Designing bifunctionalized gold nanoparticle for colorimetric detection of Pb2+ under physiological condition

► In this manuscript, we have successfully developed a colorimetric assay based on AuNPs for sensitively and selectively monitoring Pb2+ in living cell. ► The AuNPs are bifunctionalized by recognizing group (GSH) and stabilizing ligand (CALNN). ► The GSH/CALNN functionalized AuNP provides an excellent example for detecting Pb2+ in living cell with relatively low limit of detection (LOD) in the massive AuNP-based assays.