Mónica Faria

• PhD
• Instituto Superior Técnico

A novel Ortho-Centrifugal Membrane Filter (O-CMF) was designed and assessed to tackle common issues in conventional laboratory centrifugal membrane filters, e.g. non-uniform transmembrane pressure and concentration polarization, and to ease membrane replacement. The O-CMF, manufactured by additive 3D printing in acrylonitrile butadiene styrene, wit...

Chronic kidney disease (CKD), a pressing global health issue, affects millions and leads to end-stage renal disease (ESRD). Hemodialysis (HD) is a crucial treatment for ESRD, yet its limited efficiency in removing protein-bound uremic toxins (PBUTs) results in high morbidity and mortality rates. A high affinity of pharmaceutical drugs for human ser...

Objectives: Hemodialysis (HD) is inefficient in the removal of protein-bound uremic toxins (PBUTs), which circulate in the blood bonded to human serum albumin (HSA). The cut-off of conventional HD membranes is lower than the molecular weight of HSA (66.5kDa) and therefore UT-HSA complexes are retained and accumulate in the body of patients with end...

Direct liquid fuel cells (DLFCs) operate directly on liquid fuel instead of hydrogen, as in proton-exchange membrane fuel cells. DLFCs have the advantages of higher energy densities and fewer issues with the transportation and storage of their fuels compared with compressed hydrogen and are adapted to mobile applications. Among DLFCs, the direct bo...

In this paper, we propose an optimized protocol to synthesize reproducible, accurate, sustainable integrally skinned monophasic hybrid cellulose acetate/silica membranes for ultrafiltration. Eight different membrane compositions were studied, divided into two series, one and two, each composed of four membranes. The amount of silica increased from...

Currently available hemodialysis (HD) membranes are unable to safely remove protein-bound uremic toxins (PBUTs), especially those bonded to human serum albumin (HSA). To overcome this issue, the prior administration of high doses of HSA competitive binders, such as ibuprofen (IBF), has been proposed as a complementary clinical protocol to increase...

End-stage renal disease (ESRD) patients rely on renal replacement therapies to survive. Hemodialysis (HD), the most widely applied treatment, is responsible for the removal of excess fluid and uremic toxins (UTs) from blood, particularly those with low molecular weight (MW < 500 Da). The development of high-flux membranes and more efficient treatme...

Chronic kidney disease (CKD) has a prevalence from 11 to 13% in the world’s population and the main treatment which partially restores kidney function is hemodialysis (HD). Despite current HD membranes being effective in the removal of small water-soluble compounds (molecular weight (MW) <500Da) and certain middle molecules (500<MW<60000Da), protei...

The preparation of integrally skinned asymmetric CA membranes by means of the wet-phase inversion technique paved the way to the synthesis of membranes with a multitude of structures ranging from ultrafiltration to reverse osmosis as well as for the development of low-flux hemodialyzers and high-flux hemodialyzers. Nevertheless, CA membranes exhibi...

The production of medical devices follows strict guidelines where bio- and hemocompatibility, mechanical strength, and tear resistance are important features. Segmented polyurethanes (PUs) are an important class of polymers that fulfill many of these requirements, thus justifying the investigation of novel derivatives with enhanced properties, such...

Hemodialysis (HD) is a clinically well-established membrane-based treatment for blood purification under extracorporeal blood circulation [1]. Cellulose acetate (CA) membranes show great flexibility, low protein adsorption and high hemocompatibility. Furthermore, they have the ability to remove some of the accumulated uremic toxins and water, witho...

Chronic kidney disease (CKD) is acknowledged worldwide to be a grave threat to public health, with the number of US end-stage kidney disease (ESKD) patients increasing steeply from 10,000 in 1973 to 703,243 in 2015. Protein-bound uremic toxins (PBUTs) are excreted by renal tubular secretion in healthy humans, but hardly removed by traditional haemo...

A novel cellulose acetate-based monophasic hybrid skinned amine-functionalized CA-SiO2-(CH2)3NH2 membrane was synthesized using an innovative method which combines the phase inversion and sol-gel techniques. Morphological characterization was performed by scanning electron microscopy (SEM), and the chemical composition was analyzed by Fourier trans...

