Examinando por Autor "Prashar, Sanjiv"

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Albumin-Loaded Silica Nanomaterials Functionalized with Organotin(IV) Agents: Theranostic Materials Against Triple-Negative Breast Cance
(Wiley, 2024-07-11) García-Almodóvar, Victoria; Ovejero-Paredes, Karina; Díaz-García, Diana; Méndez-Arriaga, José M.; Prashar, Sanjiv; Filice, Marco; Gómez-Ruiz, Santiago
The current search for more effective and milder cancer treatments has led to the development of a wide variety of multifunctional nanoplatforms that are designed to both diagnose and treat cancer. In this study, the optimization of the synthesis of theranostic materials based on mesoporous silica nanoparticles (MSNs) functionalized with different cytotoxic (organotin(IV) compounds), imaging (fluorescein and/or indocyanine green), and targeting agents of interest, such as albumin (HA), is achieved by using different strategies. These systems shows good cytotoxic capacity against triple negative breast cancer (TNBC) cells (MDA-MB-231) in MTT (dimethylthiazolyl-diphenyl-tetrazolium bromide) assays and confocal analysis shows that the incorporation of HA as a potential active targeting molecule may enhance the cellular uptake of the nanomaterial, and thus, increasing its therapeutic potential. The analysis of the results and the effect of the imaging, targeting, and cytotoxic fragments should allow a more in-depth study of these materials in other in vitro and/or in vivo models
Amino acid-decorated mesoporous silica nanoparticles loaded with titanocene derivatives for targeted anticancer studies
(Wiley, 2024-04-21) Aondona Iorhemba, Michael; Ovejero-Paredes, Karina; Díaz-García, Diana; García-Almodóvar, Victoria; Ola Idris, Sulaiman; Adamu Shallangwa, Gideon; Abdulkadir, Ibrahim; Méndez-Arriaga, José M.; Prashar, Sanjiv; Filice, Marco; Gómez-Ruiz, Santiago
Nanostructured materials possess promising potential for cancer therapy through precise adjustment of their functionalization and physicochemical attributes. This study primarily focuses on the synthesis and characterization of mesoporous silica nanoparticles (MSN) that are functionalized with titanocene dichloride (a therapeutic agent) and one of several amino acids—cysteine, captopril, penicillamine, or methionine—utilizing 3-aminopropyltriethoxysilane (AP) as a linker. This synthesis yielded four innovative metallodrug-functionalized nanostructured materials (MSN-AP-Cys-Ti, MSN-AP-Cap-Ti, MSN-AP-Pen-Ti, and MSN-AP-Met-Ti), meticulously characterized using diverse analytical techniques such as X-ray diffraction (XRD), X-ray fluorescence (XRF), diffuse reflectance ultraviolet–visible (DR UV–Vis), Fourier transform infrared (FTIR), solid-state nuclear magnetic resonance (NMR) spectroscopy, and transmission electron microscopy (TEM). The textural properties of the nanomaterials post-functionalization displayed slight modifications, confirming the successful integration of the therapeutic agents. Evaluation of cytotoxicity in the breast cancer cell line MDA-MB-231, with the healthy cell line Hek-293T as control via MTT assays, revealed the active nature of the functionalized silica-based materials. The viability of both cell lines indicated a concentration-dependent response to the materials. Among the tested systems, cysteine and captopril exhibited the highest activity concerning IC50 relative to material concentration. The enhanced biological activity of higher functionalized nanosystems suggests a favorable cell internalization facilitated by the amino acid fragment. Additionally, qualitative DNA binding studies hinted at potential DNA adsorption on the surface of the metallodrug-functionalized nanomaterials, forming DNA adducts where a strand of DNA covalently bonds to the metallodrug moiety. This was deduced from the hypsochromic shift in absorbance of the characteristic π–π* and n–π* transitions in DNA, which occurred from 1.01 to 0.76 and 1.26–0.19 following drug (MSN-AP-Cap-Ti) interaction
