Nanoparticle Platforms for Controlled Protein Adsorption and Behavior in Protein Monolayer Electrochemistry W Synthetic models of biological interfaces are of interest for many bioanalytical applications, including biosensor development. Here we explore films of nanoparticles called monolayer protected clusters (MPCs) as a functional component of protein monoalyer electrochemistry. A major goal of our work is to see if rational design of the MPCs translated into molecular level control at the protein binding site* that affects the adsorbed electrochemistry. Cytochrome c (Cc) was adsorbed to films of MPCs assembled on modified gold substrates. Different types of hydrophilic MPCs (see below) successfully immobilized cyt c and controlled the adsorption environment on a molecular level.
protein binding site Adsorbed protein
*
Organized MPC film
O
-O O
O
-
O O
glass / gold / metal oxide
O
-
SS
SS SS SS S
-O
S S S
SS
SS
SS
O
Modifier (e.g., SAM, siloxane)
O
0.7 S S S
S
S
S
S
S
S
S
S
S
S
Current, μA
Current, μA
-0.4
-0.4
-0.6
S
S S S
S
S
S
S
S
S
S
S
S
S
Current, μA
S
-0.2
-0.2
S
0.0
0
S S
0.2
0.2
S
0.4
0.4
S S S S
0.3
0.6
0.6
0.1 -0.1 -0.3 -0.5
-0.8
-0.6 -0.8 0.25
0.5
S
S
0.8
S
S
S
S
S S
S S
0.8
S S S
S
S
S
S
S
S
S
S
S
S S S
S
S
0.15
0.05
-0.05
Potential, Volts
-0.15
-0.25
-1 0.25
0.15
0.05
-0.05
Potential, Volts
-0.15
-0.25
-0.7 0.25
0.15
0.05
-0.05
Potential, Volts
Leopold Research Group at the University of Richmond
-0.15
-0.25
