Electrochimica Acta, Vol.296, 555-564, 2019
Ultrasonic dispersion temperature- and pH-tuned spectral and electrochemical properties of bovine serum albumin on carbon nanotubes and its conformational transition
In this paper, we first report the ultrasonic dispersion temperature- and pH-tuned spectral and electrochemical properties of bovine serum albumin (BSA) on single-walled carbon nanotubes (SWCNTs) and its configurational transition. The BSA-SWCNTs exhibit an irreversible oxidation peak at 0.793 V (vs. SCE) and a couple of tryptophan (Trp)-based surface-confined redox peaks at the formal potential of 0.154 V. The decrease of the dispersion temperature down to 283 K from 313 K at pH 7.2 leads to an increase in the surface activity coefficient (gamma(s)) and exothermic reaction rate constant (k(f)). The loop (L)-shaped BSA-SWCNTs with slight beta-sheet prepared by controlling the dispersion temperature at 298 K (pH 7.2) show the maximum emission and minimum absorbance. The L-form of BSA-SWCNTs is transformed into basic (B)-form and fast migration (F)-form while controlling the dispersion temperature at 283 K and 313 K, respectively. The dispersion temperature and pH have a synergistic influence on the spectral and electrochemical properties of BSA-SWCNTs via the unfolding/refolding processes of beta-sheet driven by ultrasonic/thermal motion and surface adsorption. The present study provides an effective approach for the preparation and evaluation of serum protein-based nanomaterials with spectral and electrochemical properties tuned by dispersion pH or temperature, as well as opens the way for optoelectronic and electrochemical applications. (C) 2018 Elsevier Ltd. All rights reserved.