The remarkable physicochemical properties of carbon nanomaterials make them promising candidates for biomedical and biotechnological applications. In particular, the distinctive optical and structural characteristics of single-walled carbon nanotubes (SWCNTs) have inspired the development of biologically applicable optical sensors and molecular delivery scaffolds^1,2. Several studies have largely focused on enabling cell uptake of SWCNTs by engineering the SWCNT surface through non-covalent side-wall functionalizations. Non-covalent functionalization with a rich variety of biomolecules and polymers has been shown to potentially increase SWCNTs solubility and membrane translocation while endowing these nanostructures with enhanced biocompatibility³. These functionalizations have been engineered to permit SWCNT uptake by a variety of mammalian cells through both passive and energy-dependent pathways. Most recently, this platform was applied to intact chloroplasts to augment their photosynthetic capability in novel nanobionic devices⁴. Although factors such as cell type, functionalization zeta-potential, particle size, and membrane composition have been shown to affect uptake, these findings have largely relied on empirical approaches towards engineering uptake mechanisms^5,6.

Our work builds on these empirical findings to establish engineering design rules for enabling SWCNT-membrane interactions. We performed a systematic investigation of the effect of SWCNT functionalization on membrane penetration properties using a novel biological host. The results of this study were used to not only elucidate the underlying interaction on a molecular level, but also develop the first of a new generation of light-harvesting nanobionic devices.

References:

1. Boghossian, A. a. et al. Near-infrared fluorescent sensors based on single-walled carbon nanotubes for life sciences applications. ChemSusChem 4, 848–863 (2011).

2. Oliveira, S. F. et al. Protein Functionalized Carbon Nanomaterials for Biomedical Applications. Carbon N. Y. (2015).

3. Vardharajula, S. et al. Functionalized carbon nanotubes: biomedical applications. Int. J. Nanomedicine 7, 5361–74 (2012).

4. Giraldo, J. P. et al. Plant nanobionics approach to augment photosynthesis and biochemical sensing. Nat. Mater. 13, 400–8 (2014).

5. Kostarelos, K. et al. Cellular uptake of functionalized carbon nanotubes is independent of functional group and cell type. Nat. Nanotechnol. 2, 108–113 (2007).

6. Holt, B. D., Dahl, K. N., Islam, M. F. & Al, H. E. T. Cells Take up and Recover from Nanotubes with Two Distinct Rates. 3481–3490 (2012)