Optical sensor conjugates for detecting reactive oxygen and/or reactive nitrogen species in vivo

A composition for detecting reactive oxygen, reactive nitrogen, or both in a subject, the composition comprising a fluorogenic small molecule and a particle, wherein the fluorogenic small molecule comprises a compound of Formula I:

• or a salt thereof, wherein:
• Z is a linker and comprises C3-20 alkyl, wherein any of the carbons in C3-20 alkyl can be replaced with —C(O)—, C(O)O—, —C(O)NRA—, —C(NH)—, oxygen, sulfur, —SO2—, —NRASO2——NRa—;
• X is selected from
• N3, C(O)Cl, and C(O)ORA;
• Y is selected from O, S, Se, Te, N(RA), and C(Me)2;
• R1 is NRCRD;
• or 2 or 3 R1 adjacent to each other and together with the C atoms to which they are attached form 1 or 2 heterocycloalkyl, optionally substituted by 1, 2, 3, or 4 substituents independently selected from H, OH, C1-6 alkyl, ORA, C(O)RB, C(O)NRCRD, and C(O)ORA;
• RA, RB, RC and RD are independently selected from H, C1-6 alkyl, and succinimidyl;
• and m is 1, 2, 3, or 4.