A Low Transition Temperature Mixture-based viscosupplementation complemented with celecoxib for osteoarthritis treatment

Publisher Copyright: © 2024 The Author(s)Viscosupplementation consists of hyaluronic acid (HA) intra-articular injections, commonly applied for osteoarthritis treatment while non-steroidal anti-inflammatory drugs (NSAIDs) are widely administered for pain relief. Here, HA and a NSAID (celecoxib) were combined in a formulation based on a low transition temperature mixture (LTTM) of glycerol:sorbitol, reported to increase celecoxib's solubility, thus rendering a potential alternative viscosupplement envisioning enhanced therapeutic efficiency. The inclusion of glucosamine, a cartilage precursor, was also studied. The developed formulations were assessed in terms of rheological properties, crucial for viscosupplementation: the parameters of crossover frequency, storage (G’) and loss (G’’) moduli, zero-shear-rate viscosity, stable viscosity across temperatures, and shear thinning behaviour, support viscoelastic properties suitable for viscosupplementation. Additionally, the gels biocompatibility was confirmed in chondrogenic cells (ATDC5). Regarding drug release studies, high and low clearance scenarios demonstrated an increased celecoxib (CEX) release from the gel (6 to 73-fold), compared to dissolution in PBS. The low clearance setup presented the highest and most sustained CEX release, highlighting the importance of the gel structure in CEX delivery. NMR stability studies over time demonstrated the LTTM+HA+CEX (GHA+CEX) gel as viable candidate for further in vivo evaluation. In sum, the features of GHA+CEX support its potential use as alternative viscosupplement.publishersversionpublishe

Use of natural deep eutectic systems as new cryoprotectant agents in the vitrification of mammalian cells

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme, under grant agreement No ERC-2016-CoG 725034. Publisher Copyright: © 2022, The Author(s).In this work we present the potential of Natural Deep Eutectic Systems (NADES) as new vitrification media for the cryopreservation of mammalian cells. Several NADES composed of natural metabolites were prepared and tested as CPAs in two cell lines, L929 and HacaT cells. After the harvesting, cells were mixed with the eutectic systems, and frozen directly into liquid nitrogen to achieve a vitreous state. Then, the cells were thawed and it was observed that NADES were able to exert a significant cryoprotective effect in L929 cells, when compared with DMSO or in the absence of a CPA. For HacaT cells, only a eutectic system showed a slightly improvement in cell survival, while DMSO caused complete cell death. Moreover, the thermal behaviour of the best systems was studied for further understanding the protective properties of NADES as CPAs, and have shown a significant difference in terms of Tm and Tc when compared with DMSO and water. Additionally, the results obtained showed that NADES can be maintained in the growth media after the thawing step, without compromising cell viability. In summary, we have shown the great potential of NADES to be used as CPAs for the cryopreservation of different cell types, using the vitrification method.publishersversionpublishe

Current developments and future perspectives on biotechnology applications of natural deep eutectic systems

Funding Information: This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme, under grant agreement No ERC-2016-CoG 725034. This work was also supported by the Associate Laboratory for Green Chemistry – LAQV, financed by national funds from FCT/MCTES (UID/QUI/50006/2019) and by FCT/MCTES through the project CryoDES (PTDC/EQU-EQU/29851/2017). Publisher Copyright: © 2022 Elsevier B.V.Natural Deep Eutectic Systems (NADES) have emerged in the past years as alternative solvents to traditional organic solvents and ionic liquids. NADES are easy to produce, sustainable, biocompatible, eco-friendly, remarkable solubilizing agents, and highly task-specific. The outstanding properties of this new liquid media have attracted the attention of researchers in the last decade in many fields and biotechnology is probably one of the fields where NADES have gained more relevance. Nonetheless, the progress beyond the state of the art in this field is not yet fully explored. Most research papers regarding the use of NADES in biotechnology are related to their use as solubility enhancers for poorly soluble active ingredients, particularly for pharmaceutical applications. However, the applicability of NADES in applications such as cryopreservation, stabilization of proteins and DNA, as well as other biomedical applications, has only recently been explored and presents still a plethora of discoveries to be unravelled. The current developments in this scientific field and future perspectives will be discussed herein.publishersversionpublishe

Pattern based GUI testing for mobile applications

This paper presents a study aiming to assess the feasibility of using the Pattern Based GUI Testing approach, PBGT, to test mobile applications. PBGT is a new model based testing approach that aims to increase systematization, reusability and diminish the effort in modelling and testing. It is based on the concept of User Interface Test Patterns (UITP) that contain generic test strategies for testing common recurrent behaviour, the so-called UI Patterns, on GUIs through its possible different implementations after a configuration step. Although PBGT was developed having web applications in mind, it is possible to develop drivers for other platforms in order to test a wide set of applications. However, web and mobile applications are different and only the development of a new driver to execute test cases over mobile applications may not be enough. This paper describes a study aiming to identify the adaptations and updates the PBGT should undergo in order to test mobile applications. © 2014 IEEE

Is it possible to correlate various physicochemical properties of Natural Deep eutectic systems in order to predict their behaviours as solvents?

