Magnetophoretic mobility of iron oxide nanoparticles stabilized by small carboxylate ligands

Iron oxide nanoparticles were synthesized by the co-precipitation method and subjected to an adsorption and functionalization process at controlled pH with five different small carboxylate ligands, namely: citrate, tartrate, gluconate, succinate and β-alanine. The efficiency of the functionalization was evaluated by infrared spectroscopy and thermogravimetric measurements, finding that the presence of hydroxyl groups in the organic molecule is essential to achieve good levels of adhesion. In the three cases with higher levels of adhesion, the nanoparticles remain permanently stabilized and the system behaves like a ferrofluid at neutral pH. Colloidal properties such as the mean hydrodynamic diameter and the surface electrokinetic potential were studied over a wide pH range, being able to establish a clear correlation between the speciation equilibria of the adsorbed species, the surface charge and the formation of agglomerates between the particles. Finally, a magnetophoretic experiment was designed to evaluate and compare the mobility of the nanoparticles under a magnetic field gradient. In systems with individually stabilized nanoparticles, no magnetophoretic mobility was observed due to the low limit velocity reached by the particles. This result is consistent with a theoretical limit speed calculated considering the different parameters of the experiment and the ferrofluids. In systems with agglomerated nanoparticles it was found that the magnetophoretic mobility and the limit speed increase with the hydrodynamic diameter. In turn, this property varies strongly with the pH of the system according to the protonation / deprotonation equilibria of the surface of the nanoparticles and the formation or rupture of the agglomerates.Fil: Tancredi, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Veiga, Lionel S.. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Garate, Octavio Federico. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Ybarra, Gabriel Omar. Instituto Nacional de Tecnología Industrial; Argentin

High-performance non-enzymatic hydrogen peroxide electrochemical sensor prepared with a magnetite-loaded carbon nanotube waterborne ink

In this study, a non-enzymatic hydrogen peroxide sensor was developed employing a waterborne carbon nanotube ink containing catalytic submicrometric particles of magnetite. Magnetite particles were synthesized via a solvothermal method and characterized by scanning electron microscopy (SEM) and powder X-ray diffraction measurements (XRD). For the ink preparation, Fe3O4 particles were incorporated into a waterborne carbon nanotube ink and the mixture was drop casted onto a glassy carbon and used for coating ValoxTM strips to fabricate standalone electrodes. As a non-enzymatic amperometric sensor, the resulting Fe3O4/CNT ink coated electrodes exhibited high-performance values towards the detection of H2O2, presenting a limit of detection of 0.5 µM, a linear detection range up to 2 mM, a sensitivity of 1040 µA cm−2 mM−1 and tolerance to common interfering agents like ascorbic acid, glucose and Cl-/SO4-2 ions. Moreover, the Fe3O4/CNT electrodes presented a high stability, losing only 20% of their catalytic performance after three weeks.Fil: Garate, Octavio Federico. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Veiga, Lionel S.. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Tancredi, Pablo. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Medrano, Anahi Vanesa. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Monsalve, Leandro Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Ybarra, Gabriel Omar. Instituto Nacional de Tecnología Industrial; Argentin

Magnetic mesoporous silica nanospheres with dual probe & release fluorescent functionality

The combination of different nanomaterials through step-by-step synthesis procedures has turned into a promising alternative to fabricate high-quality nanosystems in order to satisfy the increasingly demanding requirements of the biomedical field. In this work, we report a detailed study on the synthesis and characterization of a complex nanosystem composed of nanoparticles with a single magnetic nanoparticle core and a shell of dense and mesoporous silica arranged in layers. The procedure designed to fabricate these systems lead us to the formation of a dispersion of non-agglomerated spherical nanoparticles of nearly 100 nm. The structural characterization performed over the final samples confirmed both the prevalence of single-core systems and the presence of the mesoporous silica shell in the outer layer. The performance of the nanosystem in a specific technological application was tested by sequentially loading two different fluorescents molecules by covalent and non-covalent bonding strategies. Due to the distinct loading strategies, the resulting nanosystem presented a magnetically-assisted probe & release functionality as analyzed in a magnetophoretic experiment.Fil: Tancredi, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Rivas Rojas, Patricia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Veiga, Lionel S.. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Garate, Octavio Federico. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Socolovsky, Leandro Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; ArgentinaFil: Muraca, Diego. Universidade Estadual de Campinas; BrasilFil: Ybarra, Gabriel Omar. Instituto Nacional de Tecnología Industrial; Argentin

