Two birds with one stone: colorimetric and photothermal dual-mode biosensor based on CoOOH nanorings for detecting β-galactosidase activity and Escherichia coli

A multi-colorimetric and portable photothermal dual-mode biosensor with cross-references and self-calibration was established for the analysis of β-galactosidase (β-Gal) and Escherichia coli ( E. coli ).