Percorrer por autor "Gallo, Juan"
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- Development and characterization of magnetic nanoparticles for theranostic applicationsPublication . Rodrigues, Raquel Oliveira; Bañobre-López, Manuel; Gallo, Juan; Tavares, Pedro B.; Lima, Rui A.; Silva, Adrián; Gomes, HelderMagnetic nanoparticles (MNPs), especially iron oxide nanoparticles, have attracted much attention in the last decades due to their remarkable physicochemical and magnetic properties. These properties coupled with their low toxicological effects, make MNPs ideal for biomedical applications1. In addition, chemical functionalization with specific biocompatible targeting molecules provides them with the ability to selectively attach to cells or tissues.
- Development of highly hydrophilic yolk-shell Fe3O4@C magnetic nanoparticles: a potential tool for the theranostics of cancerPublication . Rodrigues, Raquel Oliveira; Doumett, Saer; Baldi, Giovanni; Bañobre-López, Manuel; Gallo, Juan; Lima, Rui A.; Silva, Adrián; Gomes, HelderDue to their remarkable physicochemical properties acquired at the nanoscale, magnetic nanoparticles (MNPs) are of interest in several disciplines, such as data storage, water purification, biochips and biomedicine (1). In order to prevent the oxidation of the MNPs, and their aggregation, several procedures have been developed to encapsulate them as a magnetic core (2). In particular, carboncoated nanoparticles have several advantages in comparison to polymer or silica coatings, since they usually offer higher chemical and thermal stability, large surface area, biocompatibility and easier functionalization (1, 3). These properties are especially important for biomedical applications, where MNPs should be chemically-functionalized with specific biocompatible targeting molecules to allow their selective attachment to cells or tissues.
- Development of stimuli-responsive graphene-based yolk-shell magnetic nanoparticles for controlled release of anticancer drugsPublication . Rodrigues, Raquel Oliveira; Baldi, Giovanni; Doumett, Saer; Bañobre-López, Manuel; Gallo, Juan; Dražić, Goran; Lima, Rui A.; Silva, Adrián; Gomes, HelderMagnetic drug delivery systems have attracted much attention in the last decades due to the possibility to improve the therapeutic efficacy of anticancer drugs, by enabling instable and poorly soluble drug agents to reach tumour cells after being guided by low magnetic fields and monitored by magnetic resonance imaging (MRI) [1]. Hence, a lower amount of anticancer drug is needed and the typical side effects of chemotherapy are minimized [2]. Commonly, these nanoparticles are designed with a magnetic core coated with a metal or a non-metal structure, such as gold or silica. However, these approaches present some drawbacks, such as low drug loading capacity and lack of stimuli-responsive release. Alternatively, carbon-coated magnetic nanoparticles offer higher chemical and thermal stability, larger surface area, biocompatibility and easier functionalization due to the high capacity of adsorption. Moreover, these materials have shown great ability to be used as pH stimuli-responsive controlled release platforms, due to the disruption of supramolecular interaction at acidic pH [3]. In this context, graphene-coated yolk-shell magnetic nanoparticles – hybrid materials comprising a superparamagnetic core coated by a graphene-based shell that covers a hollow region (i.e., Fe3O4@void@C), – were developed as super-drug nanocarriers systems, exhibiting high loading contents of the anticancer drug Doxorubicin due to the large cavity volume between the shell and the magnetic core, and a stimuliresponsive controlled release in response to acidic environments (pH 5), such as those found in tumour tissues. These results shed light on the development of new hybrid nanomaterials with high potential to be applied in biomedical applications.
- Enhanced performance of cobalt ferrite encapsulated in graphitic shell by means of AC magnetically activated catalytic wet peroxide oxidation of 4-nitrophenolPublication . Ribeiro, Rui; Gallo, Juan; Bañobre-López, Manuel; Silva, Adrián; Faria, Joaquim; Gomes, HelderHere we report preliminary catalytic wet peroxide oxidation (CWPO) experiments performed in the presence of an alternating current (AC) magnetic field. One ferromagnetic graphitic nanocomposite – composed by a cobalt ferrite core and a graphitic shell (CoFe2O4/MGNC), was employed in the process, here named magnetically activated catalytic wet peroxide oxidation (MA-CWPO). An aqueous solution containing 5.0 g L−1 of 4-nitrophenol (4-NP) to simulate a high strength polluted stream was used as model system. The experiments were performed at room temperature and atmospheric pressure, with stoichiometric amount of hydrogen peroxide (H2O2), pH=3 and CoFe2O4/MGNC catalyst load=5.0 g L−1 (corresponding to a 4-NP/CoFe2O4 mass ratio of 6.9, as CoFe2O4 accounts for 14.4 wt% of CoFe2O4/MGNC). It was shown that the performance of CWPO is enhanced upon application of an AC magnetic field (frequency of 533.9 kHz and magnitude of 240 G). As a result, high 4-NP mineralization was obtained by MA-CWPO (as reflected by a total organic carbon abatement of 79% after 4 h of reaction, instead of 39% in the absence of a magnetic field). This positive effect was ascribed to the localised increase of CoFe2O4/MGNC surface temperature resulting from heat release upon exposure of the nanoparticulated catalyst to an AC magnetic field, which accelerates the catalytic decomposition of H2O2 via hydroxyl radicals (HO%) formation.
