Immobilizing DNA on clay mineral modified carbon paste electrodes

Al-kaolinite, Al-montmorillonite, and Al13-montmorillonite have been prepared and their electrokinetic mobility were measured to be – 2.06 × 10- 8, -0.62 × 10- 8 and +2.98 × 10- 8 m2V- 1s- 1 respectively. DNA immobilized on the clay mineral modified carbon paste electrode via the positive charges of the clay mineral. The immobilizing efficiencies of DNA were monitored with the DNA markers methylene blue (MB) and ethidium bromide (EB) and they were of the following sequence: Al-kaolinite < Al-montmorillonite < Al13-montmorillonite. The immobilization did not affect the binding event between DNA and MB or EB. The obtained DNA-sensors can be used to study the interaction between low molecular weight compounds and DNA as well as the different binding strength of low molecular weight compounds with ssDNA and dsDNA.