Surface confined interaction of TPT and dsDNA at SWCNT-PGEs. A higher DNA concentration was chosen for immobilization of DNA onto the surface of SWCNT-PGE due to the higher surface area of SWCNT modified. The unmodified/SWCNTs modified PGEs were immersed into the vials containing 110 uL of 50ug/ml dsDNA solution. The eletroded were kept in these vials for 1 hour followed by passive adsorption proceduce and washed into ABS for 5 s. Then, dsDNA immobilization PGEs were immersed into the vials containing 110 uL of 0.5 ug/mL TPT solution at required times and washed into PBS for 5 s