Transduction of molecular binding associated conformational changes to mechanical defromation
Yue Zhao (Iowa State University), Pranav Shrotriya (Iowa State University)
Mechanics of Thin Films and Multilayered Structures
Tue 9:00 - 10:30
Salomon 203
Transduction of specific analyte/receptor binding to mechanical deformation is an intriguing chemo-mechanical phenomenon and is being explored for developing biological and chemical sensors, nanoscale motors and active surfaces. The transduction strategy involves coating surface of a flexible mechanical element (microcantilevers or membrane) with a film of receptor molecules that have specific affinity for the target analyte. Binding of the analyte on the sensitized surface leads to development of surface stress and thus, transduction of chemical binding to deformation of the mechanical element. While potential uses of the chemo-mechanical transduction have been explored for a number of applications, the widespread application of this technology is severely curbed due to low magnitude of binding induced surface stress, which limits the discrimination between specific and non-specific binding on the sensitized surface. This problem is further exacerbated in cases when the concentration of target analyte is much smaller than other molecules leading to almost the same magnitude of desired signal (associated with specific binding) and noise (associated with non-specific binding). We report a novel mechanism for specific binding induced surface stress in which mechanical deformation of the underlying surface is enhanced for specific binding of the analyte compared with non-specific binding of non-analyte molecules. The receptor immobilization is designed to couple the analyte binding induced conformational change directly to surface deformation in order to ensure that specific binding transduces a large surface stress change of the underlying surface. The receptor immobilization is tested for two different analyte/receptor combinations – complimentary DNA strands and malachite green/malachite green RNA aptamer. Experimental results indicate that in both cases the modified immobilization can result in an order of magnitude larger surface stress changes.