Relationship between the stability and surface tension of the tear film

FCT, QREN and FEDER/COMPETE through CFUM

Evaluation of optical properties of different types of contact lenses

The main objective of this work was to attain a deeper knowledge of contact lenses (CL) optical properties and to understand the influence of CL power on other properties which can affect the optical performance and compromise the ocular physiology.Fundação para a Ciência e a Tecnologia (FCT), QREN/FSE/COMPETE

Vesicle-micelle transition in aqueous mixtures of the cationic dioctadecyldimethylammonium and octadecyltrimethylammonium bromide surfactants

The vesicle-micelle transition in aqueous mixtures of dioctadecyldimethylammonium and octadecyltrimethylammonium bromide (DODAB and C18TAB) cationic surfactants, having respectively double and single chain, was investigated by differential scanning calorimetry (DSC), steady state fluorescence, dynamic light scattering (DLS) and surface tension. The experiments performed at constant up to 1.0 mM total surfactant concentration reveal that these homologue surfactants mix together to form either mixed vesicles and/or micelles, or both of these structures in equilibrium, depending on the relative amount of the surfactants. The main transition melting temperature Tm of the mixed DODAB-C18TAB vesicles is larger than that for the neat DODAB in water owing to the incorporation of C18TAB in the vesicle bilayer, however, little amount of C18TAB having a minor effect on the Tm of DODAB. The surface tension decreases sigmoidally with C18TAB concentration and the inflection point lies around xDODAB ≈ 0.4, indicating the onset of micelle formation owing to saturation of DODAB vesicles by C18TAB molecules and formation of vesicle structures. At low C18TAB concentrations When xDODAB > 0.5 C18TAB molecules are mainly solubilized by the vesicles bilayers, while at high C18TAB concentrations but when xDODAB < 0.25 micelles are dominant. Fluorescence data of the Nile Red probe incorporated in the system at different surfactant molar fractions indicate the formation of micelle and vesicle structures. These structures have apparent hydrodynamic radius RH of about 180 and 500-800 nm, respectively, as obtained by DLS measurements.Fundação para a Ciência e a Tecnologia (FCT

Interactions between contact lenses and lens care solutions: Influence in optical properties

Purpose: Investigate changes in optical properties of contact lenses materials (transmittance and reflectance) and lens care solutions (absorption and fluorescence) resulting from its interaction. Methods: From an experimental study, triplicate measurements of transmittance and reflectance of five contact lenses (Senofilcon A, Lotrafilcon B, Balafilcon A, Comfilcon A, and Omafilcon A), as well as UV-vis absorption and fluorescence of four lens care solutions (LCS) (ReNu MultiPlus, Biotrue, OPTI-FREE PureMoist, and AOSept Plus), were evaluated before and after 8 h, one day and one week in storage. The outcomes were provided by Shimadzu UV3101-PC UV-vis-NIR spectrophotometer equipped with an integrating sphere, between 200-700 nm, and SPEX-Fluorolog 2 FL3-22 spectrofluorometer. Results: All variables exhibited statistically significant differences over time. Comfilcon A showed the lowest ultraviolet radiation (UVR) A & B attenuation. Balafilcon A and Lotrafilcon B displayed a slight suppression of UVR. Senofilcon A was effective in UVR protection and showed less effect on the fluorescence of lens care solutions. Overall, the reflectance decreased after storage (p < 0.05). AOSept Plus absorbance and fluorescence demonstrated lower interactions than multipurpose solutions (MPS), and Lotrafilcon B induced more remarkable changes in optical properties of LCS than the other materials. Conclusion: The findings suggest that optical variables of lens care solutions and contact lenses changed mutually after storage, probably associated with biochemical and biophysical interactions between components and the release of some polymer compounds. These findings can provide additional information about the interaction of CL materials and LCS in clinical behavior.This work was supported by the Portuguese Foundation for Science and Technology (FCT-Portugal) in the framework of the Strategic Funding of CF-UM-UP (UIDB/04650/2020)

Functionalized liposome and albumin-based systems as carriers for poorly water-soluble anticancer drugs: an updated review

