cycles at 2.7-4.5 V. Furthermore, it retains 86 and 63% of its initial discharge capacity after 400 cycles for LFP3@NCM811 and NCM811, respectively. The initial discharge capacity of the LFP3@NCM811 cathode is 218.8 mAh g-1 at 0.1 C, and the discharge capacity of the LFP3@NCM811 cathode is achieved to be 151.4 mAh g-1 at 5 C, which is 15 mAh g-1 higher than that of the NCM811 cathode. These are due to the reduction of cation mixing for a certain amount of Fe2+/Fe3+ or PO43- doped into the NCM811 surface, and the yolk-shell structure formed by coating with FePO4 helps improve the electronic conductivity and accelerate the Li+ transport. The cycling stability is mainly due to the secondary cleavage inhibition, which maintains the structural integrity of the cathode particles during the long cycle process and protects the inside of the particle from harmful electrolytes.
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In order to improve the power conversion efficiency (PCE) of quantum dot-sensitized solar cells (QDSC), a series of absorbent cotton derived carbon quantum dots (CQDs) with different dopants (namely carbamide, thiourea, and 1,3-diaminopropane) have been successfully synthesized by a one-pot hydrothermal method. The average particle sizes of the three doped CQDs are 1.7 nm, 5.6 nm, and 1.4 nm respectively, smaller than that of the undoped ones (24.2 nm). The morphological and structural characteristics of the four CQDs have been studied in detail. In addition, the three doped CQDs exhibit better optical properties compared with the undoped ones in the UV-vis and PL spectra. Then CQD-based QDSC are experimentally fabricated, showing that the short current density (Jsc) and open circuit voltage (Voc) of the QDSC are distinctly improved owing to the dopants. Especially the QDSC with the 1,3-diaminopropane doped CQD achieves the highest PCE (0.527%), 299% larger than that without dopant (0.176%). In order to highlight a reasonable mechanism, the UV-vis diffuse reflectance spectrum of CQD sensitized TiO2 and the calculated energy band structures of various CQDs are investigated. It's found from the above analysis that the addition of carbamide, thiourea, and 1,3-diaminopropane is beneficial to obtain CQDs of smaller size, and with a smaller band gap and more nitrogenous or sulphureous functional groups, which enhance the light absorption performance and photo-excitation properties. The above factors are helpful to improve the Jsc of QDSC. Nitrogen, acting as a donor to the CQDs, will assist the sensitized photoanode with a higher Fermi level, resulting in a larger Voc of the QSDC. Finally this study builds the relation among the microstructure of the CQDs, three characteristics of the CQDs (namely the spectra, energy band structure and functional groups) and the photoelectric properties of the QDSC, which will provide guidance for the modulation doping of CQDs to improve the PCE of QDSC.
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Although the multipotency of mesenchymal stem cells (MSCs) makes them an attractive choice for clinical applications, immune modulation is an important factor affecting MSC transplantation. At present, the effect of treatment with MSCs on nonalcoholic fatty liver disease (NAFLD) has received little attention. In the present study, a compact bonederived method was used to isolate mouse MSCs (mMSCs) and a highfat diet was used to establish a mouse model of NAFLD. Immunophenotypic features of mMSCs were analyzed using flow cytometry. Paraffin sections were stained with hematoxylin and eosin to assess inflammation and steatosis, and with picrosirius red to assess fibrosis. Spleen leukocytes were analyzed by flow cytometry. The results demonstrated that compact bonederived MSC transplantation decreased highfat dietinduced weight gain, expansion of subcutaneous adipose tissue, steatosis, lobular inflammation and liver fibrogenesis. Flow cytometry analysis of spleen leukocytes demonstrated that compact bonederived MSC transplantation suppressed the proliferation of cluster of differentiation (CD) 4+ T lymphocytes in the spleen, which had been induced by the highfat diet. In conclusion, compact bonederived MSCs may exhibit clinical value in the treatment of NAFLD through their capacity to suppress the activation of CD4+ T cells.