Patients with end stage renal disease (ESRD) are progressively increasing and the demand for renal replacement therapies is expanding [1]. Transplantation is the most effective option, but it is limited by the scarcity of organs thus making in-center hemodialysis (HD) the most reliable form of therapy. The crucial role of HD dosage in critically il...

Renal Replacement Therapies generally associated to the Artificial Kidney (AK) are membrane-based treatments that assure the separation functions of the failing kidney in extracorporeal blood circulation. Their progress from conventional hemodialysis towards high-flux hemodialysis (HFHD) through the introduction of ultrafiltration membranes charact...

Composite cellulose acetate (CA) membranes are widely used but their multiphase nature results in additive losses, poor mechanical strength, low chemical resistance and thermal stability, limiting their separation/purification yields. To overcome this, we fabricated monophasic hybrid membranes using a modified phase inversion technique, where tetra...

The prevalence of chronic kidney disease (CKD) in the worldwide population is currently estimated between 11 and 13%. Adequate renal clearance is compromised in these patients and the accumulation of a large number of uremic retention solutes results in an irreversible worsening of renal function which can lead to end stage renal disease (ESRD). Ap...

Two series of novel integral asymmetric monophasic hybrid membranes, cellulose acetate/silica/titania (CA/SiO 2 /TiO 2-series 1) and cellulose acetate/titania (CA/TiO 2-series 2), were developed by the coupling of sol-gel technology and a modified version of the phase inversion technique. SEM micrographs confirmed the integral asymmetric structure...

Monophasic hybrid cellulose acetate/silica (CASiO2) integrally skinned membranes with tailored hemocompatible surfaces and permeation properties that assure the kidney metabolic functions of preferential permeation of urea and the retention of albumin were synthesized by an innovative method which combines the phase inversion and sol–gel techniques...

The present work reports on the synthesis of cellulose acetate (CA) asymmetric membranes with the incorporation of inorganic fluorides, CaF2 particles. These fillers of polymeric composites can, according to the literature, promote the ordering of the polymer matrix, which can lead to interesting permeation properties. In order to achieve that, flu...

Due to their high hemocompatibility and gas permeation capacity, bi-soft segment polyurethane/polycaprolactone (PU/PCL) polymers are promising materials for use in membrane blood oxygenators. In this work, both nonporous symmetric and integral asymmetric PU/PCL membranes were synthesized, and the permeation properties of the atmospheric gases N2, O...

Monophasic hybrid cellulose acetate/silica (CASiO2) integrally skinned membranes with silica contents between 5–18 wt.% were synthetized by an innovative method which combines the phase inversion and sol-gel techniques. The morphological and topographical characterization was performed by scanning electron microscopy (SEM) and atomic force microsco...

Membrane blood oxygenators (MBOs) assure in extracorporeal blood circulation the metabolic functions of failing lungs. The technical and medical progress of the MBOs depends on two major factors: (1) hemocompatibility of the membrane/blood interfaces, and (2) enhancement of the flow management/mass transfer associated to the metabolic functions of...

Bi-soft segment polyurethane (PU) membranes containing poly(propylene oxide) as the first soft segment (SS) and different second SSs: poly(butadienediol) (PBDO), poly(dimethylsiloxane) (PDMS) and polycaprolactone (PCL) were prepared and characterized in terms of phase segregation, gas permeability and hemocompatibiliy with a view to their incorpora...

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Steady state crossflow microfiltration (CMF) is an important and often necessary means of particle separation and concentration for both industrial and biomedical processes. The factors controlling the performance of CMF have been extensively reviewed. A major factor is transmembrane pressure (TMP). Because microchannels have small height, they ten...

Cross‐flow filtration of fine suspensions through microsieves occurs in microprocessing. The interaction of particles with surfaces in microenvironments has been extensively studied, but predominantly in monolayers and not with an eye to microfiltration. Here, we introduce a microfiltration model that pertains to particles that might be seen as fin...

