70 research outputs found

    Development of pH-Sensitive magnetoliposomes containing shape anisotropic nanoparticles for potential application in combined cancer therapy

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    Late diagnosis and systemic toxicity associated with conventional treatments make oncological therapy significantly difficult. In this context, nanomedicine emerges as a new approach in the prevention, diagnosis and treatment of cancer. In this work, pH-sensitive solid magnetoliposomes (SMLs) were developed for controlled release of the chemotherapeutic drug doxorubicin (DOX). Shape anisotropic magnetic nanoparticles of magnesium ferrite with partial substitution by calcium (Mg0.75Ca0.25Fe2O4) were synthesized, with and without calcination, and their structural, morphological and magnetic properties were investigated. Their superparamagnetic properties were evaluated and heating capabilities proven, either by exposure to an alternating magnetic field (AMF) (magnetic hyperthermia) or by irradiation with near-infrared (NIR) light (photothermia). The Mg0.75Ca0.25Fe2O4 calcined nanoparticles were selected to integrate the SMLs, surrounded by a lipid bilayer of DOPE:Ch:CHEMS (45:45:10). DOX was encapsulated in the nanosystems with an efficiency above 98%. DOX release assays showed a much more efficient release of the drug at pH = 5 compared to the release kinetics at physiological pH. By subjecting tumor cells to DOX-loaded SMLs, cell viability was significantly reduced, confirming that they can release the encapsulated drug. These results point to the development of efficient pH-sensitive nanocarriers, suitable for a synergistic action in cancer therapy with magnetic targeting, stimulus-controlled drug delivery and dual hyperthermia (magnetic and plasmonic) therapy.This work was funded by the Portuguese Foundation for Science and Technology (FCT) within the framework of the Strategic Funding of Research Units UIDB/04650/2020 (CF-UM-UP), UIDB/00319/2020 (ALGORITMI), UIDB/04077/2020 (MEtRICs), UIDB/04436/2020 (CMEMS) and UIDB/00511/2020 (LEPABE). FCT, POCI, FEDER and NORTE2020 are acknowledged for funding through research projects PTDC/QUI-QFI/28020/2017, EXPL/EMD-EMD/0650/2021, PTDC/EEI-EEE/2846/2021 and NORTE-01-0145-FEDER-000054. MINECO (Spain) is acknowledged for project MAT2016-76824-C3-2-R. B.D.C. and V.M.C. acknowledge FCT for PhD grants SFRH/BD/141936/2018 (B.D.C.) and UI/BD/151028/2021 (V.M.C.). R.O.R. thanks FCT for contract 2020.03975.CEECIND

    Marine sensors: recent advances and challenges

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    [Excerpt] The ocean has a huge impact on our way of life; therefore, there is a need to monitor and protect its biodiversity. Additionally, the ocean industrial potential for health, minerals, and oil has promoted the need for constant and real-time monitoring. Due to all of these concerns, it is important to develop efficient and smart marine sensors to improve our knowledge of the sea environment and to support marine sustainable development. [...

    A review of the advances and challenges in measuring the thermal conductivity of nanofluids

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    Fluids containing colloidal suspensions of nanometer-sized particles (nanofluids) have been extensively investigated in recent decades with promising results. Driven by the increase in the thermal conductivity of these new thermofluids, this topic has been growing in order to improve the thermal capacity of a series of applications in the thermal area. However, when it comes to measure nanofluids (NFs) thermal conductivity, experimental results need to be carefully analyzed. Hence, in this review work, the main traditional and new techniques used to measure thermal conductivity of the NFs are presented and analyzed. Moreover, the fundamental parameters that affect the measurements of the NFs’ thermal conductivity, such as, temperature, concentration, preparation of NFs, characteristics and thermophysical properties of nanoparticles, are also discussed. In this review, the experimental methods are compared with the theoretical methods and, also, a comparison between experimental methods are made. Finally, it is expected that this review will provide a guidance to researchers interested in implementing and developing the most appropriate experimental protocol, with the aim of increasing the level of reliability of the equipment used to measure the NFs thermal conductivity.This work has been funded by Portuguese national funds of FCT/MCTES (PIDDAC) through the base funding from the following research units: UIDB/00532/2020, UIDB/04077/2020, UIDP/04077/2020 and UIDP/04436/2020. The authors are also grateful for the funding of FCT through the projects NORTE-01-0145-FEDER-030171, PTDC/EME-TED/7801/2020, POCI-01-0145- FEDER-016861, POCI-01-0145-FEDER-028159, funded by COMPETE2020, NORTE2020, PORTUGAL2020, and FEDER

