A thermo- and pH-responsive poly(N-isopropylacrylamide)–Mn–ZnS nanocomposite for controlled release and real-time photoluminescence tracking of doxorubicin

Abstract

Smart drug carriers with intrinsic photoluminescence (PL) tracking of controllably released drugs are of great significance to indicate in real-time where, when and how the drug was released. Herein, we present a novel multifunctional poly(N-isopropylacrylamide)–Mn–ZnS (PMZS) nanocomposite for thermo- and pH-controlled release of doxorubicin (Dox) and real-time tracking of the released Dox in a PL-enhanced manner. The simple coupling of Mn–ZnS quantum dots and poly(N-isopropylacrylamide) resulted in the unique thermo- and pH-responsive PL of PMZS. There was a much higher PL intensity at 37 °C than 25 °C and a much higher PL intensity at weakly acidic pH than at neutral pH, which is promising for PL imaging in tumor microenvironments. The PL of the PMZS composite was greatly quenched upon loading of Dox (the loading content and encapsulation efficiency of PMZS composites toward Dox were 15.2% and 84.1%, respectively), but was gradually restored with the controllable release of Dox, and the restored PL intensity was proportional to the cumulative amount of Dox released. The versatility of the PMZS composite as an effective Dox carrier and real-time PL-enhanced tracking of the controllably released Dox were further proved by cell viability assays and in vitro cell imaging experiments. The simple PMZS nanocomposite was easily-synthesized, biocompatible, and promising for PL tracking of when, where and how Dox was released.