Poster Abstracts
Salt-driven assembly of metal doped silica beads
David F.F. Brossault and Alexander F. Routh
Department of Chemical Engineering and Biotechnology, University of Cambridge
Silica particles have low toxicity and cost, as well as high surface area and stability. This allows their use in co-assembled composites with enhanced properties (i.e. Heavy metal adsorption, drug encapsulation, enhanced recovery, catalysis, etc.). However, the preparation of such systems can be time-consuming and often requires toxic chemicals or high temperatures. This poster presents a new method of producing spherical metal doped silica beads via colloidal destabilization. The instability is induced by addition of CaCl2 to a water in oil emulsion containing nanoparticles in the aqueous droplets. The use of an emulsion as a geometrical constraint results in the formation of spherical beads, as opposed to the fractal structure usually caused by addition of salt to a silica dispersion. This formulation method is facile, low cost, and has the capacity to easily incorporate various additives (Fe3O4, TiO2, etc.) as well as functional nanoparticles to the structure. Furthermore, it is possible to produce beads of sub-micron to micron diameters with varying levels of porosity depending on the emulsion conditions. These findings are promising for the preparation of new encapsulation systems for medical applications, catalysis or water treatment.
Biocoatings: A novel material for bacteria encapsulation
Yuxiu Chen,a Simone Krings,b Suzie Hingley-Wilsonb and Joseph L. Keddiea
a. Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH
b. Department of Microbial Sciences, University of Surrey, Guildford, Surrey, GU2 7XH
Bacteria are now widely used in the wastewater industry as biocatalysts to remove hazardous pollutants from the wastewater. Cell immobilisation is a technique that encapsulates bacteria using a polymer matrix so that the bacteria can be physically separated from wastewater to improve the efficiency of the bioreactors. A biocoating is a recently-developed material that employs a colloidal polymer (latex) film to confine non-growing, metabolically-active bacteria. An ideal biocoating needs to be nanoporous to allow the transfer of metabolic products through the film as well as to be hydrophilic to ease the desiccation stress of bacteria during the film formation. Biocoatings can provide cell immobilisation for wastewater treatment by encapsulating bacteria during the drying and film formation process. In this project, we have introduced halloysite, a high aspect-ratio clay nanotube, to create nanoporosity inside the polymer matrix and have used trehalose to increase the viability of the bacteria. The viability of E. coli bacteria and the distribution of the components inside the biocoatings were examined using complementary microscopies. By carefully tuning the latex composition and the film formation conditions, we are aiming to fabricate biocoatings with desired properties that could be readily used for wastewater treatment.
Microfluidic production of drug-loaded biodegradable polymer microparticles for drug-delivery applications
Tymèle Deydier, Guido Bolognesi and Goran T. Vladisavljević
Loughborough University, Department of Chemical Engineering
Biodegradable polymeric microparticles find widespread use in controlled drug delivery. In this research, biodegradable polymer microparticles with tuneable size and surface morphology containing a hydrophobic drug were produced via oil-in-water emulsion in a glass 3D flow-focusing microfluidic chip with 100μm-deep channels. The oil phase was a polymer-drug solution in a volatile organic solvent (dichloromethane or dimethyl carbonate) and the aqueous phase was a polyvinyl alcohol (PVA) solution. After solvent evaporation, the droplets solidified into particles with highly uniform size ranging from 10 to 30 μm and a coefficient of variation of less than 3%. The solvent evaporation-induced phase separation between the polymer and the drug resulted in patchy particle morphologies at very high polymer to drug ratio (4:1) in the initial oil phase and in Janus morphologies for other polymer to drug ratios (2:1, 1:1, 1:4, and 1:9).
Acknowledgement:
This work was supported by Med Alliance LLC and ESPCR National Productivity Investment Fund.
