6th Iberian Meeting of Colloids and Interfaces - RIC16: book of abstracts

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Influence of contact lens care solutions on the water content of hydrogel and silicone-hydrogel contact lenses

Purpose The aim of this work was to study variations in water content (WC) of hydrogel and silicone-hydrogel contact lenses (CL) when preserved in different lens care systems. Material and Method Four silicone-hydrogel CL (Senofilcon A, Balafilcon A, Comfilcon A, Lotrafilcon B) and one conventional CL (Etafilcon A) and commercially available lens care solutions (Renu Multiplus™ and Biotrue (Bausch & Lomb), Optifree Puremoist and Aosept® Plus (CIBA Vision) were used. Lenses were immersed in each lens care system during 12 hours and then RI was determined with the digital automated refractometer (CLR 12-70, Index Instruments, 174 Cambridge, UK). Water content was directly obtained with this instrument using RI values and the equation given in BSO ISO 10339:1997. Measurements were performed before and after the lenses have been immersed in each care solution. Two CL of each combination (CL + solution) were tested, and five measurements per lens were obtained. Results The mean values of WC (in %) obtained for each lens material when CL were removed from their blisters (baseline value) was for: Etafilcon A (55.75 ± 0.52); Comfilcon A (45.84 ± 0.28); Senofilcon A (37.01 ± 0.98), Lotrafilcon B (25.53 ± 0.42) and Balafilcon A (34.61 ± 1.03). Substantial changes and statistically significant were observed on these parameters when exposed to lens care systems depending on the CL material and the solution. Senofilcon A decreased the WC with all the solutions contrary of lotrafilcon B where it was observed an increase in WC with all the solutions. Comfilcon A remained approximately with the same values of WC. Balafilcon A and Etafilcon A showed an irregular behavior increasing or decreasing depending on the solution. Conclusions The present study reveals that solutions induce changes in the CL properties studied showing the existence of interactions between CL material and lens care solution. These interactions can be essential when eye care practitioners choose the most appropriate lens care product for CL, especially when the patient present symptoms of discomfort or dryness.info:eu-repo/semantics/publishedVersio

Adhesion of Pseudomonas aeruginosa and Staphylococcus epidermidis to silicone-hydrogel contact lenses

Purpose. The purpose of this study is to compare the adhesion capabilities of the most important etiologic agents of microbial ocular infection to the recently available silicone– hydrogel lenses with those to a conventional hydrogel lens. Methods. In vitro static adhesion assays of Pseudomonas aeruginosa 10,145, Staphylococcus epidermidis 9142 (biofilm-positive), and 12,228 (biofilm-negative) to two extended-wear silicone– hydrogel lenses (balafilcon A and lotrafilcon A), a daily wear silicone– hydrogel lens (galyfilcon A) and a conventional hydrogel (etafilcon A) were performed. To interpret the adhesion results, lens surface relative hydrophobicity was assessed by water contact angle measurements. Results. P. aeruginosa and S. epidermidis 9142 exhibited greater adhesion capabilities to the extended wear silicone– hydrogel lenses than to the daily wear silicone– and conventional hydrogel lenses (p < 0.05). No statistical differences were found between the adhesion extent of these strains to galyfilcon A and etafilcon A. The biofilm negative strain of S. epidermidis adhered in larger extents to the silicone– hydrogel lenses than to the conventional hydrogel (p < 0.05), but in much lower amounts than the biofilm-positive strain. The water contact angle measurements revealed that the extended wear silicone– hydrogel lenses are hydrophobic, whereas the daily wear silicone– and conventional hydrogel lenses are hydrophilic. Conclusions. As a result of their hydrophobicity, the extended wear silicone– hydrogel lenses (lotrafilcon A and balafilcon A) may carry higher risk of microbial contamination than both the hydrophilic daily wear silicone– hydrogel lens, galyfilcon A and the conventional hydrogel lens, etafilcon A.Fundação para a Ciência e a Tecnologia (FCT

