Galactose-Functionalized, Colloidal-Fluorescent Nanoparticle from Aggregation-Induced Emission Active Molecule via Polydopamine Coating for Cancer Cell Targeting

Aggregation-induced emission (AIE) active molecules emerge as new generation fluorescent probes, and their transformation to functional nanoparticle can greatly extend the application potential. Here we report an approach for transforming AIE active tetraphenylethene (TPE) molecule to galactose-functionalized colloidal nanoparticle that can be used for targeting/labeling of cancer cells. The approach involves polydopamine coating around aggregated TPE or TPE–chitosan conjugate followed by covalent linking with thiolated galactose. Resultant nanoparticles have 50–200 nm hydrodynamic size with good colloidal stability at physiological condition and 6–12% fluorescence quantum yield, and they selectively label cells with overexpressed galactose receptors. The unique advantage of this nanoprobe is that fluorescence remains intact in the presence of conventional quenchers. This approach may be extended for making AIE-active molecule-based various functional nanoprobes.