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Institute for Bioengineering and Biosciences
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Magnetic-Responsive Liposomal Hydrogel Membranes for Controlled Release of Small Bioactive Molecules
Publication . Pereira, Luís; Ferreira, Frederico Castelo; Pires, Filipa; Portugal, Carla A. M.; DQ - Departamento de Química; LAQV@REQUIMTE; MDPI AG
This work explores the unique features of magnetic-responsive hydrogels to obtain liposomal hydrogel delivery platforms capable of precise magnetically modulated drug release based on the mechanical responses of these hydrogels when exposed to an external magnetic field. Magnetic-responsive liposomal hydrogel delivery systems were prepared by encapsulation of 1,2-dipalmitoyl-sn-glycero-3-phosphocoline (DPPC) multilayered vesicles (MLVs) loaded with ferulic acid (FA), i.e., DPPC:FA liposomes, into gelatin hydrogel membranes containing dispersed iron oxide nanoparticles (MNPs), i.e., magnetic-responsive gelatin. The FA release mechanisms and kinetics from magnetic-responsive liposomal gelatin were studied and compared with those obtained with conventional drug delivery systems, e.g., free liposomal suspensions and hydrogel matrices, to access the effect of liposome entrapment and magnetic field on FA delivery. FA release from liposomal gelatin membranes was well described by the Korsmeyer–Peppas model, indicating that FA release occurred under a controlled diffusional regime, with or without magnetic stimulation. DPPC:FA liposomal gelatin systems provided smoother controlled FA release, relative to that obtained with the liposome suspensions and with the hydrogel platforms, suggesting the promising application of liposomal hydrogel systems in longer-term therapeutics. The magnetic field, with low intensity (0.08 T), was found to stimulate the FA release from magnetic-responsive liposomal gelatin systems, increasing the release rates while shifting the FA release to a quasi-Fickian mechanism. The magnetic-responsive liposomal hydrogels developed in this work offer the possibility to magnetically activate drug release from these liposomal platforms based on a non-thermal related delivery strategy, paving the way for the development of novel and more efficient applications of MLVs and liposomal delivery systems in biomedicine.
Long-lived NIR emission in sulfur-doped zeolites due to the presence of [S3]2- clusters
Publication . Viola, Catarina; Laia, César A. T.; Outis, Mani; Ferreira, Luís F. V.; Alves, Luís C.; Teixeira, Miguel; Folgosa, Filipe; Lima, João C.; Ruivo, Andreia; Avó, João; DQ - Departamento de Química; LAQV@REQUIMTE; VICARTE - Vidro e Cerâmica para as Artes; Instituto de Tecnologia Química e Biológica António Xavier (ITQB); Elsevier
The exploration of novel long-lived near-infrared (NIR) luminescent materials has attracted significant attention due to their applications in optical communications, anticounterfeiting, and bioimaging. However, these materials usually present low photoluminescence quantum yields and low photo- and chemical stability. Novel emitters that overcome these limitations are in demand. In this study, NIR emission was achieved using widely available, sustainable, and non-toxic materials through the synthesis of sulfur-doped zeolites, with different S/Cl ratios. With a combination of computational calculations (TD-DFT) and spectroscopic data, this emission was assigned to the radiative decay of excited triplet states of [S3]2- clusters, which resulted in a remarkably high Stokes shift (1.97 eV, 440 nm) and an average decay time of 0.54 ms. These new materials present high stability, external quantum efficiency of up to 17%, and a long-lived NIR emission, placing these compounds in a unique position to be used in applications demanding NIR emitters.
Valorisation of spent tire rubber as carbon adsorbents for Pb(II) and W(VI) in the framework of a Circular Economy
Publication . Bernardo, Maria; Lapa, Nuno; Pinto, Filomena; Nogueira, Miguel; Matos, Inês; Ventura, Márcia; Ferraria, Ana Maria; Rego, Ana Maria Botelho do; Fonseca, Isabel Maria; DQ - Departamento de Química; LAQV@REQUIMTE; Springer
Spent tire rubber-derived chars and their corresponding H3PO4 and CO2-activated chars were used as adsorbents in the recovery of Pb(II) ion and (W(VI)) oxyanion from synthetic solutions. The developed chars (both raw and activated) were thoroughly characterized to have insight about their textural and surface chemistry properties. H3PO4-activated chars presented lower surface areas than the raw chars and an acidic surface chemistry which affected the performance of these samples as they showed the lowest removals of the metallic ions. On the other hand, CO2-activated chars presented increased surface areas and increased mineral content compared to the raw chars, having presented higher uptake capacities for both Pb(II) (103–116 mg/g) and W(VI) (27–31 mg/g) ions. Cation exchange with Ca, Mg and Zn ions was appointed as a mechanism for Pb removal, as well as surface precipitation in the form of hydrocerussite (Pb3(CO3)2(OH)2). W(VI) adsorption might have been ruled by strong electrostatic attractions between the negatively charged tungstate species and the highly positively charged carbons’ surface. The results shown in this work allow concluding that the valorisation of spent tire rubber through pyrolysis and the subsequent activation of the obtained chars is an alternative and a feasible option to generate adsorbent materials with a high uptake capacity of critical metallic elements.
Towards Cost-Efficient Culture of Human Induced Pluripotent Stem Cells in Vertical-Wheel Bioreactors
Publication . Salvador, William Lewis Sullivan Coutinho de Oliveira e Sousa; Rodrigues, Carlos; Henriques, Célia
Human induced pluripotent stem cells (hiPSCs) have the ability to self-renew and to
differentiate into any cell type of the human body. For this reason they possess various
promising applications in disease modeling, drug discovery and regenerative medicine.
However, these applications require large quantities of hiPSCs, in the range of one to ten
billion cells. This work sought to identify and explore strategies with the potential to establish
an economically viable bioprocess capable of producing these large quantities of hiPSCs.
Vertical-wheel bioreactors (VWBRs) and B8 culture medium are among these strategies. An
economic model of a bioprocess envisaging the large-scale expansion of hiPSCs was
developed. The model allowed for the confirmation and quantification of the economic impact
of the considered strategies. It was observed that the supplementation of the culture medium
with dextran sulfate significantly reduced the total bioprocess cost by 38%. The same occurs
when low seeding densities are employed, with a reduction of 29%. The use of B8 instead of a
commercial medium achieves a reduction of 58% in the best case scenario. At the same time,
this work sought to reproduce the B8 formula so that it could be tested jointly with VWBRs.
The B8 produced was ineffective at maintaining the viability of hiPSCs, although it did not
negatively affect their expression of pluripotency markers. The implementation of the
strategies analyzed in this work could contribute towards the establishment of the desired
bioprocess, promoting the realization of the predicted applications of hiPSCs.
Magnetic stimulation of the angiogenic potential of mesenchymal stromal cells in vascular tissue engineering
Publication . Manjua, Ana C.; Cabral, Joaquim M. S.; Portugal, Carla A. M.; Ferreira, Frederico Castelo; LAQV@REQUIMTE; DQ - Departamento de Química; Taylor & Francis
The growing prevalence of vascular diseases worldwide has emphasized the need for novel tissue-engineered options concerning the development of vascularized 3D constructs. This study reports, for the first time, the use of external magnetic fields to stimulate mesenchymal stromal cells (MSCs) to increase the production of vascular endothelial growth factor-A (VEGF-A). Polyvinylalcohol and gelatin-based scaffolds, containing iron oxide nanoparticles, were designed for optimal cell magnetic stimulation. While the application of static magnetic fields over 24 h did not impact on MSCs proliferation, viability and phenotypic identity, it significantly increased the production of VEGF-A and guided MSCs morphology and alignment. The ability to enhance MSCs angiogenic potential was demonstrated by the increase in the number of new vessels formed in the presence of MSCs conditioned media through in vitro and in vivo models. Ultimately, this study uncovers the potential to manipulate cellular processes through short-term magnetic stimulation.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
UIDB/04565/2020