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Linfocitos T CD4-Positivos/inmunología , Dieta Alta en Grasa/efectos adversos , Cirrosis Hepática/terapia , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas/inmunología , Enfermedad del Hígado Graso no Alcohólico/terapia , Animales , Peso Corporal , Linfocitos T CD4-Positivos/patología , Proliferación Celular , Modelos Animales de Enfermedad , Hígado/inmunología , Hígado/patología , Cirrosis Hepática/etiología , Cirrosis Hepática/inmunología , Cirrosis Hepática/patología , Activación de Linfocitos , Masculino , Células Madre Mesenquimatosas/citología , Ratones , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/etiología , Enfermedad del Hígado Graso no Alcohólico/inmunología , Enfermedad del Hígado Graso no Alcohólico/patología , Bazo/inmunología , Bazo/patología , Grasa Subcutánea/inmunología , Grasa Subcutánea/patologíaRESUMEN
Increasing evidence has accrued which indicates that mesenchymal stem cells (MSCs) have a potential clinical value in the treatment of certain diseases. Globally, nonalcoholic steatohepatitis (NASH) is a widespread disorder. In the present study, MSCs were isolated successfully from compact bone and a mouse model of NASH was established as achieved with use of a methionine-choline deficient (MCD) diet. Compact bone-derived MSCs transplantation reduced MCD diet-induced weight loss, hepatic lipid peroxidation, steatosis, ballooning, lobular inflammation and fibrogenesis. It was shown that MSCs treatment hampered MCD diet-induced proliferation of CD4+ IFN-γ+ and CD4+IL-6+ T spleen cells. In addition, CD4+IL-17+ lymphocytes that associated with anti-inflammation show little change in MCD as well as in MCD+MSCs splenocytes. We conclude that MSCs may have a potential clinical value upon NASH, through their capacity to suppress activation of CD4+ IFN-γ+ and CD4+IL-6+ lymphocytes.
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Linfocitos T CD4-Positivos/inmunología , Hígado/patología , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas/inmunología , Enfermedad del Hígado Graso no Alcohólico/terapia , Animales , Diferenciación Celular , Alcaloides de Cinchona , Hueso Cortical/patología , Dieta , Modelos Animales de Enfermedad , Fibrosis , Humanos , Interferón gamma/metabolismo , Interleucina-6/metabolismo , Peroxidación de Lípido , Ratones , Ratones Endogámicos C57BLRESUMEN
A nanoporous composite film combined of conducting inorganic template (TiO2/SnO2) and conducting polymer catalyst (poly(3,4-ethylenedioxythiophene):polystyrenesulfonate, PEDOT: PSS) was developed as an alternative counter electrode for dye-sensitized solar cell (DSSC) through low-temperature process. The TiO2/SnO2 template was first fabricated by coating a homogeneous TiO2 nanoparticles blended paste containing a SnCl4 aqueous solution on the conductive substrate, followed by annealing at 150 °C. The counter electrode was then completed by spin-coating the PEDOT: PSS aqueous solution into the template and drying at 80 °C. The obtained TiO2/SnO2/ PEDOT: PSS (TSP) composite film exhibits more excellent catalytic activity for the tri-iodide reduction than the pristine PEDOT: PSS film, resulting in the significant improvements in the fill factor and efficiency of the cells. The values of the fill factor and efficiency respectively increase from 0.564 and 4.79% to 0.699 and 6.54%. Noted that the photovoltaic performances of the TSP based DSSC is very similar to those of the Pt based one. The fill factor and efficiency of the later are 0.696 and 6.48%, respectively. The outstanding properties of the TSP composite film used as the counter electrode can be ascribed to its prominent synergistic effects. In the TSP composite film, the conducting TiO2 is applied as the main skeleton material with the in-situ formed SnO2 as a binder to construct a nanoporous structure for the PEDOT: PSS coating and also to provide numerous high-speed conductive paths for the electron transportation from the substrate to the PEDOT: PSS coating, and the PEDOT: PSS adhered on the TiO2/SnO2 skeleton mainly acts as the catalyst to enlarge its surface area allowing for more active sites for the tri-iodide reduction.