    Editorial for the special issue on micro/nano devices for blood analysis, volume II

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    [Excerpt] The development of micro- and nanodevices for blood analysis continues to be a growing interdisciplinary subject that demands the careful integration of different research fields [...]- (undefined

    Micro/Nano devices for blood analysis, Volume II

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    [Excerpt] The development of micro- and nanodevices for blood analysis continues to be a growing interdisciplinary subject that demands the careful integration of different research fields. Particularly, such devices target the precise integration of mechanics, microfluidics, micro/nanotechnologies, chemistry, optics, electronics, materials engineering, informatics, biotechnology and medicine, among many other fields

    Organ-on-a-chip platforms for drug screening and delivery in tumor cells: a systematic review

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    The development of cancer models that rectify the simplicity of monolayer or static cell cultures physiologic microenvironment and, at the same time, replicate the human system more accurately than animal models has been a challenge in biomedical research. Organ-on-a-chip (OoC) devices are a solution that has been explored over the last decade. The combination of microfluidics and cell culture allows the design of a dynamic microenvironment suitable for the evaluation of treatments’ efficacy and effects, closer to the response observed in patients. This systematic review sums the studies from the last decade, where OoC with cancer cell cultures were used for drug screening assays. The studies were selected from three databases and analyzed following the research guidelines for systematic reviews proposed by PRISMA. In the selected studies, several types of cancer cells were evaluated, and the majority of treatments tested were standard chemotherapeutic drugs. Some studies reported higher drug resistance of the cultures on the OoC devices than on 2D cultures, which indicates the better resemblance to in vivo conditions of the former. Several studies also included the replication of the microvasculature or the combination of different cell cultures. The presence of vasculature can influence positively or negatively the drug efficacy since it contributes to a greater diffusion of the drug and also oxygen and nutrients. Co-cultures with liver cells contributed to the evaluation of the systemic toxicity of some drugs metabolites. Nevertheless, few studies used patient cells for the drug screening assays.This work has been supported by the projects NORTE-01-0145-FEDER-030171 (project reference PTDC/EME-SIS/30171/2017), NORTE-01-0145-FEDER-029394 (project reference PTDC/EMDEMD/29394/2017), through the COMPETE2020, the Lisb@2020, the Programa Operacional Regional do Norte–Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement through the European Regional Development Fund (FEDER) and by Fundação para a Ciência e Tecnologia (FCT), and through FEDER and FCT, project references EXPL/EMD-EMD/0650/2021 and PTDC/EEI-EEE/2846/2021. The authors also acknowledge the partial financial support within the R&D Units Project Scope: UIDB/00319/2020, UIDB/04077/2020, UIDB/00690/2020, UIDB/04436/2020. This work was also funded by AMED-CREST Grant Number JP20gm1310001h0002. Raquel O. Rodrigues (R.O.R.) thanks FCT for her contract funding provided through 2020.03975.CEECIND

    Underwater energy harvesting to extend operation time of submersible sensors

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    A linear electromagnetic energy harvesting device for underwater applications, fabricated with a simple manufacturing process, was developed to operate with movement frequencies from 0.1 to 0.4 Hz. The generator has two coils, and the effect of the combination of the two coils was investigated. The experimental study has shown that the energy capture system was able to supply energy to several ocean sensors, producing 7.77 mJ per second with wave movements at 0.4 Hz. This study shows that this energy is enough to restore the energy used by the battery or the capacitor and continue supplying energy to the sensors used in the experimental work. For an ocean wave frequency of 0.4 Hz, the generator can supply power to 8 sensors or 48 sensors, depending on the energy consumed and its optimization.This work is co-funded by the project K2D-Knowledge and Data from the Deep to Space with reference POCI-01-0247-FEDER-045941, co-financed by European Regional Development Fund (ERDF), through the Operational Program for Competitiveness and Internationalization (COMPETE2020) and by the Portuguese Foundation for Science and Technology-FCT under MIT-Portugal Program. This work is also co-financed by Programa Operacional Regional do Norte (NORTE2020), through Fundo Europeu de Desenvolvimento Regional (FEDER), Project NORTE-01-0145-FEDER000032–NextSea, and by national funds through FCT–Fundação para a Ciência e Tecnologia, I.P. under project SONDA (PTDC/EME-SIS/1960/2020)

