Porous gold surfaces for biosensor applications.
The sensitivity of optical biosensors where the detection takes place on a planar gold surface can be improved by making the surface porous. The porosity allows a larger number of ligands per surface area resulting in larger optical shifts when interacting with specifically binding analyte molecules. The porous gold was deposited as a thin layer on a planar gold surface by electrochemical deposition in a solution of tetrachloroaurate and lead acetate. A protein, streptavidin, was adsorbed into the formed porous layer and the time course of the adsorption was monitored by in-situ ellipsometry. When the porous layer was 500 nm in thickness a six-fold increase of the ellipsometric response was obtained compared with a planar gold surface. The dependency of porosity and layer thickness was explained with a mathematical model of the gold/porous gold/protein/solution system.
van Noort
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Department of Physics and Measurement Technology, Linköping University, Sweden.
Mandenius
C F
CF
D000327:Adsorption; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D006046:Gold; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D012680:Sensitivity and Specificity; D019809:Streptavidin; D013499:Surface Properties
D006046:Gold; D019809:Streptavidin