24 research outputs found
Modulation of the Magnetic Hyperthermia Response Using Different Superparamagnetic Iron Oxide Nanoparticle Morphologies
Financial support from the Spanish Institutions: Mineco, (RyC-2014-16901),
Ministerio de Ciencia, Innovación y Universidades (PGC2018-098770-B-I00), and Junta de Andalucía
(Programa Operativo Feder 2014-2020, grants BF-FQM-141-UGR18, A1-FQM-34-UGR-18, C-FQM-
497-UGR18) is gratefully acknowledged.The use of magnetic nanoparticles in hyperthermia, that is, heating induced by alternating magnetic fields, is gaining interest as a non-invasive, free of side effects technique that can be considered as a co-adjuvant of other cancer treatments. Having sufficient control on the field characteristics, within admissible limits, the focus is presently on the magnetic material. In the present contribution, no attempt has been made of using other composition than superparamagnetic iron oxide nanoparticles (SPION), or of applying surface functionalization, which opens a wider range of choices. We have used a hydrothermal synthesis route that allows preparing SPION nanoparticles in the 40 nm size range, with spherical, cuboidal or rod-like shapes, by minor changes in the synthesis steps. The three kinds of particles (an attempt to produce star-shaped colloids yielded hematite) were demonstrated to have the magnetite (or maghemite) crystallinity. Magnetization cycles showed virtually no hysteresis and demonstrated the superparamagnetic nature of the particles, cuboidal ones displaying saturation magnetization comparable to bulk magnetite, followed by rods and spheres. The three types were used as hyperthermia agents using magnetic fields of 20 kA/m amplitude and frequency in the range 136-205 kHz. All samples demonstrated to be able to raise the solution temperature from room values to 45 degrees C in a mere 60 s. Not all of them performed the same way, though. Cuboidal magnetic nanoparticles (MNPs) displayed the maximum heating power (SAR or specific absorption rate), ranging in fact among the highest reported with these geometries and raw magnetite composition.Mineco
RyC-2014-16901Ministerio de Ciencia, Innovacion y Universidades
PGC2018-098770-B-I00Junta de Andalucia
BF-FQM-141-UGR18
A1-FQM-34-UGR-18
C-FQM-497-UGR1
Hyperthermia-Triggered Gemcitabine Release from Polymer-Coated Magnetite Nanoparticles
In this work a combined, multifunctional platform, which was devised for the simultaneous
application of magnetic hyperthermia and the delivery of the antitumor drug gemcitabine, is
described and tested in vitro. The system consists of magnetite particles embedded in a polymer
envelope, designed to make them biocompatible, thanks to the presence of poly (ethylene glycol) in
the polymer shell. The commercial particles, after thorough cleaning, are provided with carboxyl
terminal groups, so that at physiological pH they present negative surface charge. This was proved by
electrophoresis, and makes it possible to electrostatically adsorb gemcitabine hydrochloride, which is
the active drug of the resulting nanostructure. Both electrophoresis and infrared spectroscopy are
used to confirm the adsorption of the drug. The gemcitabine-loaded particles are tested regarding
their ability to release it while heating the surroundings by magnetic hyperthermia, in principle
their chances as antitumor agents. The release, with first-order kinetics, is found to be faster when
carried out in a thermostated bath at 43 ºC than at 37 ºC, as expected. But, the main result of this
investigation is that while the particles retain their hyperthermia response, with reasonably high
heating power, they release the drug faster and with zeroth-order kinetics when they are maintained
at 43 ºC under the action of the alternating magnetic field used for hyperthermia.This research work is supported by MINECO Ramón y Cajal programme (RYC-2014-16901);
Junta de Andalucía (PE2012-FQM694) and Feder Funds UE
Improving the Cellular Uptake of Biomimetic Magnetic Nanoparticles
This research was funded by the FUR (Fondo Unico della Ricerca—University of Verona)
of M. Perduca. C.J.-L. acknowledges funding from projects CGL2016-76723 from the Ministerio de
Economía y Competitividad from Spain and Fondo Europeo de Desarrollo Regional (FEDER) and Programa
Operativo FEDER 2014–2020 (A-BIO-376-UGR18) Junta de Andalucia. M.P.C.-J. acknowledges
funding from projects PID2019-109294RB-100 from the Ministerio de Ciencia e Innovación from Spain.We are grateful to the “Centro Piattaforme Tecnologiche” of the University of
Verona for giving access to DLS equipment. CJL acknowledges. the Unidad Cientıfica de Excelencia
UCE PP 2016.05 (U. Granada) and Instituto de Biotecnología. Y.J. wants to acknowledge a FPU2016
grant (ref. FPU16_04580) from the Ministerio de Educación, Ciencia y Deporte y Competitividad
(Spain). AS-L is funded by the Spanish Ministry of Science, Innovation and Universities: Formación
de Doctores 2018 (ref. PRE2018-0854409). Thanks go to the Scientific Instrumentation Center (CIC)
personnel of the University of Granada for technical assistance with the TEM.We also thank Salvatore
