In Vitro Biocompatibility of Multiwalled Carbon Nanotubes with Sensory Neurons

Abstract

Multiwalled carbon nanotubes (MWCNTs) possess unique properties rendering them a potentially useful biomaterial for neurobiological applications such as providing nanoscale contact-guidance cues for directing axon growth within peripheral nerve repair scaffolds. The in vitro biocompatibility of MWCNTs with postnatal mouse spinal sensory neurons was assessed for this application. Cell culture medium conditioned with MWCNTs was not significantly toxic to dissociated cultures of postnatal mouse dorsal root ganglia (DRG) neurons. However, exposure of DRG neurons to MWCNTs dispersed in culture medium resulted in a time- and dose-dependent reduction in neuronal viability. At 250 μg mL⁻¹, dispersed MWCNTs caused significant neuronal death and unusual neurite morphologies illustrated by immunofluorescent labelling of the cytoskeletal protein beta (III) tubulin, however, at a dose of 5 μg mL⁻¹ MWCNTs were nontoxic over a 14-day period. DRG neurons grown on fabricated MWCNT substrates produced neurite outgrowths with abnormal morphologies that were significantly inferior in length to neurons grown on the control substrate laminin. This evidence demonstrates that to be utilized as a biomaterial in tissue scaffolds for nerve repair, MWCNTs will require robust surface modification to enhance biocompatibility and growth promoting properties.

Chitin and carbon nanotube composites as biocompatible scaffolds for neuron growth

“…Natural polymer-based scaffolds exhibit similar properties to soft tissues and ensure high bioactivity and maximum cell adhesion, but are difficult to surface engineer. On the other hand, MWNTs present rather attractive surfaces for their electrical properties but, according to Gladwin et.al 42 , for MWNTs to be used as scaffolds requires robust surface modification to enhance biocompatibility and cell adhesion. The study conducted in the current work showed excellent adhesion of neurons on O2-plasma-treated chitin/CNTs scaffolds.…”

Proteomic Analysis of Cellular Response Induced by Multi-Walled Carbon Nanotubes Exposure in A549 Cells

“…MWCNT could also alter the systemic immune function in mice [31]–[35], and individuals with pre-existing allergic inflammation may be susceptible to airway fibrosis from inhaled MWCNT [36]. Furthermore, recent observations suggest that the nervous system is vulnerable to MWCNT as well [37]–[39]. On the other hand, there are also reports showing no inflammation or cancer occurrence after MWCNT exposure in rats [40], [41].…”

Repairing Peripheral Nerves: Is there a Role for Carbon Nanotubes?

“…Whilst data from these preliminary studies are promising, conflicting reports of reduced neuronal viability and growth on CNTs raises uncertainty as to the suitability of CNT scaffolds for enhancing axon growth in NRCs . For example, Hu et al compared the growth of postnatal hippocampal neurons on nonfunctionalised MWCNTs with that on polyethylenimine (PEI) coated onto glass coverslips as the control substrate .…”

“…Compared to laminin, neurite outgrowth on CNT substrates is poor . However, functionalising CNTs with laminin can support substantially greater neurite outgrowth compared to laminin‐coated TCP or other laminin coated biomaterial controls .…”