Monodisperse Hyperbranched Polytriazoles as Unimolecular Nanocontainers for Encapsulation of Functional Payloads

In this work, a series of polytriazole-based unimolecular nanocontainers (UNs) with good water solubility, uniformity, and colloidal stability via a bottom-up chain-growth copper-catalyzed azide-alkyne cycloaddition (co)polymerization that features tunable size, degree of branching (DB), and functionality of the UNs is developed. A broad selection of hydrophobic payload molecules, including Nile red (NR), camptothecin, pyrene, 1-pyrenemethanol, and IR676, are successfully encapsulated to demonstrate the high versatility of these polymers as UNs. Using NR as a probe guest, the relationship between the encapsulation performance and the structural properties of UNs, including size and DB, is investigated. Furthermore, the localization and dispersity of encapsulated NR are explored and the dependence of payload's dispersity on the DB of UNs is revealed. The payload encapsulated in UNs exhibits tunable release kinetics, determined by either adjusting release conditions or including pH-responsive structural units in the UNs. Meanwhile, the dyes encapsulated in UNs exhibit improved photostability and stronger resistance to photobleaching. It is expected that these explorations address the size and stability issues widely encounter in current drug/dye nanocarriers and provide a versatile platform of polytriazole-based UNs for suitable payloads in various applications, including drug delivery and bio-imaging.