MWCNTs as promoters of pyocyanin production for anticancer research

Carbon nanotubes (CNTs) emerged as the nanomaterials with wide variety of the applications. Among them are bio-based processes that can be improved thanks to the incorporation of the CNTs. One of such examples is the stimulation of the production of the blue pigment called pyocyanin that has been reported to exhibit a potential anticancer properties.
In this work, we compared different commercially available multiwalled carbon nanotubes (MWCNTs), optimized pyocyanin production using Design of Experiment methodology and investigated the interactions between pigment-producing bacteria and nanomaterials. Moreover, the pigment was purified and analyzed using NMR and FT-IR and subsequently tested against normal and cancer cell lines. On top of that, we attempted to reuse the nanomaterial incorporated in the process and tested its physicochemical properties.
The results showed that all tested CNTs stimulated pyocyanin production. Based on these results, we chose the CNTs with most stimulative effect for optimization and obtained the best process temperature (32°C) and CNTs’ concentration (812 mg/mL). We tested how CNTs interact with the bacterial producer and noted the elevated optical density and viability, decreased pyoverdine production but no signs of oxidative stress. Moreover, the confocal microscopy revealed that the cells surrounded the aggregates of MWCNT and produced more proteins within the biofilm structure than the control. Tests on the cell lines showed an excellent antiproliferative action of pyocyanin against melanoma, without pronounced adverse effects on normal murine fibroblasts. The nanomaterial incorporated in the process was successfully reused twice making it more sustainable and cost-effective.
In conclusion, we proposed the multiuse of CNTs for boosting the pyocyanin production to enable its possible use as anticancer agent.