Tunable plasmonic colorimetric assay with inverse sensitivity for extracellular DNA quantification.

Extracellular DNA (eDNA) is a biomolecule commonly used to characterize microorganism communities in soil and aqueous environments. In this work we developed a gold nanorod (AuNR)-based colorimetric assay with inverse sensitivity and tunable dynamic range for eDNA. The effects of three key parameters, such as AuNR aspect ratio, DNA length and structure, have been identified allowing the assay to reach the detection levels necessary for the quantification of environmental eDNA.