Influence of surface charge on the rate, extent, and structure of adsorbed Bovine Serum Albumin to gold electrodes.
The objective of this work is to investigate the rate, extent, and structure of amphoteric proteins with charged solid surfaces over a range of applied potentials and surface charges. We use Electrochemical Quartz Crystal Microbalance with Dissipation Monitoring (E-QCM-D) to investigate the adsorption of amphoteric Bovine Serum Albumin (BSA) to a gold electrode while systematically varying the surface charge on the adsorbate and adsorbent by manipulating pH and applied potential, respectively. We also perform cyclic voltammetry-E-QCM-D on an adsorbed layer of BSA to elucidate conformational changes in response to varied applied potentials. We confirm previous results demonstrating that increasing magnitude of applied potential on the gold electrode is positively correlated with increasing mass adsorption when the protein and the surface are oppositely charged. On the other hand, we find that the rate of BSA adsorption is not governed by simple electrostatics, but instead depends on solution pH, an observation not well documented in the literature. Cyclic voltammetry with simultaneous E-QCM-D measurements suggest that BSA protein undergoes a conformational change as the surface potential varies.
Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA. Electronic address: bbeykal@andrew.cmu.edu.
Burcu
B
Beykal
Zuckerberg Institute for Water Research, Ben-Gurion University of the Negev, Sede Boqer 84990, Israel. Electronic address: herzberg@bgu.ac.il.
Moshe
M
Herzberg
Zuckerberg Institute for Water Research, Ben-Gurion University of the Negev, Sede Boqer 84990, Israel. Electronic address: yoramo@bgu.ac.il.
Yoram
Y
Oren
Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Department of Engineering & Public Policy, Carnegie Mellon University, Pittsburgh, PA 15213, USA. Electronic address: mauter@cmu.edu.
Meagan S
MS
Mauter
D000327:Adsorption; D000818:Animals; D002417:Cattle; D003102:Colloids / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011506:Proteins / Q000737:chemistry; D058525:Quartz Crystal Microbalance Techniques; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D055672:Static Electricity; D013499:Surface Properties
D003102:Colloids; D011506:Proteins; D012710:Serum Albumin, Bovine; D006046:Gold
Bovine Serum Albumin; Cyclic voltammetry; Electrochemical QCM-D; Protein adsorption