Examinando por Autor "González-Nilo, Fernando Danilo"
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Ítem Biomimetics: From bioinformatics to rational design of dendrimers as gene carriers(Public Library of Science, 2015-09) Márquez-Miranda, Valeria; Camarada, María Belén; Araya-Durán, Ingrid; Varas-Concha, Ignacio; Almonacid, Daniel Eduardo; González-Nilo, Fernando DaniloBiomimetics, or the use of principles of Nature for developing new materials, is a paradigm that could help Nanomedicine tremendously. One of the current challenges in Nanomedicine is the rational design of new efficient and safer gene carriers. Poly(amidoamine) (PAMAM) dendrimers are a well-known class of nanoparticles, extensively used as nonviral nucleic acid carriers, due to their positively charged end-groups. Yet, there are still several aspects that can be improved for their successful application in in vitro and in vivo systems, including their affinity for nucleic acids as well as lowering their cytotoxicity. In the search of new functional groups that could be used as new dendrimer-reactive groups, we followed a biomimetic approach to determine the amino acids with highest prevalence in protein-DNA interactions. Then we introduced them individually as terminal groups of dendrimers, generating a new class of nanoparticles. Molecular dynamics studies of two systems: PAMAM-Arg and PAMAM-Lys were also performed in order to describe the formation of complexes with DNA. Results confirmed that the introduction of amino acids as terminal groups in a dendrimer increases their affinity for DNA and the interactions in the complexes were characterized at atomic level. We end up by briefly discussing additional modifications that can be made to PAMAM dendrimers to turned them into promising new gene carriers. Copyright: © 2015 Márquez-Miranda et al.Ítem Effect of Several HIV Antigens Simultaneously Loaded with G2-NN16 Carbosilane Dendrimer in the Cell Uptake and Functionality of Human Dendritic Cells(American Chemical Society, 2016-12) Sepúlveda-Crespo, Daniel; Vacas-Córdoba, Enrique; Márquez-Miranda, Valeria; Araya-Durán, Ingrid; Gómez, Rafael; Mata, Francisco Javier De La; González-Nilo, Fernando Danilo; Muñoz-Fernández, Ma ÁngelesDendrimers are highly branched, star-shaped, and nanosized polymers that have been proposed as new carriers for specific HIV-1 peptides. Dendritic cells (DCs) are the most-potent antigen-presenting cells that play a major role in the development of cell-mediated immunotherapy due to the generation and regulation of adaptive immune responses against HIV-1. This article reports on the associated behavior of two or three HIV-derived peptides simultaneously (p24/gp160 or p24/gp160/NEF) with cationic carbosilane dendrimer G2-NN16. We have found that (i) immature DCs (iDCs) and mature (mDCs) did not capture efficiently HIV peptides regarding the uptake level when cells were treated with G2-NN16-peptide complex alone; (ii) the ability of DCs to migrate was not depending on the peptides presence; and (iii) with the use of molecular dynamic simulation, a mixture of peptides decreased the cell uptake of the other peptides (in particular, NEF hinders the binding of more peptides and is especially obstructing of the binding of gp160 to G2-NN16). The results suggest that G2-NN16 cannot be considered as an alternative carrier for delivering two or more HIV-derived peptides to DCs. © 2016 American Chemical Society.Ítem Molecular determinants for cyclo-oligosaccharide-based nanoparticle-mediated effective siRNA transfection(Future Medicine Ltd., 2017-07) Manzanares, Darío; Araya-Durán, Ingrid; Gallego-Yerga, Laura; Játiva, Pablo; Márquez-Miranda, Valeria; Canan, Jonathan; Jiménez Blanco, José Luis; Mellet, Carmen Ortiz; González-Nilo, Fernando Danilo; García Fernández, José Manuel; Ceña, ValentínAim: To study the structural requirements that a cyclooligosaccharide-based nanoparticle must fulfill to be an efficient siRNA transfection vector. Materials & methods: siRNA protection from degradation by RNAses, transfection efficiency and the thermodynamic parameters of the nanoparticle/siRNA interactions were studied on pairs of amphiphilic molecules using biochemical techniques and molecular dynamics. Results: The lower the siRNA solvent accessible surface area in the presence of the nanoparticle, higher the protection from RNAse-mediated degradation in the corresponding nanocomplex; a moderate nanoparticle/siRNA binding energy value further facilitates reversible complexation and binding to the target cellular mRNA. Conclusion: The use, in advance, of these parameters will provide a useful indication of the potential of a molecular nanoparticle as siRNA transfecting vector. © 2017 Future Medicine Ltd.Ítem Self-Assembly of Amphiphilic Dendrimers: The Role of Generation and Alkyl Chain Length in siRNA Interaction(Nature Publishing Group, 2016-07) Márquez-Miranda, Valeria; Araya-Durán, Ingrid; Camarada, María Belén; Comer, Jeffrey; Valencia-Gallegos, Jesús A.; González-Nilo, Fernando DaniloAn ideal nucleic-acid transfection system should combine the physical and chemical characteristics of cationic lipids and linear polymers to decrease cytotoxicity and uptake limitations. Previous research described new types of carriers termed amphiphilic dendrimers (ADs), which are based on polyamidoamine dendrimers (PAMAM). These ADs display the cell membrane affinity advantage of lipids and preserve the high affinity for DNA possessed by cationic dendrimers. These lipid/dendrimer hybrids consist of a low-generation, hydrophilic dendron (G2, G1, or G0) bonded to a hydrophobic tail. The G2-18C AD was reported to be an efficient siRNA vector with significant gene silencing. However, shorter tail ADs (G2-15C and G2-13C) and lower generation (G0 and G1) dendrimers failed as transfection carriers. To date, the self-assembly phenomenon of this class of amphiphilic dendrimers has not been molecularly explored using molecular simulation methods. To gain insight into these systems, the present study used coarse-grained molecular dynamics simulations to describe how ADs are able to self-assemble into an aggregate, and, specifically, how tail length and generation play a key role in this event. Finally, explanations are given for the better efficiency of G2/18-C as gene carrier in terms of binding of siRNA. This knowledge could be relevant for the design of novel, safer ADs with welloptimized affinity for siRNA.