Recent advances of smart AIEgens for photoacoustic imaging and phototherapy

• A state-of-the-art review on the photoacoustic imaging and phototherapy of AIEgens. • Rational design and synthesis of smart AIEgens with enhanced photoacoustic imaging are demonstrated. • The conjugation of AIE cores with polymers, biomolecules, and nanoparticles for multifunctional AIEgens are presented. • Smart AIEgens exhibit great potential for photoacoustic/fluorescent imaging-guided multimodal phototherapy. The design of novel nanomaterials and nanoprobes used to diagnose and treat innumerable diseases has exhibited great potential in biomedical fields, which further promoted the development of advanced imaging and therapy techniques for tumors, including computed tomography, radiotherapy, chemotherapy, fluorescent bioimaging, photoacoustic (PA) bioimaging, and phototherapy. PA imaging and photodynamic/photothermal therapy (PDT/PTT) show clear advantages for monitoring and treating tumors due to their high efficiency, spatial specificity, low side effects, and easy operation. Aggregate-induced emission luminous (AIEgens)-based nanoprobes and nanomaterials attracted widespread attention and exhibited a wide range of applications for PA imaging and PDT/PTT treatments in the last years. In this review, we present the advances in the rational design and facile synthesis of various functional AIEgens with near-infrared emission for PA imaging and phototherapy applications. The modifications of AIE cores with various substances such as polymers, biomolecules, nanoparticles, and others for the creation of smart AIEgens through chemical conjugation, nanoprecipitation, and self-assembly are demonstrated and discussed. These designed AIEgens have exhibited enhanced PA imaging efficiency and high performance for combined imaging-guided PDT/PTT treatment of tumors. This topic-focused review is helpful for the readers to understand potential strategies for the design and preparation of function-specific AIEgens, and could promote the development of PA imaging and phototherapy techniques for practical detection, diagnosis, and treatment of cancers.