Calogero Gaglio for his help in preparing Figure S4.Magnetococcus marinus magnetosome-associated protein MamC, expressed as recombinant, has been proven to mediate the formation of novel biomimetic magnetic nanoparticles (BMNPs) that are successful drug nanocarriers for targeted chemotherapy and hyperthermia agents. These BMNPs present several advantages over inorganic magnetic nanoparticles, such as larger sizes that allow the former to have larger magnetic moment per particle, and an isoelectric point at acidic pH values, which allows both the stable functionalization of BMNPs at physiological pH value and the molecule release at acidic (tumor) environments, simply based on electrostatic interactions. However, difficulties for BMNPs cell internalization still hold back the efficiency of these nanoparticles as drug nanocarriers and hyperthermia agents. In the present study we explore the enhanced BMNPs internalization following upon their encapsulation by poly (lactic-co-glycolic) acid (PLGA), a Food and Drug Administration (FDA) approved molecule. Internalization is further optimized by the functionalization of the nanoformulation with the cell-penetrating TAT peptide (TATp). Our results evidence that cells treated with the nanoformulation [TAT-PLGA(BMNPs)] show up to 80% more iron internalized (after 72 h) compared to that of cells treated with BMNPs (40%), without any significant decrease in cell viability. This nanoformulation showing optimal internalization is further characterized. In particular, the present manuscript demonstrates that neither its magnetic properties nor its performance as a hyperthermia agent are significantly altered due to the encapsulation. In vitro experiments demonstrate that, following upon the application of an alternating magnetic field on U87MG cells treated with BMNPs and TAT-PLGA(BMNPs), the cytotoxic effect of BMNPs was not affected by the TAT-PLGA enveloping. Based on that, difficulties shown in previous studies related to poor cell uptake of BMNPs can be overcome by the novel nanoassembly described here.FUR (Fondo Unico della Ricerca-University of Verona)Ministerio de Economia y Competitividad from Spain
CGL2016-76723European Commission
CGL2016-76723Junta de Andalucia
A-BIO-376-UGR18Spanish Government
PID2019-109294RB-10
Synergistic Photothermal-Chemotherapy Based on the Use of Biomimetic Magnetic Nanoparticles
MamC-mediated biomimetic magnetic nanoparticles (BMNPs) have emerged as one of
the most promising nanomaterials due to their magnetic features (superparamagnetic character and
large magnetic moment per particle), their novel surface properties determined by MamC, their
biocompatibility and their ability as magnetic hyperthermia agents. However, the current clinical
application of magnetic hyperthermia is limited due to the fact that, in order to be able to reach
an effective temperature at the target site, relatively high nanoparticle concentration, as well as
high magnetic field strength and/or AC frequency are needed. In the present study, the potential
of BMNPs to increase the temperature upon irradiation of a laser beam in the near infrared, at
a wavelength at which tissues become partially transparent, is explored. Moreover, our results
also demonstrate the synergy between photothermia and chemotherapy in terms of drug release
and cytotoxicity, by using BMNPs functionalized with doxorubicin, and the effectiveness of this
combination therapy against tumor cells in in vitro experiments. Therefore, the findings of the
present study open the possibility of a novel, alternative approach to fight localized tumors.Ministerio de Economía y Competitividad (CGL2016-
76723 and PID2019-109294RB-100 projects)Ramón y Cajal program (RYC-2014-16901)Junta de
Andalucía. Programa Operativo FEDER 2014–2020. (A1-FQM-341-UGR18, C-FQM-497-UGR18, A-BIO376-UGR18).Andalusian regional government (CTS-236)Formación de Doctores 2018 grant (ref. PRE2018-085440) from the Ministerio de
Ciencia, Innovación y Universidades (Spain)Unidad Cientifica de Excelencia UCE-PP2016-05Instituto de Biotecnología of the University of
Granad
Assembly of Soft Electrodes and Ion Exchange Membranes for Capacitive Deionization
The responsible use of water, as well as its reuse and purification, has been a major problem
for decades now. In this work, we study a method for adsorbing ions from aqueous solutions on
charged interfaces using highly porous electrodes. This water purification process is based on the
electric double layer concept, using the method known as capacitive deionization (CDI): If we pump
salty solutions through the volume comprised between two porous electrodes while applying a
potential difference to them, ions present in the solution are partially removed and trapped on the
electrode surfaces. It has been well established that the use of carbon electrodes in combination with
ion exchange membranes (membrane-CDI) improves the efficiency of the method above that achieved
with bare activated carbon. Another approach that has been tested is based on coating the carbon
with polyelectrolyte layers, converting them into “soft electrodes” (SEs). Here we investigate the
improvement found when combining SEs with membranes, and it is shown that the amount of ions
adsorbed and the ratio between ions removed and electrons transported reach superior values, also
associated with a faster kinetics of the process. The method is applied to the partial desalination of up
to 100 mM NaCl solutions, something hardly achievable with bare or membrane-covered electrodes.
