Compuestos híbridos con nanopartículas plasmónicas o magnéticas funcionales alargadas para aplicaciones ambientales o biomédicas

The aim of this work is the development of plasmonic-magnetic nanoparticles hybrid systems as a multifunctional platform for synergic magnetic hyperthermia and photothermal therapy. Silica nanoparticles are going to be used as a template for plasmonic (gold NPS) and magnetic nanoparticles. The efficacy of the hybrid system to be synthesized will be evaluated by photocatalytic activity studies and external magnetic field applications. Eventually, their effects on tumor cells will be investigated in detail by cell culture studies.El objetivo de este trabajo es el desarrollo de sistemas híbridos de nanopartículas plasmónicas y magnéticas, como una plataforma multifuncional para la hipertermia magnética sinérgica y la terapia fototérmica. Las nanopartículas de sílice se utilizarán como soporte para las nanopartículas plasmónicas (NPS de oro) y magnéticas. La eficacia del sistema híbrido que se va a sintetizar se evaluará mediante estudios de actividad fotocatalítica y la aplicación de campos magnéticos externos. Finalmente, se investigan en detalle los efectos de estas estructuras en las células tumorales por medio de estudios de cultivos celulares.O obxectivo deste traballo é o desenvolvemento de sistemas híbridos de nanopartículas plasmónicas e magnéticas, como unha plataforma multifuncional para a hipertermia magnética sinérxica e a terapia fototérmica. As nanopartículas de sílice utilizaranse como soporte para as nanopartículas plasmónicas (NPS de ouro) e magnéticas. A eficacia do sistema híbrido que se vai sintetizar avaliarase mediante estudos de actividade fotocatalítica e a aplicación de campos magnéticos externos. Finalmente, investíganse en detalle os efectos destas estruturas nas células tumorais por medio de estudos de cultivos celulares

Magnetism Engineering in Antiferromagnetic β‑FeOOH Nanostructures via Chemically Induced Lattice Defects

Elongated akaganéite (β-FeOOH) nanostructures were synthesized through a simple hydrothermal route, in which a careful selection of the experimental conditions allows for a tunable length and aspect ratio and concomitantly predetermines the magnetic response. An in-depth structural characterization using transmission electron microscopy, X-ray diffraction, and Raman spectroscopy, jointly with DC magnetic measurements, reveals a complex scenario where the interstitial Cl– content dictates the β-FeOOH thermal stability and leads to the formation of bulk uncompensated spins along the inner channels. The coexistence of different magnetic contributions is observed to result in a non-monotonic dependence of the coercivity and exchange bias field on both temperature and size, posing major limitations for the archetypical magnetic core–shell model generally assumed for nanostructured antiferromagnets. As a proof of concept, we further show how the β-FeOOH internal microstructure can be chemically manipulated through Cl– anion exchange, giving rise to a superparamagnetic component that comes along with an almost 20-fold increase in the coercivity at low temperature. The evaluation of these results reveals the potential of controlling the interplay between the crystal and magnetic structure via intercalation chemistry in antiferromagnets, expanding fundamental science knowledge and supporting practical applications, given their huge role in the technological fields of spintronics and magnonics

Tuning the drug multimodal release through a co-assembly strategy based on magnetic gels

Self-assembled short peptide-based gels are highly promising drug delivery systems. However, implementing a stimulus often requires screening different structures to obtain gels with suitable properties, and drugs might not be well encapsulated and/or cause undesirable effects on the gel's properties. To overcome this challenge, a new design approach is presented to modulate the release of doxorubicin as a model chemotherapeutic drug through the interplay of (di)phenylalanine-coated magnetic nanoparticles, PEGylated liposomes and doxorubicin co-assembly in dehydropeptide-based gels. The composites enable an enhancement of the gelation kinetics in a concentration-dependent manner, mainly through the use of PEGylated liposomes. The effect of the co-assembly of phenylalanine-coated nanoparticles with the hydrogel displays a concentration and size dependence. Finally, the integration of liposomes as doxorubicin storage units and of nanoparticles as composites that co-assemble with the gel matrix enables the tuneability of both passive and active doxorubicin release through a thermal, and a low-frequency alternating magnetic field-based trigger. In addition to the modulation of the gel properties, the functionalization with (di)phenylalanine improves the cytocompatibility of the nanoparticles. Hereby, this work paves a way for the development of peptide-based supramolecular systems for on-demand and controlled release of drugs.This work was funded by Ministerio de Economia y Competitividad de Espana (PID2020-113704RB-I00 and PID2020-119242RB-I00), Xunta de Galicia (Centro Singular de Investigacion 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, and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UIDB/04650/2020), IPC (UID/CTM/50025/2020) and CQUM (UIDB/00686/2020). FCT, FEDER, PORTUGAL2020 and COMPETE2020 are also acknowledged for funding under research projects PTDC/QUI-QFI/28020/2017 (POCI-01-0145-FEDER-028020) and PTDC/QUI-QOR/29015/2017 (POCI-01-0145-FEDER-029015). S. R. S. Veloso acknowledges FCT for a PhD grant (SFRH/BD/144017/2019). Support from MAP-Fis Doctoral Programme is also acknowledged