Cancer is one of the leading causes of death worldwide. In the available treatments, chemotherapy is one of the most used, but has several associated problems, namely the high toxicity to normal cells and the resistance acquired by cancer cells to the therapeutic agents. The scientific community has been battling against this disease, developing new strategies and new potential chemotherapeutic agents. However, new drugs often exhibit poor solubility in water, which led researchers to develop functionalized nanosystems to carry and, specifically deliver, the drugs to cancer cells, targeting overexpressed receptors, proteins, and organelles. Thus, this review is focused on the recent developments of functionalized nanosystems used to carry poorly water-soluble drugs, with special emphasis on liposomes and albumin-based nanosystems, two major classes of organic nanocarriers with formulations already approved by the U.S. Food and Drug Administration (FDA) for cancer therapeutics.This work was supported by Fundacao para a Ciencia e a Tecnologia (FCT-Portugal) in the framework of the Strategic Funding of CF-UM-UP (UIDB/04650/2020) and CQUM(UIDB/00686/2020), and by funds from FEDER/FCT through the project PTDC/MED-ONC/31354/2017. S. Teixeira acknowledges FCT and FSE (Fundo Social Europeu) through "Programa Operacional Regional Norte" for funding the PhD grant 2020.04975.BD

DODAB/Monoolein mixed cationic liposomes for gene delivery : investigation by DLS, DSC, fluorescence spectroscopy and phase scanning microscopy

FCT and FEDER for financial support to CFUM and also by funding through project PTDC/QUI/69795/2006 and PhD grant of J.P.N. Silva (SFRH/BD/46968/2009)

Interaction of DODAB with neutral phospholipids and cholesterol studied using fluorescence anisotropy

Liposomes composed of cationic lipids and neutral phospholipids have been used as vehicles for cellular delivery of DNA and drug delivery. The aim of this study is to get a better understanding of phospholipid–cationic lipid interactions that is essential for the development of this potential. We have studied the interaction between cationic lipid liposomes primarily composed of dioctadecyldimethylammonium bromide (DODAB) with two different phospholipids, dioleoyl phosphatidylethanolamine (DOPE) and soybean phosphatidylcholine (PC), as well as with cholesterol. The effect of these components on the liposome’s physical properties (microviscosity and polarity) was accessed by studying, both the steady-state and time-resolved, fluorescence anisotropy of the dye Nile Red. This information combined with analysis of the steady-state emission and fluorescence lifetime of Nile Red using the different lipids and cholesterol provided information concerning the polarity and hydration level changes in these vesicle systems along with organisational information

Tungsten oxide nanoparticles prepared with soft templating methods

Fundação para a Ciência e a Tecnologia (FCT

Shape anisotropic iron oxide-based magnetic nanoparticles: synthesis and biomedical applications

Research on iron oxide-based magnetic nanoparticles and their clinical use has been, so far, mainly focused on the spherical shape. However, efforts have been made to develop synthetic routes that produce different anisotropic shapes not only in magnetite nanoparticles, but also in other ferrites, as their magnetic behavior and biological activity can be improved by controlling the shape. Ferrite nanoparticles show several properties that arise from finite-size and surface effects, like high magnetization and superparamagnetism, which make them interesting for use in nanomedicine. Herein, we show recent developments on the synthesis of anisotropic ferrite nanoparticles and the importance of shape-dependent properties for biomedical applications, such as magnetic drug delivery, magnetic hyperthermia and magnetic resonance imaging. A brief discussion on toxicity of iron oxide nanoparticles is also included.This research was funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UID/FIS/04650/2019) and through the research project PTDC/QUI–QFI/28020/2017 (POCI-01–0145-FEDER-028020), financed by European Fund of Regional Development (FEDER), COMPETE2020 and Portugal2020. The APC was also funded by FCT. S.R.S. Veloso acknowledges FCT for a PhD grant (SFRH/BD/144017/2019)

Alterações na transmitância UV-Visível induzidas pelo uso de lentes de contacto de silicone-hidrogel

Fundação para a Ciência e a Tecnologia (FCT) through Centro de Física da U