Fabrication of h-BN-rGO@PDA nanohybrids for composite coatings with enhanced anticorrosion performance
Haowei Huang a, b, Xiaofeng Huang, Yuhui Xie, Yuqin Tian, Xiang Jiang*, Xinya Zhang*
a Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K.
b School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China
Inspired by mussels’ universal adhesive ability to various substrates, polydopamine (PDA) was used to bind graphene oxide (GO) and hexagonal boron nitride (h-BN) together to fabricate h-BN-rGO@PDA nanohybrids. The as-prepared h-BN-rGO@PDA nanohybrids were served as anticorrosive nanofillers for polyvinylbutyral (PVB) coatings on mild steel. The structure of h-BN-rGO@PDA nanohybrids were characterized by SEM, XRD, FT-IR, UV–vis and Raman spectroscopies. Electrochemical corrosion tests were conducted to examine the anticorrosion properties of h-BN-rGO@PDA/PVB composite coatings. The results show that the stacked h-BN nanosheets are exfoliated by GO. And PDA is successfully grafted onto the surface of h-BN-rGO@PDA and simultaneously reduced GO into rGO. The h-BN-rGO@PDA nanohybrids are homogeneously distributed in the PVB matrix. When the mass ratio of GO to h-BN in h-BN-rGO@PDA is 1:1, the as-prepared h-BN-rGO@PDA possesses effective aspect ratio and thus its PVB composite coating obtains the optimal anticorrosion performance with 2 orders of magnitude higher than pure PVB.
Surface Energy and Solubility Parameter Analysis of Soluplus® using Inverse Gas Chromatography
Nachal Subramanian, Majid Naderi, Daniel Burnett, Armando Garcia
Surface Measurement Systems Ltd., Unit 5 Wharfside, Alperton, London, UK
Soluplus®, a polyethylene glycol, polyvinyl acetate and polyvinylcaprolactame-based graft copolymer (PEG/PVCp/PVAc), has been extensively studied as a polymeric solubilizer to enhance the solubility of poorly soluble drugs using the solid solution/dispersion approach. It has a low glass transition temperature (Tg), low hygroscopicity and high solubility in water and organic solvents, which offers advantages over cellulose based and/or PVP based excipients. Most techniques that are used to investigate the solubility/miscibility of polymers with drugs require a complete understanding of the chemical structure or composition of the polymer and the drug which often leads to inaccurate results. In contrast, iGC SEA technique provides accurate values of solubility parameters without requiring the polymer structure or composition. In this study, inverse gas chromatography Surface Energy Analyzer (iGC SEA) was used to examine the surface energy properties - dispersive and specific surface energies, and free energy of desorption for various polar solvents. In addition, solubility parameters of Soluplus® and the extrudate with carbamazepine as a model Class II drug were determined.
Electrospray-based fabrication of polymer particles and their applicability for gastrointestinal delivery of probiotics
Phuong Linh Taa,b,c, Dimitris Charalampopoulosb, Vitaliy Khutoryanskiyc
aFaculty of Food Science, Szent Istvan University, Budapest 1118, Hungary
bDepartment of Food and Nutritional Sciences, University of Reading, Reading RG6 6AD, UK
cReading School of Pharmacy, University of Reading, Reading RG6 6AD, UK
Designing micro delivery system for probiotic encapsulation provides a chance for probiotics to maintain their viability and beneficial health effects on human hosts by protecting them against adverse, often lethal environmental factors.
In this research, our aim was to investigate the applicability of the novel electrospraying technique for the above-mentioned purposes, using Lactobacillus plantarum NCDO 1752 as a model probiotic strain. The encapsulations were carried out into calcium alginate and resistant starch containing calcium alginate particles. Additionally, the calcium alginate capsules were supplied with chitosan coating. Based on a microscopical analysis these particles exhibited mostly spherical shape, with an average diameter of around 300 µm for uncoated beads and 600 µm for coated beads. Bacteria-loaded calcium alginate microparticles were produced with the efficiency of 6% live counts and with 10% when resistant starch, as a prebiotic component was included into the capsule matrix. The stability and cell protection ability of each variation of particle have also been investigated by their passage through simulated gastrointestinal conditions.