Eu3+-induced polysaccharide nano-dumbbell aggregates (PNDA) as drug carriers to smartly report drug concentration through variable fluorescence

Abstract

Nanoparticle drug delivery systems are designed to be biocompatible and to control the distribution of poorly soluble drugs. Fluorescent nanoparticle drug carriers have been designed to enable fluorescence tracking. While such particles enable tracking of the carrier, this tracking does not report the local drug concentration. In this article, we report new nanoparticle drug carriers with stable, high-intensity fluorescence that sensitively reports the loaded drug concentration. The dumbbell-shaped nanoparticles are synthesized by combining europium (Eu) complexes with hyaluronic acid. The Eu complexes are superior to organic fluorophores, providing a narrow emission peak, high fluorescence intensity, long fluorescence lifetime, and insensitivity to photobleaching. The hyaluronic acid compatibilizes the nanoparticles with aqueous environments, and provides biocompatibility. We demonstrate that these polysaccharide nano-dumbbell aggregates (PNDAs) can effectively load drugs through structural changes, and sense the amount of drug loaded through changes in fluorescence intensity, enabling precise tracking of drug loading and release.