title: Altered cell mechanics from the inside: dispersed single wall carbon nanotubes integrate with and restructure actin.
abstract: With a range of desirable mechanical and optical properties, single wall carbon nanotubes (SWCNTs) are a promising material for nanobiotechnologies. SWCNTs also have potential as biomaterials for modulation of cellular structures. Previously, we showed that highly purified, dispersed SWCNTs grossly alter F-actin inside cells. F-actin plays critical roles in the maintenance of cell structure, force transduction, transport and cytokinesis. Thus, quantification of SWCNT-actin interactions ranging from molecular, sub-cellular and cellular levels with both structure and function is critical for developing SWCNT-based biotechnologies. Further, this interaction can be exploited, using SWCNTs as a unique actin-altering material. Here, we utilized molecular dynamics simulations to explore the interactions of SWCNTs with actin filaments. Fluorescence lifetime imaging microscopy confirmed that SWCNTs were located within ~5 nm of F-actin in cells but did not interact with G-actin. SWCNTs did not alter myosin II sub-cellular localization, and SWCNT treatment in cells led to significantly shorter actin filaments. Functionally, cells with internalized SWCNTs had greatly reduced cell traction force. Combined, these results demonstrate direct, specific SWCNT alteration of F-actin structures which can be exploited for SWCNT-based biotechnologies and utilized as a new method to probe fundamental actin-related cellular processes and biophysics.
authors: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA. bholt@andrew.cmu.edu.
authors: Brian D
authors: BD
authors: Holt
authors: Department of Bioengineering, University of California, Berkeley, CA 94720, USA. hengameh@Berkeley.edu.
authors: Hengameh
authors: H
authors: Shams
authors: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA. thorst@andrew.cmu.edu.
authors: Travis A
authors: TA
authors: Horst
authors: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA. sauravb@cmu.edu.
authors: Saurav
authors: S
authors: Basu
authors: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA. arape@andrew.cmu.edu.
authors: Andrew D
authors: AD
authors: Rape
authors: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA. yuliwang@andrew.cmu.edu.
authors: Yu-Li
authors: YL
authors: Wang
authors: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA. gustavor@cmu.edu.
authors: Gustavo K
authors: GK
authors: Rohde
authors: Department of Bioengineering, University of California, Berkeley, CA 94720, USA. mofrad@berkeley.edu.
authors: Mohammad R K
authors: MR
authors: Mofrad
authors: Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA. krisdahl@cmu.edu.
authors: Mohammad F
authors: MF
authors: Islam
authors: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA. mohammad@cmu.edu.
authors: Kris Noel
authors: KN
authors: Dahl