Measurement of potential dependent DNA orientation on Indium Tin Oxide surfaces by fluorescent-self interference microscopy

We present a platform for the measurement of DNA orientation on an Indium Tin Oxide surface. We apply an interferometric measurement technique called spectral self-interference fluorescent microscopy (SSFM) that allows precise distance measurements of fluorophores from the sensor surface. SSFM can be used to infer the orientation and conformation of bound biomolecules, such as double stranded DNA. High electric fields are induced at the sensor surface through application of an electric potential between the sensor and a counter-electrode in solution and resulting orientation changes of the immobilized DNA are observed. The platform is scalable to allow micro-arrayed, high-throughput measurement of bimolecular interactions.