Funding Information: This project has received funding from the European Union’s Horizon 2020 – European Research Council (ERC) – under grant agreement No ERC-2016-CoG 725034. The authors also greatly thanks to Professor Madalena Dionísio and the technician Maurício Malheiro for all the support and instruments made available. Funding Information: This project has received funding from the European Union's Horizon 2020 – European Research Council (ERC) – under grant agreement No ERC-2016-CoG 725034. The authors also greatly thanks to Professor Madalena Dionísio and the technician Maurício Malheiro for all the support and instruments made available. Publisher Copyright: © 2023 The Author(s)The classification of Natural Deep Eutectic Systems (NADES) as promising alternative solvents for the 21st century has been reported. Although this is mainly due to their very interesting characteristics that have attracted the attention of the scientific community, there is, however, a lack of information regarding many physicochemical properties of these compounds. Therefore, the main objective of this work was to characterize and relate the properties, both of hydrophilic and hydrophilic NADES, regarding their water content, density, viscosity, refractive index, dielectric constant, dipole moment, surface tension, as well solvatochromic parameters. Comparatively to the set of organic solvents also explored, it was observed that for these parameters studied, the values of hydrophilic systems are mostly higher than those of organic solvents, which in turn tend to be higher than those of hydrophobic systems. Moreover, the analysis of solvatochromic parameters (polarity and Kamlet-Taft parameters) provided new evidence for the usefulness of NADES as potential substitute solvents for sustainable development. Finally, regarding the general list of compounds, it was proved with statistical parameters (Pearson correlation coefficient and p-value) that most of the studied properties are strong and significantly correlated with each other.publishersversionpublishe

Using Natural Deep Eutectic Systems as Alternative Media for Ocular Applications

Funding Information: This research was funded by European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme, under grant agreement No ERC-2016-CoG 725034 and CryoDES ERC-2022-POC2 101101088. This work was also supported by the Associate Laboratory for Green Chemistry—LAQV, financed by national funds from FCT/MCTES (UID/QUI/50006/2019) and by FCT/MCTES through the project CryoDES (PTDC/EQU-EQU/29851/2017). The authors also acknowledge the PhD grant from Fundação para a Ciência e Tecnologia (2021.07457.BD). Publisher Copyright: © 2023 by the authors.The major goal of this work was to study the potential of natural deep eutectic systems (NADES) as new media for ocular formulations. In formulating eye drops, it is important to increase the retention time of the drug on the surface of eye; hence, due to their high viscosity, NADES may be interesting candidates for formulation. Different systems composed of combinations of sugars, polyols, amino acids, and choline derivatives were prepared and then characterized in terms of rheological and physicochemical properties. Our results showed that 5–10% (w/v) aqueous solutions of NADES have a good profile in terms of viscosity (0.8 to 1.2 mPa.s), osmolarity (412 to 1883 mOsmol), and pH (7.4) for their incorporation of ocular drops. Additionally, contact angle and refractive index were determined. Acetazolamide (ACZ), a highly insoluble drug used to treat glaucoma, was used as proof-of-concept. Herein, we show that NADES can increase the solubility of ACZ in aqueous solutions by at least up to 3 times, making it useful for the formulation of ACZ into ocular drops and thereby enabling more efficient treatment. The cytotoxicity assays demonstrated that NADES are biocompatible up to 5% (w/v) in aqueous media, promoting cell viability (above 80%) when compared to the control after 24 h incubation in ARPE-19 cells. Furthermore, when ACZ is dissolved in aqueous solutions of NADES, the cytotoxicity is not affected in this range of concentrations. Although further studies are necessary to design an optimal formulation incorporating NADES, this study shows that these eutectics can be powerful tools in the formulation of ocular drugs.publishersversionpublishe

Cellulose acetate/carbon nanotube composites by melt mixing

Cellulose acetate (CA) is produced from a natural polymer and presents excellent properties, finding applications in a variety of areas. Unlike cellulose, CA is melt processable and may be molded into parts and formed into fibers or films. In this context, the production of conductive CA composites that may be processable and integrated into parts to provide specific functionalities is an area of increasing interest. The present work aims to prepare electrically conductive composites based on CA and carbon nanotubes (CNTs) by melt mixing. The nanocomposites were produced with pure and pyrrolidine-functionalized nanotubes, using a batch mixer and a twin-screw extruder. The morphology of carbon nanotube dispersion, the rheological behavior and the electrical conductivity of the final composites were evaluated. Rheological percolation was achieved for the composites with 0.5 wt% of CNT—both pure and functionalized—produced by extrusion; while electrical percolation was observed only for the composites with pure CNT.The authors acknowledge the Portuguese Foundation of Science and Technology (SFRH/BD/81711/2011 and PEst-C/CTM/LA0025/2011) and n-SteP – Nanostructured Systems for Tailored Properties, with reference NORTE-07-0124-FEDER-000039, supported by the Programa Operacional Regional do Norte (ON.2).info:eu-repo/semantics/publishedVersio

