Theoretical model for the detection of charged proteins with a silicon-on-insulator sensor

For a bio-sensor device based on a silicon-on-insulator structure, we calculate the sensitivity to specific charge distributions in the electrolyte solution that arise from protein binding to the semiconductor surface. This surface is bio-functionalized with a lipid layer so that proteins can specif...

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Bibliographic Details
Published in:Journal of physics. Conference series 2008-03, Vol.107 (1), p.012002
Main Authors: Birner, S, Uhl, C, Bayer, M, Vogl, P
Format: Article
Language:English
Subjects:
Binding sites
Biosensors
Boltzmann transport equation
Charge density
Electrolytes
Fluorescence
Lipids
Mathematical analysis
Physics
Proteins
Quantum mechanics
Silicon
SOI (semiconductors)
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Summary:For a bio-sensor device based on a silicon-on-insulator structure, we calculate the sensitivity to specific charge distributions in the electrolyte solution that arise from protein binding to the semiconductor surface. This surface is bio-functionalized with a lipid layer so that proteins can specifically bind to the headgroups of the lipids on the surface. We consider charged proteins such as the green fluorescent protein (GFP) and artificial proteins that consist of a variable number of aspartic acids. Specifically, we calculate self-consistently the spatial charge and electrostatic potential distributions for different ion concentrations in the electrolyte. We fully take into account the quantum mechanical charge density in the semiconductor. We determine the potential change at the binding sites as a function of protein charge and ionic strength. Comparison with experiment is generally very good. Furthermore, we demonstrate the superiority of the full Poisson-Boltzmann equation by comparing its results to the simplified Debye-Hückel approximation.
ISSN:1742-6596
1742-6588
1742-6596
DOI:10.1088/1742-6596/107/1/012002