Carbon nanotubes functionalized with folic acid attached via biomimetic peptide linker.

Aim: Anchoring folic acid (FA) with a biomimetic peptidic linker resistant to proteolytic degradation to act as a homing device on functionalized carbon nanotubes.

Materials & Methods: Ethylenediamine was attached to oxidized multiwalled carbon nanotubes (MWNTs) using 4-(4,6-dimethoxy-[1,3,5]triazin-2-yl)-4-methylmorpholinium tetrafluoroborate. FA was coupled with 6-aminohexanoic acid and derivatives of β-alanine, affording four intermediates, which connected to the MWNTs via peptidic linkers of various lengths.

Results: Biomimetic nanomaterials were produced with FA as a homing molecule. The structure and properties of the nanomaterials were analyzed, confirming the versatility of the peptides used as linkers.

Conclusion: Conjugates of FA attached to MWNTs via peptide linkers prepared from β-alanine residues are resistant to proteolytic degradation. Viability in colon cancer cells and normal colonocytes confirmed their lack of cytotoxicity.