NOTEBOOK

Immobilization Process

The electric charge of the nanocomposite is then developed negative due to various functional groups such as carboxylic acids, hydroxyl and epoxy groups (oxidized graphene) and sulfonic groups of polyaniline. Therefore, the immobilization of probe DNA was mediated by aluminum nitrate, which enabled the immobilization of the phosphate groups of the nanocomposite matrix. The modification of the electrode was initially performed with 100 ul of the solution of nanocomposite mixed with 50mL of 0.1M aluminum nitrate. Then, 50mL of the final solution was mixed with 50mL DNA probe and remained under stirring 300 rpm for 30 minutes. Finally, 5μl of the compound was added to the labor "drop-by-drop" technique for electrode and dried for 30 minutes in an oven at 50 ºC.