Diseño, fabricación y aplicaciones analíticas de nanocelulosa y sus híbridos

El gran avance nanotecnológico que ha experimentado la Química Analítica en los últimos años ha sido un indicador del grado de bienestar de la sociedad. La multidisciplinaridad de la Nanociencia y Nanotecnología ha sido esencial para el avance de los métodos y herramientas analíticas, así como para llevar a cabo la automatización, simplificación y miniaturización de los procesos analíticos integrados en los laboratorios [1]. En este campo, son muchos los nanomateriales explorados por sus propiedades excepcionales (ópticas, eléctricas, magnéticas) como sensores y sorbentes así como su amplio rango de aplicación de interés medioambiental o en bienes de consumo, cosmética, agroalimentación, entre otros. Sin embargo, la nanocelulosa no se ha explorado en química analítica aun siendo postulada como uno de los nanomateriales emergentes del siglo XXI, debido a su carácter biodegradable y su abundancia en la naturaleza, así como a otras fascinantes propiedades que le confieren un sinfín de aplicaciones. No cabe duda que en la búsqueda de los nanomateriales del futuro la nanocelulosa revolucionará las industrias electrónica, textil, farmacéutica y la energética, por su producción a gran escala con bajo coste a partir de un recurso natural renovable. Teniendo en cuenta lo anteriormente expuesto, la Tesis Doctoral tiene como objetivo general el estudio de la nanocelulosa en química analítica, centrándonos en el diseño de nanofibras de celulosa como herramienta en la mejora de los procesos analíticos, así como en la separación de productos farmacéuticos y otros

New Type of Modified Nanocellulose with Cyclodextrins for Analytical Applications

Extended Abstract Nanomaterials are of great interest due to their numerous applications in many areas owing to their unique thermal, mechanical, electronic and biological properties not found in conventional materials. Nanocellulose (NC) consists in single individual fibers with nanometric size based on natural and renewable biopolymer. NC exhibit fascinating properties such as high specific surface area, high chemical or biological reactivity, and occasionally even high porosity. β-cyclodextrin (β-CD) is a cyclic oligosaccharide with the ability to form stable and reversible inclusion complexes and recognize analytes selectively In this study, we described the preparation of functionalized NC with β-cyclodextrin for the first time. The introduction of β-cyclodextrin was performed via amidation reaction with the use of coupling reagents. Characterization of modified NC with CD was performed by using Kaiser Test, TGA, NMR and IR spectroscopy. Application of β-cyclodextrin functionalized NC as efficient and selective sorbent in Solid Phase Microextraction (SPME) for preconcentrating specific analytes is shown in this communication. Due to the uncontrolled use of veterinary fluoroquinolones and their unfavorable effects on the environment, we proposed a methodology for the selective preconcentration of Danofloxacin and posterior determination using fluorescence measurements. This innovative nanomaterial presented reusable properties and reproducible extraction efficiency (98.1 %) for at least 30 direct extractions of Danofloxacin (relative standard deviation (RSD) is 0.62%). The reproducibility between SPME cartridges in terms of relative standard deviation is 1.38%. The optimization of the elution was performed by varying the proportions of organic solvent, phosphate buffer, and pH value. The proposed method allows their automatization owing to the high reusability of SPME cartridges with reproducible timing of extraction and desorption steps. The whole fluidics circuit is powered by a peristaltic pump programmed and controlled by a computer. Reglo ICC peristaltic pump is able to control all three channels that are involved in the sample preparation independently. This allows for individual optimization of extraction, preconcentration and elution processes. The method was characterized on the basis of its linearity, sensibility, precision and recovery. The sensitivity of the method was evaluated according to the limit of detection (LOD). LOD is calculated, as three times the standard deviation of the blank signal divided by the slope of the calibration curve, was 0.11 mg L −1 . The limit of quantification (LQ), established for ten times the standard deviation of the blank signal divided by the slope of the calibration curve, was 0.36 mg L −1

EVI1 as a Prognostic and Predictive Biomarker of Clear Cell Renal Cell Carcinoma

The transcription factor EVI1 plays an oncogenic role in several types of neoplasms by promoting aggressive cancer features. EVI1 contributes to epigenetic regulation and transcriptional control, and its overexpression has been associated with enhanced PI3K-AKT-mTOR signaling in some settings. These observations raise the possibility that EVI1 influences the prognosis and everolimus-based therapy outcome of clear cell renal cell carcinoma (ccRCC). Here, gene expression and protein immunohistochemical studies of ccRCC show that EVI1 overexpression is associated with advanced disease features and with poorer outcome-particularly in the CC-e.3 subtype defined by The Cancer Genome Atlas. Overexpression of an oncogenic EVI1 isoform in RCC cell lines confers substantial resistance to everolimus. The EVI1 rs1344555 genetic variant is associated with poorer survival and greater progression of metastatic ccRCC patients treated with everolimus. This study leads us to propose that evaluation of EVI1 protein or gene expression, and of EVI1 genetic variants may help improve estimates of prognosis and the benefit of everolimus-based therapy in ccRCC

