Person: Sánchez Sánchez, Alfredo
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First Name
Alfredo
Last Name
Sánchez Sánchez
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Analítica
Area
Química Analítica
Identifiers
8 results
Search Results
Now showing 1 - 8 of 8
Item A glutathione disulfide-sensitive Janus nanomachine controlled by an enzymatic and logic gate for smart delivery(Nanoscale, 2021) Mayol Hornero, Beatriz; Díez-Sánchez, Paula; Sánchez Sánchez, Alfredo; Torre, Cristina de la; Villalonga, Anabel; Lucena-Sánchez, Elena; Sancenón, Félix; Martínez Ruiz, María Paloma; Vilela García, Diana; Martínez-Máñez, Ramón; Villalonga Santana, ReynaldoThis work describes the assembly of a novel enzyme-controlled nanomachine operated through an AND Boolean logic gate for on-command delivery. The nanodevice was constructed on Au-mesoporous silica Janus nanoparticles capped with a thiol-sensitive gate-like molecular ensemble on the mesoporous face and functionalized with glutathione reductase on the gold face. This autonomous nanomachine employed NADPH and glutathione disulfide as input chemical signals, leading to the enzymatic production of reduced glutathione that causes the disruption of the gating mechanism on the mesoporous face and the consequent payload release as an output signal. The nanodevice was successfully used for the autonomous release of doxorubicin in HeLa cancer cells and RAW 264.7 macrophage cells.- Project number: 73
Item Implementación de aplicaciones móviles como herramientas de enseñanza aprendizaje en Química Analítica(2018) Villalonga Santana, Reynaldo; Parrado Quintela, Concepción; Sánchez Sánchez, Alfredo; Reviejo García, Ángel Julio; Pérez Quintanilla, Damián; Díez Sánchez, Paula; Jiménez Falcao, Sandra Item Supramolecular Enzymatic Labeling for Aptamer Switch-Based Electrochemical Biosensor(Biosensors, 2022) Villalonga Chico, Anabel; Parrado Quintela, Concepción; Diaz, Raúl; Sánchez Sánchez, Alfredo; Mayol Hornero, Beatriz; Martínez-Ruíz, Paloma; Vilela García, Diana; Villalonga Santana, ReynaldoHere we report a novel labeling strategy for electrochemical aptasensors based on enzymatic marking via supramolecular host–guest interactions. This approach relies on the use of an adamantane-modified target-responsive hairpin DNA aptamer as an affinity bioreceptor, and a neoglycoconjugate of β-cyclodextin (CD) covalently attached to a redox enzyme as a labeling element. As a proof of concept, an amperometric aptasensor for a carcinoembryonic antigen was assembled on screen-printed carbon electrodes modified with electrodeposited fern-like gold nanoparticles/graphene oxide and, by using a horseradish peroxidase-CD neoglycoenzyme as a biocatalytic redox label. This aptasensor was able to detect the biomarker in the concentration range from 10 pg/mL to 1 ng/mL with a high selectivity and a low detection limit of 3.1 pg/mL in human serum samples.Item Effect of Mesoporous Silica Nanoparticles on Glycerol-Plasticized Anionic and Cationic Polysaccharide Edible Films(Coatings, 2019) Giosafatto, Concetta; Sabbah, Mohammed; Al-Asmar, Asmaa; Esposito, Marilena; Sánchez Sánchez, Alfredo; Villalonga Santana, Reynaldo; Cammarota, Marcella; Mariniello, Loredana; Di Pierro, Prospero; Porta, RaffaeleThis study describes the production of reinforced polysaccharide (PS)-based films, by adding mesoporous silica nanoparticles (MSNs), to either pectin (PEC) or chitosan (CH) film forming solutions, either containing glycerol (GLY) as a plasticizer, or not. Film characterization demonstrated that MSNs and GLY were able to significantly increase the plasticity of both PS-based biomaterials and that the interactions between PSs and nanoparticles were mainly due to hydrogen bonds. Moreover, MSN-containing films were less transparent, compared to controls prepared with either PEC or CH, in the absence of GLY, while all films containing MSNs, but obtained with the plasticizer, were as transparent as the films prepared with PEC or CH alone. MSN addition did not influence the thickness of the PEC-based films, but increased that of CH-based ones, prepared both in the absence and presence of GLY. MSN-containing PEC-based films possessed a more compact and homogeneous morphology, with respect to both control films, prepared, with or without GLY, and to the CH-based films, containing MSNs, the structure of which showed numerous agglomerations. Finally, moisture content and uptake were reduced, in all films prepared in the presence of MSNs. The suggested addition of MSNs might have given rise to