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Compuestos Bicíclicos Heterocíclicos con Puentes/química , Nanoporos , Polímeros/química , Poliestirenos/química , Compuestos de Estaño/química , Titanio/química , ElectrodosRESUMEN
Copper ion (Cu(2+)) and L-cysteine (CySH) are closely correlated with physiological and pathological events of Alzheimer's Disease (AD), however the detailed mechanism is still unclear, mainly owing to a lack of accurate analytical methods in live brains. Herein, we report a single biosensor for electrochemical ratiometric detection of Cu(2+) and CySH in live rat brains with AD. N,N-di-(2-picoly)ethylenediamine (DPEA) is first synthesized for specific recognition of Cu(2+) to form a DPEA-Cu(2+) complex. This complex shows high selectivity for CySH owing to the release of Cu(2+) from the complex through CySH binding to Cu(2+) center. In parallel, 5'-MB-GGCGCGATTTTTTTTTTTTT-SH-3' (HS-DNA-MB, MB=Methylene Blue) is designed as an inner-reference for providing a built-in correction to improve the accuracy. As a result, combined with the amplified effect of Au nanoleaves, our single ratiometric biosensor can be successfully applied in real-time detection of Cu(2+) and CySH in the live rat brains with AD. To our knowledge, this is the first report on the accurate concentrations of Cu(2+) and CySH in live rat brains with AD.
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Enfermedad de Alzheimer/metabolismo , Técnicas Biosensibles , Química Encefálica , Cobre/análisis , Cisteína/análisis , Técnicas Electroquímicas , Enfermedad de Alzheimer/diagnóstico , Animales , Estructura Molecular , Tamaño de la Partícula , Ratas , Propiedades de SuperficieRESUMEN
Microtubules are essential for various cellular activities and ß-tubulins are the target of benzimidazole fungicides. However, the evolution and molecular mechanisms driving functional diversification in fungal tubulins are not clear. In this study, we systematically identified tubulin genes from 59 representative fungi across the fungal kingdom. Phylogenetic analysis showed that α-/ß-tubulin genes underwent multiple independent duplications and losses in different fungal lineages and formed distinct paralogous/orthologous clades. The last common ancestor of basidiomycetes and ascomycetes likely possessed two paralogs of α-tubulin (α1/α2) and ß-tubulin (ß1/ß2) genes but α2-tubulin genes were lost in basidiomycetes and ß2-tubulin genes were lost in most ascomycetes. Molecular evolutionary analysis indicated that α1, α2, and ß2-tubulins have been under strong divergent selection and adaptive positive selection. Many positively selected sites are at or adjacent to important functional sites and likely contribute to functional diversification. We further experimentally confirmed functional divergence of two ß-tubulins in Fusarium and identified type II variations in FgTub2 responsible for function shifts. In this study, we also identified δ-/ε-/η-tubulins in Chytridiomycetes. Overall, our results illustrated that different evolutionary mechanisms drive functional diversification of α-/ß-tubulin genes in different fungal lineages, and residues under positive selection could provide targets for further experimental study.
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Evolución Molecular , Hongos/genética , Familia de Multigenes/genética , Tubulina (Proteína)/genética , Variación Genética , Filogenia , Tubulina (Proteína)/metabolismoRESUMEN
The Kin1/Par-1/MARK kinases regulate various cellular processes in eukaryotic organisms. Kin1 orthologs are well conserved in fungal pathogens but none of them have been functionally characterized. Here, we show that KIN1 is important for pathogenesis and growth in two phytopathogenic fungi and that FgKin1 regulates ascospore germination and the localization of Tub1 ß-tubulins in Fusarium graminearum. The Fgkin1 mutant and putative FgKIN1(S172A) kinase dead (nonactivatable) transformants were characterized for defects in plant infection, sexual and asexual reproduction, and stress responses. The localization of FgKin1 and two ß-tubulins were examined in the wild-type and mutant backgrounds. Deletion of FgKIN1 resulted in reduced virulence and defects in ascospore germination and release. FgKin1 localized to the center of septal pores. FgKIN1 deletion had no effect on Tub2 microtubules but disrupted Tub1 localization. In the mutant, Tub1 appeared to be enriched in the nucleolus. In Magnaporthe oryzae, MoKin1 has similar functions in growth and infection and it also localizes to septal pores. The S172A mutation had no effect on the localization and function of FgKIN1 during sexual reproduction. These results indicate that FgKIN1 has kinase-dependent and independent functions and it specifically regulates Tub1 ß-tubulins. FgKin1 plays a critical role in ascospore discharge, germination, and plant infection.