    Recent developments on the thermal properties, stability and applications of nanofluids in machining, solar energy and biomedicine

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    In this review work, the recent progress made in the use of nanofluids (NFs) applied in three specific areas will be presented: machining, solar energy, and biomedical engineering. Within this context, the discussions will be guided by emphasizing the thermal and stability properties of these fluids. In machining, NFs play a prominent role in the processes of turning, milling, drilling, and grinding, being responsible for their optimization as well as improving the useful life of the tools and reducing costs. In the solar energy field, NFs have been used in the thermal management of the panels, controlling and homogenizing the operating temperature of these systems. In the biomedical area, the advantages of using NFs come from the treatment of cancer cells, the development of vaccines before the improvement of diagnostic imaging, and many others. In all lines of research mentioned in this study, the main parameters that have limited or encouraged the use of these fluids are also identified and debated. Finally, the discussions presented in this review will inspire and guide researchers in developing new techniques to improve the applications of NFs in several fields.This research was partially funded by the Portuguese national funds of FCT/MCTES (PIDDAC) through the base funding from the following research units: UIDB/00690/2020 (CIMO), UIDB/04077/2020 (MEtRICs), and UIDB/00532/2020 (CEFT). The authors are also grateful for the funding of ANI and CIMO through the projects POCI-01-02B7-FEDER-069844 and CMFPE3- EXPL2021CIMO_01, respectively. The authors also acknowledge partial financial support from the project NORTE-01-0145-FEDER-030171 (PTDC/EMD-EMD/30171/2017), PTDC/EME-TED/7801/ 2020 and EXPL/EME-EME/0732/2021 funded by the NORTE 2020 Portugal Regional Operational Programme, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) and by Fundação para a Ciência e Tecnologia (FCT)

    Analysis of a vegetable oil performance in a milling process by MQL Lubrication

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    In this work, we carried out a comparison between the dry machining of an aluminum block with conventional cutting oil and a block with vegetable oil. The two oils had different flow rates. Using the Taguchi method, it was possible to determine the matrices for optimizing the best parameters for each group of tests. Then, we studied the utility of using vegetable oil as a cutting lubricant. We found that the vegetable oil studied in this work had good properties in terms of reducing cutting temperatures but was less effective than conventional cutting oil in reducing the surface roughness of the machined part. Tribological tests were carried out to understand the influence of the selected lubricants in reducing friction and wear. After the sliding experiments, which were performed without lubrication in the presence of the same lubricants that were used in the machining tests and in the presence of distilled water, we concluded that vegetable oil has satisfactory lubricating properties that are similar to those of the conventional cutting fluid, indicating a potential for consideration as an effective alternative to the conventional cutting fluid, with economic, environmental, and health advantages.Financial support was provided by Portugal’s national funding FCT/MCTES (PIDDAC) to Centro de Investigação de Montanha (CIMO) (UIDB/00690/2020 and UIDP/00690/2020) and SusTEC (LA/P/0007/2020). Additionally, this work was partially supported by Portuguese FCT, under the reference projects UIDB/04077/2020, UIDB/00532/2020 and UIDB/04436/2020. This research was also partially funded by EXPL2021CIMO_01. Inês Afonso acknowledges the financial support of CIMO through EXPL2021CIMO_01

    Diagnosis methods for COVID-19: A systematic review

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    At the end of 2019, the coronavirus appeared and spread extremely rapidly, causing millions of infections and deaths worldwide, and becoming a global pandemic. For this reason, it became urgent and essential to find adequate tests for an accurate and fast diagnosis of this disease. In the present study, a systematic review was performed in order to provide an overview of the COVID-19 diagnosis methods and tests already available, as well as their evolution in recent months. For this purpose, the Science Direct, PubMed, and Scopus databases were used to collect the data and three authors independently screened the references, extracted the main information, and assessed the quality of the included studies. After the analysis of the collected data, 34 studies reporting new methods to diagnose COVID-19 were selected. Although RT-PCR is the gold-standard method for COVID-19 diagnosis, it cannot fulfill all the requirements of this pandemic, being limited by the need for highly specialized equipment and personnel to perform the assays, as well as the long time to get the test results. To fulfill the limitations of this method, other alternatives, including biological and imaging analysis methods, also became commonly reported. The comparison of the different diagnosis tests allowed to understand the importance and potential of combining different techniques, not only to improve diagnosis but also for a further understanding of the virus, the disease, and their implications in humans
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