- Haemocompatibility of iron oxide nanoparticles synthesized for theranostic applications: a high-sensitivity microfluidic toolPublication . Rodrigues, Raquel Oliveira; Bañobre-López, Manuel; Gallo, Juan; Tavares, Pedro B.; Silva, Adrián; Lima, Rui A.; Gomes, HelderThe poor heating efficiency of the most reported magnetic nanoparticles (MNPs), allied to the lack of comprehensive biocompatibility and haemodynamic studies, hampers the spread of multifunctional nanoparticles as the next generation of therapeutic bio-agents in medicine. The present work reports the synthesis and characterization, with special focus on biological/toxicological compatibility, of superparamagnetic nanoparticles with diameter around 18 nm, suitable for theranostic applications (i.e. simultaneous diagnosis and therapy of cancer). Envisioning more insights into the complex nanoparticle-red blood cells (RBCs) membrane interaction, the deformability of the human RBCs in contact with magnetic nanoparticles (MNPs) was assessed for the first time with a microfluidic extensional approach, and used as an indicator of haematological disorders in comparison with a conventional haematological test, i.e. the haemolysis analysis. Microfluidic results highlight the potential of this microfluidic tool over traditional haemolysis analysis, by detecting small increments in the rigidity of the blood cells, when traditional haemotoxicology analysis showed no significant alteration (haemolysis rates lower than 2 %). The detected rigidity has been predicted to be due to the wrapping of small MNPs by the bilayer membrane of the RBCs, which is directly related to MNPs size, shape and composition. The proposed microfluidic tool adds a new dimension into the field of nanomedicine, allowing to be applied as a highsensitivity technique capable of bringing a better understanding of the biological impact of nanoparticles developed for clinical applications.
- Multifunctional graphene-based magnetic nanocarriers for combined hyperthermia and dual stimuli-responsive drug deliveryPublication . Rodrigues, Raquel Oliveira; Baldi, Giovanni; Doumett, Saer; Garcia-Hevia, Lorena; Gallo, Juan; Bañobre-López, Manuel; Dražić, Goran; Calhelha, Ricardo C.; Ferreira, Isabel C.F.R.; Lima, Rui A.; Gomes, Helder; Silva, AdriánThe synthesis of hydrophilic graphene-based yolk-shell magnetic nanoparticles functionalized with copolymer pluronic F-127 (GYSMNP@PF127) is herein reported to achieve an efficient multifunctional biomedical system for mild hyperthermia and stimuli-responsive drug delivery. In vitro tests revealed the extraordinary ability of GYSMNP@PF127 to act as smart stimuli-responsive multifunctional nanomedicine platform for cancer therapy, exhibiting (i) an outstanding loading capacity of91% (w/w,representing 910μgmg−1) of the chemotherapeutic drug doxorubicin, (ii) a high heating efficiency under an alternating (AC) magnetic field (intrinsic power loss ranging from 2.1–2.7nHm2kg−1), and (iii) a dual pH and thermal stimuli-responsive drug controlled release (46% at acidic tumour pH vs 7% at physiological pH) under AC magnetic field, in just 30min. Additionally, GYSMNP@PF127 presents optimal hydrodynamic diameter (DH=180nm) with negative surface charge, high haemocompatibility for blood stream applications and tumour cellular uptake of drug nanocarriers. Due to its physicochemical, magnetic and biocompatibility properties, the developed graphene-based magnetic nanocarrier shows high promise as dual exogenous (AC field)/endogenous (pH) stimuli-responsive actuators for targeted thermo-chemotherapy, combining magnetic hyperthermia and controlled drug release triggered by the abnormal tumour environment. The presented strategy and findings can represent a new way to design and develop highly stable added-value graphene-based nanostructures for the combined treatment of cancer.
- A new microfluidic methodology to assess the haemocompatibility of magnetic nanoparticles designed for theranostic applicationsPublication . Rodrigues, Raquel Oliveira; Bañobre-López, Manuel; Gallo, Juan; Tavares, Pedro B.; Silva, Adrián; Gomes, Helder; Lima, Rui A.The remarkable physicochemical properties of magnetic nanoparticles (MNPs) at the nanoscale have boosted the development of new and promising strategies for the simultaneous diagnosis and treatment of diseases, particularly in cancer therapy Ð the so-called theranostic applications (1). In these strategies, the intrinsic superparamagnetic properties of MNPs have been exploited to gain access into multifunctional systems able to simultaneously perform as enhanced magnetic resonance imaging (MRI) contrast agents, efficient nanocarriers for drug delivery and nanoheaters in magnetic hyperthermia based therapy (2), among others.
- A Tailor-made protocol to synthesize yolk-shell graphene-based magnetic nanoparticles for nanomedicinePublication . Rodrigues, Raquel Oliveira; Baldi, Giovanni; Doumett, Saer; Gallo, Juan; Bañobre-López, Manuel; Dražić, Goran; Calhelha, Ricardo C.; Ferreira, Isabel C.F.R.; Lima, Rui A.; Silva, Adrián; Gomes, HelderA simple tailor-made protocol to synthesize graphene-based magnetic nanoparticles (GbMNPs) for nanomedicine is herein reported. Different GbMNPs with very distinctive physicochemical and toxicological properties were synthesized by adjusting the number of carbon precursors in the coating of superparamagnetic iron oxide nanoparticles. In vitro tests show the ability to use these GbMNPs as intelligent and on-demand drug nanocarrier systems for drug delivery, exhibiting the following features: good colloidal stability, good loading capacity of the chemotherapeutic drug doxorubicin, high pH-controlled release of the encapsulated drug (targeting tumour acidic pH conditions), superparamagnetic behaviour and biocompatibility. Due to their combined properties (i.e., physicochemical, magnetic, and biocompatibility), GbMNPs show high potentiality to be combined with other biomedical techniques, such as magnetic hyperthermia, which can represent an enhancement in the treatment of cancer.