Biological Use of Nanostructured Silica-Based Materials Functionalized with Metallodrugs: The Spanish Perspective
(MDPI, 2023-01-25) Díaz-García, Diana; Prashar, Sanjiv; Gómez-Ruiz, Santiago
Since the pioneering work of Vallet-Regí’s group on the design and synthesis of mesoporous silica-based materials with therapeutic applications, during the last 15 years, the potential use of mesoporous silica nanostructured materials as drug delivery vehicles has been extensively explored. The versatility of these materials allows the design of a wide variety of platforms that can incorporate numerous agents of interest (fluorophores, proteins, drugs, etc.) in a single scaffold. However, the use of these systems loaded with metallodrugs as cytotoxic agents against different diseases and with distinct therapeutic targets has been studied to a much lesser extent. This review will focus on the work carried out in this field, highlighting both the pioneering and recent contributions of Spanish groups that have synthesized a wide variety of systems based on titanium, tin, ruthenium, copper and silver complexes supported onto nanostructured silica. In addition, this article will also discuss the importance of the structural features of the systems for evaluating and modulating their therapeutic properties. Finally, the most interesting results obtained in the study of the potential therapeutic application of these metallodrug-functionalized silica-based materials against cancer and bacteria will be described, paying special attention to preclinical trials in vivo.
Copper-functionalized nanostructured silica-based systems: Study of the antimicrobial applications and ROS generation against gram positive and gram negative bacteria
(Elsevier, 2019-11-19) Díaz-García, Diana; Ardiles, Perla R.; Díaz-Sánchez, Miguel; Mena-Palomo, Irene; del Hierro, Isabel; Prashar, Sanjiv; Rodríguez-Diéguez, Antonio; Paulina L., Páez; Gómez-Ruiz, Santiago
A series of copper-functionalized SBA-15 (Santa Barbara Amorphous) materials containing the ligands triethoxysilylpropylmaleamic acid (maleamic) or triethoxy-3-(2-imidazolin-1-yl)propylsilane (imidazoline) have been prepared. The nanostructured silica-based systems SBA-maleamic, SBA-imidazoline, SBA-maleamic-Cu and SBA-imidazoline-Cu were characterized by several methods observing that the functionalization took place mainly inside the pores of the mesoporous system. The antimicrobial behaviour of the synthesized materials against Staphylococcus aureus and Escherichia coli was tested observing a very potent activity of the copperfunctionalized systems (minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for SBA-maleamic-Cu of ca. 31.25 μg/mL, which correspond with ca. 1.13 μg/mL of Cu). A study of the oxidative stress promoted by the synthesized materials showed that the SBA-maleamic-Cu and the SBAimidazoline- Cu were able to increase the reactive oxygen species (ROS) production in S. aureus by 427% and 373%, respectively, while this increase was slightly lower in E. coli (387 and 324%, respectively). Furthermore, an electrochemical study was carried out in order to determine if these materials interact with lysine or alanine to validate a potential antimicrobial mechanism based on the inhibition of the synthesis of the peptidoglycan of the bacterial wall. Finally, these studies were also performed to determine the potential interaction of the copper-containing materials with glutathione in order to assess if they are able to perturb the metabolism of this tripeptide.
