Study on protein conformation and adsorption behaviors in nanodiamond particle–proteincomplexes

Abstract

In the present research, the conformation of bovine serum albumin (BSA) in thenanodiamond particle (ND)–BSA complex was studied by Fourier transform infraredspectroscopy, fluorescence spectroscopy, UV–vis spectroscopy, and circular dichroismspectroscopy. The spectroscopic study revealed that most BSA structural features could bepreserved in the complex though the BSA underwent conformational changes in thecomplex due to ND–BSA interaction. In addition, BSA adsorption isotherms andzeta-potential measurements were employed to investigate the pH dependence of theND–BSA interaction. The changes in surface charge of the ND–BSA complex with pHvariations indicated that the binding of BSA to ND might lead to not only the adsorptionof BSA onto the ND surface but also the partial breakup of ND aggregates intorelatively small ND–BSA aggregates because of the strong binding force betweenND and BSA. The results show that ND is an excellent platform for proteinimmobilization with high affinity and holds great potential to be used for biosensorapplications.