Interactions of Oxidized Multi-Walled Carbon Nanotubes with Supported

Lipid Bilayers

Alec E. KinczewskiREV Mentor: Laura Olenick

Geiger Group Northwestern University

July 29, 2015

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Background: Carbon Nanotubes (CNTs)

- Carbon nanotubes (CNTs) have become prominent in science and engineering primarily due to their adaptable surface chemistry and the following properties:

+ High electrical conductivity+ High thermal conductivity+ Mechanical strength

- In these experiments, we used oxidized multi-walled carbon nanotubes (O-MWCNTs) and pure DMPC bilayers.

De Volder, M. F. L.; Tawfick, S. H.; Baughman, R. H.; Hart, A. J. Science 2013, 339, 535

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Characterization of O-MWCNTs - Characterized O-MWCNTs using TEM, UV-Vis, FT-IR, DLS, and ζ-

potential + DLS: 96.75 ± 0.96 nm diameter (in Millipore) + ζ-potential: -35.4 ± 2.3 mV (in Millipore)

1ppm O-MWCNTs in 100 mM NaCl, 10 mM Tris, pH 7.4

Transition Electron Microscopy (TEM)

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Interactions of O-MWCNTs and SLBs

Yi, P.; Chen, K. L. Environmental Science & Technology 2013, 47, 5711

- Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D) can be used to study nanoparticle interactions with supported

lipid bilayers

- QCM-D studies on the interactions of O-MWCNTs with DMPC bilayers from the Pedersen lab indicate that negatively charged CNTs attach to negatively charged bilayers

- Previous QCM-D studies with DOPC found MWCNT binding is increased by increasing ionic strength of the aqueous solution

+ Binding was found to be largely irreversible (80%) at low ionic strength and pH 7.3

Sum Frequency Generation (SFG)

Center of Symmetry No SFG

Different Head Group EnvironmentsPossibly SFG

Disordered leafletSFG Signal

Asymmetricleaflets

SFG Signal

- SFG is sensitive to order and orientation

= CH2 oscillator = CH3 oscillator

IR

Vis SFGSFG

broadbandIR BeamVisible Beam

- Our system is tuned to the C-H stretching region

Shen, Y. R. Nature 1989, 337, 519.Shen, Y. R. The Principles of Nonlinear Optics; John Wiley & Sons, Inc.: Hoboken, NJ, 2003.Liu, J.; Conboy, J. C. Biophysical Journal 2005, 89, 2522.Liu, J.; Conboy, J. C. The Journal of Physical Chemistry C 2007, 111, 8988.

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Wipeout Increased Intensity

9:1 DMPC/DMPG

PAH-Au Rinsed

9:1 DMPC/DMPG

LiCoO2

SFG Signal and SLBs

Dogangun, M. et. al. in review at ACS Nano.Troiano, J. M. et. al. The Journal of Physical Chemistry C 2015, 119 534.

- Previous SFG experiments have shown different effects of the introduction of nanoparticles on SFG signal from bilayers

10 mM Tris, 100 mM NaCl, pH 7.4, 12.8 nM PAH-AuNP

10 mM Tris, 100 mM NaCl, pH 7.4, 5 ppm LiCoO2

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- Using SFG to monitor the interaction between O-MWCNTs and a pure DMPC bilayer, signal was maintained throughout

10 mM Tris, 100 mM NaCl, pH 7.4, DMPC, 1ppm O-MWCNTs from the Fairbrother Group

Interactions of O-MWCNTs and SLBs

DMPC

O-MWCNT Rinsed

7% Oxidized O-MWCNT 12% Oxidized O-MWCNT

O-MWCNT

DMPC

O-MWCNT Rinsed

O-MWCNT

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Future Work

Xinghua, S.; Yong, K; Huajian, G. Acta Mech Sin 2008, 24, 161 Pogodin, S.; Baulin, V. A. Acs Nano 2010, 4, 5293 Zagnoni, M. Lab on a Chip 2012, 12, 1026

- Exploring mechanisms:+ Simulations suggest perpendicular insertion + Visualization of the piercing mechanism

- Utilizing different models and tools+ Free standing Black Lipid Membranes + AFM, to observe O-MWCNTs on bilayers after

irreversible interactions

Acknowledgements

Blog: http://sustainable-nano.com[Phase I] This work was supported by the National Science Foundation Centers for Chemical

Innovation Program, CHE-1240151

Team of Teams

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