Posters at Innovations in Encapsulation

We are pleased to announce that there will be prizes for the best posters. 

 

Poster prizes sponsored by

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Abstracts

Here are the abstracts of the posters that will be presented at the conference

 

Microfluidic production of monodispersed microspheres and microcapsules for photocatalytic water treatment and CO2 capture

Ruqaiya Al nuumani, Goran T. Vladisavljević, Guido Bolognesi

Chemical Engineering Department, Loughborough University, Loughborough, UK

Drop microfluidics is a highly promising technique for production of monodispersed droplets and particles with tuneable size and morphology. In this work, polymeric particles with tailored properties were produced continuously, in a single step, using microfluidic emulsification and subsequent on-the-fly photopolymerization (Figure 1). (Solid-in-oil)-in-water (S/O)/W, water-in-(solid-in-oil)-in-water W/(S/O)/W, and water-in-oil-in-water (W/O/W) emulsions were used as a template for particle synthesis. The fabricated particles include acrylate microspheres embedded with TiO2 for photocatalytic water treatment, polymeric microcapsules consisting of a controlled number of liquid cores embedded in a polymer matrix, and core-shell microcapsules comprised of a thin polymer shell and a CO2-selective liquid core for CO2 capture.  For photocatalysis, TiO2 nanoparticles were dispersed in a UV-curable monomer to form a S/O phase, which was then dispersed in an aqueous solution consisting of 4 wt% PVA and 40 wt %glycerol. The droplets were polymerized with a UV-lamp and characterized using SEM, TGA, XRD, and FT-IR. The photocatalytic activity of the particles was confirmed by measuring the degradation rate of methylene blue as a module contaminant with a UV-visible spectrophotometer at lmax = 664 nm. For CO2 capture, the inner fluid was 5 wt% K2CO3 solution, the middle fluid was a 3 wt% PGPR solution in a UV-curable liquid acrylate monomer, and the outer fluid was an aqueous solution of glycerol and PVA. The saturation of the liquid core with CO2 was visualised by adding m-cresol purple, a pH indicator, in the inner fluid.

Continuous Flow Manufacturing of Microencapsulates

Alix Barton, Konstantin Loponov, Anna Trybaba, Richard Holdich, Marijana Dragosavac

Department of Chemical Engineering, Loughborough University, UK

This research is aimed at developing a novel, scaled-up continuous flow system for microencapsulation of oil- or water-soluble compounds using Membrane Emulsification (ME) integrated with an Oscillatory Flow Reactor (OFR), which allows custom microcapsule properties such as size and shell thickness. ME is a relatively new tool for low energy input generation of monosized emulsions in a highly controllable manner.[1] Moreover, high throughput generation of emulsions in continuous flow has recently been demonstrated using different ME systems.[2,3] In this study, azimuthally oscillating ME system[2] was used for continuous generation of water-in-oil-in-water double emulsions (50-350 µm, span=0.6). A primary water-in-oil emulsion was obtained by homogenising water with sunflower oil which then was dispersed into a continuous phase of aqueous bovine gelatine and gum arabic at 37ºC. Complex coacervation[4] requires slow cooling of the emulsion to room temperature (≤1ºC min-1[5]) as both shell thickness and encapsulation efficiency are influenced by cooling rate. Capsule shells are usually cross-linked by glutaraldehyde to increase their stability. To account for this, OFR was selected as a device which can operate with slurries and emulsions under plug flow conditions. [6] Furthermore, shell thickness can be customised by varying the cooling gradient along the OFR. The cooling profile inside the OFR was investigated at different flowrates and cooling liquid temperatures using thermotropic liquid crystal capsules (80µm) with colour change range between 25 and 37ºC. The optimal cooling profile in the OFR was then validated by continuous microencapsulation of sunflower oil.

