40 research outputs found
A simple microfluidic device for the deformability assessment of blood cells in a continuous flow
Blood flow presents several interesting phenomena in microcirculation that can be used to develop microfluidic devices capable to promote blood cells separation and analysis in continuous flow. In the last decade there have been numerous microfluidic studies focused on the deformation of red blood cells (RBCs) flowing through geometries mimicking microvessels. In contrast, studies focusing on the deformation of white blood cells (WBCs) are scarce despite this phenomenon often happens in the microcirculation. In this work, we present a novel integrative microfluidic device able to perform continuous separation of a desired amount of blood cells, without clogging or jamming, and at the same time, capable to assess the deformation index (DI) of both WBCs and RBCs. To determine the DI of both WBCs and RBCs, a hyperbolic converging microchannel was used, as well as a suitable image analysis technique to measure the DIs of these blood cells along the regions of interest. The results show that the WBCs have a much lower deformability than RBCs when subjected to the same in vitro flow conditions, which is directly related to their cytoskeleton and nucleus contents. The proposed strategy can be easily transformed into a simple and inexpensive diagnostic microfluidic system to simultaneously separate and assess blood cells deformability.The authors acknowledge the financial support
provided by PTDC/SAU-ENB/116929/2010 and EXPL/EMS-SIS/
2215/2013 from FCT (Fundação para a Ciência e a Tecnologia), COMPETE,
QREN and European Union (FEDER). R. O. Rodrigues, D. Pinho
and V. Faustino acknowledge respectively, the PhD scholarships
SFRH/BD/97658/2013, SFRH/BD/89077/2012 and SFRH/BD/99696/
2014 granted by FCT. The authors would also like to thank Dr. Ângela
Fernandes for providing the blood samples and Dr. Ricardo Calhelha for
supplying the tissue culture medium used in this work.info:eu-repo/semantics/publishedVersio
Low cost microfluidic device for partial cell separation: micromilling approach
Several studies have already demonstrated that it
is possible to perform blood flow studies in microfluidic systems
fabricated by using low-cost techniques. However, most of these
techniques do not produce microchannels smaller than 100
microns and as a result they have several limitations related to
blood cell separation. Recently, manufacturers have been able to
produce milling tools smaller than 100 microns, which
consequently have promoted the ability of micromilling machines
to fabricate microfluidic devices able to perform separation of
red blood cells (RBCs) from plasma. In this work, we show the
ability of a micromilling machine to manufacture microchannels
with dimensions down to 30 microns. Additionally, we show for
the first time the ability of the proposed microfluidic device to
enhance the cell-free layer close to the walls, leading to perform
partial separation of RBCs from plasma.The authors acknowledge the financial support provided by
PTDC/SAU-ENB/116929/2010 and EXPL/EMSSIS/2215/2013
from FCT (Science and Technology
Foundation), COMPETE, QREN and European Union
(FEDER). RR and DP acknowledge, respectively, the PhD
scholarships SFRH/BD/97658/2013 and
SFRH/BD/89077/2012 attributed by FCT.info:eu-repo/semantics/publishedVersio
A rapid and low-cost nonlithographic method to fabricate biomedical microdevices for blood flow analysis
Microfluidic devices are electrical/mechanical systems that offer the ability to
work with minimal sample volumes, short reactions times, and have the possibility to
perform massive parallel operations. An important application of microfluidics is blood
rheology in microdevices, which has played a key role in recent developments of lab-on-chip
devices for blood sampling and analysis. The most popular and traditional method to
fabricate these types of devices is the polydimethylsiloxane (PDMS) soft lithography
technique, which requires molds, usually produced by photolithography. Although the
research results are extremely encouraging, the high costs and time involved in the
production of molds by photolithography is currently slowing down the development cycle
of these types of devices. Here we present a simple, rapid, and low-cost nonlithographic
technique to create microfluidic systems for biomedical applications. The results demonstrate
the ability of the proposed method to perform cell free layer (CFL) measurements and the
formation of microbubbles in continuous blood flow.The authors acknowledge the financial support provided by PTDC/SAU-BEB/105650/2008,
PTDC/SAU-ENB/116929/2010, EXPL/EMS-SIS/2215/2013 and scholarship SFRH/BD/89077/2012 and SFRH/BD/97658/2013 from FCT (Science and Technology Foundation), COMPETE, QREN and
European Union (FEDER).info:eu-repo/semantics/publishedVersio
Haemocompatibility of iron oxide nanoparticles synthesized for theranostic applications: a high-sensitivity microfluidic tool
The 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.This work was financially supported by:
Project POCI-01-0145-FEDER-006984 – Associate Laboratory
J Nanopart Res (2016) 18:194 Page 15 of 17 194
123 LSRE-LCM funded by FEDER funds through COMPETE2020 -
Programa Operacional Competitividade e Internacionalizac¸a˜o
(POCI) – and by national funds through FCT - Fundac¸a˜o para a
Cieˆncia e a Tecnologia. R.O.R. acknowledges the Ph.D.
