Programming an enhanced uptake and the intracellular fate of magnetic microbeads

This study compares two kinds of magnetic microbeads with different surface features and cell entry pathways, aiming to provide insights into how to program their cell uptake and intracellular fate. It is found that a rougher surface enhances the cell uptake of the microbeads, regardless of whether they are pulled by a magnetic field gradient or adsorbed by the cell membrane. However, the entry route affects the intracellular localization of the microbeads: The magnetically dragged microbeads reach the cytoplasm, while the adsorbed microbeads stay in the late endosomes and lysosomes. This suggests that different strategies can be used to target different cellular compartments with magnetic microbeads. Moreover, it is demonstrated that the cells containing the microbeads can be moved and regrown at specific locations by applying a magnetic field gradient, showing the potential of these magnetic microbeads for cell delivery and manipulation.Agencia Estatal de Investigación | Ref. PID2019-109669RB-I00Agencia Estatal de Investigación | Ref. PID2020-119242RB-I00Xunta de GaliciaUniversidade de Vigo/CISU

Nanoparticle biocoating to create ATP-powered swimmers capable of repairing proteins on the fly

In this study, we combine nanotechnology and biotechnology to design a biocompatible propulsion system based on the molecular chaperone Hsp90, a heat-shock protein (Hsp) that, in the presence of adenosine 5'-triphosphate (ATP), undergoes nanoscale conformational changes while trapping and renaturing other proteins. We show how, subjected to ATP availability in the medium, Hsp90-functionalized particles significantly enhance their diffusion motion, being able to achieve ballistic motion, while keeping the ability to restore the activity of surrounding heat-inactivated proteins. This biomechanics-based propulsion mechanism represents a promising strategy for the design of self-propelled nanodevices capable of performing sophisticated tasks in live biological contexts that include sensing the environment, recognizing and capturing, folding, and restoring defective proteins on the fly. In the short term, Hsp90-driven nanodevices could be applied to improve industrial processes that require enzymatic catalysis and high temperatures. But in the medium to long term, this bioactive coating could be used in the design of nanomachines that, like mini-robots, navigate the complex body cavities of biological tissues, deliver therapies and/or remove misfolded proteins in disorders such as Alzheimer's or Parkinson's disease.Acknowledgments: The authors acknowledge the financial support from the Spanish Instituto de Salud Carlos iii, and the European Union FEDER funds under Projects ref. PI22/00030, PI19/00349, from the Spanish Ministerio de Ciencia e Innovacion under project PID2020-119242RB-I00 and the European Union H2020-MSCA-RISE-2019 PEPSA-MATE project. ARR and MARD acknowledge financial support from IDIVAL (PREVAL19/04) and the Xunta de Galicia (2017- ED481A/322) respectively. We also acknowledge IDIVAL projects INNVAL19/12 and INNVAL21/1

Microswimmers with heat delivery capacity for 3D cell spheroid penetration

Micro- and nanoswimmers are a fast emerging concept that changes how colloidal and biological systems interact. They can support drug delivery vehicles, assist in crossing biological barriers, or improve diagnostics. We report microswimmers that employ collagen, a major extracellular matrix (ECM) constituent, as fuel and that have the ability to deliver heat via incorporated magnetic nanoparticles when exposed to an alternating magnetic field (AMF). Their assembly and heating properties are outlined followed by the assessment of their calcium-triggered mobility in aqueous solution and collagen gels. It is illustrated that the swimmers in collagen gel in the presence of a steep calcium gradient exhibit fast and directed mobility. The experimental data are supported with theoretical considerations. Finally, the successful penetration of the swimmers into 3D cell spheroids is shown, and upon exposure to an AMF, the cell viability is impaired due to the locally delivered heat. This report illustrates an opportunity to employ swimmers to enhance tissue penetration for cargo delivery via controlled interaction with the ECM.Xunta de Galicia | Ref. ED431C 2016-034Ministerio de Economía y Competitividad | Ref. CTM2014-58481-RXunta de Galicia | Ref. 2017 ED481AUniversidade de Vig

Magnetically propelled chained nanocomposites for biologically relevant media exploration

