Tuning Single-Walled Carbon Nanotube (SWCNT) Membrane Interactions

Abstract

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 scaffolds1,2. 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 mechanisms5,6. 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.