The present disclosure provides activatable and detectable membrane-interacting peptides that, following activation, can interact with phospholipid bilayers, such as cell membranes. The present disclosure also provides methods of use of such compounds. The compounds of the present disclosure are of the general structure X1a-A-X2—Z—X1b, where A is a membrane-interacting peptide region having a plurality of nonpolar hydrophobic amino acid residues that, following separation from portions Z, is capable of interaction with a phospholipid bilayer; Z is an inhibitory peptide region that can inhibit the activity of portion A; X2 is a cleavable linker that can be cleaved to release cleavage products from the compound; and X1a and X1b are optionally-present chemical handles that facilitate conjugation of various cargo moieties to the compound. Prior to cleavage of the composition at X2, the composition acts as a promolecule that does not associate with cellular membranes to a significant or detectable level. Following cleavage at cleavable linker X2, the cleavage product including portion A is free to interact with a phospholipid bilayer (e.g., a cell membrane), and thus accumulate at a site associated with a cleavage-promoting environment. Detection of the membrane-associated cleavage product can be accomplished by detection of a moiety attached through X1a and/or X1b. Such compositions can be used in a variety of methods, including, for example, use in directly imaging active clotting within a subject.