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Proteínas Fúngicas/metabolismo , Fusarium/patogenicidad , Esporas Fúngicas/crecimiento & desarrollo , Tubulina (Proteína)/metabolismo , Pared Celular/metabolismo , Proteínas Fúngicas/genética , Fusarium/metabolismo , Fusarium/fisiología , Eliminación de Gen , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Hifa/crecimiento & desarrollo , Hifa/metabolismo , Magnaporthe/metabolismo , Magnaporthe/patogenicidad , Mutación , Organismos Modificados Genéticamente , Proteínas Serina-Treonina Quinasas/metabolismo , Esporas Fúngicas/metabolismo , Virulencia/genética , Zea mays/microbiologíaRESUMEN
By immobilizing synthesized Mn-TPAA (TPAA=tris[2-[N-(2-pyridylmethyl) amino] ethyl] amine) on TiO(2) nanoneedle surface, a biosensor for superoxide ion (O(2)(-)) has been developed and applied for determination of O(2)(-) released from living cells. Direct electron transfer of Mn-TPAA is realized with a formal redox potential (E°') falling in the range of the E°' values of the redox couples O(2)/O(2)(-) and O(2)(-)/H(2)O(2). This suggests that Mn-TPAA on TiO(2) films is electrochemically active and capable of thermodynamically mediating both the oxidation of O(2)(-) to O(2) and the reduction of O(2)(-) to H(2)O(2). Therefore, Mn-TPAA immobilized on the TiO(2) films can be used electrochemically for determination of O(2)(-) due to its electrochemical activities and biomimetic catalytic activities like superoxide dismutase (SOD) toward O(2)(-). The present biomimetic O(2)(-) sensor shows high selectivity at the low working potential of 0V vs. Ag|AgCl, a wide linear range from 10(-7)M to 10(-4)M and a quick response time within 6s. By taking advantage of the developed method and the properties of biomimetic SOD themselves, we have realized the real-time monitoring of O(2)(-) concentration released from living cells and investigated the relationship between the concentration changes of O(2)(-) and intracelluar Ca(2+), which may gain additional insights on the reactive oxygen species (ROS) signal transduction and other physiological and pathological events.
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Técnicas Biosensibles/métodos , Superóxidos/análisis , Materiales Biomiméticos/síntesis química , Materiales Biomiméticos/química , Señalización del Calcio , Técnicas Electroquímicas , Etilenodiaminas , Espacio Extracelular/metabolismo , Células HeLa , Humanos , Manganeso , Nanoestructuras/química , Oxidación-Reducción , Piridinas , Superóxido Dismutasa , Superóxidos/metabolismo , TitanioRESUMEN
This paper demonstrates a reliable and durable method for in situ real-time determination of O(2)Ë(-) based on direct electron transfer of Mn(3)(PO(4))(2), which acts as a superoxide dismutase (SOD). Mn(2+) is ion-exchanged into zeolite-ZSM-5 microstructures, and further coated with poly(diallyldimethylammonium chloride) (PDDA). Direct electron transfer of Mn(2+) is greatly facilitated by zeolite microstructures with the formal potential of 561 ± 6 mV vs. Ag|AgCl, which is just located between thermodynamic potentials of O(2)Ë(-)/O(2) and O(2)Ë(-)/H(2)O(2). The biomimetic catalytic activity of Mn(3)(PO(4))(2), together with the enhanced electron transfer of Mn(2+) obtained at the zeolite electrode has provided a platform for determination of O(2)Ë(-) with high selectivity, wide linear range, low detection limit, and quick response. On the other hand, the present Mn(2+)-ZSM/PDDA electrode shows relatively long-term stability, good reproducibility, and biocompatibility, which opens up a way to adhering cells directly onto the film surface for in situ monitoring of cellular species. As a sequence, the remarkable analytical performance of the present O(2)Ë(-) biosensor, combined with the characteristics of the Mn(2+)-ZSM/PDDA electrode surface has established a novel approach for real-time determination of O(2)Ë(-) released from living cells.