The influence of melt mixing on the stability of cellulose acetate and its carbon nanotube composites

Cellulose derivatives, such as cellulose acetate (CA), are commonly used due to their ease of processing. These polymers present interesting mechanical properties and biodegradability, but low thermal stability under melt processing conditions. Composites of carbon nanotubes (CNTs) and cellulose derivatives are expected to present enhanced properties, depending on the effect of nanotubes on polymer structure and thermal properties. This work aims to investigate the influence of melt mixing on the stability of CA and its CNT composites. Composites with 0 wt%, 0.1 wt% and 0.5 wt% CNTs, as received and functionalized with pyrrolidine groups, were prepared using a batch mixer and an extruder. Chain scission of CA occurred during processing, but the effect was considerably reduced in the presence of CNTs. The incorporation of small amounts of CNTs (with or without functionalization) decreased polymer degradation by thermomechanical effects induced during polymer processing.The authors acknowledge the Portuguese Foundation for Science and Technology (SFRH/ BD/81711/2011) and n-STeP – Nanostructured systems for Tailored Properties, with reference NORTE-07-0124- FEDER-000039, supported by the Programa Operacional Regional do Norte (ON.2).info:eu-repo/semantics/publishedVersio

Model-based user interface testing with Spec Explorer and ConcurTaskTrees

Analytic usability analysis methods have been proposed as an alternative to user testing in early phases of development due to the cost of the latter approach. By working with models of the systems, analytic models are not capable of identifying implementation related problems that might have an impact on usability. Model-based testing enables the testing of an implemented software artefact against a model of what it should be (the oracle). In the case of model-based user interface testing, the models should be expressed at an adequate level of abstraction, adequately modelling the interaction process. This paper describes an effort to develop tool support enabling the use of task models as oracles for model-based testing of user interfaces.FCT -Fuel Cell Technologies Program(POSC/EIA/56646/2004

Low-Phytotoxic Deep Eutectic Systems as Alternative Extraction Media for the Recovery of Chitin from Brown Crab Shells

Funding Information: This work was financed by Portugal 2020 through the European Regional Development Fund (ERDF) in the frame of Operational Competitiveness and Internationalization Program (POCI) in the scope of the project MultiBiorefinery—POCI-01-0145-FEDER-016403, co-financed by national funds through the FCT/MEC. Additional funding was received from PTDC/EQU-EQU/29851/2017 project, financed by national funds (FCT/MEC); and from ERC-2016-CoG 725034 grant agreement, financed by the European Union’s Horizon 2020 (European Research Council). This work was also supported by the funding received from INTERFACE Program, through the Innovation, Technology and Circular Economy Fund (FITEC); and from iNOVA4Health (UIDB/04462/2020) and the Associate Laboratory for Green Chemistry—LAQV (UIDB/50006/2020), programs financially supported by FCT/MEC, through national funds. This work has also received support from COST Action CA18224 through an STSM Grant. Liliana A. Rodrigues, Alexandre Paiva, and Ana A. Matias have also received financial support from FCT through the SFRH/BD/116002/2016, IF/01146/2015, and IF/00723/2014 grants, respectively. The authors are grateful to Tejo Ribeirinho Lda. for kindly supplying the biomass used in this work. Publisher Copyright: © 2021 American Chemical Society.The versatility of chitin and its derivatives has allowed their utilization in a wide range of applications, from wastewater treatment to pharmaceutical or biomedical industries. However, even though the extraction method used industrially is extremely efficient, it involves the use of strong acids and bases and results in the disposal of large quantities of toxic effluents. Deep eutectic systems (DESs) have emerged as a promising new class of alternative solvents, including for chitin recovery. Yet, the assessment of their toxicity has often been neglected. Therefore, in this work, the phytotoxicity of choline chloride (ChCl)/organic acid-based DESs toward wheat seeds was evaluated by measuring different growth parameters and stress biomarkers. DESs were then explored for the efficient recovery of chitin contained in brown crab shell residues at varying conditions of temperature and processing time as well as with and without water addition. The obtained chitin was then characterized through different analytical techniques and compared to a standard as well as to chitin obtained by a conventional acid/alkaline hydrolysis. Results have shown that by applying a ChCl/lactic acid-based DES (which was the system that showed the least phytotoxic effects on wheat; EC50 ≥ 1.6 mg/mL) at 130 °C, it was possible to obtain pure chitin (up to 98%) with characteristics similar to those presented by commercial chitin or chitin recovered by conventional hydrolysis in a shorter time (more than 8-fold faster), thus suggesting that ChCl/organic acid-based DESs can truly represent a low-phytotoxic alternative extraction media for the recovery of chitin from the crab shell biomass.publishersversionpublishe