Amphiphilic Polymeric Nanocarriers with Luminescent Gold Nanoclusters for Concurrent Bioimaging and Controlled Drug Release

Multifunctional theranostic systems with good biocompatibility, strong clinical imaging capability, and target specificity are the desired features of future medicine. Here, the design of a theranostic nanocomposite capable of simultaneous targeting and imaging of the cancer cells is presented. It releases its drug payload by a controlled release mechanism. The nanocomposite contains luminescent gold nanocluster (L-AuNC) photostable and biocompatible diagnostic probes conjugated to a folic acid (FA)-modified pH-responsive amphiphilic polymeric system for controlled drug release. The nanocomposite uses a core-satellite structure to encapsulate hydrophobic drugs and releases the drug payload in mildly acidic endosomal/lysosomal compartments by the action of the pH-labile linkages in the polymer. In vivo studies show the selective accumulation of the FA-conjugated nanocomposite in tumor tissues by folate-receptor-mediated endocytosis. These findings demonstrate the potential of the nanocomposite as a nontoxic, folate-targeting, pH-responsive drug carrier that is useful for the early detection and therapy of folate-overexpressing cancerous cells.