Decker Supramolecular Architecture-Derived Near-Infrared Luminescent Materials for Bioimaging Application

The in vivo performance of near-infrared (NIR) fluorescence imaging probes is governed by fluorophore aggregation behavior and molecular arrangement, with π–π stacking-induced aggregation-caused quenching (ACQ) being the key bottleneck limiting imaging efficacy. Conventional modification strategies are confined to monofunctional design, failing to synergistically achieve ACQ inhibition and spectral red shift. To address these issues, this study proposes an efficient synthetic strategy for decker structures, which relies on terpyridine steric hindrance design to enable precise, selective self-assembly and avoid multicomponent coassembly issues. We anchored aza-boron-dipyrromethene (aza-BODIPY) fluorophores and sterically hindered tetraphenylethylene (TPE) units onto terpyridine ligands. We designed and synthesized three systems with tailored TPE contents (nTPE/n(BDP+TPE)): free aza-BODIPY BDP (0%), triple-decker S1 (33%), and double-decker S2 (50%). TPE-induced steric hindrance precisely modulates fluorophore arrangement and π–π stacking, enabling graded ACQ suppression while preserving the intrinsic NIR optical properties of aza-BODIPY. Among them, nanoparticles (NPs) formulated from S2 with the highest TPE content (50%) retain ∼20% of the native brightness (9.3% for S1, while retention for BDP is negligible), achieving high-contrast deep-tissue NIR imaging (SBR = 5.6 at 1300 nm). This strategy provides an ideal model for elucidating fluorophore structure–property relationships and guides the design of high-performance NIR imaging probes.