Issue 7, 2013

Carbon nanotube bundling: influence on layer-by-layer assembly and antimicrobial activity

Abstract

Antimicrobial surfaces are needed for many health care applications. Single walled carbon nanotubes (SWNT) have shown promise as antimicrobial agents, but important questions persist concerning the effects of tube bundling, a common phenomenon owing to strong hydrophobicity. We investigate here the influence of bundling on the layer-by-layer (LbL) assembly of SWNT with charged polymers, and on the antimicrobial properties of the resultant films. We employ a poly(ethylene glycol) functionalized phospholipid (PL-PEG) to disperse SWNT in aqueous solution, and consider cases where SWNT are dispersed (i) as essentially isolated objects and (ii) as small bundles. Quartz crystal microgravimetry with dissipation (QCMD) and ellipsometry measurements show the bundled SWNT system to adsorb in an unusually strong fashion – with layers twice (when hydrated) and three times (when dried) as thick as those of isolated SWNT. Molecular dynamics simulation reveals a lower PL-PEG density and degree of solution extension on bundled versus isolated SWNT, suggesting thicker adsorbed layers may result from suppressed steric repulsion between bundled nanotubes. Enhanced van der Waals attraction in the bundled system may also play a role. Scanning electron micrographs reveal Escherichia coli on films with bundled SWNT to be essentially engulfed by the nanotubes, whereas the bacteria rest upon films with isolated SWNT. While both systems inactivate 90% of bacteria in 24 h, the bundled SWNT system is “fast-acting,” reaching this inactivation rate in 1 h. This study demonstrates the significant impact of SWNT bundling on LbL assembly and antimicrobial activity, explores the molecular basis of nanotubenanotube interactions, and demonstrates the possibility of bacteria-engulfing, fast-acting, SWNT-based antimicrobial coatings.

Graphical abstract: Carbon nanotube bundling: influence on layer-by-layer assembly and antimicrobial activity

Supplementary files

Article information

Article type
Paper
Submitted
23 Oct 2012
Accepted
18 Dec 2012
First published
07 Jan 2013

Soft Matter, 2013,9, 2136-2144

Carbon nanotube bundling: influence on layer-by-layer assembly and antimicrobial activity

S. Aslan, J. Määttä, B. Z. Haznedaroglu, J. P. M. Goodman, L. D. Pfefferle, M. Elimelech, E. Pauthe, M. Sammalkorpi and P. R. Van Tassel, Soft Matter, 2013, 9, 2136 DOI: 10.1039/C2SM27444B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements