Diseño y caracterización de nanobioconjugados. Nuevos elementos en la construcción de interfases biológicas

Los grandes avances científicos en las dos últimas décadas en el campo de la Nanociencia han propiciado el interés por la utilización de los nanomateriales (NMs) en diversas áreas. Uno de los campos en el que se presume que estos NMs van a tener una gran aplicación es el de la Biomedicina. Las propiedades fisicoquímicas únicas que presentan estos sistemas los hace prometedores no solo en terapias, donde se tratan de aplicar como sistemas de distribución controlada de fármacos o agentes fototérmicos, sino también en diagnóstico, debido a sus propiedades como agentes de contraste en imagen. Todo ello ha dado lugar a una nueva disciplina, la Teragnóstica. Sin embargo, antes de que esto sea posible será necesario superar algunas barreras, siendo una de las más importantes, el conocimiento y control de la interfase entre los NMs y los sistemas biológicos, lo que ha venido en llamarse, interfase nano-bio. Es, precisamente, en este aspecto, donde se centra la presente Tesis Doctoral. A la vista de las evidencias recientes sobre la existencia de la corona de proteínas, la película de material biológico, fundamentalmente proteínas, que rodean a los NMs, cuando se ponen en contacto con los sistemas biológicos, parece interesante abordar el estudio de la formación, estructura, función e interacciones que muestran estas entidades. Los estudios que se presentan en esta memoria están basados en nanopartículas de oro de diferente tamaño y forma. La elección de oro como material de base se hace por su biocompatibilidad contrastada y su capacidad para generar NMs de diversa morfología. Una primera cuestión a tener en cuenta antes de buscar aplicaciones es conocer el comportamiento de los NMs sintetizados en medios acuosos, enfocando principalmente en la estabilidad de las dispersiones que forman. El material prístino que se obtiene se encuentra protegido por una capa molecular o película cuya naturaleza depende de la metodología de síntesis empleada. Este punto marca la necesidad de dotar a estos NMs de la capa molecular funcional apropiada que, en la mayoría de los casos y por diversas razones, no es la que poseen en tal estado prístino. Así, la segunda cuestión que se aborda en el presente trabajo es la funcionalización superficial de los NMs con las películas moleculares adecuadas y la caracterización de las mismas tanto estructuralmente como desde el punto de vista de la estabilidad que confiere a los NMs en disolución. La tercera cuestión que se plantea es el estudio de la formación y caracterización de la corona de proteínas que se puede establecer con los NMs obtenidos. Para ello, se ha utilizado la proteína hemoglobina, tanto por su presencia en el fluido sanguíneo, como por sus propias características fisicoquímicas. El enfoque de este estudio se hace desde un punto de vista fisicoquímico, contando para ello con un abanico de metodologías de síntesis y funcionalización y de técnicas instrumentales que van desde la microscopia a las espectroscópicas, así como las técnicas electroquímicas.The great scientific advances in the last two decades in the field of Nanoscience have led to the interest in the use of nanomaterials (NMs) in various areas. One of the fields in which these NMs are going to have a great application is that of biomedicine. The unique physicochemical properties presented by these systems make them promising not only in therapies, where they try to apply as controlled distribution systems of drugs or photothermic agents, but also in diagnosis, due to their properties as contrast agents in image. All this has given rise to a new discipline, the Theragnosis. However, before this is possible, it will be necessary to overcome some barriers, being one of the most important, the knowledge and control of the interface between the NMs and the biological systems, what has come to be called, nano-bio interface. It is precisely in this aspect, where the present Doctoral thesis is focused. In view of the recent evidence about the existence of the protein corona, the film of biological material, mainly proteins, that surround the NMs, when they come into contact with biological systems, it seems interesting to study the formation, structure, function and interactions that these entities can show. The studies presented in this Thesis are based on gold nanoparticles of different size and shape. The choice of gold as base material is made by its proven biocompatibility and its ability to generate NMs of diverse morphology. A first issue to consider before looking for applications is to know the behavior of the NMs synthesized in aqueous media, focusing mainly on the stability of the dispersions they form. The pristine material, that is obtained, is protected by a molecular layer or film whose nature depends on the synthesis methodology used. This point marks the need to endow these NMs with the appropriate functional molecular layer, which, in most cases and for various reasons, is not what they possess in such a pristine state. Thus, the second issue addressed in the present work is the surface functionalization of the NMs with the appropriate molecular films and the characterization of them, both structurally and from the point of view of the stability that confers NMs in solution. The third question that arises is the study of the formation and characterization of the protein corona that can be established with the NMs obtained. For this purpose, hemoglobin protein has been used, both for its presence in the bloodstream and for its own physicochemical characteristics. The focus of this study is from a physicochemical point of view, counting with a rango of methodologies of synthesis and functionality and instrumental techniques ranging from microscopy to spectroscopy, as well as electrochemical techniques

