Continuous-flow precipitation of hydroxyapatite at 37 °C in a meso oscillatory flow reactor

Continuous-flow precipitation of hydroxyapatite (HAp) was investigated in a meso oscillatory flow reactor (meso- OFR) and in a scaled-up meso-OFR, obtained by associating in series eight vertical meso-ORFs. Experiments were carried out under near-physiological conditions of temperature and pH, using fixed frequency ( f = 0.83 Hz) and amplitude (x0 = 4.5 mm), and varying the residence time from 0.4 to 6.7 min. It has been shown that the mean particle size and the aggregation degree of the prepared HAp particles decrease with decreasing residence time. HAp nanoparticles with a mean size (d50) of 77 nm, narrow size distribution, and uniform morphology were obtained at the lowest residence times, τ = 0.4 and 3.3 min in the meso-OFR and the scaled-up meso-OFR, respectively. These results show the capability of the meso-OFR and the scaled-up meso-OFR for continuous production of uniform HAp nanoparticles, while also confirming the possibility of OFR scale-up by in series association of individual OFRs

Characterization of intermediate stages in the precipitation of hydroxyapatite at 37°C

Precipitation of hydroxyapatite Ca 5(PO 4) 3OH (HAp) was carried out by mixing a saturated calcium hydroxide aqueous solution with an orthophosphoric acid aqueous solution at 37°C. In order to promote optimal conditions for the production of HAp with high yields, mixing of the reaction medium was assured by a novel metal stirrer. Different experimental conditions were studied varying the mixing Ca/P molar ratio from 1 to 1.67. After process optimization, a suspension of HAp particles with pH close to 7 was obtained for a mixing molar ratio Ca/P=1.33. The precipitation process was then characterized as a function of pH and calcium concentration, revealing the existence of three different stages. The precipitate formed in each stage was characterized by scanning electron microscopy and X-ray diffraction.This work was supported by the Portuguese Foundation for Science and Technology (SFRH/BD/42992/2008) through the MIT-Portugal Program, Bioengineering Systems Focus Area. The authors are thankful to Dr. Jorge Ferreira from LNEG (Laboratorio Nacional de Energia e Geologia) for carrying out the X-ray measurements and their help with the interpretation of results

Factors affecting polyhydroxyalkanoates biodegradation in soil

Polyhydroxyalkanoates (PHAs) are polymers with widespread applications, from medical devices to packaging. PHAs can be biodegradable in natural environments, such as soil, but the blend of PHA with other materials can change the polymer properties and consequently affect the biodegradation process. The composition of the microbial communities in soil also significantly affects the biodegradation, but other factors such as temperature, pH, and soil moisture, can also be determinant. These ecological and physic/chemical factors change in different seasons and in different soil layers. It is essential to know how these factors influence the PHAs biodegradation to understand the impact of PHAs in nature. This review compiles the results on PHA polymers and PHA blends biodegradation, with focus on laboratory tests. The main factors affecting PHA's biodegradation in soil, both in laboratory tests and in the environment are also discussed.Miguel Fernandes acknowledges the grant PD/BD/146195/2019 provided by the Portuguese Foundation for Science and Technology (FCT). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020–Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Unravelling the behavior of nanostructures during digestion and absorption

The food industry is increasingly focused on preventing nutrition-related diseases and improving consumers’ wellbeing. As a result, there is a growing trend towards healthy foods, enriched with bioactive compounds (such as vitamins, probiotics, bioactive peptides and antioxidants) produced through the application of innovative and safe technologies. In this context, the development of novel delivery systems for food applications through the use of nanotechnology has been extensively explored [1]. In fact, the encapsulation of bioactive compounds in bio-based nanostructures have been reported as promising mean of protecting the valuable bioactive compounds and providing new functionalities (e.g. increase of bioavailability). However, the use of very small particle sizes may alter the biological fate of the ingested materials and bioactive compounds, which could potentially have adverse effects on human health [2]. Therefore, the emerging field of nanotechnology offers new challenges to food industry not only by offering novel tools to improve food quality and human health, but also by introducing questions about nanostructures’ behaviour within the human body. The challenges that must be overcome before nanotechnology can be entirely embraced by food industry, includes the optimisation of nanostructures’ formulations to increase stability and bioactive compounds’ bio availability and the risk assessment of their use in food. The understanding of the behaviour of different nano-based delivery systems (e.g. nanoemulsions, nanoparticles) under digestion conditions, assessing their efficiency and safety is therefore of utmost importance to enable its widespread application in the food industry. This evaluation can be challenging, however, there are opportunities to take advantage from the lessons learned from pharmaceutical industry and of the considerable progress in the development of more realistic in vitro models to more accurately predict the behaviour of bio-based nanostructures once ingestedinfo:eu-repo/semantics/publishedVersio

Incorporation of solid lipid nanoparticles into stirred yogurt: effects in physicochemical and rheological properties during shelf-life

