Surface-initiated DNA self-assembly as an enzyme-free and nanoparticle-free strategy towards signal amplification of an electrochemical DNA sensor.

Surface-initiated DNA polymerization has been employed in this work as an appealing signal amplification strategy for electrochemical DNA sensors. This strategy is especially superior in that enzymes, colloidal particles and other bulky structures are not involved in order to achieve amplified signals, and thus is highly promising in circumventing problems due to uncontrolled nucleation, adsorption, aggregation or disassembly of nanoparticles, liposomes and proteins, as well as enzyme deactivations. Our preliminary results have shown that a decrease (as compared to an amplification-free system) in detection limit by a factor greater than 300 can be easily achieved by cyclic voltammetry under still not optimized conditions, with an ability of differentiating a single base mutation.