Design of new hybrid nanomaterials with molecular gates as nanodevices for therapeutic applications

Tesis por compendioLa presente tesis doctoral, que lleva por título “Diseño de nuevos nanomateriales híbridos con puertas moleculares como nanodispositivos para aplicaciones terapéuticas” está centrada en el desarrollo de nuevos materiales funcionales híbridos orgánico-inorgánicos para aplicaciones de liberación controlada. Los dos capítulos de la presente tesis en los que se describen los resultados obtenidos (el segundo y el tercer capítulos) están directamente relacionados con el uso de las nanopartículas mesoporosas de sílice como matriz inorgánica en el desarrollo de nuevos materiales híbridos orgánico-inorgánicos para aplicaciones en liberación controlada. Aun así, los resultados se han dividido en dos capítulos, dependiendo del estímulo aplicado para la liberación de la molécula encapsulada. En uno de los capítulos, los diferentes materiales desarrollados se basan en nanodispositivos controlados enzimáticamente, mientras que en el otro capítulo es un cambio de pH o de fuerza electroestática (en los dos casos debido a la presencia de un microorganismo patógeno) el que causa la consecuente liberación de la carga. En el caso de los nanodispositivos controlados enzimáticamente, los cuales se describen en el Capítulo 2, se desarrollaron tres sólidos diferentes. El primer ejemplo se basó en el diseño, síntesis y caracterización de nanopartículas mesoporosas de sílice recubiertas con sales de azopiridinio, que se hidrolizan en presencia de esterasas y reductasas, las cuales se encuentran en la microflora del colon. Estas sales, que contienen un enlace azoico, se seleccionaron para una posible liberación selectiva en el colon. Los estudios de viabilidad celular e internalización se llevaron a cabo con células HeLa, así como los estudios de liberación del agente quimioterapéutico camptotecina. Un segundo ejemplo se centró en el diseño, síntesis, caracterización y aplicaciones de un nuevo nanodispositivo que responde a la presencia de proteasas para liberación controlada, empleando nanopartículas de sílice cubiertas con el polímero -poli-L-lisina. En este caso, se pretendía evaluar dos mecanismos diferentes de anclaje del polímero y los dos dieron resultados positivos, aunque presentaron diferentes perfiles de liberación en cada caso. También se realizaron estudios de viabilidad e internalización celular con este nuevo nanodispositivo, así como la liberación de camptotecina en células HeLa. Finalmente, el último nanodispositivo que responde a la acción de un enzima; incluye el diseño y aplicación de un “scaffold” 3D inteligente con puertas moleculares, el cual consiste en la combinación de nanopartículas mesoporosas de sílice con puertas y biomateriales porosos clásicos. En este caso, las nanopartículas mesoporosas de sílice se cubrieron con poliaminas y ATP. Estas nanopartículas se incorporaron durante la síntesis de un “scaffold” de gelatina, el cual se preparó mediante técnicas de prototipado rápido (RP). En presencia de fosfatasa ácida se induce la liberación del colorante encapsulado en los poros de las nanopartículas. La fosfatasa ácida se seleccionó como estímulo activador de este material diseñado, ya que es un enzima cuya concentración se emplea para evaluar la actividad de los osteoclastos en procesos de remodelación ósea y como marcador en metástasis de huesos. Estas propiedades abren posibilidades de uso de esta combinación en el diseño de materiales funcionales para la preparación de numerosos “scaffolds” avanzados con puertas moleculares, que puedan ayudar en aplicaciones de medicina regenerativa y terapias de cáncer de huesos. Con respecto al otro tipo de nanodispositivos, que se muestra en el Capítulo 3, se ha evaluado el posible uso de las nanopartículas mesoporosas de sílice con puertas moleculares como posibles vehículos para la liberación controlada de fármacos cuando un microorganismo patógeno está presente. En este caso, el diseño y desarrollo de nuevos materiales híbridos orgánico-inorgánicos se ha basado en el uso de nanopartículas mesoporosas de sílice como matriz inorgánica, cubiertas con entidades moleculares orgánicas que podrían responder a un cambio en el pH del ambiente o a un cambio en la fuerza electroestática, debido a la presencia de un microorganismo patógeno, tales como hongos o bacterias. Uno de estos nanodispositivos desarrollados demuestra las aplicaciones y propiedades antifúngicas de un soporte cargado con tebuconazol y cubierto con moléculas que actúan de puerta molecular dirigida mediante un cambio de pH. El otro material presenta aplicaciones antibacterianas contra bacterias gram-positivas y gram-negativas, ya que se utiliza un nanodispositivo cargado con vancomicina y funcionalizado con -poli-L-lisina. En los dos casos, se ha demostrado que el uso de la nanoformulación puede mejorar la efectividad del fármaco encapsulado, mejorando y ampliando el espectro de acción del mismo, lo cual abre un gran abanico de posibilidades en aplicaciones de estos nanodispositivos en el tratamiento de infecciones. En resumen, se puede concluir que en la presente tesis se han desarrollado nuevos sólidos híbridos orgánico-inorgánicos, así como se han descrito las aplicaciones de estos nanodisposotivos como sistemas de liberación controlada. Los resultados obtenidos podrían ser útiles en futuros diseños de materiales híbridos avanzados en biotecnología, biomedicina y, concretamente, en aplicaciones terapéuticas (como terapias contra el cáncer, tratamiento de infecciones, medicina regenerativa, etc.)Mas Font, N. (2014). Design of new hybrid nanomaterials with molecular gates as nanodevices for therapeutic applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48491TESISCompendi

