Double-strand DNA melted by laser micro-flow method

We present a physical method, based on laser micro-flow, to melt double-strands of DNA. When DNA molecules are immobilized on a quartz surface, the hydrogen bonds between complementary strands can be broken rapidly under the control of a laser evanescent wave and micro-flow oscillation. Employing a single-molecule fluorescence resonance energy transfertechnique, the dynamics of DNA melting is studied at the single-molecule level. When the DNA is in a special position, it can be melted by a laser beam focused to a pinpoint. It is shown that the percentage of melted DNA increases proportionally with laser power. Furthermore, we can determine the contribution of the micro-flow mechanics in the melting process.