Electrostatic Interactions Influence Protein Adsorption
(but Not Desorption) at the Silica–Aqueous Interface
Aaron
C. McUmber
Theodore W. Randolph
Daniel K. Schwartz
10.1021/acs.jpclett.5b00933.s001
https://acs.figshare.com/articles/journal_contribution/Electrostatic_Interactions_Influence_Protein_Adsorption_but_Not_Desorption_at_the_Silica_Aqueous_Interface/2051610
High-throughput single-molecule total
internal reflection fluorescence
microscopy was used to investigate the effects of pH and ionic strength
on bovine serum albumin (BSA) adsorption, desorption, and interfacial
diffusion at the aqueous–fused silica interface. At high pH
and low ionic strength, negatively charged BSA adsorbed slowly to
the negatively charged fused silica surface. At low pH and low ionic
strength, where BSA was positively charged, or in solutions at higher
ionic strength, adsorption was approximately 1000 times faster. Interestingly,
neither surface residence times nor the interfacial diffusion coefficients
of BSA were influenced by pH or ionic strength. These findings suggested
that adsorption kinetics were dominated by energy barriers associated
with electrostatic interactions, but once adsorbed, protein–surface
interactions were dominated by short-range nonelectrostatic interactions.
These results highlight the ability of single-molecule techniques
to isolate elementary processes (e.g., adsorption and desorption)
under steady-state conditions, which would be impossible to measure
using ensemble-averaging methods.
2015-12-17 08:34:55
nonelectrostatic interactions
energy barriers
pH
diffusion coefficients
adsorption kinetics
reflection fluorescence microscopy
strength
1000 times
silica surface
BSA
desorption
surface residence times
Electrostatic Interactions Influence Protein Adsorption
serum albumin