scholarship SFRH/BD/97658/2013 Granted by FCT. A.M.T.S
acknowledges the FCT Investigator 2013 Programme (IF/01501/
2013), with financing from the European Social Fund and the
Human Potential Operational Programme. M.B. would like to
thank ERDF (European Regional Development Fund) under
grant PO Norte CCDR-N/ON.2 Programme. J.G. also thanks the
European Union’s Seventh Framework Programme for research,
technological development and demonstration under grant
agreement no. 600375.info:eu-repo/semantics/publishedVersio
Loss of postprandial insulin clearance control by Insulin-degrading enzyme drives dysmetabolism traits
Systemic insulin availability is determined by a balance between beta-cell secretion capacity and insulin clearance (IC). Insulin-degrading enzyme (IDE) is involved in the intracellular mechanisms underlying IC. The liver is a major player in IC control yet the role of hepatic IDE in glucose and lipid homeostasis remains unexplored. We hypothesized that IDE governs postprandial IC and hepatic IDE dysfunction amplifies dysmetabolic responses and prediabetes traits such as hepatic steatosis. In a European/Portuguese population-based cohort, IDE SNPs were strongly associated with postprandial IC in normoglycemic men but to a considerably lesser extent in women or in subjects with prediabetes. Liver-specific knockout-mice (LS-IDE KO) under normal chow diet (NCD), showed reduced postprandial IC with glucose intolerance and under high fat diet (HFD) were more susceptible to hepatic steatosis than control mice. This suggests that regulation of IC by IDE contributes to liver metabolic resilience. In agreement, LS-IDE KO hepatocytes revealed reduction of Glut2 expression levels with consequent impairment of glucose uptake and upregulation of CD36, a major hepatic free fatty acid transporter. Together these findings provide strong evidence that dysfunctional IC due to abnormal IDE regulation directly impairs postprandial hepatic glucose disposal and increases susceptibility to dysmetabolic conditions in the setting of Western diet/lifestyle.publishe
Development of pH-Sensitive magnetoliposomes containing shape anisotropic nanoparticles for potential application in combined cancer therapy
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
A tailor-made protocol to synthesize yolk-shell graphene-based magnetic nanoparticles for nanomedicine
A 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.This research was funded by Project POCI-01-0145-FEDER-006984 - Associate Laboratory LSRE-LCM funded by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) - and by national funds through FCT - Fundação para a Ciência e a Tecnologia, and by project NORTE-01-0145-FEDER-029394, RTChip4Theranostics, supported by Programa Operacional Regional do Norte - Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) and by Fundação para a Ciência e Tecnologia (FCT), IP.R.O.R. acknowledges the Ph.D. scholarship SFRH/BD/97658/2013 granted by FCT. G.D. acknowledges financing by Slovene Research Agency (J2-6754). The authors also would like to acknowledge the financial support provided by COST—European Cooperation in Science and Technology, in the form of a short term scientific mission (STSM) granted by COST Action TD1402: RADIOMAG.info:eu-repo/semantics/publishedVersio
Mitochondrial physiology
As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery