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Da Silva L.P.,ICVS 3Bs PT Government Asociate Laboratory | Cerqueira M.T.,ICVS 3Bs PT Government Asociate Laboratory | Sousa R.A.,ICVS 3Bs PT Government Asociate Laboratory | Reis R.L.,ICVS 3Bs PT Government Asociate Laboratory | And 2 more authors.
Acta Biomaterialia | Year: 2014

The similarity between the extracellular matrix of soft tissue and hydrogels, characterized by high-water-content viscoelastic polymeric networks, has been sustaining the advancement of hydrogels for tissue engineering and regenerative medicine (TERM) purposes. Current research on hydrogels has focused on introducing cell-adhesive peptides to promote cell adhesion and spreading, a critical applicability limitation. Here we report the development of gellan gum (GG) spongy-like hydrogels with ameliorated mechanical performance and flexibility in relation to hydrogels, using a simple and cost-effective method. Most importantly, these materials allow the entrapment of different cell types representing mesenchymal, epidermal and osteoblastic phenotypes that spread within the three-dimensional microstructure. This effect was associated with microstructural rearrangements characterized by pore wall thickening and pore size augmentation, and lower water content than precursor hydrogels. These properties significantly affected protein adsorption once cell adhesion was inhibited in the absence of serum. Spongy-like hydrogels are not adhesive for endothelial cells; however, this issue was surpassed by a pre-incubation with a cell-adhesive protein, as demonstrated for other substrates but not for traditional hydrogels. The proposed cell-compatible GG-based structures avoid time-consuming and expensive strategies that have been used to include cell-adhesive features in traditional hydrogels. This, associated with their off-the-shelf availability in an intermediary dried state, represents unique and highly relevant features for diverse TERM applications. © 2014 Acta Materialia Inc.

Branca M.,National Institute of Health ISS | Longatto-Filho A.,University of Sao Paulo | Longatto-Filho A.,Molecular Oncology Research Center | Longatto-Filho A.,University of Minho | Longatto-Filho A.,ICVS 3Bs PT Government Asociate Laboratory
Acta Cytologica | Year: 2015

Objective: We aimed to critically evaluate the importance of quality control (QC) and quality assurance (QA) strategies in the routine work of uterine cervix cytology. Study Design: We revised all the main principles of QC and QA that are already being implemented worldwide and then discussed the positive aspects and limitations of these as well as proposing alternatives when pertinent. Results: A literature review was introduced after highlighting the main historical revisions, and then a critical evaluation of the principal innovations in screening programmes was conducted, with recommendations being postulated. Conclusions: Based on the analysed data, QC and QA are two essential arms that support the quality of a screening programme. © 2015 © 2015 S. Karger AG, Basel.

Topete A.,University of Santiago de Compostela | Alatorre-Meda M.,University of Santiago de Compostela | Alatorre-Meda M.,University of Minho | Alatorre-Meda M.,ICVS 3Bs PT Government Asociate Laboratory | And 6 more authors.
ACS Nano | Year: 2014

Here we report the synthesis of PLGA/DOXO-core Au-branched shell nanostructures (BGNSHs) functionalized with a human serum albumin/indocyanine green/folic acid complex (HSA-ICG-FA) to configure a multifunctional nanotheranostic platform. First, branched gold nanoshells (BGNSHs) were obtained through a seeded-growth surfactant-less method. These BGNSHs were loaded during the synthetic process with the chemotherapeutic drug doxorubicin, a DNA intercalating agent and topoisomerase II inhibitior. In parallel, the fluorescent near-infrared (NIR) dye indocyanine green (ICG) was conjugated to the protein human serum albumin (HSA) by electrostatic and hydrophobic interactions. Subsequently, folic acid was covalently attached to the HSA-ICG complex. In this way, we created a protein complex with targeting specificity and fluorescent imaging capability. The resulting HSA-ICG-FA complex was adsorbed to the gold nanostructures surface (BGNSH-HSA-ICG-FA) in a straightforward incubation process thanks to the high affinity of HSA to gold surface. In this manner, BGNSH-HSA-ICG-FA platforms were featured with multifunctional abilities: the possibility of fluorescence imaging for diagnosis and therapy monitoring by exploiting the inherent fluorescence of the dye, and a multimodal therapy approach consisting of the simultaneous combination of chemotherapy, provided by the loaded drug, and the potential cytotoxic effect of photodynamic and photothermal therapies provided by the dye and the gold nanolayer of the hybrid structure, respectively, upon NIR light irradiation of suitable wavelength. The combination of this trimodal approach was observed to exert a synergistic effect on the cytotoxicity of tumoral cells in vitro. Furthermore, FA was proved to enhance the internalization of nanoplatform. The ability of the nanoplatforms as fluorescence imaging contrast agents was tested by preliminary analyzing their biodistribution in vivo in a tumor-bearing mice model. © 2014 American Chemical Society.

