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Electrochemical Modelling of Nanoparticle Toxicity
|Andrew L. Nelson|
University of Leeds (UOL), Woodhouse Lane, Leeds ls2-9jt, United Kingdom
This talk describes the interaction of SiO2,ZnO and organic polymeric nanoparticles with the chip-supported phospholipid membranes  of the ENNSATOX nanosensor. SiO2 dispersions of particle size 14 to 150 nm were tested and were found to be stable within the time of the experiment. The interaction of SiO2 particle dispersions with dioleoyl lecithin (DOPC) membranes were characterised by an interference with the electrically-induced phase transitions (Figure 1) and inversely related to the particle size (Figure 2) and impedance measurements of the SiO2-DOPC interaction confirmed this finding. Uniquely novel experiments using scanning electron microscopy (SEM) showed that SiO2 nanoparticles of all size ranges adsorbed on the DOPC surface (Figure 3). It can be concluded from these results that the relationship of SiO2 activity on the DOPC membrane with particle size is due to the geometrical proximity of the SiO2 surface to the DOPC polar groups. A one parameter geometric model was fitted to the data as shown in Figure 3 and an interfacial distance of 3.2nm was estimated within which the SiO2 surface influenced the fluidity of the DOPC.
Similar experiments were carried out with ZnO nanoparticle dispersions from different sources. Only the ZnO dispersions of small particle size were found to interact strongly with the DOPC membrane. The solubility of the ZnO and the release of Zn2+from the nanoparticles was also measured using the ENNSATOX nanosensor. In comparison with the inorganic nanoparticles, experiments were also carried out investigating the interaction organic polymers and organic polymeric nanoparticles with DOPC membranes. The polymers showed considerably stronger DOPC membrane activity. The rates of interaction of the inorganic nanoparticles, the organic polymers and the organic polymeric nanoparticles with the DOPC membrane are compared.
The biological relevance of the ENNSATOX nanosensor has been tested by intercalibrating the results from the sensor with those obtained from the interaction of the nanoparticles with biological organisms of increasing levels of complexity.
 Z. Coldrick, et al 2009, Electrochim.Acta 54,4944-4962.
Presentation: Keynote lecture at SMCBS'2011 International Workshop, by Andrew L. Nelson
See On-line Journal of SMCBS'2011 International Workshop
Submitted: 2011-08-12 17:46 Revised: 2011-08-12 17:48