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Quantifying the effect of ionic screening with protein-decorated graphene transistors
Jinglei Ping1, Jin Xi2, Jeffery G Saven3
1Department of Physics and Astronomy, University of Pennsylvania, Philadelphia 19104, USA.
Biosensors & Bioelectronics
|December 3, 2015
Summary
Researchers developed a model for protein-decorated graphene field-effect transistors (FETs) to understand how charged biomolecules affect device readings in liquid. This work links biomolecule charge to FET output for better biosensor development.
Area of Science:
- Materials Science
- Biophysics
- Electrical Engineering
Background:
- Liquid-based applications of biomolecule-decorated field-effect transistors (FETs) are expanding into biosensing and medical implants.
- A key challenge is quantifying the impact of charged biomolecules in solution on FET performance.
Purpose of the Study:
- To quantitatively understand the gating effect of charged biomolecules on FETs in ionic solutions.
- To develop a predictive model for biomolecule-induced electrical signal changes in FETs.
Main Methods:
- Fabrication of protein-decorated graphene FETs.
- Measurement of electrical properties, specifically Dirac voltage shifts, in solutions with varying ionic strengths.
- Development and application of a theoretical model incorporating graphene polarization and ionic screening.
Main Results:
- Excellent quantitative agreement was achieved between experimental measurements and the developed model.
- The model successfully accounted for graphene polarization, ionic screening, and charged amino acids on the protein.
- A direct correlation was established between biomolecule charge and FET readout.
Conclusions:
- The presented technique and analysis provide a quantitative link between biomolecule charge and liquid-phase FET signals.
- This approach is applicable to graphene and other 2D material-based liquid-phase FETs.
- Enables more accurate biosensing and development of in vivo implantable devices.
