Direct electrostatic DNA detection by its intrinsic molecular charge

3 DIRECT ELECTROSTATIC DNA DETECTION BY ITS INTRINSIC MOLECULAR CHARGE 

Electrochemical Sensors, Biosensors and Their Biomedical Applications 

eq is the permittivity of vacuum, ei the dielectric constant of the electrolyte, z is the valency of the ions in the electrolyte, and 7 represents the ionic strength, which for a 1 1 salt, can be replaced by the electrolyte concentration iiq. 

FIGURE 7.5 FED with 10-bases DNA molecule oriented normal to the sensor surface and Debye length Xd in the electrolyte with different ionic strengths (schematically). Increasing ionic strength of the electrolyte solution decreases the fraction of DNA charge that can be detected by the FED. 

gh is the charge change indnced npon the hybridization, m = q j /b is the fraction of DNA charge in the double layer (for simplicity, DNA molecules are considered 

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Direct electrostatic DNA detection by its intrinsic molecular charge... 

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