In this study, we explored the capability of tartrate resistant acid phosphatase (TRAcP), a bone resorption marker, to degrade carboxylated single-walled carbon nanotubes (C-SWCNTs). Optical observations and Raman and high-resolution transmission electron microscopy studies show that the enzyme contributes to the degradation of C-SWCNTs, although the degradation is not complete. Molecular modeling implemented to investigate the binding sites for carboxylated and pristine SWCNTs to TRAcP elucidate the varying proximity of SWCNTs to the binuclear iron active site and the active site residues of TRAcP, which is clearly dependent upon the degree of carboxylation introduced into the SWCNT model. The modeling results presented provide justification to the propensity of TRAcP to degrade the C-SWCNTs alluding to the possibility of C-SWCNTs to be used as a potential degradable biomaterial for use in therapeutic applications of mineralized tissue related conditions.
Keywords: biodegradation; bone marker; carbon nanotubes; tartrate resistant acid phosphatase.