A theoretical model is presented for the ion transport in the presence of both the membrane and the
polyelectrolyte coating.This research was funded by MINECO, Spain, grant number PGC2018-098770-B-I00 and RYC-2014-1690
Stacking of capacitive cells for electrical energy production by salinity exchange
Publisher's link: http://www.sciencedirect.com/science/article/pii/S0378775316303676?np=yHa estado embargado durante 1 año, hasta julio 2017In this paper we explore methods for stacking individual cells in order to increase the amount of energy that can be extracted from salinity gradient cycles (capmix methods). Each of the cells consists of a pair of parallel electrodes made of activated carbon particles, either bare or coated by a layer of polyelectrolyte. In these methods, energy is produced based on the modifications in the electrical double layer (EDL) structure in the pores of the carbon particles upon exchange of the salinity of the surrounding medium. In the case of the bare carbon particles, the electrodes are externally charged in presence of high-salt concentration, and discharged after exchanging the solution for a dilute one (sea- vs. river-water cycles). In a first stacking approach, we simply connect the electrodes side-by-side and only the outermost ones can be connected to the external source. Using a stack where potential and current between cells can be measured, it is shown that only the external electrodes seem to work, and it is suggested that this is a consequence of internal short-circuit currents between oppositely charged electrodes of different cells through the electrolyte. In contrast, the side-by-side configuration is operational if coated electrodes are used.MICINN, Spain (Project FIS2013-47666-C3-1R)RYC-2014-16901 (MINECO)FEDER Funds E
New energy sources: Blue energy study in Central America
The following article has been submitted to/accepted by Journal of Renewable and Sustainable Energy. After it is published, it will be found at http://dx.doi.org/10.1063/1.4976326.Blue energy or salinity difference energy takes advantage of the free energy released in the mixture of two
solutions with different salinity concentrations as it happens continuously in river mouths. Among the large
number of available techniques that aim to harness blue energy, capmix (or capacitive mixing) methods allow
to directly extract electrical energy without the need of any electromechanical converter such as turbines or
heat engines. The main goal of this article is to analyze the potential of blue energy by capmix methods in
Central America. So far, blue energy studies have been principally carried out in countries from the global
North. Therefore, we describe experimental results with real sea and river waters from the Gulf of Fonseca,
an area of special interest due to its hydrographic richness, which is situated among Honduras, El Salvador
and Nicaragua. An electrochemical cell, which consists of a pair of activated carbon electrodes coated with
cationic and anionic polyelectrolyte layers respectively, is used in the experiments. The cell voltage in open
circuit (OCV) is used as a measure of the performance of the capmix process. It is found that the OCV is
larger when natural river water is used instead of low salinity NaCl solutions. The rainy season in which
the experiments were performed reduced the ionic content of the river, increasing the salinity difference with
ocean waters. The feasibility of capmix as a means of clean energy production is discussed.Eureka SD Project
(agreement number 2013-2591), Erasmus Mundus programme of the European Union.Ministerio de Economía y Competitividad of Spain (Project FIS2013-47666-C3-
1-R)Junta de Andalucía (Spain) project PE-2012-
FQM0694EU FEDER FUND
Poly(ethylene-imine)-Functionalized Magnetite Nanoparticles Derivatized with Folic Acid: Heating and Targeting Properties
Magnetite nanoparticles (MNPs) coated by branched poly (ethylene-imine) (PEI) were
synthesized in a one-pot. Three molecular weights of PEI were tested, namely, 1.8 kDa (sample
MNP-1), 10 kDa (sample MNP-2), and 25 kDa (sample MNP-3). The MNP-1 particles were further
functionalized with folic acid (FA) (sample MNP-4). The four types of particles were found to behave
magnetically as superparamagnetic, with MNP-1 showing the highest magnetization saturation.
