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Protein adsorption on functionalized multiwalled carbon nanotubes with amino-cyclodextrin



A novel amino-cyclodextrin was synthesized, and it was covalently attached to multiwalled carbon nanotubes (MWNTs). The functionalized MWNTs (f-MWNTs) have very good aqueous dispersibility. Bovine serum albumin (BSA) was adsorbed onto f-MWNTs through noncovalent interactions, including the hydrophobic interaction of the residues of BSA with the wall of MWNT and the guest–host interaction of the residues with the cyclodextrin (CD) moieties of f-MWNTs. The ultraviolet–visible (UV–vis) absorption of the f-MWNT-BSA hybrid was measured with UV–vis spectrometer, and the absorbance can be described well with the Beer–Lambert law. The X-ray diffraction patterns have indicated that the crystalline form of BSA has been changed after the adsorption of BSA on f-MWNTs. The circular dichroism spectra have shown that a high percentage of α-helical content can be retained for BSA adsorbed on f-MWNTs. The results also indicate that the change of secondary structure of BSA is mainly due to the hydrophobic interaction of the residues of BSA with the wall of f-MWNT, whereas the secondary structure is much less affected by the interaction of the CD moieties with BSA. © 2011 American Institute of Chemical Engineers AIChE J, 2011