Plasmonic Sensor Could Enable Label-Free DNA Sequencing.

We demonstrated a proof-of-principle concept of a label-free platform that enables nucleic acid sequencing by binding methodology. The system utilizes gold surfaces having high fidelity plasmonic nanohole arrays which are very sensitive to minute changes of local refractive indices. Our novel surface chemistry approach ensures accurate identification of correct bases at individual positions along a targeted DNA sequence on the gold surface. Binding of the correct base on the gold sensing surface triggers strong spectral variations within the nanohole optical response, which provides a high signal-to-noise ratio and accurate sequence data. Integrating our label-free sequencing platform with a lens-free imaging-based device, we reliably determined targeted DNA sequences by monitoring the changes within the plasmonic diffraction images. Consequently, this new label-free surface chemistry technique, integrated with plasmonic lens-free imaging platform, will enable monitoring multiple biomolecular binding events, which could initiate new avenues for high-throughput nucleic acid sequencing.