Tumor expression of cyclin-dependent kinase 5 (Cdk5) is a prognostic biomarker and predicts outcome of oxaliplatin-treated metastatic colorectal cancer patients

Colorectal cancer; Cyclin-dependent kinase 5 (Cdk5); Prognostic and predictive biomarkerCáncer colorrectal; Quinasa dependiente de ciclina 5 (Cdk5); Biomarcador pronóstico y predictivoCàncer colorectal; Quinasa dependent de ciclina 5 (CDK5); Biomarcador pronòstic i predictiuIn recent years, an increasing number of studies have shown that elevated expression of cyclin dependent kinase (Cdk5) contributes to the oncogenic initiation and progression of many types of cancers. In this study, we investigated the expression pattern of Cdk5 in colorectal cancer (CRC) cell lines and in a large number of tumor samples in order to evaluate its relevance in this pathogenesis and possible use as a prognostic marker. We found that Cdk5 is highly expressed and activated in CRC cell lines and that silencing of the kinase decreases their migration ability. In tumor tissues, Cdk5 is overexpressed compared to normal tissues due to a copy number gain. In patients with localized disease, we found that high Cdk5 levels correlate with poor prognosis, while in the metastatic setting, this was only the case for patients receiving an oxaliplatin-based treatment. When exploring the Cdk5 levels in the consensus molecular subtypes (CMS), we found the lowest levels in subtype 1, where high Cdk5 again was associated with a poorer prognosis. In conclusion, we confirm that Cdk5 is involved in CRC and disease progression and that it could serve as a prognostic and predictive biomarker in this disease.This work has been funded by the ISCIII grants from the Spanish Government, project numbers PI09/01334 and PI12/02228, and the Departament d’Innovació, Universitats i Empresa, Generalitat de Catalunya, project numbers 2014-SGR-1494, 2017-SGR-1705 and 2017-SGR-723. The group from Eva Martinez Balibrea is furthermore funded by the PIE16/00011 and the group from Diego Arango by the PI16/00540 and AC15/00066 grants

DNA polymerase λ, a novel DNA repair enzyme in human cells

DNA polymerase lambda (pol λ) is a novel family X DNA polymerase that has been suggested to play a role in meiotic recombination and DNA repair. The recent demonstration of an intrinsic 5′-deoxyribose-5-phosphate lyase activity in pol λ supports a function of this enzyme in base excision repair. However, the biochemical properties of the polymerization activity of this enzyme are still largely unknown. We have cloned and purified human pol λ to homogeneity in a soluble and active form, and we present here a biochemical description of its polymerization features. In support of a role in DNA repair, pol λ inserts nucleotides in a DNA template-dependent manner and is processive in small gaps containing a 5′-phosphate group. These properties, together with its nucleotide insertion fidelity parameters and lack of proofreading activity, indicate that pol λ is a novel β-like DNA polymerase. However, the high affinity of pol λ for dNTPs (37-fold over pol β) is consistent with its possible involvement in DNA transactions occurring under low cellular levels of dNTPs. This suggests that, despite their similarities, pol β and pol λ have nonredundant in vivo functions.This work was supported by Ministerio de Ciencia y Tecnologı´a Grant BMC2000-1138, Comunidad Auto´noma de Madrid Grant 08.5/0063/2000 (to L. B.) and by an institutional grant from Fundacio´n Ramo´n Areces

DNA polymerase λ, a novel DNA repair enzyme in human cells

DNA polymerase lambda (pol λ) is a novel family X DNA polymerase that has been suggested to play a role in meiotic recombination and DNA repair. The recent demonstration of an intrinsic 5′-deoxyribose-5-phosphate lyase activity in pol A supports a function of this enzyme in base excision repair. However, the biochemical properties of the polymerization activity of this enzyme are still largely unknown. We have cloned and purified human pol A to homogeneity in a soluble and active form, and we present here a biochemical description of its polymerization features. In support of a role in DNA repair, pol λ inserts nucleotides in a DNA template-dependent manner and is processive in small gaps containing a 5′-phosphate group. These properties, together with its nucleotide insertion fidelity parameters and lack of proofreading activity, indicate that pol A is a novel β-like DNA polymerase. However, the high affinity of pol λ for dNTPs (37-fold over pol β) is consistent with its possible involvement in DNA transactions occurring under low cellular levels of dNTPs. This suggests that, despite their similarities, pol β and pol λ have nonredundant in vivo function