Polymer nanocomposites with antimicrobial and biocompatible properties are of growing interest thanks to the variety of applications in areas such as biosensing and biomedical devices. Other uses include water treatment, for example, as membranes for water purification and disinfection. Currently, studies on biomedical, industrial and water-treatment applications of graphene-containing polymer nanocomposites have focused either on the material’s antimicrobial properties or on its human cytotoxity.

In order for these graphene-based nanocomposites to be used safely, they need to have both low mammalian toxicity and efficient antimicrobial characteristics. Researchers from the University of Houston and Case Western Reserve University have teamed up to prepare and characterize highly stable graphene (G) poly(N-vinylcarbazole) (PVK) dispersions and films for biomedical and industrial applications, reporting their results in the journal Nanotechnology.

Antimicrobial action

The team led by Debora Rodrigues and Rigoberto Advincula prepared highly dispersed PVK-G (97/3 w/w %) nanocomposite solutions in various organic and aqueous solvents by solution mixing and sonication methods, while thin films were fabricated by electrodeposition. The antimicrobial property of the polymer nanocomposite was then tested against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis).

In the study, the scientists found that microbial growth after exposure to the nanocomposite PVK–G presented fewer viable and active bacteria compared with exposure to pure PVK or pure graphene solutions. Furthermore, the PVK–G thin film showed ~80% inhibition of biofilm formation while the PVK and the unmodified surfaces showed almost full coverage (i.e. >80 %).

Highly biocompatible

The biocompatibility of the exfoliated PVK–G solutions on mammalian cells was evaluated and presented ~80% cell survival, which suggests that the polymer nanocomposite is highly biocompatible.

Overall the team’s results support the potential use of PVK–G for a wide variety of biomedical and industrial applications where bactericidal properties coupled with low cytotoxicity to mammalian cells are vital.

Additional details can be found in the journal Nanotechnology.