Graphene-DNAzyme Junctions: A Platform for Direct Metal Ion Detection with Ultrahigh Sensitivity.

Many metal ions are present in biology and in the human body in trace amounts. Despite numerous efforts, metal sensors with ultrahigh sensitivity (< a few picomolar) are rarely achieved. Here, we describe a platform method that integrates a Cu-dependent DNAzyme into graphene-molecule junctions and its application for direct detection of paramagnetic Cu with femtomolar sensitivity and high selectivity.