Figure 1.

Historical origins of activity-based sensing (ABS). Key advances in the development of the field of ABS stemming from the evolution of fundamental supramolecular host–guest chemistry of crown ethers, cryptands, and spherands to BBS of calcium and other metal ions. Likewise, the advent of chemodosimeters led to the concept of ABS, where the development of synthetic methods can be leveraged in a retrosynthetic manner to cage and uncage fluorescent dyes and other molecular imaging agents for the detection of biological analytes by using them for selective protection-deprotection chemistry.