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGElongated nanostructures to be remotely and magnetically propelled in biologically relevant media, have gained attention as offering themselves as effective tools or carriers in theragnostics applications. However, the magnetic actuation associated remains challenging due to the lack of mechanical information in the media of interest, taking into account biophysical or biomedical purposes. In this study, we detail the magnetic actuation of magnetically propelled chained nanocomposites considering their dynamics, in which their velocity can be modulated in terms of the viscosity of the medium considered, given a magnetic field gradient. Simpler cases of distilled water, a water/glycerol mixture and a fluid made of cell extracts (imitating the cytosol of cells) of known viscosity are the basis experiments for the study of more complex media inside HeLa cells, murine NIH-3T3 fibroblasts and zebrafish larvae, offering the mechanical information required. The experimental results indicate that the magnetically propelled performance of the chained nanostructures can be precisely controlled in potentially changing scenarios, where drug and heat delivery, magnetic separation, or microfluidic technologies are demanded, using a magnetic field gradient and providing good estimations of the dynamical parameters involved.Xunta de Galicia | Ref. ED481A/322Xunta de Galicia | Ref. IN606A-2018/019Xunta de Galicia | Ref. IN853B 2018/03Ministerio de Economía y Competitividad | Ref. PI16/00496Instituto de Salud Carlos III | Ref. PI19/00349Instituto de Salud Carlos III | Ref. DTS19/00033Agencia Estatal de Investigación | Ref. MAT2016-81955-REDTAgencia Estatal de Investigación | Ref. PID2020-119242-I0

Magnetically induced CO2 methanation using exchange‐coupled spinel ferrites in cuboctahedron‐shaped nanocrystals

Magnetically induced catalysis can be promoted taking advantage of optimal heating properties from the magnetic nanoparticles to be employed. However, when unprotected, these heating agents that are usually air-sensitive, get sintered under the harsh catalytic conditions. In this context, we present, to the best of our knowledge, the first example of air-stable magnetic nanoparticles that: 1) show excellent performance as heating agents in the CO2 methanation catalyzed by Ni/SiRAlOx, with CH4 yields above 95 %, and 2) do not sinter under reaction conditions. To attain both characteristics we demonstrate, first the exchange-coupled magnetic approach as an alternative and effective way to tune the magnetic response and heating efficiency, and second, the chemical stability of cuboctahedron-shaped core–shell hard CoFe2O4–soft Fe3O4 nanoparticles.Xunta de Galicia | Ref. IN607 A 2018/5Xunta de Galicia | Ref. ED431C 2016-034Agencia Estatal de Investigación | Ref. CTM2017-84050-

Synergistic interaction of clusters of iron oxide nanoparticles and reduced graphene oxide for high supercapacitor performance

Supercapacitors have been recognized as one of the more promising energy storage devices, with great potential use in portable electronics and hybrid vehicles. In this study, a composite made of clusters of iron oxide (Fe3O4-γFe2O3) nanoparticles and reduced graphene oxide (rGO) has been developed through a simple one-step solvothermal synthesis method for a high-performance supercapacitor electrode. Electrochemical assessment via cyclic voltammetry, galvanostatic charge–discharge experiments, and electrochemical impedance spectroscopy (EIS) revealed that the Fe3O4-γFe2O3/rGO nanocomposite showed much higher specific capacitance than either rGO or bare clusters of Fe3O4-γFe2O3 nanoparticles. In particular, specific capacitance values of 100 F g−1, 250 F g−1, and 528 F g−1 were obtained for the clusters of iron oxide nanoparticles, rGO, and the hybrid nanostructure, respectively. The enhancement of the electrochemical performance of the composite material may be attributed to the synergistic interaction between the layers of graphene oxide and the clusters of iron oxide nanoparticles. The intimate contact between the two phases eliminates the interface, thus enabling facile electron transport, which is key to attaining high specific capacitance and, consequently, enhanced charge–discharge time. Performance evaluation in consecutive cycles has demonstrated that the composite material retains 110% of its initial capacitance after 3000 cycles, making it a promising candidate for supercapacitors.Ministerio de Ciencia e Innovación | Ref. PID2020-119242RB-I00Xunta de Galicia | Ref. ED431B 2021/14Ministerio de Economía y Competitividad | Ref. PID2020-113704RB-I00Xunta de Galicia/FEDER | Ref. IN607A 2018/5Xunta de Galicia | Ref. ED431G 2019-06Interreg España-Portugal | Ref. 0712_ACUINANO_1_EInterreg España-Portugal | Ref. 0624_2IQBIONEURO_6_

Ostwald Ripening of Platinum Nanoparticles Confined in a Carbon Nanotube/Silica-Templated Cylindrical Space

Sintering of nanoparticles mediated by an Ostwald ripening mechanism is generally assessed examining the final particle size distributions. Based on this methodology, a general approach for depositing platinum nanoparticles onto carbon nanotubes in solution has been employed in order to evaluate the sintering process of these metallic nanoparticles at increasing temperatures in a carbon nanotube/silica-templated confined space

Oxidative precipitation synthesis of calcium-doped manganese ferrite nanoparticles for magnetic hyperthermia