Encapsulation and Triggered Release of Hydrophobic and Hydrophilic Actives Using Silica Colloidosomes

Mariana B. T. Cardoso1*, Zhibing Zhang2, Pierre Verstraete3, Jon A. Preece1

1School of Chemistry, 2School of Chemical Engineering, Univeristy of Birmingham, Birmingham B15 2TT, UK

3Procter and Gamble, Brussel Innovation Center, Temselaan 100, 1853 Bever, Belgium

Colloidosomes were studied for the encapsulation of hydrophobic or hydrophilic actives via the formation of particle-stabilized emulsions, so called Pickering emulsions1. The formation of Pickering emulsions is carried out via the self-assembly of solid colloidal particles at the interface between two highly immiscible liquids such as water and oil, lowering the interfacial energy and stabilizing the emulsion2. Silica colloidal particles (SiO2 CPs) with variable surface properties were used to assess the formation of stable Pickering emulsions between water and hexyl salicylate. The emulsions were further stabilized using a SiO2 precursor forming colloidosome capsules. The capsule mechanical properties were characterized using a micromanipulation technique (Figure 1) which can measure the rupture force and the deformation of single capsules when a force is applied3. The experiment suggests that the colloidosome capsules formed are strong enough to survive air-drying and can be ruptured using mechanical force, releasing the core material. This type of trigger release is interesting when it comes to formulations where the active ingredient needs to be released via bursting when a specific mechanical force is applied. 

Thermal Stability, Storage, Release and Delivery of Insulin – A Protection Through Sol-Gel Tailored Silica

Yun-Chu Chen, Francoise Koumanov, Karen J. Edler, Asel Sartbaeva.

University of Bath

Stability of biological substances based on proteins, including vaccines and drugs, is critically linked to its thermal environment. Their storage and distribution therefore relies on a “cold chain”. This is costly and not always effective in medical applications. Diabetes is predicted to be the 7th leading cause of death. According to WHO, access to insulin is still beyond the reach of millions diabetes. The need for a cold chain during transport and storage has caused poor insulin availability and affordability. We have published a protocol of “ensilication”, enclosing protein in a deposited silica “cage” to prevent the protein from the denaturing process.  The investigation was continued onto the mechanism of the ensilication using SAXS and DLS, and an artificial digestion system has also been tested for oral delivery. This innovative method has been applied to insulin, which is also served as a model of negative charged proteins. The research has a profound impact on our ability to store temperature sensitive matter and remove our constant dependence on cold-chain, enabling insulin and other biological materials to be taken anywhere in the world without refrigeration.

Controlling metal coated microcapsule shell thickness.

Assim Fiaz, Dr Olivier Cayre

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At the University of Leeds, we have recently developed metal-coated microcapsules, which can retain a volatile active core in a very broad range of formulation conditions. For the process of depositing a metallic shell to result in impermeable microcapsules, we have found that good control of the reaction rate is necessary to retain shell impermeability while varying the shell thickness. The metal deposition process in this case is a two-step catalytic reaction, which can be manipulated via the surface density of the catalytic nanoparticles used, the reaction temperature and the reactant concentrations.

In this work, we will demonstrate how different shell thicknesses can be obtained by varying the parameters above. In addition, we will describe how a method has been developed to accurately measure metallic microcapsule shell thickness by combining several analytical characterisation techniques together, including light scattering, microscopy, UV-vis adsorption and thermo-gravimetric techniques. This method will eventually provide a simple and time effective approach to predicting and subsequently controlling microcapsule metal shell thicknesses.

Starch-silver-nanoparticles encapsulated dichlorvos and chlorpyrifos insecticide formulations: characterization and release studies.

Nnemeka Edith Ihegwuagu1-4*, Rufus Sha’Ato4, Terrumun Amom Tor-Anyiin4, Lami Angela Nnamonu4,  Bertrand Sone1-2 and Malik Maaza1-2

1.    UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies,University of South Africa, Muckleneuk ridge, POBox 392, Pretoria-South Africa,

2.    Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, POBox 722, Somerset West, Western Cape Province, South Africa.

3.    Agricultural Research Council of Nigeria, CTRP, Agricultural Research House, Mabushi, P. O. Box 5026, Wuse, Abuja-Nigeria.

4.    Department of Chemistry & Centre for Agrochemical Technology, University of Agriculture, P.M.B. 2373, Makurdi, Benue State, Nigeria.

The encapsulation of two widely used organophosphorus insecticides in Nigeria namely dichlorvos and chlorpyrifos, were achieved in situ on to cassava starch nanosilver particle matrices with the aim to give more effective, cheaper and safer slow/controlled delivery than conventional pesticide formulations over a longer time. The starch -silver nanoparticle matrices were synthesized during the chemical reduction of silver nitrate by glucose employing direct heating. The starch-silver nanoparticles encapsulation of dichlorvos (ST-AgNP-VOS) and chlorpyrifos (ST-AgNP-FOS) were confirmed by UV-Vis spectroscopy and characterized by HR-TEM, EDX, SAED, FTIR, XRD and FESEM.

