Application Of Tunable Nanoparticles With Aggregation-induced Emission Characteristics In Multimodal Image-guided Synergistic Phototherapy

Fluorescent organic nanoparticles(NPs)with aggregation-induced emission(AIE)characteristics hold remarkable potential for bioimaging and image-guided phototherapy.The molecular packing is key point for optimizing the performance of AIE luminogens(AIEgens)in the aggregated state or solid state.However,so far,the packing mode of AIEgens in NPs is still vague,causing some challenges for understanding the relationship between the photophysical property and packing mode,as well as further optimizing the performance of NPs for biomedical applications.In this contribution,by simply controlling the length of alkoxy chains in the donoracceptor conjugated OPTPA,a packing balance between the twisted molecular structure and effective π-conjugation has been actualized,which results in high solid-state NIR emission,distinct bathochromic absorption/emission and AIE characteristics.Subsequently,we present for the first time the possibility of amorphous-crystalline transition of AIEgens in the polymer-encapsulated NPs,and further optimize the comprehensive performance of NPs,such as simultaneously enhanced bathochromic absorption/emission,improved reactive oxygen species generation and superior photothermal conversion effect.Both in vitro and in vivo experiments indicate that crystalline AIEgen-based NPs with excellent biocompatibility and biosafety are remarkably effective in trimodal imaging-guided synergistic photodynamic therapy(PDT)and photothermal therapy(PTT).