Removal of Antimicrobial Peptides from Aqueous Solutions Using Carbon Nanotubes

Abstract

The aim of this work is to study the possibility of removing antimicrobial peptides arenicin-1 and tachyplesin-1 from aqueous solutions using new highly hydrophobic nanomaterials—carbon nanotubes (CNTs) Taunit-M. Two types of CNTs, respectively, functionalized and nonfunctionalized with–COOH groups are studied. The RP HPLC method is used for the quantification of peptides in solutions before and after the sorption on the CNTs. It is revealed that tachyplesin-1 and arenicin-1 are actually not adsorbed on nonfunctionalized CNTs. A theoretical calculation of specific hydrophobicity and aliphatic index shows that both peptides have poorly expressed hydrophobic properties, and this can explain lack of their adsorption. On the contrary, using functionalized CNTs makes it possible to remove up to 89% of arenicin-1 and 92% of tachyplesin-1 from the solution. A comparative study of adsorption of the antimicrobial peptide tachyplesin- 1 on nonfunctionalized activated carbons and functionalized CNTs shows that the amount of peptide adsorbed on activated carbons is about three times less than that absorbed on CNTs. It is assumed that the high adsorption capacity of the functionalized CNTs toward the studied peptides results from the functionalization of the sorbent surface with the–COOH groups capable of forming ionic bonds with free–NH₂ groups of peptides. This shows the prospects for using functionalized CNTs as sorbents for the removal of toxic preparations of peptide origin from aqueous solutions.