Design of Mesoporous Silica Nanoparticles for the Treatment of Amyotrophic Lateral Sclerosis (ALS) with a Therapeutic Cocktail Based on Leptin and Pioglitazone
(ACS, 2022) Díaz-García, Diana; Ferrer-Donato, Águeda; Méndez-Arriaga, José M.; Cabrera-Pinto, Marta; Díaz-Sánchez, Miguel; Prashar, Sanjiv; Fernandez-Martos, Carmen M.; Gómez-Ruiz, Santiago
Amyotrophic lateral sclerosis (ALS) is a devasting neurodegenerative disease with no cure to date. Therapeutic agents used to treat ALS are very limited, although combined therapies may offer a more effective treatment strategy. Herein, we have studied the potential of nanomedicine to prepare a single platform based on mesoporous silica nanoparticles (MSNs) for the treatment of an ALS animal model with a cocktail of agents such as leptin (neuroprotective) and pioglitazone (anti-inflammatory), which have already demonstrated promising therapeutic ability in other neurodegenerative diseases. Our goal is to study the potential of functionalized mesoporous materials as therapeutic agents against ALS using MSNs as nanocarriers for the proposed drug cocktail leptin/pioglitazone (MSN-LEP-PIO). The nanostructured materials have been characterized by different techniques, which confirmed the incorporation of both agents in the nanosystem. Subsequently, the effect, in vivo, of the proposed drug cocktail, MSN-LEP-PIO, was used in the murine model of TDP-43 proteinopathy (TDP-43A315T mice). Body weight loss was studied, and using the rotarod test, motor performance was assessed, observing a continuous reduction in body weight and motor coordination in TDP-43A315T mice and wild-type (WT) mice. Nevertheless, the disease progression was slower and showed significant improvements in motor performance, indicating that TDP-43A315T mice treated with MSN-LEP-PIO seem to have less energy demand in the late stage of the symptoms of ALS. Collectively, these results seem to indicate the efficiency of the systems in vivo and the usefulness of their use in neurodegenerative models, including ALS.
Design of Novel Group 4 ansa-Metallocene Compounds and their Role as Catalysts in the Polymerization of Olefins
(2014-01-28) Prashar, Sanjiv; Gómez-Ruiz, Santiago; Fajardo, Mariano; Antiñolo, Antonio; Fernández-Galán, Rafael; Otero, Antonio; Rivilla, Iván
Since the discovery by Sinn and Kaminsky that zirconocene complexes in the presence of MAO were able to polymerize olefins there has been a dramatic expansion in this field. One of the main focuses of this research is centred on the tailoring of metallocene complexes that can direct the catalytic reaction in producing polymers with desired physical properties. Ligand design is therefore of utmost importance in the development of "made to measure" single-site olefin polymerization catalysts. In addition the introduction of functional groups in the ligand system can be later exploited in immobilizing the catalyst on different substrates. In this communication we describe the synthetic strategies used in the design of group four ansa-metallocene complexes and the application of these compounds as catalysts in the polymerization of ethylene and propylene. The principal design aims addressed include: 1. Variable substitution at the ansa-carbon bridging atom of the metallocene catalysts 2. Synthesis of hydride silylene ansa-bridged complexes that act as hydrosilylation reagents. 3. Functionalization of ansa-metallocene complexes 4. Synthesis of C1 symmetric ansa-metallocene catalysts which are isospecfic in the polymerization of propylene
Elementos de Coordinación en el nuevo Grado en Ciencias Experimentales de la Universidad Rey Juan Carlos
(2012-12-04) Prashar, Sanjiv
En esta comunicación se relata la puesta en marcha del Grado en Ciencias Experimentales que ha tenido muy en cuenta las tareas de coordinación en diferentes niveles y ámbitos como: Coordinación entre asignaturas de contenidos Coordinación entre asignaturas de las competencias a desarrollar Coordinación entre asignaturas en actividades a desarrollar Coordinación entre asignaturas de metodologías y criterios de evaluación Coordinación entre asignaturas de horarios y calendarios de actividades y pruebas Coordinación dentro de la Comisión de Calidad para detectar problemas y proponer mejoras en todos ámbitos del grado
Hydrosilylation in the Design and Functionalization of ansa-Metallocene Olefin Polymerization Catalysts
(2014-01-29) Gómez-Ruiz, Santiago; Prashar, Sanjiv; Fajardo, Mariano; Antiñolo, Antonio; Otero, Antonio
The group 4 ansa-metallocene complexes [M{Me(H)Si(¿5-C5Me4)(¿5-C5H4)}Cl2] (M = Ti, Zr, Hf),that contain a Si-H bond, have been used as hydrosilylation reagents with the silane substrates, Si(CH=CH2)4 and Me2Si(CH=CH2)2. Our results show that the hydrosilylation reaction takes place at only one of the vinyl groups to give [M{(CH2=CH)3SiCH2CH2(Me)Si(¿5-C5Me4)(¿5-C5H4)}Cl2] (M = Ti, Zr, Hf) and [M{(CH2=CH)Me2SiCH2CH2(Me)Si(¿5-C5Me4)(¿5-C5H4)}Cl2] (M = Ti, Zr, Hf). Hydrosilylation of the remaining vinyl groups can be achieved by using simple silane reagents, for example, HSiEt3 to give [M{(Et3SiCH2CH2)3SiCH2CH2(Me)Si(¿5-C5Me4)(¿5-C5H4)}Cl2] (M = Ti, Zr) and [M{(Et3SiCH2CH2)Me2SiCH2CH2(Me)Si(¿5-C5Me4)(¿5-C5H4)}Cl2] (M = Ti, Zr). All the compounds have been tested as homogeneous catalysts in the polymerization of ethylene and propylene
Mesoporous SBA-15 Modified with Titanocene Complexes and Ionic liquids: Interactions with DNA and other Molecules of Biological Interest Studied by Solid State Electrochemical Techniques.