Increasing genetic variability in black oats using gamma irradiation

The black oat (Avena strigosa Schreb) is commonly used for forage, soil cover, and green manure. Despite its importance, little improvement has been made to this species, leading to high levels of genotypic disuniformity within commercial cultivars. The objective of this study was to evaluate the efficiency of different doses of gamma rays [ ^60 Co] applied to black oat seeds on the increase of genetic variability of agronomic traits. We applied doses of 0, 10, 50, 100, and 200 Gy to the genotype ALPHA 94087 through exposure to [ ^60 Co]. Two experiments were conducted in the winter of 2008. The first aimed to test forage trait measurements such as plant height, dry matter yield, number of surviving tillers, and seedling stand. The second test assessed seed traits, such as yield and dormancy levels. Gamma irradiation seems not to increase seed yield in black oats, but it was effective in generating variability for the other traits. Tiller number and plant height are important selection traits to increase dry matter yield. Selection in advanced generations of mutant populations can increase the probability of identifying superior genotypes

Monoolein-based nanocarriers for enhanced folate receptor-mediated RNA delivery to cancer cells

We report the development and characterization of a novel nanometric system for specific delivery of therapeutic siRNA for cancer treatment. This vector is based on a binary mixture of the cationic surfactant dioctadecyldimethylammonium chloride (DODAC) and the helper lipid monoolein (MO). These liposomes were previously validated by our research group as promising non-viral vectors for nucleic acid delivery. In this work, the DODAC:MO vesicles were for the first time functionalized with polyethylene glycol and PEG-folate conjugates to achieve both maximal stability in biological fluids and increase selectivity toward folate receptor α expressing cells. The produced DODAC:MO:PEG liposomes were highly effective in RNA complexation (close to 100%), and the resulting lipoplexes also demonstrated high stability in conditions simulating their administration by intravenous injection (physiological pH, high NaCl, heparin and fetal bovine serum concentrations). In addition, cell uptake of the PEG-folate-coated lipoplexes was significantly greater in folate receptor α positive breast cancer cells (39% for 25 µg/mL of lipid and 31% for 40 µg/mL) when compared with folate receptor α negative cells (31% for 25 µg/mL of lipid and 23% for 40 µg/mL) and to systems without PEG-folate (≈13% to 16% for all tested conditions), supporting their selectivity towards the receptor. Overall, the results support these systems as appealing vectors for selective delivery of siRNA to cancer cells by folate receptor α-mediated internalization, aiming at future therapeutic applications of interest

DODAB:MO versus novel liposomes for protein delivery: comparing toxicity and encapsulation efficiency

UID/BIA/04050/2019, funded by national funds through the FCT IP, and project FUN2CYT: Harnessing the potential for biomedical applications of pleiotropic cytokines LIF and oncostatin M (PTDC/BTM-MAT/30568/2017, POCI-01-0145-FEDER-030568) supported by POCI through FEDER and FCT IPinfo:eu-repo/semantics/publishedVersio

Microfluidics for controlled self-assembly of cubosome nanoparticles of tunable size

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Effective cytocompatible nanovectors based on serine-derived gemini surfactants and monoolein for small interfering RNA delivery

