Person: Vallet Regí, María Dulce Nombre
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First Name
María Dulce Nombre
Last Name
Vallet Regí
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Farmacia
Department
Química en Ciencias Farmacéuticas
Area
Química Inorgánica
Identifiers
6 results
Search Results
Now showing 1 - 6 of 6
Item Enriched mesoporous bioactive glass scaffolds as bone substitutes in critical diaphyseal bone defects in rabbits(Acta Biomaterialia, 2024) García Lamas, Lorena; Lozano Borregón, Daniel; Jiménez Díaz, Verónica; Bravo Giménez, Beatriz; Sánchez Salcedo, Sandra; Abella, Mónica; Desco, Manuel; Jiménez Holguín, Javier; Vallet Regí, María Dulce Nombre; Cecilia López, David; Salinas Sánchez, Antonio JesúsIn the field of orthopedic surgery, there is an increasing need for the development of bone replacement materials for the treatment of bone defects. One of the main focuses of biomaterials engineering are ad- vanced bioceramics like mesoporous bioactive glasses (MBG´s). The present study compared the new bone formation after 12 weeks of implantation of MBG scaffolds with composition 82,5SiO2 –10CaO–5P2 O5 - x 2.5SrO alone (MBGA), enriched with osteostatin, an osteoinductive peptide, (MBGO) or enriched with bone marrow aspirate (MBGB) in a long bone critical defect in radius bone of adult New Zealand rab- bits. New bone formation from the MBG scaffold groups was compared to the gold standard defect filled with iliac crest autograft and to the unfilled defect. Radiographic follow-up was performed at 2, 6, and 12 weeks, and microCT and histologic examination were performed at 12 weeks. X-Ray study showed the highest bone formation scores in the group with the defect filled with autograft, followed by the MBGB group, in addition, the microCT study showed that bone within defect scores (BV/TV) were higher in the MBGO group. This difference could be explained by the higher density of newly formed bone in the os- teostatin enriched MBG scaffold group. Therefore, MBG scaffold alone and enriched with osteostatin or bone marrow aspirate increase bone formation compared to defect unfilled, being higher in the osteo- statin group. The present results showed the potential to treat critical bone defects by combining MBGs with osteogenic peptides such as osteostatin, with good prospects for translation into clinical practice.Item Tailoring the biological response of mesoporous bioactive materials(Journal of Materials Chemistry B, 2013) Gómez Cerezo, María Natividad; Izquierdo Barba, Isabel; Arcos Navarrete, Daniel; Vallet Regí, María Dulce NombreSilica mesoporous nanomaterials have been proved to have meaningful application in biotechnology and biomedicine. Particularly, mesoporous bioactive glasses are recently gaining importance thanks to their bone regenerative properties. Moreover, the mesoporous nature of these materials makes them suitable for drug delivery applications, opening new lines in the field of bone therapies. In this work, we have developed innovative nanodevices based on the implementation of adenosine triphosphate (ATP) and ε-poly-l-lysine molecular gates using a mesoporous bioglass as an inorganic support. The systems have been previously proved to work properly with a fluorescence probe and subsequently with an antibiotic (levofloxacin) and an antitumoral drug (doxorubicin). The bioactivity of the prepared materials has also been tested, giving promising results. Finally, in vitro cell culture studies have been carried out; demonstrating that this gated devices can provide useful approaches for bone cancer and bone infection treatments.Item Nanoparticles for multimodal antivascular therapeutics: Dual drug release, photothermal and photodynamic therapy(2020) Paris, Juan L.; Villaverde Cantizano, Gonzalo; Gómez Graña, Sergio; Vallet Regí, María Dulce NombreThe poor delivery of nanoparticles to target cancer cells hinders their success in the clinical setting. In this work, an alternative target readily available for circulating nanoparticles has been selected to eliminate the need for nanoparticle penetration in the tissue: the tumor blood vessels. A tumor endotheliumtargeted nanoparticle (employing an RGD-containing peptide) capable of co-delivering two anti-vascular drugs (one anti-angiogenic drug and one vascular disruption agent) is here presented. Furthermore, the nanodevice presents two additional anti-vascular capabilities upon activation by Near-Infrared light: provoking local hyperthermia (by gold nanorods in the system) and generating toxic reactive oxygen species (by the presence of a photosensitizer). RGD-targeting is shown to increase uptake by HUVEC cells, and while the nanoparticles are shown not to be toxic for these cells, upon Near-Infrared irradiation their almost complete killing is achieved. The combination of all four therapeutic modalities is then evaluated in an ex ovo fibrosarcoma xenograft model, which shows a significant reduction in the number of blood vessels irrigating the xenografts when the nanoparticles are present, as well as the destruction of the existing blood vessels upon irradiation. These results suggest that the combination of different antivascular therapeutic strategies in a single nanocarrier appears promising and should be further