Figure 2.

Comparison of the kinetics of hybridization at open circuit (squares) and under electrochemical control at an applied potential of +300 mV (circles) and −300 mV (triangles). Data are shown for the interaction of the fully complementary target (solid symbols) for the 2-bp mismatched target (open symbols). For each electrochemical experiment, hybridization proceeds for 3 minutes before the selected potential is applied (see text for details). Here only the first 30 min are shown, although each hybridization proceeds for at least 5 h. The magnitude of hybridization is compared with the steady-state value reached after 14 h of unassisted (open circuit) hybridization in an unstirred cell. All experiments were carried out in 1 M NaCl solution containing 1 μM oligonucleotide probe on the same immobilized ssDNA thiol probe film. The probe coverage remains constant (within 10%) when regenerated by rinsing with hot water between runs.