Pathogen sensing device based on 2D MoS2/graphene heterostructure

In this work we propose a new methodology for selective and sensitive pathogen detection based on a 2D layered heterostructured biosensing platform. As a proof of concept, we have chosen SARS-CoV-2 virus because the availability of new methods to detect this virus is still a great deal of interest. The prepared platform is based on the covalent immobilization of molybdenum disulphide functionalized with a diazonium salt (f-MoS2) onto graphene screen-printed electrodes (GPH SPE) by electrografting of the diazonium salt. This chemistry-based method generates an improved heterostructured biosensing platform for aptamer immobilization and aptasensor development. Electrochemical impedance spectroscopy (EIS) is used to obtain the signal response of the device, proving the ability of the sensor platform to detect the virus. SARS-CoV-2 spike RBD recombinant protein (SARS-CoV-2 S1 protein) has been detected and quantified with a low detection limit of 2.10 fg/mL. The selectivity of the developed biosensor has been confirmed after detecting the S1 protein even in presence of other interfering proteins. Moreover, the ability of the device to detect SARS-CoV-2 S1 protein has been also tested in nasopharyngeal swab samplesThis work has been financially supported by the Spanish Ministry of Economy and Competitiveness (PID2020-116728RB-I00, PID2020- 116661RB-I00, CTQ2015-71955-REDT (ELECTROBIONET)) and Community of Madrid (TRANSNANOAVANSENS, S2018/NMT-4349, and PhotoArt P2018/NMT-4367). E. Enebral thank the financial support of “Nanotecnología para detección del SARS-CoV-2 y sus variantes. NANOCOV” project. IMDEA Nanociencia receives support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, Grant CEX2020-001039-S). We also thank the Spanish Ministry of Universities for supporting Laura Gutiérrez-Galvez with the Formación del Profesorado Universitario (FPU) grant (FPU19/06309

A MoS2 platform and thionine-carbon nanodots for sensitive and selective detection of pathogens

This work focuses on the combination of molybdenum disulfide (MoS2) and à la carte functionalized carbon nanodots (CNDs) for the development of DNA biosensors for selective and sensitive detection of pathogens. MoS2 flakes prepared through liquid-phase exfoliation, serves as platform for thiolated DNA probe immobilization, while thionine functionalized carbon nanodots (Thi-CNDs) are used as electrochemical indicator of the hybridization event. Spectroscopic and electrochemical studies confirmed the interaction of Thi-CNDs with DNA. As an illustration of the pathogen biosensor functioning, DNA sequences from InIA gen of Listeria monocytogenes bacteria and open reading frame sequence (ORF1ab) of SARS-CoV-2 virus were detected and quantified with a detection limit of 67.0 fM and 1.01 pM, respectively. Given the paradigmatic selectivity of the DNA hybridization, this approach allows pathogen detection in the presence of other pathogens, demonstrated by the detection of Listeria monocytogenes in presence of Escherichia coli. We note that this design is in principle amenable to any pathogen for which the DNA has been sequenced, including other viruses and bacteria. As example of the application of the method in real samples it has been used to directly detect Listeria monocytogenes in cultures without any DNA Polymerase Chain Reaction (PCR) amplification processAuthors thank the financial support from the Comunidad de Madrid (NANOAVANSENS, S2013/MIT-3029, MAD2D-CM Program, S2013/ MIT-3007 and 2017-T1/BIO-5435), Ministerio de Economía, Industria y Competitividad (CTQ 2015-71955-REDT (ELECTROBIONET), CTQ2014-53334-C2-1-R. and MAT 2015-71879-P). EMP acknowledges the European Research Council (ERC-PoC-842606), MINECO (CTQ 2017- 86060-P), Comunidad de Madrid (MAD2D-CM S2013/MIT-3007). IMDEA Nanociencia acknowledges support from the ‘Severo Ochoa’ Programme for Centres of Excellence in R&D (MINECO, Grant SEV2016–0686). RdC acknowledges support from UAM, Banco Santander, Fundacion ´ IMDEA (convocatoria CRUE–CSIC–SANTANDER, fondo supera 2020, project with reference 10.01.03.02.41). Authors also acknowledge BAT unit of CIA

