For the first time, the connection between surface stress and nanoscopic interactions of DNA adsorbed on microcantilever is established by combining Strey's mesoscopic liquid crystal theory and Stoney's formula. It is shown that surface stress depends not only on biomolecular interactions of DNA biofilm but also on mechanical properties of cantilever. Considering the correlativity between grafting density and chain length of DNA chain, we discuss the differences between DNA-microcantilever system and DNA solution system. The major theoretical achievement of this model is to identify the main contributions to surface stress under different detection conditions. This provides guidelines for designing new biosensors with high sensitivity and improved reliability.