Supplementary data to this article can be found online athttps://doi.org/10.1016/j.jcis.2020.09.077.Non-viral gene therapy based on gene silencing with small interfering RNA (siRNA) has attracted great interest over recent years. Among various types of cationic complexation agents, amino acid-based surfactants have been recently explored for nucleic acid delivery due to their low toxicity and high biocompatibility. Monoolein (MO), in turn, has been used as helper lipid in liposomal systems due to its ability to form inverted nonbilayer structures that enhance fusogenicity, thus contributing to higher transfection efficiency. In this work, we focused on the development of nanovectors for siRNA delivery based on three gemini amino acid-based surfactants derived from serine (12Ser)2N12, amine derivative; (12Ser)2COO12, ester derivative; and (12Ser)2CON12, amide derivative individually combined with MO as helper lipid. The inclusion of MO in the cationic surfactant system influences the morphology and size of the mixed aggregates. Furthermore, the gemini surfactant:MO systems showed the ability to efficiently complex siRNA, forming stable lipoplexes, in some cases clearly depending on the MO content, without inducing significant levels of cytotoxicity. High levels of gene silencing were achieved in comparison with a commercially available standard indicating that these gemini:MO systems are promising candidates as lipofection vectors for RNA interference (RNAi)-based therapies.The authors acknowledge Fundação para a Ciência e a Tecnolo-gia (FCT) for financial support through projects UIDB/00081/2020 and UIDB/50006/2020. This work was supported by the‘‘Contrato-Programa” UIDB/04050/2020 funded by national fundsthrough the FCT I.P. Dr. Marisa Passos is gratefully acknowledged for help with the statistical analysis of cytotoxicity data. Fundingby the CCDR-N/NORTE2020/Portugal2020 through project DESign-BIOtechHealth (ref. Norte-01-0145-FEDER-000024) is also acknowledged. I. S. Oliveira and S.G. Silva also acknowledge finan-cial support from FCT through PhD grant SFRH/BD/108629/2015 and Individual Call to Scientific Employment Stimulus - CEEC Indi-vidual grant CEECIND/01932/2017, respectivelyinfo:eu-repo/semantics/publishedVersio

Counter ions and constituents combination affect DODAX: MO nanocarriers toxicity in vitro and in vivo

Liposomes have received extensive attention as nanocarriers for bioactive compounds due to their good biocompatibility, possibility of targeting and incorporation of hydrophilic and hydrophobic compounds. Although generally considered as safe, detailed knowledge of the effects induced in cells and tissues with which they interact is still underexplored. The aim of this study is to gain insight into the toxicity profile of dioctadecyldimethylammonium (DODAX) : monoolein(MO) liposomes (X is bromide or chloride), previously validated for gene therapy, by evaluating the effect of the counter ions Br− or Cl−, and of the cationic : neutral lipid molar fraction, both in vitro and in vivo. Effects on cellular metabolism and proliferation, plasma membrane integrity, oxidative stress, mitochondrial membrane potential dysfunction and ability to trigger apoptosis and necrosis were evaluated in a dose-/time-dependent manner in normal human skin fibroblasts. Also, newly fertilized zebrafish zygotes were exposed to liposomes, permitting a fast-track evaluation of the morphophysiological modifications. In vitro data showed that only very high doses of DODAX : MO induce apoptosis and necrosis, inhibit cell proliferation, and affect the metabolism and plasma membrane integrity of fibroblasts in a dose-/time-dependent manner. Furthermore, liposomes affected mitochondrial function, increasing ROS accumulation and disturbing mitochondrial membrane potential. DODAC-based liposomes were consistently more toxic when compared to DODAB-based formulations; furthermore, the inclusion of MO was found to reduce toxicity, in contrast to liposomes with cationic DODAX only, especially in DODAB : MO (1 : 2) nanocarriers. These results were corroborated, in a holistic approach, by cytotoxicity profiling in five additional human cell lines, and also with the zebrafish embryotoxicity testing, which constitutes a sensitive and informative tool and accurately extends cell-based assays.This work was supported by the strategic programme UID/BIA/ 04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI); by FEDER through POFCCOMPETE; and by national funds from FCT through PEstC/FIS/UI0607/2013 (CFUM) and PTDC/QUI/69795/2006. Ana Oliveira held the scholarship, SFRH/BD/68588/2010. Marisa P. Sárria holds a Marie Curie COFUND fellowship funding from the European Union’s7 th Framework Programme for research, technological development and demonstration under grant agreement 600375. The authors are grateful to the technical support of Marinnova – Marine and Environmental Innovation, Technology and Services, a R&I company anchored to the Centre of Marine and Environmental Research (CIIMAR – University of Porto, Portugal), focused at providing innovative services and products in the field of marine and environmental sciences