Paving the way to point of care (POC) devices for SARS-CoV-2 detection

In this work we present a powerful, affordable, and portable biosensor to develop Point of care (POC) SARS-CoV-2 virus detection. It is constructed from a fast, low cost, portable and electronically automatized potentiostat that controls the potential applied to a disposable screen-printed electrochemical platform and the current response. The potentiostat was designed to get the best signal-to-noise ratio, a very simple user interface offering the possibility to be used by any device (computer, mobile phone or tablet), to have a small and portable size, and a cheap manufacturing cost. Furthermore, the device includes as main components, a data acquisition board, a controller board and a hybridization chamber with a final size of 10 × 8 × 4 cm. The device has been tested by detecting specific SARS-CoV-2 virus sequences, reaching a detection limit of 22.1 fM. Results agree well with those obtained using a conventional potentiostat, which validate the device and pave the way to the development of POC biosensors. In this sense, the device has finally applied to directly detect the presence of the virus in nasopharyngeal samples of COVID-19 patients and results confirm its utility for the rapid detection infected samples avoiding any amplification process.This work has been financially supported by the Spanish Ministry of Economy and Competitiveness (PID2020-116728RB-I00, CTQ2015-71955-REDT (ELECTROBIONET)) and Community of Madrid (TRANSNANOAVANSENS, S2018/NMT-4349). Authors also acknowledge REACT EU NANOCOV-CM project. We acknowledge the service from the MiNa Laboratory at IMN, and funding from Community of Madrid (project S2018/NMT-4291 TEC2SPACE), MINECO (project CSIC13-4E-1794) and EU (FEDER, FSE)”. RdC gratefully thanks support from Fundación IMDEA, UAM and Banco Santander (fondo supera 2020, convocatoria CRUE–CSIC–SANTANDER, project with reference 10.01.03.02.41).Peer reviewe

Methylene Blue functionalized carbon nanodots combined with different shape gold nanostructures for sensitive and selective SARS-CoV-2 sensing

The development of DNA-sensing platforms based on new synthetized Methylene Blue functionalized carbon nanodots combined with different shape gold nanostructures (AuNs), as a new pathway to develop a selective and sensitive methodology for SARS-CoV-2 detection is presented. A mixture of gold nanoparticles and gold nanotriangles have been synthetized to modify disposable electrodes that act as an enhanced nanostructured electrochemical surface for DNA probe immobilization. On the other hand, modified carbon nanodots prepared a la carte to contain Methylene Blue (MB-CDs) are used as electrochemical indicators of the hybridization event. These MB-CDs, due to their structure, are able to interact differently with double and single-stranded DNA molecules. Based on this strategy, target sequences of the SARS-CoV-2 virus have been detected in a straightforward way and rapidly with a detection limit of 2.00 aM. Moreover, this platform allows the detection of the SARS-CoV-2 sequence in the presence of other viruses, and also a single nucleotide polymorphism (SNPs). The developed approach has been tested directly on RNA obtained from nasopharyngeal samples from COVID-19 patients, avoiding any amplification process. The results agree well with those obtained by RT-qPCR or reverse transcription quantitative polymerase chain reaction technique.We acknowledge the support from the Comunidad de Madrid (TRANSNANOAVANSENS-CM, S2018/NMT-4349, NANOCOV-CM, SI3/PJI/2021–00341) and Ministerio de economia y competitividad de España (PID2020–116728RB-100, CTQ2015–71955-REDT (ELECTROBIONET)). IMDEA Nanociencia acknowledges support from the Programme for Centres of Excellence in R&D ‘Severo Ochoa’ (CEX2020–001039-S, MINECO). Authors also acknowledge REACT EU NANOCOV-CM project. RdC acknowledges support from Fundación IMDEA Nanociencia, Banco Santander, UAM (convocatoria CRUE- SANTANDER-CSIC, reference 10.01.03.02.41).Peer reviewe