(Royal Society of Chemistry, 2018) del Hierro, Isabel; Gómez-Ruiz, Santiago; Pérez, Yolanda; Cruz, Paula; Prashar, Sanjiv; Fajardo, Mariano
The immobilization of two titanocene complexes on SBA-15 has been accomplished following post-synthetic procedures. The ionic liquid, 1-methyl-3-[(triethoxysilyl)propyl]imidazolium chloride, has also been incorporated into the titanium containing materials to determine its influence on the interaction with molecules of biological interest. Cyclic voltammetry has been used to study the influence of the ionic liquid on the mechanism of reduction of titanocene derivatives. The interaction of titanocene and titanocene/ ionic liquid-containing mesoporous silica SBA-15 materials, with molecules of biological interest associated with important processes of metallodrug action against cancer cells, has been studied. Thus, we have carried out hydrolysis experiments on the materials functionalized with titanocene derivatives in physiological media to determine their stability and the interaction with serum/transport proteins such as transferrin and BSA and with target molecules such as guanosine, single-stranded DNA and double-stranded DNA by means of solid state voltammetry techniques. A qualitative analysis of the data based on peak current and reduction potential value changes of the couple Ti(IV)/Ti(III) in the presence of biomolecules at physiological pH, has revealed that grafted titanocene complexes show higher affinity for serum/transport proteins than for nucleic acids, indicating that the transport steps to the cells may be easier than the subsequent attack on DNA.
Mesoporous silica nanoparticles functionalized with a dialkoxide diorganotin(IV) compound: In search of more selective systems against cancer cells
(Elsevier, 2020-03-09) Díaz-García, Diana; Sommerova, Lucia; Martisova, Andrea; Skoupilova, Hana; Prashar, Sanjiv; Vaculovic, Tomas; Kanicky, Viktor; del Hierro, Isabel; Hrstka, Roman; Gómez-Ruiz, Santiago
Mesoporous silica nanoparticles (MSN) have been functionalized with the polyamino ligand N1-(3-trimethoxysilylpropyl) diethylenetriamine to give the material MSN-DETATMS (M1). The reaction of M1 with the diphenyltin(IV) compound Sn1 [obtained previously from the reaction of (3-glycidyloxypropyl)trimethoxysilane and diphenyltin(IV) dichloride in the presence of two equivalents of sodium hydroxide] in a quantity to obtain a theoretical 10% wt Sn/SiO2, gave the material MSN-DETATMS-O2-SnPh2 (M2). Alternatively, M1 was reacted with folic acid to achieve the incorporation of the folate fragment via formation of an amido bond MSNDETATMS-FA (M3) and subsequently with Sn1 to give the tin-functionalized material MSN-DETATMS-FA-O2-SnPh2 (M4). M1‒M4 have been characterized by several methods such as infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), X-ray fluorescence (XRF), solid-state NMR spectroscopy, nitrogen adsorption-desorption isotherms, electrochemical methods, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). All the synthesized nanomaterials have been tested in vitro against a wide variety of cancer and noncancer cells in order to determine different aspects of their antitumour effects such as cell uptake, cell death, cell migration and cell invasion, to observe whether the incorporation of folate fragments may increase the cell uptake and selectivity towards cancer cells, thus increasing their potential applicability in future chemotherapeutic approaches.
