A microenvironment sensitive pillar[5]arene-based fluorescent probe for cell imaging and drug delivery

ABSTRACT Dansylamide (DNSA) is a typical ICT probe that has a favorable serum albumin sensitivity. Inspired by this, we designed a microenvironment sensitive fluorescent probe 4C-G through introducing DNSA into pillar[5]arene. Unlike DNSA, 4C-G displayed differentiated sensitivity to multiple proteins, which was benefit from pillar[5]arene assisted the probe to form complexes with proteins. 4C-G could not only be applied in imaging of HepG2, but also act as a favorable drug carrier for regorafenib (REG) encapsulation. The 4C-G-REG complex would aggregate into high drug-loading fluorescent nanoparticles in a physiological environment (pH 7.4). Such nanoparticles exhibited pH-triggered enrichment ability, which rapidly enriched REG in the acidic environment (pH 6.0). Furthermore, the complexation between 4C-G and REG maintained the imaging property of the probe and the excellent anticancer activity of the drug on HepG2.