The aim of this work was to develop a yogurt fortified with curcumin. Curcumin is a lipophilic compound with a wide range of biological activities; however, it presents low water solubility and low bioavailability, and therefore it was the first to be encapsulated in solid lipid nanoparticles (SLNs). Then the influence of the incorporation of curcumin-loaded SLNs on the physicochemical (i.e., pH, titratable acidity, syneresis and color) and rheological properties of yogurt during its shelf-life (30 days at 4 °C) was evaluated. SLN incorporation into yogurt did not affect pH and titratable acidity compared to the control (i.e., plain yogurt) during shelf-life, even though the yogurt with SLNs presented lower values of pH (4.25 and 4.34) and acidity (0.74% lactic acid and 0.84% lactic acid) than the control in the end, respectively. Furthermore, the yogurt with SLNs presented slightly higher values of syneresis than the control during the shelf-life; however, it did not present visual differences in whey separation. Relative to the color, the incorporation of SLNs into the yogurt imparted a strong yellow color to the sample but did not affect color stability during shelf-life. Both samples showed flow curves with yield stress and shear-thinning behavior during shelf-life, and, regarding the viscoelastic behavior, both showed a typical weak viscoelastic gel with an elastic structure. Overall, curcumin-loaded SLNs incorporation did not affect the physicochemical and rheological stability of yogurt during shelf-life, showing a promising application for the development of new functional foods.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and by LABBELS Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020.info:eu-repo/semantics/publishedVersio

Separation and purification of biomacromolecules based on microfluidics

Separation and purification of biomacromolecules either in biopharmaceuticals and fine chemicals manufacturing, or in diagnostics and biological characterization, can substantially benefit from application of microfluidic devices. Small volumes of equipment, very efficient mass and heat transfer together with high process control result in process intensification, high throughputs, low energy consumption and reduced waste production as compared to conventional processing. This review highlights microfluidics-based separation and purification of proteins and nucleic acids with the focus on liquid-liquid extractions, particularly with biocompatible aqueous two-phase systems, which represent a cost-effective and green alternative. A variety of microflow set-ups are shown to enable sustainable and efficient isolation of target biomolecules both for preparative, as well as for analytical purposes.publishe

Lipid-based nanostructures as strategies to enhance curcumins bioavailability: effect of carrier oil physical state

This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the Project PTDC/AGR-TEC/5215/2014, the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Nanoemulsions for enhancement of curcumin bioavailability and their safety evaluation: effect of emulsifier type

This work aimed at evaluating the effects of different emulsifiers on curcumin-loaded nanoemulsions behavior during digestion, its safety and absorption, to develop nanoemulsions that provide safety and improved curcumin functionality. Nanoemulsions (NEs) were produced using two bio-based (lecithin (LEC) and rhamnolipids (RHAM)) and one synthetic (Tween®80 (TWE)) emulsifier at similar concentrations. Different NEs were subjected to in vitro digestion. The cytotoxicity and permeability tests were performed in Caco-2 cells. NE_TWE were stable during all phases of in vitro digestion, whereas NE_LEC and NE_RHAM were found to be unstable from the gastric phase. NE_TWE showed 100% of free fatty acids released, followed by NE_RHAM and NE_LEC. Curcumins bioaccessibility and stability increased in the following order: NE_LEC > NE_RHAM > NE_TWE. NE_LEC and NE_TWE did not show cytotoxic effects in any of the concentrations tested, while NE_RHAM presented high cytotoxicity in all concentrations tested. The apparent permeability coefficients were determined for NE_LEC and NE_TWE; however, the results were not statistically different. These results showed that the emulsifier used has a high impact on nanoemulsions behavior under the digestion process and on their cytotoxicity. This work contributed to the state-of-the-arts progress on the development of safer curcumin delivery systems with improved functionality, particularly regarding the proper selection of ingredients to produce said systems.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and under the scope of project PTDC/AGR-TEC/5215/2014.info:eu-repo/semantics/publishedVersio

Uso de microsistemas na precipitação em contínuo de hidroxiapatite

Neste trabalho é apresentado o estudo de dois microreatores ultrasónicos para a precipitação em contínuo de hidroxiapatite Ca5(PO4)3OH (HAp) a 37 º C. O primeiro reator consiste num microreator tubular imerso num banho ultrasónico, onde os fluxos laminar e segmentado (gás-líquido) foram ambos avaliados. De seguida, o estudo em regime laminar foi conduzido num novo dispositivo microfluídico desenvolvido no MIT. Este é constituído por uma pilha de placas de Teflon com um elemento piezoelétrico integrado, permitindo assim a transmissão direta de ultrassons para o reator. Para todos os microsistemas estudados foram obtidas nanopartículas de HAp, em condições próximas das condições fisiológicas de pH e temperatura. Além disso, as partículas produzidas apresentam-se sob a forma de bastonetes de aproximadamente 100 nm de comprimento e 20 a 50 nm de largura. Os microreatores utilizados produziram partículas de HAp num tempo muito curto e com maior cristalinidade, comparado com as partículas produzidas num reator batch. Também foi possível reduzir significativamente a agregação das partículas nos microsistemas, ao contrário do sistema batch, onde não foi possível evitar a formação de agregados.info:eu-repo/semantics/publishedVersio