Superparamagnetic nanoparticles are of high interest for therapeutic applications. In this work, nanoparticles of calcium-doped manganese ferrites (CaxMn1−xFe2O4) functionalized with citrate were synthesized through thermally assisted oxidative precipitation in aqueous media. The method provided well dispersed aqueous suspensions of nanoparticles through a one-pot synthesis, in which the temperature and Ca/Mn ratio were found to influence the particles microstructure and morphology. Consequently, changes were obtained in the optical and magnetic properties that were studied through UV-Vis absorption and SQUID, respectively. XRD and Raman spectroscopy studies were carried out to assess the microstructural changes associated with stoichiometry of the particles, and the stability in physiological pH was studied through DLS. The nanoparticles displayed high values of magnetization and heating efficiency for several alternating magnetic field conditions, compatible with biological applications. Hereby, the employed method provides a promising strategy for the development of particles with adequate properties for magnetic hyperthermia applications, such as drug delivery and cancer therapy.This work was funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UIDB/04650/2020, UIDP/04650/2020), CQUM (UIDB/00686/2020), CICECO Aveiro Institute of Materials (UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020) and by Ministerio de Economía y Competitividad de España (PID2020-113704RB-I00 and PID2020-119242RB-I00), Xunta de Galicia (Centro Singular de Investigación de Galicia—Accreditation 2019-2022 ED431G 2019/06 and IN607A 2018/5 and project ED431C 2020-06), and European Union (EU-ERDF Interreg V-A—Spain-Portugal 0245_IBEROS_1_E, 0712_ACUINANO_1_E, and 0624_2IQBIONEURO_6_E, and Interreg Atlantic Area NANOCULTURE 1.102.531), and the European Union H2020-MSCA-RISE-2019 PEPSA-MATE project. S.R.S. (872233) Veloso acknowledges FCT for a PhD grant (SFRH/BD/144017/2019). Support from MAP-Fis Doctoral Programme is also acknowledged

Impact of citrate and lipid-functionalized magnetic nanoparticles in dehydropeptide supramolecular magnetogels: properties, design and drug release

Currently, the nanoparticle functionalization effect on supramolecular peptide-based hydrogels remains undescribed, but is expected to affect the hydrogels' self-assembly and final magnetic gel properties. Herein, two different functionalized nanoparticles: citrate-stabilized (14.4 ± 2.6 nm) and lipid-coated (8.9 ± 2.1 nm) magnetic nanoparticles, were used for the formation of dehydropeptide-based supramolecular magnetogels consisting of the ultra-short hydrogelator Cbz-L-Met-Z-ΔPhe-OH, with an assessment of their effect over gel properties. The lipid-coated nanoparticles were distributed along the hydrogel fibers, while citrate-stabilized nanoparticles were aggregated upon gelation, which resulted into a heating efficiency improvement and decrease, respectively. Further, the lipid-coated nanoparticles did not affect drug encapsulation and displayed improved drug release reproducibility compared to citrate-stabilized nanoparticles, despite the latter attaining a stronger AMF-trigger. This report points out that adsorption of nanoparticles to hydrogel fibers, which display domains that improve or do not affect drug encapsulation, can be explored as a means to optimize the development of supramolecular magnetogels to advance theranostic applications.Ministerio de Economía y Competitividad (MINECO, Spain) under the Grant (CTM2017-84050-R), Xunta de Galicia/FEDER (IN607A 2018/5 and Centro Singular de Investigación de Galicia accreditation 2019-2022, ED431G 2019/06), 0712_ACUINANO_1_E, 0624_2IQBIONEURO_6_E and NANOCULTURE cofounded by FEDER through the program Interreg V-A España-Portugal (POCTEP), NANOCULTURE (ERDF: 1.102.531) Interreg Atlantic Area, the European Union (European Regional Development Fund-ERDF)

Unraveling the multi-featured magnetic behavior of Nd0.75Sr0.25CoO3 perovskite nanocrystals annealed at different temperatures

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGPerovskite nanocrystals are gaining increased attention because of their magnetic, transport and catalytic properties, and particularly there is a renewable interest of cobalt perovskites for catalysis. Accordingly, the correct interpretation of their properties stemming from a particular configuration of the cations within this crystalline structure is compulsory. Herein, we report the synthesis of Nd0.75Sr0.25CoO3 nanocrystals using the citrate sol-gel method and annealed at different final temperatures (600 °C, 700 °C, 800 °C and 1150 °C). Their characterization was carried out combining transmission electron microscopy, X-ray diffraction, Raman spectroscopy and vibrating sample magnetometry, demonstrating their complementarity to get the whole picture of the multi-featured perovskite-based nanocrystal behavior.Xunta de Galicia | Ref. ED431C 2016-034Ministerio de Economía y Competitividad | Ref. CTM2017-84050-