Modulation of the mechanism of apoptosis in cancer cell lines by treatment with silica-based nanostructured materials functionalized with different metallodrugs
(Royal Society of Chemistry, 2018-08-10) Díaz-García, Diana; Cenariu, Diana; Pérez, Yolanda; Cruz, Paula; del Hierro, Isabel; Prashar, Sanjiv; Fischer-Fodor, Eva; Gómez-Ruiz, Santiago
The mesoporous silica-based material SBA-15 (Santa Barbara Amorphous-15) has been modified with the aminodiol ligand 3-[bis(2-hydroxyethyl)amino]propyltriethoxysilane (PADOH) to give the corresponding material SBA-PADOH. Subsequent functionalization with a diorganotin(IV) compound, SnPh2Cl2 (1), and with two titanocene derivatives, TiCp2Cl2 ([Ti(η5-C5H5)2Cl2] (2)) and TiCpCpPhNfCl2 ([Ti(η5-C5H5) (η5-C5H4CHPhNf)Cl2] (3) (Ph = C6H5; Nf = C10H7)), gave the materials SBA-PADO-SnPh2 (M1), SBA-PADO-TiCp2 (M2) and SBA-PADO-TiCpCp* (M3), respectively. SBA-PADOH and M1–M3 have been characterized by various techniques such as FT-IR, XRD, XRF, solid-state NMR, nitrogen adsorption– desorption isotherms, electrochemical methods, SEM and TEM, observing that the functionalization has mainly taken place inside the pores of the corresponding porous system. In addition, mechanistic aspects of the apoptosis triggered by the synthesized materials have been studied in vitro in tumour cell lines derived from three distinct types of cancer in order to elucidate their growth inhibition and interference with the expression of tumour necrosis factor alfa (TNF-α) and the first apoptosis signal receptor (Fas or tumour necrosis factor receptor 6). It was observed that the antiproliferative and proapoptotic capacity of the materials depends on their functionalization with the different cytotoxic prodrugs (organotin or titanocene derivatives). The study shows that M1–M3 influence the metabolic activity of the tumour cells and modulate the apoptotic pathways by different mechanisms, according to the active compound inside the material.
Organotin(IV)-Decorated Graphene Quantum Dots as Dual Platform for Molecular Imaging and Treatment of Triple Negative Breast Cancer
(Wiley, 2023) Gómez, Jénnifer; Ovejero-Paredes, Karina; Méndez-Arriaga, José Manuel; Pizúrová, Naděžda; Filice, Marco; Zajíčková, Lenka; Prashar, Sanjiv; Gómez-Ruiz, Santiago
The pharmacological activity of organotin(IV) complexes in cancer therapy is well recognized but their large applicability is hampered by their poor water solubility. Hence, carbon dots, in particular nitrogen-doped graphene quantum dots (NGQDs), may be a promising alternative for the efficient delivery of organotin(IV) compounds as they have a substantial aqueous solubility, a good chemical stability, and non-toxicity as well as a bright photoluminescence that make them ideal for theranostic applications against cancer. Two different multifunctional nanosystems have been synthesized and fully characterized based on two fragments of organotin-based cytotoxic compounds and 4-formylbenzoic acid (FBA), covalently grafted onto the NGQDs surface. Subsequently, an in vitro determination of the therapeutic and theranostic potential of the achieved multifunctional systems was carried out. The results showed a high cytotoxic potential of the NGQDs-FBA-Sn materials against breast cancer cell line (MDA-MB-231) and a lower effect on a non-cancer cell line (kidney cells, HEK293T). Besides, thanks to their optical properties, the dots enabled their fluorescence molecular imaging in the cytoplasmatic region of the cells pointing towards a successful cellular uptake and a release of the metallodrug inside cancer cells (NGQDs-FBA-Sn).
