A perylenediimide-based nanocarrier monitors curcumin release with an “off–on” fluorescence switch

Perylenediimide-cored (PDI-cored) polymers have been widely applied as fluorescent drug carriers due to their high fluorescence quantum yield and outstanding chemical/photophysical stability. However, most of these delivery systems lack detailed drug delivery specifics, especially when and where the drug is released. In this study, a PDI-based nanocarrier (PPL-B) is constructed and applied to monitor curcumin release with an " off-on" fluorescence switch. The star-shaped drug carrier has an amphiphilic structure with fluorescent PDI as the core and poly(amino acid) as the shell, which is suitable for drug delivery. A model drug curcumin is loaded to PPL-B and quenches its fluorescence significantly through photoinduced electron transfer (PET). Upon curcumin release, the fluorescence of PPL-B achieves an " off-on" switch as a result of PET interruption. In light of this, curcumin release is successfully monitored by CUR@ PPL-B at the cellular level. This PDI-based nanocarrier for drug release monitoring with a PET mechanism shows great potential in the drug delivery field.