Enhanced antifungal efficacy of tebuconazole using gated pH-driven mesoporous nanoparticles

pH-sensitive gated mesoporous silica nanoparticles have been synthesized. Increased extracellular pH and internalization into living yeast cells triggered molecular gate aperture and cargo release. Proper performance of the system was demonstrated with nanodevices loaded with fluorescein or with the antifungal agent tebuconazole. Interestingly, nanodevices loaded with tebuconazole significantly enhanced tebuconazole cytotoxicity. As alterations of acidic external pH are a key parameter in the onset of fungal vaginitis, this nanodevice could improve the treatment for vaginal mycoses.Mas Font, N.; Galiana, I.; Hurtado, S.; Mondragón Martínez, L.; Bernardos Bau, A.; Sancenón Galarza, F.; Marcos Martínez, MD.... (2014). Enhanced antifungal efficacy of tebuconazole using gated pH-driven mesoporous nanoparticles. International Journal of Nanomedicine. 9:2597-2606. doi:10.2147/IJN.S59654S25972606

Towards the Development of Smart 3D "Gated Scaffolds" for On-Command Delivery

A new approach towards the design of "gated scaffolds" based on the combination of capped mesoporous silica nanoparticles (MSNs) with porous biomaterials is reported. Using this approach, a 3D gelatin-based scaffold able to selectively deliver cargo in the presence of an APase enzyme is prepared and tested. This new design opens up the possibility of developing new smart biomaterials with advanced drug-delivery features.The authors thank the Spanish Government (projects MAT2012-38429-C04-01, AGL2012-39597-C02-02, MAT2012-35556, and CSO2010-11384-E), the Generalitat Valenciana (Project PRO-METEO/2009/016) and the CIBER-BBN (BIO-GATES Project) for their support. N. M. also thanks the Spanish Ministry of Science and Innovation for her FPI grant.Mas Font, N.; Arcos, D.; Polo Aguado, L.; Aznar Gimeno, E.; Sánchez Salcedo, S.; Sancenón Galarza, F.; García, A.... (2014). Towards the Development of Smart 3D "Gated Scaffolds" for On-Command Delivery. Small. 10(23):4859-4864. https://doi.org/10.1002/smll.201401227S48594864102

Thrombin-Responsive Gated Silica Mesoporous Nanoparticles As Coagulation Regulators

[EN] The possibility of achieving sophisticated actions in complex biological environments using gated nanoparticles is an exciting prospect with much potential. We herein describe new gated mesoporous silica nanoparticles (MSN) loaded with an anticoagulant drug and capped with a peptide containing a thrombin-specific cleavage site. When the coagulation cascade was triggered, active thrombin degraded the capping peptidic sequence and induced the-release of anticoagulant drugs to delay the clotting process. The thrombin-dependent response was assessed and a significant increase in coagulation time in plasma from 2.6 min to 5 min was found. This work broadens the application of gated silica nanoparticles and demonstrates their ability to act as controllers in a complex scenario such as hemostasis.Authors thank Spanish Government (Project Nos. MAT2012-38429-C04, AGL2012-39597-C02-02) and Generalitat Valenciana (Project No. PROMETEOII/2014/047) for support. R.B. is thankful to Svagata.eu (Erasmus Mundus Action-II program) for his fellowship. A.R. thanks UPV for her predoctoral fellowship. N.M. thanks Spanish MINECO for her FPI fellowship. The authors also thank the Electron Microscopy Service at the UPV for support.Bhat, R.; Ribes, À.; Mas Font, N.; Aznar, E.; Sancenón Galarza, F.; Marcos Martínez, MD.; Murguía, JR.... (2016). Thrombin-Responsive Gated Silica Mesoporous Nanoparticles As Coagulation Regulators. Langmuir. 32(5):1195-1200. https://doi.org/10.1021/acs.langmuir.5b04038S1195120032

