Figure 4: Comparative study of Sensors using 2-terminal characterization. ▲: Sensor 1: Silicon based substrate with 2 hours of pG-AuNPs incubation period, ●: Sensor 2: Silicon substrate with 4 hours of pG-AuNPs incubation period. ✶: Sensor 3: Silicon/Silicon Dioxide substrate with 4 hours of pGAuNPs incubation period. (a): Impedance Z versus frequency f, (b) Capacitance C versus frequency f.