Fig. 3. US-induced scission of disulfide-centered polymers and release of drug or reporting molecules. Generated thiols undergo (a) intermolecular Michael-addition to initiate retro Diels–Alder reaction releasing furylated doxorubicin,79 (b) intramolecular 5-exo-trig cyclization to release camptothecin,61 (c) intramolecular 5-exo-trig cyclization to release camptothecin and fluorescent umbelliferone simultaneously.85.