The particles were evaluated as possible hyperthermia agents by subjecting them to magnetic fields
of 12 kA/m strength and frequencies ranging between 115 and 175 kHz. MNP-1 released the
maximum heating power, reaching 330 W/g at the highest frequency, in the high side of reported
values for spherical MNPs. In vitro cell viability assays of MNP-1 and MNP-4 against three cell
lines expressing different levels of FA receptors (FR), namely, HEK (low expression), and HeLa (high
expression), and HepG2 (high expression), demonstrated that they are not cytotoxic. When the cells
were incubated in the presence of a 175 kHz magnetic field, a significant reduction in cell viability
and clone formation was obtained for the high expressing FR cells incubated with MNP-4, suggesting
that MNP-4 particles are good candidates for magnetic field hyperthermia and active targeting.Spanish Institutions: Ministerio de Ciencia, Innovación y
Universidades (PGC2018-098770-B-I00 and CTQ2017-86125-P)Junta de Andalucía (ProgramaOperativo FEDER 2014-2020, grants B-FQM-141-UGR18, A1-FQM-341-UGR-18, C-FQM-497-UGR18
Combined Magnetic Hyperthermia and Photothermia with Polyelectrolyte/Gold-Coated Magnetic Nanorods
Magnetite nanorods (MNRs) are synthesized based on the use of hematite nanoparticles of the desired geometry and dimensions as templates. The nanorods are shown to be highly monodisperse, with a 5:1 axial ratio, and with a 275 nm long semiaxis. The MNRs are intended to be employed as magnetic hyperthermia and photothermia agents, and as drug vehicles. To achieve a better control of their photothermia response, the particles are coated with a layer of gold, after applying a branched polyethyleneimine (PEI, 2 kDa molecular weight) shell. Magnetic hyperthermia is performed by application of alternating magnetic fields with frequencies in the range 118-210 kHz and amplitudes up to 22 kA/m. Photothermia is carried out by subjecting the particles to a near-infrared (850 nm) laser, and three monochromatic lasers in the visible spectrum with wavelengths 480 nm, 505 nm, and 638 nm. Best results are obtained with the 505 nm laser, because of the proximity between this wavelength and that of the plasmon resonance. A so-called dual therapy is also tested, and the heating of the samples is found to be faster than with either method separately, so the strengths of the individual fields can be reduced. Due to toxicity concerns with PEI coatings, viability of human hepatoblastoma HepG2 cells was tested after contact with nanorod suspensions up to 500 mu g/mL in concentration. It was found that the cell viability was indistinguishable from control systems, so the particles can be considered non-cytotoxic in vitro. Finally, the release of the antitumor drug doxorubicin is investigated for the first time in the presence of the two external fields, and of their combination, with a clear improvement in the rate of drug release in the latter case.Ministry of Science and Innovation, Spain (MICINN) EQC2019-005930-PSpanish Government PID2019109294RB-100Junta de AndaluciaEuropean CommissionConsejeria de Economia y Conocimiento/Proyectos de I + D + I del Plan Andaluz de Investigacion, Desarrollo e Innovacion/Grants P20_00346, P20_0023
Polyelectrolyte-coated carbons used in the generation of blue energy from salinity differences
This is the unedited version of this manuscript. The publisher's edited version can be reached at this URL: http://pubs.rsc.org/en/content/articlelanding/2014/cp/c4cp03527e#!divAbstractIn this work we present a method for the production of
clean, renewable electrical energy from the exchange of
solutions with different salinities. Activated carbon films
are coated with negatively or positively charged polyelectrolytes
by well-established adsorption methods. When
two oppositely charged coated films are placed in contact
with an ionic solution, the potential difference between
them will be equal to the difference between their Donnan
potentials, and hence, energy can be extracted by building
an electrochemical cell with such electrodes. A model is
elaborated on the operation of the cell, based on the electrokinetic
theory of soft particles. All the features of the
model are experimentally reproduced, although a small
quantitative difference concerning the maximum opencircuit
voltage is found, suggesting that the coating is the
key point to improve the efficiency. In the used experimental
conditions, we obtain a power of 12.1 mW/m2. Overall,
the method proves to be a fruitful and simple approach to
salinity-gradient energy production.
Obtaining energy from salinity differences asDepartamento de Física AplicadaThe research leading to these results received funding from the European Union 7th Framework Programme (FP7/2007-2013) under agreement No. 256868. Further financial sup-
ports from Junta de Andalucía, project PE2012-FQM694, and Ministerio de Economía y Competitividad (Spain), project
FIS2013-47666-C3-1-R