Fluorescent Poly(ε-Caprolactone)s Micelles for Anticancer Drug Delivery and Bioimaging

Despite significant advancements in polymer-based nanomedicine, the clinical translation of biodegradable micellar drug delivery systems is limited due to premature drug release, low drug-loading capacity (DLC), and lack of inherent therapeutic and bioimaging functionalities. To overcome these challenges, we designed a novel poly(ε-caprolactone) (PCL)-based amphiphilic diblock copolymer that possesses inherent anticancer activity, fluorescence imaging capabilities, and multistimuli-responsive drug release. This platform features a fluorescent hydrophilic shell comprising of two triethylene glycol units and a hydrophobic core containing anticancer naphthalene moieties. This unique architecture imparts remarkable properties: the triethylene glycol units confer thermoresponsive behavior for precise drug release and enable intracellular tracking, while the naphthalene pendants enhance DLC (3.7%) through π-π interactions with doxorubicin (DOX). The micelles exhibit a low critical micelle concentration (7.8 × 10^-3 g/L), demonstrate strong stability for long storage times, and show significant cytotoxicity against the MDA-MB-231 cell line, highlighting their combined therapeutic efficacy.