PhD candidate: Camille LEGROS
Date and place of defence: October 31, 2014 -
Nanotechnology is anticipated to be an important platform for many technological innovations over the next 50 years, and nanoparticles are important ingredients for various product formulations, such as drug delivery systems, food, and personal home care systems.We believe there is tremendous opportunity to use cellulosic materials as basic building blocks for designing novel biocompatible and biodegradable nanoparticles for use in personal home care and biomedical applications. This can be accomplished by utilising inverse microemulsion polymerisation technique, where nanosize water droplets can be generated, and carboxymethylcellulose (CMC) and chitosan (CS) can be partitioned into these nano-reactors. The carboxylic acid groups on CMC and amine groups on CS can be readily cross-linked using the well-established carbodiimide chemistry, which is simple and cheap.We have conducted a thorough literature search, and we found that this is an unexplored area that could have significant potential for producing biocompatible and biodegradable nanoparticles for many practical uses.
The research program will involve the design and optimisation of the inverse micro-emulsion formulations using biodegradable and biocompatible surfactant systems, and vegetable oils. With the appropriate water/surfactant/oil system, we will identify the phase-inversion-temperature (PIT) suitable for conducting the cross-linking reaction using the inverse microemulsion system. The preformed cellulose based nanoparticles (CNP) can either be purified by centrifugation or other environmentally friendly extraction techniques. The CNPs are interesting materials because they possess free amine and carboxylic acid groups that impart pH-responsive characteristics to them. They possess positive charges at low pH, and negative charges at high pH, and zero charge at the iso-electric point.We have developed significant expertise in designing and elucidating the swelling/deswelling properties of various polyampholyte microgels.The stability, swelling, and deswelling properties of the CNP will be elucidated. If further stabilisation is needed, we can readily graft polyethylene-glycol after the CNP has been preformed to provide steric stabilisation to the nanoparticle.We will explore the binding of these nanoparticles with drug molecules, proteins, and DNAs and to explore their potential use as delivery systems in biomedical applications. To evaluate their suitability for use in personal home care product and formulations, their interactions with surfactants and other amphiphilic molecules will be elucidated. Techniques, such as static and dynamic light scattering will be used to quantify their microstructure and the isothermal titration calorimeter will be used to elucidate their thermodynamic binding interactions.
Biological tests will be conducted in the third University partner in Liege (ULG) in the group lead by Dr. Marie – Claire Gillet – De Pauw, at the Biomedical Sciences and Preclinical Department. M. C. Gillet is specialized in histology, cytology, cell culture and tissue engineering. These competencies are thus complementary to those of the two other University partners (Waterloo and Bordeaux). Her role in this project will be to develop biocompatibility tests in vitro and/or in vivo, and to evaluate the cellular interactions with the biocompatible nano/microgels; also, the cellular response to xenobiotics (chemical contaminants or drugs) will be analyzed.
Successful applicant will have the opportunity to work in the laboratories of Professors Lecommandoux and Taton (University of Bordeaux 1, France) and Professor Tam (University of Waterloo, Canada). Biological tests will be conducted in the third University partner in Liege (Dr.Gillet – De Pauw).
Taton, D.; Baussard, J.F.; Dupayage, L.; Poly, J.; Gnanou, Y.; Ponsinet, V.; Destarac, M.; Mignaud, C.; Pitois, C., Water soluble polymeric nanogels by xanthate-mediated radical crosslinking copolymerization, Chemical Communications (2006), 18, 1953-1955.
Tan, B.H., Ravi, P., Tan, L.N., Tam, K.C., Synthesis and Aqueous Solution Properties of Sterically Stabilized pH-Responsive Polyampholyte Microgels, Journal of Colloid & Interfacial Science (2007), 309 (2), 453-463.
Tan, B.H., Tam, K.C., Review on the Dynamics and Microstructure of pH-Responsive Nano-Colloidal System, Advances in Colloid and Interface Science (2008), 136, 25-44.
Ho, B.S.; Tan, B.H.; Tan, J.P.K.; Tam, K.C., Inverse Microemulsion Polymerization of sterically stabilized polyampholyte microgels, Langmuir, (2008), 24 (15), 7698–7703.