novel biomaterials for food or pharmaceutical applications.Item Dendrimers as Soft Nanomaterials for Electrochemical Immunosensors(Nanomaterials, 2019) Sánchez Sánchez, Alfredo; Villalonga, Anabel; Martínez García, Gonzalo; Parrado Quintela, Concepción; Villalonga Santana, ReynaldoElectrochemical immunosensors are antibody-based affinity biosensors with a high impact on clinical, environmental, food, and pharmaceutical analysis. In general, the analytical performance of these devices is critically determined by the materials and reagents used for their construction, signal production and amplification. Dendrimers are monodisperse and highly branched polymers with three-dimensional structures widely employed as “soft” nanomaterials in electrochemical immunosensor technology. This review provides an overview on the state-of-the-art in dendrimer-based electrochemical immunosensors, focusing on those using polyamidoamine and poly (propylene imine) dendrimers. Special emphasis is given to the most original methods recently reported for the construction of immunosensor architectures incorporating dendrimers, as well as to novel sensing approaches based on dendrimer-assisted signal enhancement strategies.- Project number: 172
Item Mentoría pedagógica como método de formación del profesorado universitario. Experiencia en la asignatura "Química Analítica I" del grado en Química(2023) Sánchez Sánchez, Alfredo; Villalonga Santana, Reynaldo; Urraca Ruiz, Javier; Gracia Lor, Emma; Vilela García, Diana; Rodríguez Bencomo, Juan José; Molla Escudero, David; Mayol Hornero, Beatriz; Villalonga Chico, Anabel Item Effect of Mesoporous Silica Nanoparticles on The Physicochemical Properties of Pectin Packaging Material for Strawberry Wrapping(Nanomaterials, 2019) Al-Asmar, Asmaa; Giosafatto, C. Valeria L.; Sabbah, Mohammed; Sánchez Sánchez, Alfredo; Villalonga Santana, Reynaldo; Mariniello, LoredanaCitrus peel pectin was used to prepare films (cast with or without glycerol) containing mesoporous silica nanoparticles. Nanoparticles reduced significantly the particle size, and had no effect on the Zeta potential of pectin solutions. Mechanical characterization demonstrates that pectin+nanoparticles containing films slightly increased tensile strength and significantly decreased the Young’s modulus in comparison to films made only of pectin. However, elongation at the break increased in the pectin+nanoparticles films cast in the presence of glycerol, while both Young’s modulus and tensile strength were reduced. Moreover, nanoparticles were able to reduce the barrier properties of pectin films prepared with or without glycerol, whereas positively affected the thermal stability of pectin films and the seal strength. The 0.6% pectin films reinforced or not with 3% nanoparticles in the presence of 30% glycerol were used to wrap strawberries in order to extend the fruit’s shelf-life, over a period of eighty days, by improving their physicochemical properties.Item Disposable electrochemical biosensors for Brettanomyces bruxellensis and total yeast content in wine based on core-shell magnetic nanoparticles(Sensors & Actuators: B. Chemical, 2018) Villalonga, María ; Borisova, Boryana; Arenas, Christian ; Villalonga, Anabel; Arévalo-Villena, María; Sánchez Sánchez, Alfredo; Pingarrón Carrazón, José Manuel; Briones-Pérez, Ana; Villalonga Santana, ReynaldoTwo different disposable amperometric biosensors for the rapid detection and quantification of Brettanomyces bruxellensis (Brett) and total yeast content in wine were constructed. The biosensing approach implied the use of magnetic capturing elements based on core-shell Fe3O4@SiO2 superparamagnetic nanoparticles (NanoCaptors) functionalized with specific bioreceptors: Concanavalin A (Con A) for total yeast analysis, and anti-Brett polyclonal antibodies for Brett. A Con A-peroxidase conjugate and carbon screen printed electrodes were used as signaling element and sensing interfaces, respectively. The biosensor based on antibody-modified magnetic nanoparticles allowed the amperometric detection of B. bruxellensis in buffer solution and red wine samples in the range of 10 - 106 CFU/mL, with low detection limits of 6 CFU/mL and 8 CFU/mL, respectively. In addition, the use of Con A-linked magnetic nanoparticles as capturing elements allowed determination of total yeast content in buffer solution and red wine in the range of 10 - 106 CFU/mL, with detection limit of 5 CFU/mL. These electrochemical biosensors also exhibited high reproducibility, selectivity and storage stability.