a) Steady state amperometric response of (PLL-SWCNT2)-(PLL-Ab)/Ag assembly on addition of hydrogen peroxide (2000 rpm, 0.1 mM H2Q, 40 μM H2O2 additions and 0.5 mg mL−1Ab (except for control) and 50 pmol mL−1 Ag). b) Steady state amperometric response of (PLL-SWCNT2)-(PLL-Ab)/Ag sensor with varying biotin-HRP concentration on addition of hydrogen peroxide (2000 rpm, 0.1 mM H2Q, 40 μM H2O2, and 0.5 mg mL−1 Ab). Response corrected for control.