Corrección del Artefacto de Truncamiento en TAC mediante Aprendizaje profundo

Actas de: CASEIB 2020: XXXVIII Congreso Anual de la Sociedad Española de Ingeniería Biomédica, 25–27 Nov, 2020 (congreso virtual).La adquisición de proyecciones incompletas debido a que parte de la muestra se extiende fuera del campo de visión, resulta en inconsistencias en los datos que dan lugar a lo que se conoce como artefacto de truncamiento. Se han propuesto varios métodos para la compensación de la falta de datos, basados en la extrapolación de las proyecciones, pero ninguno consigue recuperar completamente los datos truncados. Este trabajo presenta un nuevo método de compensación del artefacto de truncamiento en imágenes de TAC basado en técnicas de aprendizaje profundo. La evaluación en datos simulados a partir de estudios de roedores muestra la viabilidad de la propuesta.Este trabajo ha sido financiado por el Ministerio de Ciencia, Innovación y Universidades (Instituto de Salud Carlos III, proyecto DTS17/00122; Agencia Estatal de Investigación, proyecto DPI2016-79075-R-AEI/FEDER, UE), cofinanciado por Fondos de la Unión Europea (FEDER), "A way of making Europe". Además, ha sido financiado por el Programa de apoyo a la realización de proyectos interdisciplinares de I+D para jóvenes investigadores de la Universidad Carlos III de Madrid 2019-2020 en el marco del Convenio Plurianual Comunidad de Madrid- Universidad Carlos III de Madrid (proyecto DEEPCT-CM-UC3M). El CNIC está financiado por el Ministerio de Ciencia, Innovación y Universidades y la fundación PRO-CNIC y es un centro de excelencia Severo Ochoa (SEV-2015-0505)

Real-Time Nanoparticle–Cell Interactions in Physiological Media by Atomic Force Microscopy

Particle–cell interactions in physiological media are important in determining the fate and transport of nanoparticles and biological responses to them. In this work, these interactions are assessed in real time using a novel atomic force microscopy (AFM) based platform. Industry-relevant CeO2 and Fe2O3 engineered nanoparticles (ENPs) of two primary particle sizes were synthesized by the flame spray pyrolysis (FSP) based Harvard Versatile Engineering Nanomaterials Generation System (Harvard VENGES) and used in this study. The ENPs were attached on AFM tips, and the atomic force between the tip and lung epithelia cells (A549), adhered on a substrate, was measured in biological media, with and without the presence of serum proteins. Two metrics were used to assess the nanoparticle cell: the detachment force required to separate the ENP from the cell and the number of bonds formed between the cell and the ENPs. The results indicate that these atomic level ENP–cell interaction forces strongly depend on the physiological media. The presence of serum proteins reduced both the detachment force and the number of bonds by approximately 50% indicating the important role of the protein corona on the particle cell interactions. Additionally, it was shown that particle to cell interactions were size and material dependent

Effects of a Delocalizable Cation on the Headgroup of Gemini Lipids on the Lipoplex-Type Nanoaggregates Directly Formed from Plasmid DNA

Lipoplex-type nanoaggregates prepared from pEGFP-C3 plasmid DNA (pDNA) and mixed liposomes, with a gemini cationic lipid (CL) 1,2-bis(hexadecyl imidazolium) alkanes], referred as (C(16)Im)(2)C-n (where C-n is the alkane spacer length, n = 2, 3, 5, or 12, between the imidazolium heads) and DOPE zwitterionic lipid, have been analyzed by zeta potential, gel electrophoresis, SAXS, cryo-TEM, fluorescence anisotropy, transfection efficiency, fluorescence confocal microscopy, and cell viability/cytotoxicity experiments to establish a structure-biological activity relationship. The study, carried out at several mixed liposome compositions, alpha, and effective charge ratios, rho(eff), of the lipoplex, demonstrates that the transfection of pDNA using CLs initially requires the determination of the effective charge of both. The electrochemical study confirms that CLs with a delocalizable positive charge in their headgroups yield an effective positive charge that is 90% of their expected nominal one, while pDNA is compacted yielding an effective negative charge which is only 10-25% than that of the linear DNA. SAXS diffractograms show that lipoplexes formed by CLs with shorter spacer (n = 2, 3, or 5) present three lamellar structures, two of them in coexistence, while those formed by CL with longest spacer (n = 12) present two additional inverted hexagonal structures. Cryo-TEM micrographs show nanoaggregates with two multilamellar structures, a cluster-type (at low alpha value) and a fingerprint-type, that coexist with the cluster-type at moderate alpha composition. The optimized transfection efficiency (TE) of pDNA, in HEK293T, HeLa, and H1299 cells was higher using lipoplexes containing gemini CLs with shorter spacers at low a value. Each lipid formulation did not show any significant levels of toxicity, the reported lipoplexes being adequate DNA vectors for gene therapy and considerably better than both Lipofectamine 2000 and CLs of the 1,2-bis(hexadecyl ammnoniun) alkane series, recently reported

Analytical Methods for Characterizing the Nanoparticle–Protein Corona

When nanoparticles (NPs) enter a biological environment, medium components, especially proteins, compete for binding to the NP's surface, leading to development of a new interface, commonly referred to as the "protein corona." This rich protein shell gives the NPs a biological identity that can be very different from their synthetic one, in terms of their chemical-physical properties. Understanding NP-protein interaction is crucial for both the bioapplications and safety of nanomaterials. The protein corona provides the primary contact to the cells and their receptors. It defines in vivo fate of the delivery systems, governing the stability, immunogenicity, circulation, clearance rates and organ biodistribution of the NPs. Given its importance, the application and the development of analytical methods to investigate the protein corona are crucial. This review gives an overview of chromatographic, electrophoretic, mass spectrometric and proteomic methods because these techniques have the advantage to be able to identify and quantify individual proteins adsorbed onto the corona. This capability opens up the possibility to exploit the protein corona for specific cell targeting. © 2014 Springer-Verlag