Cerámica farmacéutica : apuntes para su estudio

Bibliografía : p. 86-88Ilustrada con diez lám. en fototipi

Análisis dinamico del cabezal estereoscópico Lince en maniobras de persecución de objetivos

En este artículo se presenta un estudio dinámico del cabezal estereoscópico LINCE. Este estudio se ha realizado desde el punto de vista tradicional en robótica pero haciendo una serie de consideraciones importantes que permite simplificar todo el proceso de cálculo. El modelo dinámico se ha obtenido haciendo uso de la formulación de Lagrange – Euler y mediante el método propuesto por C.S.G. Lee. Para obtener la distribución de masas del cabezal LINCE se hizo el modelado de sólidos en AUTOCAD. Este estudio está siendo muy útil para trabajos de simulación, re- diseño mecánico y optimización del consumo de energía (en aplicaciones donde la energía se suministra desde baterías)

Behind the Optimization of the Sensor Film: Bioconjugation of Triangular Gold Nanoparticles with Hemoproteins for Sensitivity Enhancement of Enzymatic Biosensors

Electrochemical biosensors are widely used in a multitude of applications, such as medical, nutrition, research, among other fields. These sensors have been historically used and have not undergone many changes in terms of the involved electrochemical processes. In this work, we propose a new approach on the immobilization and enhancement of the electrochemical properties of the sensing layers through the control and bioconjugation of hemoproteins (hemoglobin, myoglobin, and cytochrome C) on anisotropic gold nanoparticles (gold nanotriangles (AuNTs)). The hemeproteins and the AuNTs are mixed in a solution, resulting in stable bioconjugates that are deposited onto the electrode surface to obtain the biosensors. All the systems proposed herein exhibited direct well-defined redox responses, highlighting the key role of the AuNTs acting as mediators of such electron transfers. Several protein layers surrounding the AuNTs are electroactive, as demonstrated from the charge measured by cyclic voltammetry. The retention of the stability of the hemeproteins once they are part of the bioconjugates is evidenced towards the electrocatalytic reduction of hydrogen peroxide, oxygen, and nitrite. The parameters obtained for the proposed biosensors are similar or even lower than those previously reported for similar systems based on nanomaterials, and they exhibit attractive properties that make them potential candidates for the latest developments in the field of sensing devices

Ovarian involvement in Crohn's disease: a rare complication

Background: The transmural condition of Crohn's disease predisposes to fistulae or abscesses. The internal fistula incidence is about 15%. Among them, enteroovarian fistula is rarely described on the literature. Herein, the authors present three cases of enteroovarian fistulas. Case reports: Two women are diagnosed with ileal Crohn's disease that presented a pelvic abscess diagnosed by ultrasound and CT. On surgery, an inflammatory mass involving the ileum and the ovary was found. The third woman was operated because of a tuboovarian abscess and was diagnosed with ileal Crohn's disease afterwards. In the three cases, the histopathological analysis of the ovary showed granulomas with abscess compatible with Crohn's disease. In one of the cases, multinucleated giant cells were found in the foreign body reaction to vegetable matter. A right ileocolectomy and an adnexectomy were performed in all three cases. No further involvement of the contralateral ovary or other gynaecological complications was observed. Discussion: The treatment of Crohn's disease complications should be individualized. In the case of ovarian involvement, surgical treatment should include adnexectomy