The unmodified/SWCNT modified PGEs were immersed into the vials containing 110 of various concentrations of TPT between 0.05 to 10 ug/mL. The electrodes were then kept in these vials for 30 min.followed by passive adsorption procedure. The electroded were washed with PBS (pH=7.4) foe 5 s to eliminate unspesific binding.