The characteristic colour of AgNPs was observed and Surface Plasmon Resonance (SPR) at 418-422nm. The XRD results revealed silver diffraction peaks at 2θ angles in each formulation. Encapsulation efficiency was 95% for ST-AgNP-VOS and 98% for ST-AgNP-FOS both better than control having no silver (NDVOS). Their HR-TEM and FESEM images analysis indicated spheres with an average particle size range of 23nm–35nm. FTIR also confirmed the loading of dichlorvos and chlorpyrifos with additional peaks corresponding to them and control had none. nano- formulations showed an enhanced aqueous release over the control.

This current synthetic/encapsulation process can be scaled up as slow release formulations with silver nanoparticles acting as anti-microbial agent.

Co-encapsulation of Methotrexate and beta carotene in glycosylated lipid polymer hybrid nanoparticles to improve the biopharmaceuticals attributes and to abolish the toxicity of methotrexate

Ashay Jain1, 2, 3, Gajanand Sharma1, Varun Kuswah4, Gargi Ghoshal3*, Bhupinder Singh3, Sanyog Jain4, U.S. Shivhare3 and O.P. Katare1

1Division of Pharmaceutics, University Institute of Pharmaceutical Sciences, UGC-Centre of Advanced Studies, Panjab University, Chandigarh 160 014, India

2UGC-Centre of Excellence in Applications of Nanomaterials, Nanoparticles and Nanocomposites, Panjab University, Chandigarh 160 014, India

3Dr. S. S. Bhatnagar University Institute of Chemical Engineering & Technology, Panjab University, Chandigarh, 160 014, India

4Centre for Pharmaceutical Nanotechnology, Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, SAS Nagar, Punjab, 160062, India


The fabrication of surface modified beta carotene and methotreaxate co-encapsulated lipid polymer hybrid nanoparticles (LPHNPs) was described as a substantial drug delivery platform, with maximum drug entrapment, spatial and controlled drug release, exceptional biopharmaceutical attributes, and site specific delivery of bioactives. Beta carotene and methotreaxate co-encapsulated LPHNPs were fabricated using modified one step self-assembled nano-precipitation technique. Fructose was conjugated on the surface of the particles to make the nanoparticles admirable for lectin receptor mediated targeted delivery. Prepared hybrid nano-formulations were measured in ultra-fine size (70–130 nm) with sphere-shaped. The percent drug entrapment of prepared LPHNPs was estimated in the range to 60 and 80%. In vitro percent cumulative release study demonstrated deaden and extended drug release i.e. approximately 65% following 5th day. The in vitro percent cell survival (cytotoxicity study), sub-cellular localization and apoptotic activity of prepared nanoparticles was evaluated against MCF-7 breast cancer cells. The anti-tumor potential of prepared hybrid nanoparticles were further investigated. It may quite reasonable that glycol-conjugated beta carotene and MTX co-loaded LPHNPs are competent to selectively convey the chemotherapeutic agent to the breast cancers while withhold the minimum adverse effects, thus signifying their feasible usefulness in cancer therapeutic and intervention.

Polyelectrolyte complexes of PEGylated Eudragits as nanocontainers for drug delivery

Natalia Porfiryeva1, Rouslan I. Moustafine1, Vitaliy Khutoryanskiy2

1Department of Pharmacy, Kazan State Medical University, Kazan 420012, Russia

2School of Pharmacy, University of Reading, Reading RG6 6AD, United Kingdom


Eudragit® are copolymer series manufactured by «Evonik Ind.» are widely used in pharmaceutical dosage forms as enteric coatings. These materials typically composed of copolymers of acrylic and methacrylic acid with more hydrophobic monomers such as methylmethacrylate and ethylmethacrylate. In this work we have synthesised PEGylated Eudragit L100-55 by its chemical conjugation with O-(2-aminoethyl)polyethyleneglycol (5 and 10 kDa) mediated with N-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. These PEGylated Eudragit derivatives were subsequently used to form polyelectrolyte complexes with cationic Eudragit EPO, resulting in nanoparticles with PEGylated surfaces. These nanoparticles exhibited good colloidal stability and were used for encapsulation of model drugs such as caffeine. The application of these complexes as nanocontainers for drug delivery will be presented.