explored in the future.Item Squaraine-loaded mesoporous silica nanoparticles for antimicrobial Photodynamic Therapy against bacterial infection(Microporous and Mesoporous Materials, 2024) Melese Dereje, Degnet; García Fontecha, Ana; Pontremoli, Carlotta; González Ortiz, Blanca; Colilla Nieto, Montserrat; Vallet Regí, María Dulce Nombre; Izquierdo Barba, Isabel; Barbero, NadiaAntimicrobial photodynamic therapy (aPDT) shows promise as a complementary or alternative approach to conventional antimicrobial treatments. Despite possessing some key advantages, many challenges remain, such as optimizing the delivery of photosensitizers, improving light penetration into tissues, and determining the most effective combinations of photosensitizers and light wavelengths for different infections. Moreover, addressing the challenges associated with the aggregation tendency and poor solubility of some photosensitizers, squaraine dyes (SQs) in particular, is crucial for unlocking their full potential in biomedical applications. This contribution focuses on designing innovative anophotosensitizers with antimicrobial properties using mesoporous silica nanoparticles (MSNs) loaded with a SQ dye (i.e. Br-SQ). MSNs before and after Br-SQ loading were deeply characterized using different techniques, proving the successful incorporation of the dye into the nanocarriers. Upon visible light (640 nm) irradiation, these nanosystems demonstrated remarkable antibacterial activities against both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). Our results confirmed that MSNs are valuable nanocarriers of hydrophobic photosensitizers, such as Br-SQ, bringing up new opportunities to develop antibiotic-free anoformulations to treat bacterial infection while minimizing the risk of antimicrobial resistance.Item Poly Lactic-co-Glycolic Acid (PLGA) Loaded with a Squaraine Dye as Photosensitizer for Antimicrobial Photodynamic Therapy(Polymers, 2024) Melese Dereje, Degnet; Pontremoli, Carlotta; García Fontecha, Ana; Galliano, Simone; Colilla Nieto, Montserrat; González Ortiz, Blanca; Vallet Regí, María Dulce Nombre; Izquierdo Barba, Isabel; Barbero, NadiaAntimicrobial Photodynamic Therapy (aPDT) is an innovative and promising method for combating infections, reducing the risk of antimicrobial resistance compared to traditional antibiotics. Squaraine (SQ) dyes can be considered promising photosensitizers (PSs) but are generally hydrophobic molecules that can self-aggregate under physiological conditions. To overcome these drawbacks, a possible solution is to incorporate SQs inside nanoparticles (NPs). The present work deals with the design and development of innovative nanophotosensitizers based on poly lactic-co-glycolic acid (PLGA) NPs incorporating a brominated squaraine (BrSQ) with potential application in aPDT. Two designs of experiments (DoEs) based on the single emulsion and nanoprecipitation methods were set up to investigate how different variables (type of solvent, solvent ratio, concentration of PLGA, stabilizer and dye, sonication power and time) can affect the size, zeta (ζ)-potential, yield, entrapment efficiency, and drug loading capacity of the SQ-PLGA NPs. SQ-PLGA NPs were characterized by NTA, FE-SEM, and UV-Vis spectroscopy and the ability to produce reactive oxygen species (ROS) was evaluated, proving that ROS generation ability is preserved in SQ-PLGA. In vitro antimicrobial activity against Gram-positive bacteria in planktonic state using Staphylococcus aureus was conducted in different conditions and pH to evaluate the potential of these nanophotosensitizers for aPDT in the local treatment of infections.Item Osteoimmune Properties of Mesoporous Bioactive Nanospheres: A Study on T Helper Lymphocytes(Nanomaterials, 2023) Casarrubios Molina, Laura; Cicuéndez Maroto, Mónica; Vallet Regí, María Dulce Nombre; Portolés Pérez, María Teresa; Arcos Navarrete, Daniel; Feito Castellano, María JoséBioactive mesoporous glass nanospheres (nanoMBGs) charged with antiosteoporotic drugs have great potential for the treatment of osteoporosis and fracture prevention. In this scenario, cells of the immune system are essential both in the development of disease and in their potential to stimulate therapeutic effects. In the present work, we hypothesize that nanoMBGs loaded with ipriflavone can exert a positive osteoimmune effect. With this objective, we assessed the effects of non-loaded and ipriflavone-loaded nanoparticles (nanoMBGs and nanoMBG-IPs, respectively) on CD4+ Th2 lymphocytes because this kind of cell is implicated in the inhibition of osseous loss by reducing the RANKL/OPG relationship through the secretion of cytokines. The results indicate that nanoMBGs enter efficiently in CD4+ Th2 lymphocytes, mainly through phagocytosis and clathrindependent mechanisms, without affecting the function of these T cells or inducing inflammatory mediators or oxidative stress, thus maintaining the reparative Th2 phenotype. Furthermore, the incorporation of the anti-osteoporotic drug ipriflavone reduces the potential unwanted inflammatory response by decreasing the presence of ROS and stimulating intracellular anti-inflammatory cytokine release like IL-4. These results evidenced that nanoMBG loaded with ipriflavone exerts a positive osteoimmune effect.