Objectives: Mass transfer resistance for O2 and CO2 have to be reduced for efficient operation of membrane oxygenators and artificial lung devices. In this study we investigate the influence of blood side concentration polarization effects for O2 and CO2 applying different high performance membranes. The findings are relevant both for the developme...

Artificial Organs are generally associated to clinically well established membrane-based treatments that assure in extracorporeal blood circulation devices the separation functions of a failing organ like the hemodialyzer (HD) for the kidney or the membrane blood oxygenator (MBO) for the lungs. Current available medical devices used in these treatm...

Crossflow microfiltration of plasma from blood through microsieves in a microchannel is potentially useful in many biomedical applications, including clinically as a wearable water removal device under development by the authors. We report experiments that correlate filtration rates, transmembrane pressures (TMP) and shear rates during filtration t...

This work addresses oxygen mass transfer in a Membrane Blood Oxygenator (MBO) surrogate system. It consists of a slit for water circulation as a surrogate blood flow channel and a constant pressure oxygen chamber separated by an integral asymmetric hemocompatible polyurethane based membrane. The oxygenated stream enters a well‐mixed reservoir of co...

Hybrid cellulose acetate (CA) silica (SiO2) (CA/SiO2) membranes were synthesized by promoting the in situ condensation between silanols from the SiO2 precursor and the COH or acetate groups from the CA polymer. For all the CA/SiO2 membranes, the ATR-FTIR peak assigned to (SiOC) proves the hybrid condensation reaction and confirms the synthesis of m...

Peristaltic pumps rely on constant compression of elastomeric tubing from which particles may be shed, a phenomenon known as spallation. We studied spallated particles on microfluidic filtration devices with photolithographically prepared micron-level pore fields. Filtration of ultra-pure water through these pores was analyzed using either the usua...

In most extracorporeal filtration devices such as hemodialysis a peristaltic pump is used to circulate blood. Pump function requires the repeated compression of an elastomeric tube from which particles may be shed into the circulatory system, a process called spallation. Earlier studies are likely to have missed the large number of small particles...

Segmented poly (urethane urea) membranes, containing two soft segments, poly(propylene oxide) and poly(caprolactone), were prepared by extending a poly(propylene oxide) based tri-isocyanated prepolymer with poly(caprolactone) diol. The membranes synthesized with poly(caprolactone) diol content ranging from 0 wt.% to 15 wt.% were characterized by in...

Integral asymmetric bi-soft segment poly (ester urethane urea) membranes are casted through a novel procedure where a reaction is introduced in the casting solutions preparation step of the phase inversion technique. Two reactive pre-polymers, the polypropylene oxide-based with three terminal isocyanate groups and the polycaprolactone diol with two...

Asymmetric bi-soft segment poly(ester urethane urea) (PEUU) membranes containing polycaprolactone (PCL) as a second soft segment are synthesized with PCL-diol ranging from 0% to 15% (w/w). Bulk and surface characteristics of the PEUU membranes were investigated by scanning electron microscopy (SEM), static water contact angles, and surface streamin...

Enhancement of membrane hemocompatibility is achieved through the control of the surface morphology. Bi-soft segment integrally skinned poly(ester urethane urea) (PEUU) membranes containing polycaprolactone (PCL) as a second soft segment are synthesized with PCL-diol ranging from 0% to 15% (w/w). Scanning electron microscopy and atomic force micros...

In this study, surface, bulk, and hemocompatibility characteristics of crosslinked, bi-soft segment poly (ester urethane urea) membranes, prepared by extending a poly(propylene oxide)-based triisocyanate-terminated prepolymer (PU) with a polycaprolactone diol (PCL), were investigated. Variation of the ratio of PU to PCL diol content in the membrane...

Cross-linked urethane/urea membranes with two soft segments were prepared by extending a poly(propylene oxide) based tri-isocyanate-terminated prepolymer (PUR) with polybutadiene diol (PBDO). The ratio of prepolymer and polybutadiene diol was varied to yield cross-linked membranes with different compositions, exhibiting different degrees of phase-s...