Preparation and study of the antibacterial applications and oxidative stress induction of copper maleamate-functionalized mesoporous silica nanoparticles
(MDPI, 2019-01-14) Díaz-García, Diana; Ardiles, Perla R.; Prashar, Sanjiv; Rodríguez-Diéguez, Antonio; Páez, Paulina L.; Gómez-Ruiz, Santiago
Mesoporous silica nanoparticles (MSNs) are an interesting class of nanomaterials with potential applications in different therapeutic areas and that have been extensively used as drug carriers in different fields of medicine. The present work is focused on the synthesis of MSNs containing a maleamato ligand (MSN-maleamic) and the subsequent coordination of copper(II) ions (MSN-maleamic-Cu) for the exploration of their potential application as antibacterial agents. The Cu-containing nanomaterials have been characterized by different techniques and the preliminary antibacterial effect of the supported maleamato-copper(II) complexes has been tested against two types of bacteria (Gram positive and Gram negative) in different assays to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The biological results showed a moderate antibacterial activity against Escherichia coli which motivated a more detailed study of the antibacterial mechanism of action of the synthesized maleamate-containing nanosystems and whose findings showed oxidative stress generation in bacterial cells. All the prepared nanomaterials were also tested as catalysts in the “solvent free” selective oxidation of benzyl alcohol, to observe if there is a potential correlation between the catalytic oxidation capacity of the materials and the observed oxidative stress in bacteria. This may help in the future, for a more accurate rational design of antibacterial nanosystems, based on their observed catalytic oxidation activity.
Síntesis y estudio electroquímico de complejos de niobio incorporando ligandos ansa-ciclopentadienilo asimétricos
(2014-01-29) Antiñolo, Antonio; Expósito, Teresa; Hierro, Isabel del; Lucas, Dominique; Mugnier, Yves; Orive, Irache; Otero, Antonio; Prashar, Sanjiv
Se han preparado los complejos asimétricos bicloruro de ansa-nioboceno(IV): [Nb{Me2Si(eta5-C5Me4)(eta5-C5H3R)}Cl2] (R = H (1a), Me (2a), SiMe3 (3a), Pri (4a), PPh2 (5a)). 1a-5a se han caracterizado mediante los correspondientes espectros de RSE, IR y análisis elemental. Los estudios electroquímicos de estos derivados nos han permitido evaluar los potenciales de oxidación y reducción que se han comparados con complejos análogos no ansa. También han sido sintetizados nuevos complejos niobocenos [Nb(eta5-C5H4R)2}Cl2] (R = Pri (6a), PPh2 (7a)) y estudiados electroquímicamente.
Study of cancer cell cytotoxicity, internalization and modulation of growth factors induced by transferrin-conjugated formulations of metallodrug-functionalized mesoporous silica nanoparticles
(Elsevier, 2021) Díaz-García, Diana; Fischer-Fodor, Eva; Vlad, Cătălin Ioan; Méndez-Arriaga, José M.; Prashar, Sanjiv; Gómez-Ruiz, Santiago
Nano-sized materials have shown to have very high potential in anticancer therapy by an adequate tuning of their functionalization and physico-chemical properties. This study is focused on the synthesis and characterization of mesoporous silica nanoparticles (MSN) functionalized with a titanium(IV) or an organotin(IV) compound (therapeutic agents), fluorescein isothiocyanate (image agent) and transferrin (targeting molecule). The analysis of the biological activity of the metallodrug-functionalized systems with and without transferrin has been evaluated and the cell internalization with respect to the presence of the protein has been assessed. The biological results show, as expected, that Sn-based materials are more active than the Ti-based systems with some of the tin-functionalized nanoparticles being almost 50 times more active than carboplatin. In contrast, the cellular uptake seems to be higher in Ti-based materials, which take advantage of the stronger interaction with transferrin to internalize the cells with more effectivity. Finally, a study of vascular endothelial growth factor A (VEGF-A), human fibroblast growth factor 2 (FGF-2) and nuclear factor κβ transcription factor (NF-κβ) show that, specially the Sn-based MSNs, were able to modulate these factors in A2780 cells showing anti-angiogenic effects through VEGF-A and FGF-2, probably due to interaction of the materials with transferrin.