Stimuli-responsive lipogel capsules

Natasha Rigby1, Jonathan West2, Margarita Staykova1

1Durham University, SOFI CDT

2IfLS, University of Southampton


Previous work into lipid bilayers coupled to flexible substrates has shown that they can form reversible pores, whose diameter can be controlled by the magnitude of the substrate stretch1. The aim of this work is to utilise the process of controlled pore formation in the design of stimuli-responsive lipogel capsules capable of releasing actives in response to external triggers.

We use inverse emulsion templating microfluidics to prepare polymer microgel beads whose diameter and composition can be easily controlled. The beads are coated with lipid membrane by vesicle fusion. Initial experiments and characterisation by fluorescence microscopy have verified the feasibility of this method to produce capsules with homogeneous membrane coating. Our next step is to create microgel cores which, by deforming upon external triggers (e.g. temperature, pH), will trigger the formation of pores in the membrane coating and the release of encapsulated actives for the duration of the stimulus.

Microfluidic Solvent Extraction for Precise Formation of Polymer Particles and Capsules

William Sharratt and João T. Cabral

Department of Chemical Engineering, Imperial College London, SW7 2AZ

Polymer capsules are versatile functional materials with applications ranging from encapsulation in the pharmaceutical, cosmetic and personal care industries to advanced sensing and coatings. Precisely templating liquid droplets, via well-defined physical-chemical routes to induce solidification, into polymeric and composite particles, can impart non-trivial rheo-mechanical properties and tunable spatio-temporal release profiles. By contrast with traditional large-scale processes, e.g. spray drying or emulsion polymerization, microflow routes offer precise control of particle characteristics, such as morphology, size and composition.1, 2 Exploiting simple and rapid solidification routes while carefully manipulating polymer and colloid ‘building blocks’ into hierarchical particles, can realise this ambition. We resolve the underlying thermodynamics and phase behaviour within liquids as they transition to solid particles, upon application of an environmental stimuli. The combination of microfluidic techniques, for generation and control over multiphase liquid flows, with addition of multivalent crosslinking salts or a non-solvent to form soft gel-like solids or polymer-rich skins, emerges as a simple platform for polymer capsule formation.

Free and surface-bound supramolecular cyclodextrin inclusion complexes: superior vehicles for delivering photoactivated antibacterial activity of curcumin

Ilya Shlar1,2, Samir Droby1 and Victor Rodov1

1Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel

2The Hebrew University of Jerusalem, Rehovot, Israel


Curcumin is known for a long time for its antimicrobial properties that are further increased by exposure to light. Due to the low solubility of curcumin, appropriate delivery systems are required to facilitate its implementation. In this work, we compared the antimicrobial activity toward Escherichia coli of two curcumin formulations: methyl-β-cyclodextrin supramolecular inclusion complex and polyelectrolyte-coated monolithic nanoparticles.  The two formulations showed disparity both in extent and in the mode of toxicity. While curcumin-β-cyclodextrin complex exhibited a potent bactericidal activity, the curcumin nanoparticles were bacteriostatic. The photodynamic activation significantly increased the bactericidal efficacy of curcumin-cyclodextrin complexes but had limited influence on the nanoparticulate curcumin. The antimicrobial effect of supramolecular complex was predominantly characterized by the increase in ROS and inhibition of electron transport, while the primary attributes of the nanoparticle action were membrane depolarization and reduced ATP concentrations. The mechanistic aspects of the antibacterial effects of curcumin-β-cyclodextrin complexes were further examined by toxicoproteomic approach. Curcumin treatment in the dark evoked adaptive responses aimed at mitigation of oxidative stress and modulation of cellular redox state. The ROS burst induced upon curcumin treatment under light overrode these adaptive mechanisms by disrupting the iron metabolism, deregulating the iron-sulfur cluster biosynthesis and eventually leading to cell death. Multilayer coating including curcumin-loaded carboxymethyl-β-cyclodextrin imparted light-activated antimicrobial capacity to polyethylene terephthalate film. The results obtained suggest that cyclodextrin inclusion complexes facilitate curcumin penetration into bacterial cells. The significant antimicrobial efficacy of free and surface-bound curcumin-cyclodextrin inclusion complexes make them a promising tool for bacterial contamination control.