Barroso T.R.G.,University of Minho | Barroso T.R.G.,ICVS 3Bs PT Government Asociate Laboratory | Barroso T.R.G.,International Iberian Nanotechnology Laboratory | Martins V.C.,International Iberian Nanotechnology Laboratory | And 8 more authors.
Journal of Nano Research | Year: 2015

Tuberculosis is still a major global health concern, causing the estimated death of 1.5 million people per year and being associated with high morbidity. The development of point-of-care diagnostic tools for tuberculosis is mandatory, especially because the fast and accurate detection of the slow-growing Mycobacterium tuberculosis by the conventional diagnostic tests is difficult. The objective of this work was to develop the first steps to achieve a portable method for the diagnosis of tuberculosis, by a sandwich-immunoassay combined with magnetoresistive biochip technology. With the purpose of conjugating 250 nm streptavidin-coated magnetic nanoparticles with anti-M. tuberculosis biotinylated antibodies, Mycobacterium bovis Bacillus Calmette-Guérin was used as a surrogate for M. tuberculosis bacteria. After magnetic capture, target bacteria were brought in contact with the surface of the magnetoresistive biochip previously functionalized with a secondary anti-M. tuberculosis antibody. Magnetically labeled cells were detected by an array of spin-valve sensors, which change their electrical resistance in the presence of the fringe field of the magnetic particles. Optimization studies on the efficiency of the magnetic capture and further recognition of the bacteria by the secondary antibody on the biochip surface were conducted. The results on the magnetoresistive biochip showed a clear difference in the signal between specific and control (nonspecific) sensors, suggesting the usefulness of this technique as a potential biorecognition tool for the development of a point-of-care diagnostic method for tuberculosis.

Oliveira M.B.,European Institute of Excellence on Tissue Engineering and Regenerative Medicine | Oliveira M.B.,ICVS 3Bs PT Government Asociate Laboratory | Luz G.M.,European Institute of Excellence on Tissue Engineering and Regenerative Medicine | Luz G.M.,ICVS 3Bs PT Government Asociate Laboratory | And 2 more authors.
Journal of Materials Chemistry B | Year: 2014

Nanocomposite hydrogels were prepared in a combinatorial way with chitosan, bioglass nanoparticles (BG-NPs) and distinct amounts of crosslinker (genipin), in a total of 30 formulations. Such miniaturized hydrogels were prepared by dispensing the precursor solutions in wettable spots previously patterned onto superhydrophobic surfaces. The chips were used as platforms to analyze the biomaterials on-chip both for mechanical/viscoelastic and cell-biomaterial interactions. We adapted a mechanical dynamic analyzer (DMA) in order to perform the in situ totally unconfined solid-state rheological characterization of biomaterials under physiological-like conditions. We concluded that the viscoelastic properties of the hydrogels are dependent on the three factors studied. Besides influencing biomaterials' mechanical properties, bioglass fillers also confer bioactivity. We immersed the chips with 20 distinct biomaterial formulations in a cell suspension of MC3T3-E1 pre-osteoblasts and quantified-using image analysis compatible with the maintenance of the integrity of the chip-selective cell adhesion after 1 day of cell culture, as well as cell proliferation and cell morphology at day 3. Linear regression studies showed that for the range of conditions studied herein, neither cell adhesion nor proliferation depended directly on the biomaterials' mechanical/viscoelastic properties. Rather, cell proliferation was favoured in the presence of an intermediate amount of BGNPs (12.5% w/w) for all chitosan/genipin conditions, especially in softer hydrogels (2% (w/v) chitosan, 2.5% (w/w) genipin). This hit-spotted condition also favoured cell spreading. Interestingly, the elastic modulus measured for this formulation meets the values reported for the granulation tissue occurring during bone regeneration, where fibroblasts produce collagen. We believe that this approach will facilitate the complete on-chip rapid study of miniaturized biomaterials, in order to get more adequate formulations to be used in tissue engineering or other biomedical applications. This journal is © the Partner Organisations 2014.

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