Synthesis of a theranostic platform based on fibrous silica nanoparticles for the enhanced treatment of triple-negative breast cancer promoted by a combination of chemotherapeutic agents
(Elsevier, 2022) Ovejero-Paredes, Karina; Díaz-García, Diana; Mena-Palomo, Irene; Marciello, Marzia; Lozano-Chamizo, Laura; Luengo Morato, Yurena; Prashar, Sanjiv; Gómez-Ruiz, Santiago; Filice, Marco
A new series of theranostic silica materials based on fibrous silica particles acting as nanocarriers of two different cytotoxic agents, namely, chlorambucil and an organotin metallodrug have been prepared and structurally characterized. Besides the combined therapeutic activity, these platforms have been decorated with a targeting molecule (folic acid, to selectively target triple negative breast cancer) and a molecular imaging agent (Alexa Fluor 647, to enable their tracking both in vitro and in vivo). The in vitro behaviour of the multifunctional silica systems showed a synergistic activity of the two chemotherapeutic agents in the form of an enhanced cytotoxicity against MDA-MB-231 cells (triple negative breast cancer) as well as by a higher cell migration inhibition. Subsequently, the in vivo applicability of the siliceous nanotheranostics was successfully assessed by observing with in vivo optical imaging techniques a selective tumour accumulation (targeting ability), a marked inhibition of tumour growth paired to a marked antiangiogenic ability after 13 days of systemic administration, thus, confirming the enhanced theranostic activity. The systemic nanotoxicity was also evaluated by analyzing specific biochemical markers. The results showed a positive effect in form of reduced cytotoxicity when both chemotherapeutics are administered in combination thanks to the fibrous silica nanoparticles. Overall, our results confirm the promising applicability of these novel silica-based nanoplatforms as advanced drug-delivery systems for the synergistic theranosis of triple negative breast cancer.
Synthesis of cationic niobocene imido derivatives
(2014-01-29) Hierro, Isabel del; Fajardo, Mariano; Garcés, Andrés; Gómez-Ruiz, Santiago; Pérez, Yolanda; Prashar, Sanjiv; Antiñolo, Antonio; Otero, Antonio; López-Mardomingo, Carmen
Following from our previous work in the synthesis and reactivity of niobium imido complexes,1 we have studied the preparation of cationic derivatives. The reduction of [Nb(=NPh)(eta5-C5H4SiMe3)2Cl] gives the short-lived niobocene(IV) radical [Nb(=NPh)(eta5-C5H4SiMe3)2. which was rapidly oxidized to the niobocene(V) cationic species [Nb(=NPh)(eta5-C5H4SiMe3)2(L)]+ (L = CO, ButNC) by the reaction with [Fe(eta5-C5H5)2][BPh4]. In a similar manner, the ansa-niobocene compound [Nb(=NBut){Me2Si(eta5-C5Me4)(eta5-C5H4)}(ButNC)][BPh4] was synthesized. However, in the attempted reduction of [Nb(=NBut){Me2Si(eta5-C5H4)2}Cl], the expected radical species was not observed. Instead the niobocene (V) imido dimer product was identified. The reaction with H2 and I2 gave [Nb(=NBut){Me2Si(eta5-C5H4)2}H] and [Nb(=NBut){Me2Si(eta5-C5H4)2}I], respectively.
Synthesis of new titanocene(IV) carboxylate complexes: an alternative chemotherapeutic treatment against cancer
(Departamento de Química Inorgánica y Analítica, E.S.C.E.T., Universidad Rey Juan Carlos, 2012-05) Ceballos Torres, Jesús; Caballero Rodríguez, María J.; Prashar, Sanjiv; Paschke, Reinhard; Steinborn, Dirk; Kaluderovic, Goran N.; Gómez Ruiz, Santiago