Conformationally Adaptive PTrp-BODIPY Host-Guest Interfaces for Multichannel Phototheranostics

To overcome the intrinsic photophysical limitations of aggregation-induced emission luminogens (AIEgen) and aggregation-caused quenching luminogens (ACQgen) systems, constructing synergistic architectures for complementary performance has become a critical focus in current phototheranostic research. Herein, we propose a strategy to polymerize tryptophan (Trp) monomers with ACQ characteristics into flexible macromolecular hosts, whereby the resulting polytryptophan (PTrp) is endowed with partial ACQ or AIE photophysical properties. Subsequently, pairing PTrp with three BODIPY derivative guests systematically elucidated the role of interfacial adaptability in excited-state energy redistribution. Compared with Trp, PTrp provides flexible chains and multisite interaction sites, enabling the formation of adaptive cavities that create continuous and size-matched interfaces on different BODIPY surfaces. This adaptive interface strengthens electrostatic matching and weak interactions, promoting the redistribution across different energy channels. Notably, the flexible host-guest architecture ensures tight molecular packing, driving the formation of unique rod-like nanoparticles that exhibit concentration-dependent secondary self-assembly. This behavior enables a prolonged tumor retention effect of over 96 h and a significant tumor inhibition rate of 94%. The conformationally adaptive host-guest strategy proposed in this study provides a versatile and efficient non-covalent paradigm for constructing long-retained, multichannel phototheranostics.