Immobilization of DNA onto Polymer-Modified Electrode Surface

1 Immobilization of DNA onto Polymer-Modified Electrode Surface 

DNA can be attached to the polymer-modified electrode surface using several methods simple adsorption, covalent bonds (first appropriate functional groups are introduced to the polymer, then DNA is covalently attached), or affinity binding (avidin-biotin). 

Immobilization of the DNA onto polymer modified surface can be realized by electrodeposition, which is a well-known method [25]. Application of positive potential in this process can enhance the DNA immobilization as well as the stability of immobilized DNA. Diaz-Gonzalez etal. [26] studied the DNA immobilization onto a polylysine-modified electrode at different potentials. The best results were obtained using a potential of-1-0.5 V for 120 seconds. DNA was also electrodeposited onto a poly(p-aminobenzensulfonic acid)-modified glassy carbon electrode (GCE) at -fl.5 V for 30 minutes [27] or onto overoxidized Ppy-modified electrode at -1-1.8 V for 30 minutes [28]. 

Indirect immobilization of DNA using intermediate system avidin-biotin is reported as a form of affinity binding [38]. Avidin with an activated —COOH group was attached onto PANl film electropolymerized at the surface of a Pt electrode, and then a 

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