Novel nano-cocoon like structures of polyethylene glycol–multiwalled carbon nanotubes for biomedical applications

Abstract

In this article, we report the synthesis and use of a novel drug delivery particle, based on bio-compatible polymer polyethylene glycol (PEG-400) and multi-walled carbon nanotubes (MWCNTs). MWCNTs in PEG-400 were broken into small tubes by vortex mixing with tungsten-carbide balls for about 15 h. Length separation of MWCNTs was then done using differential centrifugation with various concentrations of PEG-400. The separated MWCNTs in PEG solution were further pelletized using high speed centrifugation and re-dispersed in water. Novel cocoon like oval nanoparticles of about 100–200 nm size was observed in one of the centrifuged fractions. TEM shows that the cocoons primarily have PEG enclosing few MWCNTs. However, similar structures were not found when differential centrifugation was done without MWCNTs. These nano-cocoons are hemo-compatible, non-toxic to mice fibroblast cell lines (L929), have great potential to be used as nano biomaterials and they could be loaded with naturally anti-cancerous drug curcumin. The cocoon–curcumin complex is dispersible in saline and could be internalized by brain cancer cells (C6 glioma) while free curcumin dispersed in saline could not enter C6 glioma cells.