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Materiales Biomiméticos/química , Técnicas Electroquímicas/métodos , Superóxidos/análisis , Zeolitas/química , Materiales Biomiméticos/metabolismo , Catálisis , Línea Celular Tumoral , Complejos de Coordinación/química , Electrodos , Transporte de Electrón , Humanos , Manganeso/química , Polietilenos/química , Compuestos de Amonio Cuaternario/química , Superóxido Dismutasa/metabolismoRESUMEN
In this work, direct electron transfer of cytochrome c (cyt. c)--a model for studying the electron transfer of enzymes is achieved at hexagonal ZnO nanosheets by one-step electrodeposition. UV-vis spectra and electrochemical data demonstrate that such ZnO nanosheets can supply a bio-compatible surface to keep the bioactivity of cyt. c. The redox formal potential (E(0)') of cyt. c is estimated to be 338.2+/-4.3 mV (vs. AgAgCl) at the nanostructured ZnO surface. This value is much more positive than those of enzymes previously obtained at other metal oxides and zeolite surfaces. Experiment data show, under the optimized potential of 0.0 V (vs. AgAgCl), the electrochemical determination of H(2)O(2) is free from not only anodic interferences like ascorbic acid (AA) and dopamine (DA), but also a cathodic interference-O(2). Such an excellent selectivity enable the present H(2)O(2) biosensor determine the extracellular H(2)O(2) released from living human hepatoma cells.
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Técnicas Biosensibles , Citocromos c/metabolismo , Peróxido de Hidrógeno/análisis , Neoplasias Hepáticas/metabolismo , Nanotubos/química , Óxido de Zinc/química , Adsorción , Animales , Biocatálisis , Línea Celular Tumoral , Citocromos c/química , Electroquímica , Transporte de Electrón , Caballos , Humanos , Neoplasias Hepáticas/patología , Oxidación-Reducción , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
This paper demonstrates a novel strategy for site-selective cell adhesion and in situ cultivation of living cells, integrated with real-time monitoring of cellular small biomolecules based on dual functional protein microarrays. The protein microarrays have been produced on the superhydrophobic|philic Au-TiO2 micropatterns, through further modification of L-cysteine (Cys) and followed by successive immobilization of a model protein, cytochrome c (cyt c). Experimental results have revealed that the created cyt c microarrays play dual functions: one is employed as a robust substrate for site-selective cell adhesion and in situ cultivation of living cells, because the protein microarrays exhibit high selectivity and bioaffinity toward cells, as well as long biostability under cell culture condition up to 7 days. Meanwhile, the cyt c microarrays can also serve as sensing elements for hydrogen peroxide (H2O2) due to the inherent enzymatic activity of the heme center in cyt c. Direct electron transfer of cyt c has been enhanced at the Cys-modified Au-TiO2 (Au-TiO2/Cys) microarrays, and the electrochemical behavior can be tuned by varying the width and spacing of the microband arrays. Furthermore, cyt c is stably immobilized on the Au-TiO2/Cys microarrays and maintains its enzymatic activity after confined on the microarrays. Thus, the optimized cyt c microarrays show striking analytical performance for H2O2 determination, e.g., high sensitivity and selectivity, broad linear range from 10(-9) M to 10(-2) M, low detection limit down to 2 nM, and short response time within 5 s. As a result, the excellent analytical properties of the cyt c microarrays, as well as the characteristic of the protein microarrays themselves, including high selectivity, long biostability, and good bioaffinity, opens up a method for selective in situ cultivation of cells integrated with real-time detection of signaling biomolecules such as H2O2 released from living cells, which shows potential for physiological and pathological investigations.
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Técnicas Electroquímicas/métodos , Oro/química , Peróxido de Hidrógeno/análisis , Análisis por Matrices de Proteínas/métodos , Titanio/química , Línea Celular Tumoral , Cisteína/química , Citocromos c/química , Citocromos c/metabolismo , Humanos , Propiedades de Superficie , Factores de TiempoRESUMEN
A simple route for controlling the direction of plasmon-induced photocurrents at gold nanoparticles deposited on TiO(2) films is reported for the first time that is based on the electronic state of gold nanoparticles conjugated to redox-active cytochrome c and plasmon-enhanced electron exchange.