Tuning polyaniline doped with poly(4-styrenesulfonic acid) (PANI : PSS) as a nano-drug carrier for insulin delivery

Polyaniline (PANI) is one of the most well-known conductive polymers, but it is not soluble in water. PSS, a polyelectrolyte and dopant, has demonstrated the ability to enhance both electrical conductivity and solubility in water. PANI : PSS were synthesized under the effect of polymerization times, oxidant (APS) ratios, and dopant (PSS) ratios. The suitable synthesized PANI : PSS was the ANI : APS mole ratio of 1 : 1 and ANI : PSS wt ratio of 1 : 5 for 24 h providing the highest electrical conductivity (6.84 x 10^-2 ± 4.30 x 10^-4 S cm^-1) and still remained as nanoparticles (42.11 ± 7.41 nm). Insulin, a model drug, was ion-exchanged with PANI : PSS, replacing PSS. The amount of insulin loaded into PANI : PSS (insulin-PANI : PSS) was varied with weight ratios of 0.5 : 1, 1 : 1, and 3 : 1, with the 1 : 1 wt ratio exhibiting 96.4% loading efficiency. The synthesized PANI : PSS is demonstrated as a potential insulin carrier for transdermal drug delivery.