Actin Reorganization through Dynamic Interactions with Single-Wall Carbon Nanotubes

Abstract

Single-wall carbon nanotubes (SWCNTs) have been widely used for biological applications in recent years, and thus, it is critical to understand how these inert nanomaterials influence cell behavior. Recently, it has been observed that cellular phenotypes such as proliferation, force generation and growth change upon SWCNT treatment, and SWCNTs directly affect the organization and redistribution of the actin cytoskeleton. However, the interactions between SWCNTs and actin at the molecular level or how this interaction changes actin structure remain largely unknown. Here, we investigated direct interaction of actin with SWCNT using all-atom molecular dynamics simulations and NIR spectroscopy of actin-dispersed SWCNTs. Actin can stably bind to the SWCNT surfaces via hydrophobic interactions but still allows nanotubes to slide and rotate on the actin surface. Our results establish several nanoscale conformational changes for the actin-SWCNT complexes, and we suggest these changes likely induce reorganization of actin filaments observed at larger scales.

Anti-Cancer Cytotoxic Effects of Multiwalled Carbon Nanotubes

“…These filaments are well documented to interact with the biological matter and to penetrate inside tissues and cells where they intermingle with many of the intracellular structures [63][64][65][66][67]. Once in the cytoplasm, CNTs have been reported to interact with most cellular nanofilaments such as DNA [49][50], actin microfilaments [68][69][70] and microtubules [71][72][73][74], triggering different biological responses [42][43][44][45][46][47][48][49][50][51][52][53][54][55]. There are studies demonstrating how the different morphological or physical characteristics of CNTs -i.e.…”

“…For example, single-walled CNTs have been reported to destroy the DNA double helix, producing lethal clastogenic effects [43][44][45][46][47][48][49][50]. These nanofilaments also interact with the actin microfilaments reorganizing actin and producing severe abnormalities such as multinucleation in different dividing cells [68,70]. On the other hand, MWCNTs have been claimed to preferably interact with tubulin or actin [69,[72][73][74] triggering cell death and cytotoxicity by different mechanisms in vitro [42,44,51,75,76,79,82,83,89,[91][92][93] and in vivo [75,76,100,101].…”

The winding road for carbon nanotubes in nanomedicine

“…These results suggest shape as a relevant parameter for protein-CNT interactions in vivo, a concept already introduced a few years ago when CNTs were proposed as microtubule biomimetics because of the striking similarities in size and morphology between the two structures [64]. In light of these facts, it is thus perhaps not too surprising that CNTs are able to interfere with cytoskeletal organization [65] also inside cells [66][67][68][69][70]. Importantly, such an effect was noted only at relatively high doses (i.e.…”

Cytotoxicity induced by carbon nanotubes in experimental malignant glioma

“…The MWCNTs used in this study induced cell death in both astrocytes and cultured RG2 cells at all concentrations used (Figures 2 and 3), as has been previously reported. [37][38][39] After observing the results, we decided to use the 50 µg/mL dose for further experiments; at this concentration, all MWCNTs induced a significant percentage of cell death. Considering that the standard treatment for GBM consists in surgical resection accompanied by radiotherapy and chemotherapy with TMZ, 40,41 the next step was to use MWCNTs in combination with TMZ.…”