Electrochemical Sweat Sensors

Sweat analysis by means of minimally invasive wearable sensors is considered a potentiallydisruptive method for assessing clinical parameters, with exciting applications in early medicaldiagnostics and high-performance sports. Electrochemical sensors and biosensors are especiallyattractive because of the possibility of the electronic integration of wearable devices. In this article, wereview several aspects regarding the potentialities and present limitations of electrochemical sweat(bio)sensors, including: the main target analytes and their relationships with clinical conditions; mostusual electrochemical techniques of transduction used according to the nature of the target analytes;issues connected to the collection of representative sweat samples; aspects regarding the associated,miniaturized electronic instrumentation used for signal processing and communication; and signalprocessing by machine learning.Fil: Bilbao, Emanuel. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garate, Octavio Federico. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario; ArgentinaFil: Rodríguez Campos, Theo. Universidad Nacional de San Martin. Instituto de Calidad Industrial. - Instituto Nacional de Tecnologia Industrial. Instituto de Calidad Industrial.; ArgentinaFil: Roberti, Mariano. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario; ArgentinaFil: Mass, Mijal Inés. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario; ArgentinaFil: Lozano, Alex. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario; ArgentinaFil: Longinotti, Gloria. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario; ArgentinaFil: Monsalve, Leandro Nicolas. Instituto Nacional de Tecnología Industrial. Centro de Micro y Nanoelectrónica del Bicentenario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ybarra, Gabriel Omar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Two-Step Preparation of Protein-Decorated Biohybrid Quantum Dot Nanoparticles for Cellular Uptake

Decoration of nanoparticles with specific molecules such as antibodies, peptides, and proteins that preserve their biological properties is essential for the recognition and internalization of their specific target cells. Inefficient preparation of such decorated nanoparticles leads to nonspecific interactions diverting them from their desired target. We report a simple two-step procedure for the preparation of biohybrid nanoparticles containing a core of hydrophobic quantum dots coated with a multilayer of human serum albumin. These nanoparticles were prepared by ultra-sonication, crosslinked using glutaraldehyde, and decorated with proteins such as human serum albumin or human transferrin in their native conformations. These nanoparticles were homogeneous in size (20–30 nm), retained the fluorescent properties of quantum dots, and did not show a “corona effect” in the presence of serum. The uptake of transferrin-decorated quantum dot nanoparticles was observed in A549 lung cancer and SH-SY5Y neuroblastoma cells but not in non-cancerous 16HB14o- or retinoic acid dopaminergic neurons differentiated SH-SY5Y cells. Furthermore, digitoxin-loaded transferrin-decorated nanoparticles decreased the number of A549 cells without effect on 16HB14o-. Finally, we analyzed the in vivo uptake of these biohybrids by murine retinal cells, demonstrating their capacity to selectively target and deliver into specific cell types with excellent traceability.Fil: Traverso, Agata Noelia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Tecnologias Emergentes y Ciencias Aplicadas. - Universidad Nacional de San Martin. Instituto de Tecnologias Emergentes y Ciencias Aplicadas.; ArgentinaFil: Fragale, David José. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Tecnologias Emergentes y Ciencias Aplicadas. - Universidad Nacional de San Martin. Instituto de Tecnologias Emergentes y Ciencias Aplicadas.; ArgentinaFil: Viale, Diego Luis. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Tecnologias Emergentes y Ciencias Aplicadas. - Universidad Nacional de San Martin. Instituto de Tecnologias Emergentes y Ciencias Aplicadas.; ArgentinaFil: Garate, Octavio Federico. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Torres, Pablo Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; ArgentinaFil: Valverde, Gastón. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología; ArgentinaFil: Berra, Alejandro. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología; ArgentinaFil: Torbidoni, Ana Vanesa. Universidad "juan Agustin Maza". Vicerrectorado de Investigación, Extensión y Vinculación.. Instituto Argentino de Veterinaria, Ambiente y Salud.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Yakisich, Juan Sebastián. Hampton University; Estados UnidosFil: Grasselli, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Radrizzani, Martín. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto de Tecnologias Emergentes y Ciencias Aplicadas. - Universidad Nacional de San Martin. Instituto de Tecnologias Emergentes y Ciencias Aplicadas.; Argentin