Smartphone-assisted copper nanoclusters fluorescent sensing platform for visual determination of Congo red.

In order to realize efficient detection of Congo red, fluorescence analytical method were adopted and investigated systematically. Based on the superior properties of papain and excellent performance of copper nanoclusters, papain stabilized copper nanoclusters (Cu NCs@PP) with blue fluorescence were rapidly synthesized via a one-pot method. The spherical Cu NCs@PP uniformly dispersed with an average size of about 2.