Predicting and rationalizing the effect of surface charge distribution and orientation on nano-wire based FET bio-sensor
De Vico L., Iversen L., Sørensen M. H., Brandbyge M., Nygård J., Martinez K. L., Jensen J. H.
Nanoscale, DOI: 10.1039/C1NR10316D
Abstract: A single charge screening model of surface charge sensors in liquids (De Vico et al., Nanoscale, 2011, 3, 706-717) is extended to multiple charges to model the effect of the charge distributions of analyte proteins on FET sensor response. With this model we show that counter-intuitive signal changes (e.g. a positive signal change due to a net positive protein binding to a p-type conductor) can occur for certain combinations of charge distributions and Debye lengths. The new method is applied to interpret published experimental data on Streptavidin (Ishikawa et al. ACS Nano 2009, 3, 3969-3976) and Nucleocapsid protein (Ishikawa et al. ACS Nano 2009, 3, 1219-1224)
We analyze how appropriate combinations of buffer conditions and charge distributions and orientation may lead to a counter-intuitive signal in BioFETs.