The surface area and shape of oxidized multi-walled carbon nanotubes (O-MWCNTs) are physical properties that have led to their proposed use in energy, environmental remediation, biomedicine and electronics. While these materials hold promise to benefit society, concern is rising about the potential biological consequences that O-MWCNTs could have upon direct or indirect exposure to biological and environmental systems. Therefore, the possible interactions CNTs on biological systems warrant investigation. Here, we use synthetic supported lipid bilayers (SLBs) composed of 1,2-dimyristoyl-<i>sn</i>-glycero-3-phosphatidylcholine (DMPC) as an idealized model system to study interactions between O-MWCNTs and cellular membranes using second harmonic generation (SHG), sum frequency generation (SFG), fluorescence microscopy and mass measurements using quartz crystal microbalance with dissipation (QCM-D). Ultraviolet-visible spectroscopy (UV-Vis) and dynamic light scattering (DLS) were used to study O-MWCNT aggregation as a function of ionic strength and time. SHG data showed increases in signal intensity, which suggests that the O-MWCNTs are interacting with the DMPC bilayer. SHG data also indicate that the degree of adsorption to the model cellular membrane depends on ionic strength with more adsorption at higher ionic strengths. SFG data suggests if particles are present, they do not alter the local structure of the DMPC bilayer. SHG, SFG and QCM-D results are presented to assess the reversibility of O-MWCNT-SLB interactions, and fluorescence microscopy indicates lipid-O-MWCNT accretion. UV-Vis and DLS indicate that despite initial aggregation, O-MWCNTs will largely remain suspended under our experimental conditions. Our results allow us to explore the mechanism through which O-MWCNTs interact with DMPC, our model cell membrane.

Probing nano-bio interactions via a multipronged approach

251st National Meeting (2016)

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