Encapsulation of organic pigment particles via multilayer approach using in situ sol-gel synthesis

Erika Švara Fabjana,b, Zineb Saghic,d, Paul A. Midgleyc, Mojca Otoničare, Goran Dražićf, Miran Gaberščekb,f, Andrijana Sever Škapina

aNational Building and Civil Engineering Institute of Slovenia, Dimičeva 12, 1000 Ljubljana, Slovenia

bUniversity of Ljubljana, Faculty of Chemistry and Chemical Technology, Večna pot 113, 1000 Ljubljana, Slovenia

cUniversity of Cambridge, Department of Materials Science and Metallurgy, 27 Charles Babbage Road, Cambridge CB3 0FS, UK

dUniversity of Grenoble Alpes, Grenoble F-38000, France; CEA, LETI, MINATEC Campus, Grenoble F- 38054, France

eJožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia

fNational Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia


Organic pigment nanoparticles offer several extraordinary colour properties, like wide range of nuances and high values of colour strength. But their use is limited due to a poor photochemical stability. In order to improve the stability the pigment particles were encapsulated by formation multilayer SiO2 shell onto the each nanoparticle. The main synthesis consists of repeating the basic two-step process: (i) pigment surface pre-modification using surfactants (ii) silica encapsulation via in-situ sol gel process using potassium silicate as silica precursor, several times. The influence of variations in synthesis parameters (i.e. precursor concentration, number of repeated synthesis) on the properties of encapsulated pigment particles were studied in detail using transmission electron microscopy (TEM, STEM and EFTEM), FT-IR spectroscopy, TG/DTA analysis, N2 sorption and measurement of colorimetric variations after photocatalyst/UV exposure. It was found that after single or multilayer encapsulation the continuous SiO2 shell was achieved, which follows the shape of organic pigment particles. The precursor concentration minorly affected the thickness and porosity of the silica shell. Whereas the multilayer encapsulation leads to thicker shell and improved photochemical protection: the thickest shell was performed using triple layer encapsulation with the highest precursor concentration, which also enables the highest photochemical stability (45 %).

Enzyme Encapsulation in Permeable Polymersomes by Polymerization-Induced Self-Assembly (PISA) for the Development of Cascade Nanoreactors

Spyridon Varlas,a Lewis D. Blackman,a Maria C. Arno,a Alice Fayter,a Matthew I. Gibson,a,b* Rachel K. O’Reillya*

a Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK

b Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK


Enzyme loading of polymersomes requires permeability to enable them to interact with the external environment, typically requiring addition of complex functionality to enable porosity. Herein, we describe a synthetic route towards inherently permeable polymersomes loaded with functional enzymes using initiator-free visible light-mediated polymerization-induced self-assembly (photo-PISA) under mild, aqueous conditions using a commercial monomer. Compartmentalization and retention of protein functionality was demonstrated by encapsulating green fluorescent protein (GFP) as a macromolecular chromophore. Catalytic enzyme-loaded vesicles using horseradish peroxidase (HRP) and glucose oxidase (GOx) were prepared and the permeability of the membrane towards their small molecule substrates was also revealed. Finally, the interaction of the compartmentalized enzymes between separate polymersomes was validated by means of an enzymatic cascade reaction. This one-pot, mild approach is highly versatile and could be applied to a wide range of functional enzymes. The findings have a broad scope as the methodology could be applied for the encapsulation of a large range of macromolecules for advancements in nanotechnology, nanomedicine and other bio-related fields
.

Development of Microfluidic Pilot Line for Encapsulation of Active Pharmaceutical Ingredients

Graham Worrall

Centre for Process Innovation Ltd

Encapsulation of active pharmaceutical ingredients in to either polymeric or lipid structures is well established at the laboratory scale.  Scaling microfluidics has long been the major challenge preventing adoption by the wider market sector.  A pilot line is currently being developed at the Centre for Process Innovation in which the scale of production is taken from 1 to 80ml/min using a modified Nanoassemblr TM Blaze TM from Precision Nanosystems.  This unique facility will provide a test bed for small and medium enterprises to demonstrate scalability and robustness of their new processes to prospective manufacturers.