A Dual‐Response DNA Probe for Simultaneously Monitoring Enzymatic Activity and Environmental pH Using a Nanopore

Both protease overexpression and local pH changes are key signatures of cancer. However, the sensitive detection of protease activities and the accurate measurement of pH in a tumor environment remain challenging. Here, we develop a dual‐response DNA probe that can simultaneously monitor protease activities and measure the local pH by translocation through α‐hemolysin (αHL). The DNA probe bears a short peptide containing phenylalanine at a pre‐designed position. Enzymatic cleavage of the peptide either exposes or removes the N‐terminal phenylalanine that can form a complex with cucurbit[7]uril. Translocation of the DNA hybrid through αHL generates current signatures that can be used to quantify protease activities. Furthermore, the current signatures possess a pH‐dependent pattern that reflects the local pH. Our results demonstrate that the versatile DNA probe may be further explored for simultaneously measuring multiple parameters of a complex system such as single cells in the future.