Electrochemical measurements of DNA melting on surfaces

Thermal denaturation, or melting, measurements are a classic technique for analysis of thermodynamics of nucleic base driven associations in solution, as well as of interactions between nucleic acids and small molecule ligands such as drugs or carcinogens. Performed on surface-immobilized DNA films, this well-established technique can help understand how energetics of surface hybridization relate to those in solution, as well as provide high-throughput platforms for screening of small molecule ligands. Here we describe methods for measuring DNA melting transitions at solid/liquid interfaces with focus on the role of immobilization chemistry, including a common "immobilization- through-self-assembly" approach that is effective at moderate temperatures, and a thermo-stable approach based on polymer-supported DNA monolayers that can be used at elevated temperatures. We also discuss conditions necessary for reversible measurements, as signified by superimposition of the association (cooling) and dissociation (heating) transitions of immobilized DNA strands.