Integration of a peptide–DNA conjugate with multiple cyclic signal amplification for the ultrasensitive detection of cathepsin B activity

Abstract

We develop a simple fluorescence method for the sensitive detection of cathepsin B activity based on the integration of a peptide–DNA conjugate with multiple cyclic signal amplification. This method can detect cathepsin B activity with an extremely low detection limit of 8.1 × 10⁻¹² g mL⁻¹ and a large dynamic range of 4 orders of magnitude from 1 × 10⁻¹¹ to 1 × 10⁻⁷ g mL⁻¹, and it can even measure cathepsin B activity at the single-cell level. This method can be further used for the screening of cathepsin B inhibitors.