Ophelie Zeyons

Service de Chimie Moleculaire

+33 1 69 08 96 43

+33 1 69 08 66 40

Present Statut (until October 2008)

PhD student in laboratory LIONS, CEA research centre, Saclay, France

(Laboratory in Interdisciplinary researches on matter Organisation at Nanometric and Supramolecular scales)

PhD research subject

Understand and quantify biological and physicochemical interactions

between nanoparticles and bacteria.

Nanoparticles have shown great promise in many technical fields, such as medicine, electronic, and new materials. Their extended use has been however widely questioned by customers as well as in many U.S. and European reports. Indeed, their extraordinary physical and biological properties may not only lead to benefits but also to serious safety problems for workers, users, and environment due to their ability to interact with biological systems at a cell scale. Already many papers studied the impact of such nanomaterials on mammalian cells; fewer on bacteria cells. In any case, these studies often reported very different results even when considering very similar systems. This statement has leaded many international reports and conferences to ask for more efforts to normalize nanotoxicity studies.

During my PhD I highlight the importance of understanding the complexity of every study parameters previous to any normalization procedure. I can already emphasize the importance of four parameters: the choice of a biological model, the physicochemical state of nanoparticles, the chemical environment of nanoparticles and the choice of a reliable survival test.

Our main biological models are : Synechocystis PCC6803 and Esherichia Coli RR1.

Our main nanoparticles are : Cerium, Titanium oxide and maghemite nanoparticles.

Synechocystis (cyanobacterium) with TiO₂ nanoparticles.

Experiences

2005-2008 3 years, PhD Student, CEA (Saclay), France

Characterize the physicochemical specificities and stability of inorganic nanoparticles.
Create and develop toxicity assays to understand interactions of nanoparticles with bacteria.

2005 6 months, industrial trainee, Flamel Technologies (Vénissieux), France

Designed and optimised new formulations for control delivery of injectable proteins.

2003-2004 1 year, industrial trainee, Syngenta (Jealott's Hill Research Centre), England

Achieved two herbicide formulations (solution and emulsion) to make compatible new adjuvants with high strength active solution.
Developed validation tests and provided technical support for several different units of a high throughput formulation robot.

Education

2005-2008 PhD in physical chemistry, university Paris VI, France

2001-2005 Diplôme d'ingénieur chimiste, CPE Lyon, France

CPE Lyon, French Grande Ecole, equivalent to a National Graduation School (Master degree in Chemistry)

3thd year specialization : physical chemistry, formulation and process in divided solids.

Publications and Communications

2007 Poster communication for the Symposium ESF-EMBO (November, Spain):

Nanoparticles Vs Bacteria

Zeyons O., Thill A., Spalla O., Cassier-Chauvat C., Chauvat F., Menguy N.

2007 Oral communication at the conference C’Nano île de France (June, Jussieu, France) :

« Etudes des interactions physicochimiques et biologiques entre nanoparticules et bactéries. Comparaison de deux systèmes bactériens. »

2007 Oral communication for a conference organised by the company Malvern (June, Orsay, France):

« Importance of physical chemistry for toxicity tests with nanoparticles ».

2006 Publication: Thill A., Zeyons O., Spalla O., Chauvat F., Rose J., Auffan M., Flank, A.M.

Cytotoxicity of CeO2 nanoparticles for Escherichia coli. Physico-chemical insight of the cytotoxicity mechanism, (2006) Environmental Science and Technology, 40 (19), pp. 6151-6156.

2006 Poster communication for the physics school des Houches « Colloids in medecine and biology »:

Physicochemical and biological interactions between nanoparticles and environmental bacteria.

Zeyons O., Thill A., Spalla O., Cassier-Chauvat C., Chauvat F.

Leisures

2005-2008 Member of 2 PhD students associations: active part in the creation of the association « Doc Up » and design and publication of a member’s directory for the association “MAIOT”.

2001-2003 Organisation of a cabaret show at CPE and member of the mountain club and “chimiste en herbe” club (organisation of leisure activities in practical chemistry for adolescents).

Sports and leisure: Capoeira, modern-jazz dance, and piano.

Keywords

Physical chemistry, formulation: emulsion technology, rheology, stability tests, controlled release, wettability test, surface tension, dynamic light scattering, polymers and surfactants for emulsions, solutions and suspensions.

Nanoparticles: characterization, size, zeta potential, RedOx (XANES, XPS), stability to dissolution (ICP-MS, electrophoresis), and shape (AFM, TEM).

Bacteria: cultures, growth tests, CFU counting tests, respiration tests, integrity membranes assays, electronic microscopy (SEM, TEM), metabolomics (NMR), exopolysaccharides.