Microfluidic devices for continuous liquid-liquid-solid chemical extractions

In this study the unique properties of microfluidic flow have been exploited to generate efficient mass-transfer in continuous segmented flow to investigate an alternative approach for performing chemical extractions. The concept of extraction-enhancement, by incorporation of a solid absorbent in the extracting phase, was explored. Proof-of-principle studies focused on the use of molecularly imprinted polymers (MIPs) to increase the effectiveness of conventional approaches. Laser machining and micro-milling were used to prepare PTFE microfluidic separation devices. Importantly, this included the design and integration of a continuous-flow microfluidic liquid phase separator. Propranolol selective molecularly imprinted polymer microspheres (3.6 µm) were prepared by precipitation polymerisation. MIP performance was assessed using conventional (equilibrium batch rebinding) and segmented-flow liquid-liquid systems. Interfacial mass transfer processes that occur during segmented flow were characterised with respect to flow variables, fluid properties and channel geometries. Segment aspect ratio and flow velocity, together with channel diameter and curvature, were shown to be important. The MIP was shown to possess high affinity and selectivity for the template (propranolol). Incorporation of the MIP into a segmented flow extraction regime was shown to significantly enhance the extent of analyte extraction. Mathematical optimisation approaches showed good correlation with experimental data. On-chip phase separation was demonstrated to be 100% efficient for particle-containing and particle-free immiscible flows. The discovery of soluble MIP species possessing similar binding characteristics to their insoluble counterparts may further improve the kinetics of the reported solid-liquid-liquid extractions. It was successfully demonstrated that a solid phase material can be incorporated into an organic phase to enhance extraction from an aqueous sample either in continuous segmented flow or under equilibrium conditions. The integration of the segmented flow approach with an on-chip liquid phase separator provides a novel platform for the development of unique and highly-efficient continuous flow devices for molecular enrichments, separations and manipulations.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Microfluidic devices for continuous liquid-liquid-solid chemical extractions.

In this study the unique properties of microfluidic flow have been exploited to generate efficient mass-transfer in continuous segmented flow to investigate an alternative approach for performing chemical extractions. The concept of extraction-enhancement, by incorporation of a solid absorbent in the extracting phase, was explored. Proof-of-principle studies focused on the use of molecularly imprinted polymers (MIPs) to increase the effectiveness of conventional approaches. Laser machining and micro-milling were used to prepare PTFE microfluidic separation devices. Importantly, this included the design and integration of a continuous-flow microfluidic liquid phase separator. Propranolol selective molecularly imprinted polymer microspheres (3.6 um) were prepared by precipitation polymerisation. MIP performance was assessed using conventional (equilibrium batch rebinding) and segmented-flow liquid-liquid systems. Interfacial mass transfer processes that occur during segmented flow were characterised with respect to flow variables, fluid properties and channel geometries. Segment aspect ratio and flow velocity, together with channel diameter and curvature, were shown to be important. The MIP was shown to possess high affinity and selectivity for the template (propranolol). Incorporation of the MIP into a segmented flow extraction regime was shown to significantly enhance the extent of analyte extraction. Mathematical optimisation approaches showed good correlation with experimental data. On-chip phase separation was demonstrated to be 100% efficient for particle-containing and particle-free immiscible flows. The discovery of soluble MIP species possessing similar binding characteristics to their insoluble counterparts may further improve the kinetics of the reported solid-liquid-liquid extractions. It was successfully demonstrated that a solid phase material can be incorporated into an organic phase to enhance extraction from an aqueous sample either in continuous segmented flow or under equilibrium conditions. The integration of the segmented flow approach with an on-chip liquid phase separator provides a novel platform for the development of unique and highly-efficient continuous flow devices for molecular enrichments, separations and manipulations

Label-free volumetric imaging of synthetic cell chassis using optical coherence tomography

Bottom-up, chemically formed synthetic cells are usually imaged by optical microscopy, and the cell sizes and shapes are mostly estimated from acquired 2D images. The three-dimensional (3D) structures of a compartmentalised synthetic cell can be analysed by axially stacking 2D images, typically by using a high-resolution imaging systems, such as laser confocal scanning microscopy and light sheet microscopy. However, these techniques require the synthetic cell to be labelled with fluorescent tags, and have performance limits such as being restricted to volumes less than (approximately) 200 ìm3. Here, we present the label-free, 3D imaging of soft, free-standing, multicompartment synthetic cell using optical coherence tomography (OCT). The volumes of sub-cellular compartments within individual synthetic cells can be obtained via OCT imaging measurement. The spatial arrangements of the compartments and their contact angle information can be illustrated and measured, respectively. This approach provides a new method to evaluate multiphase soft materials spanning the range of micrometres to millimetres, towards the optimisation of synthetic cell construction for novel biomimetic material development

Dynamic tuneable G protein-coupled receptor monomer-dimer populations

G protein-coupled receptors (GPCRs) are the largest class of membrane receptors, playing a key role in the regulation of processes as varied as neurotransmission and immune response. Evidence for GPCR oligomerisation has been accumulating that challenges the idea that GPCRs function solely as monomeric receptors; however, GPCR oligomerisation remains controversial primarily due to the difficulties in comparing evidence from very different types of structural and dynamic data. Using a combination of single-molecule and ensemble FRET, double electron–electron resonance spectroscopy, and simulations, we show that dimerisation of the GPCR neurotensin receptor 1 is regulated by receptor density and is dynamically tuneable over the physiological range. We propose a “rolling dimer” interface model in which multiple dimer conformations co-exist and interconvert. These findings unite previous seemingly conflicting observations, provide a compelling mechanism for regulating receptor signalling, and act as a guide for future physiological studies

Immunomodulatory effect and maternal transmission of a probiotic strain of Lactobacillus isolated from human milk

Podeu consultar el III Workshop anual INSA-UB complet a: http://hdl.handle.net/2445/118993Sessió 1. Resultats del Programa FRI-INS

Lactobacillus fermentum CECT5716 Supplementation in Rats During Pregnancy and Lactation Impacts Maternal and Offspring Lipid Profile, Immune System and Microbiota

Probiotics have shown potential for their use in early life. This study aimed to investigate whether the administration of Lactobacillus fermentum CECT5716 during pregnancy and lactation periods impacts maternal and offspring plasma lipid profile, immune system and microbiota. Rats were supplemented with the probiotic during gestation and two weeks of lactation. After supplementation, although the microbiota composition was not affected, the probiotic strain was detected in all cecal contents of dams and in some of their pups. Dams showed reduced proportion of T cytotoxic cells in the mesenteric lymph nodes, modulation of intestinal cytokines (IL-10 and IL-12) and changes in plasma fatty acids (20:0, 22:0, 20:5 n-3, and 18:3 n-6). Pups showed changes in immunoglobulins (intestinal IgA and plasmatic IgG2a and IgG2c) and fatty acid profile (17:0, 22:0, and 18:2 n-6). Overall, Lactobacillus fermentum CECT5716 supplementation contributed to beneficially modulating the immune system of the mother and its offspring