Fabrication and biological applications of luminescent polyamidoamine dendrimers with aggregation-induced emission feature

Abstract

The luminescent polymeric nanoparticles (LPNs) with aggregation-induced emission (AIE) properties have emerged as one of the most promising nanoprobes for their unique optical properties. The typical optical feature of AIE-active LPNs should be their obviously enhanced luminescence in aggregation or solid state, which can effectively overcome aggregation caused quenching effects of conventional organic dyes. In this study, we reported for the first time that highly emissive LPNs (named as TPE-E-PAMAM) can be simply fabricated via direct conjugation of tetraphenylethene derivative (TPE-E) with polyamidoamine (PAMAM) dendrimers, which relied on a one-step Michael addition reaction between ene group of TPE-E and amino group of PAMAM dendrimers under rather mild experimental conditions. Because of the strong intermolecular interaction of TPE-E PAMAM copolymers, they can form compact spheres in water and exhibit strong fluorescence in aqueous solution. TPE-E PAMAM LPNs possess high water dispersity, uniform morphology and desirable biocompatibility for biological imaging. More importantly, with large numbers of amino groups on the shell and valid space in the core, PAMAM-TPE-E LPNs have great potential for targeted gene delivery. Taken together, we described a facile one-step covalent strategy for developing AIE-active amphipathic dendrimers, which showed great potential for biomedicine applications.