Genomics of ecological adaptation in cactophilic Drosophila

Cactophilic Drosophila species provide a valuable model to study gene-environment interactions and ecological adaptation. Drosophila buzzatii and Drosophila mojavensis are two cactophilic species that belong to the repleta group, but have very different geographical distributions and primary host plants. To investigate the genomic basis of ecological adaptation, we sequenced the genome and developmental transcriptome of D. buzzatii and compared its gene content with that of D. mojavensis and two other noncactophilic Drosophila species in the same subgenus. The newly sequenced D. buzzatii genome (161.5 Mb) comprises 826 scaffolds (>3 kb) and contains 13,657 annotated protein-coding genes. Using RNA sequencing data of five life-stages we found expression of 15,026 genes, 80% protein-coding genes, and 20% noncoding RNA genes. In total, we detected 1,294 genes putatively under positive selection. Interestingly, among genes under positive selection in the D. mojavensis lineage, there is an excess of genes involved in metabolism of heterocyclic compounds that are abundant in Stenocereus cacti and toxic to nonresident Drosophila species. We found 117 orphan genes in the shared D. buzzatii-D. mojavensis lineage. In addition, gene duplication analysis identified lineage-specific expanded families with functional annotations associated with proteolysis, zinc ion binding, chitin binding, sensory perception, ethanol tolerance, immunity, physiology, and reproduction. In summary, we identified genetic signatures of adaptation in the shared D. buzzatii-D. mojavensis lineage, and in the two separate D. buzzatii and D. mojavensis lineages. Many of the novel lineage-specific genomic features are promising candidates for explaining the adaptation of these species to their distinct ecological niches

Genomics of ecological adaptation in cactophilic Drosophila

Cactophilic Drosophila species provide a valuable model to study gene-environment interactions and ecological adaptation. Drosophila buzzatii and Drosophila mojavensis are two cactophilic species that belong to the repleta group, but have very different geographical distributions and primary host plants. To investigate the genomic basis of ecological adaptation, we sequenced the genome and developmental transcriptome of D. buzzatii and compared its gene content with that of D. mojavensis and two other noncactophilic Drosophila species in the same subgenus. The newly sequenced D. buzzatii genome (161.5 Mb) comprises 826 scaffolds (>3 kb) and contains 13,657 annotated protein-coding genes. Using RNA sequencing data of five life-stages we found expression of 15,026 genes, 80% protein-coding genes, and 20% noncoding RNA genes. In total, we detected 1,294 genes putatively under positive selection. Interestingly, among genes under positive selection in the D. mojavensis lineage, there is an excess of genes involved in metabolism of heterocyclic compounds that are abundant in Stenocereus cacti and toxic to nonresident Drosophila species. We found 117 orphan genes in the shared D. buzzatii-D. mojavensis lineage. In addition, gene duplication analysis identified lineage-specific expanded families with functional annotations associated with proteolysis, zinc ion binding, chitin binding, sensory perception, ethanol tolerance, immunity, physiology, and reproduction. In summary, we identified genetic signatures of adaptation in the shared D. buzzatii-D. mojavensis lineage, and in the two separate D. buzzatii and D. mojavensis lineages. Many of the novel lineage-specific genomic features are promising candidates for explaining the adaptation of these species to their distinct ecological niches

Chasing Gravitational Waves with the Chereknov Telescope Array

Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 2023 (arXiv:2309.08219)2310.07413International audienceThe detection of gravitational waves from a binary neutron star merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this gravitational wave event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a gravitational wave signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. New observing modes and follow-up strategies are being developed for CTA to rapidly cover localization areas of gravitational wave events that are typically larger than the CTA field of view. This work will evaluate and provide estimations on the expected number of of gravitational wave events that will be observable with CTA, considering both on- and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA

Performance of a proposed event-type based analysis for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) will be the next-generation observatory in the field of very-high-energy (20 GeV to 300 TeV) gamma-ray astroparticle physics. Classically, data analysis in the field maximizes sensitivity by applying quality cuts on the data acquired. These cuts, optimized using Monte Carlo simulations, select higher quality events from the initial dataset. Subsequent steps of the analysis typically use the surviving events to calculate one set of instrument response functions (IRFs). An alternative approach is the use of event types, as implemented in experiments such as the Fermi-LAT. In this approach, events are divided into sub-samples based on their reconstruction quality, and a set of IRFs is calculated for each sub-sample. The sub-samples are then combined in a joint analysis, treating them as independent observations. This leads to an improvement in performance parameters such as sensitivity, angular and energy resolution. Data loss is reduced since lower quality events are included in the analysis as well, rather than discarded. In this study, machine learning methods will be used to classify events according to their expected angular reconstruction quality. We will report the impact on CTA high-level performance when applying such an event-type classification, compared to the classical procedure

Chasing Gravitational Waves with the Chereknov Telescope Array

Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 2023 (arXiv:2309.08219)2310.07413International audienceThe detection of gravitational waves from a binary neutron star merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this gravitational wave event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a gravitational wave signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. New observing modes and follow-up strategies are being developed for CTA to rapidly cover localization areas of gravitational wave events that are typically larger than the CTA field of view. This work will evaluate and provide estimations on the expected number of of gravitational wave events that will be observable with CTA, considering both on- and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA

Chasing Gravitational Waves with the Chereknov Telescope Array

Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 2023 (arXiv:2309.08219)2310.07413International audienceThe detection of gravitational waves from a binary neutron star merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this gravitational wave event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a gravitational wave signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. New observing modes and follow-up strategies are being developed for CTA to rapidly cover localization areas of gravitational wave events that are typically larger than the CTA field of view. This work will evaluate and provide estimations on the expected number of of gravitational wave events that will be observable with CTA, considering both on- and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA