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The abnormal evolution of membrane-less organelles into amyloid fibrils is a causative factor in many neurodegenerative diseases. Fundamental research on evolving organic aggregates is thus instructive for understanding the root causes of these diseases. In-situ monitoring of evolving molecular aggregates with built-in fluorescence properties is a reliable approach to reflect their subtle structural variation. To increase the sensitivity of real-time monitoring, we presented organic aggregates assembled by TPAN-2MeO, which is a triphenyl acrylonitrile derivative. TPAN-2MeO showed a morphological evolution with distinct turn-on emission. Upon rapid nanoaggregation, it formed non-emissive spherical aggregates in the kinetically metastable state. Experimental and simulation results revealed that the weak homotypic interactions between the TPAN-2MeO molecules liberated their molecular motion for efficient non-radiative decay, and the strong heterotypic interactions between TPAN-2MeO and water stabilized the molecular geometry favorable for the non-fluorescent state. After ultrasonication, the decreased heterotypic interactions and increased homotypic interactions acted synergistically to allow access to the emissive thermodynamic equilibrium state with a decent photoluminescence quantum yield (PLQY). The spherical aggregates were eventually transformed into micrometer-sized blocklike particles. Under mechanical stirring, the co-assembly of TPAN-2MeO and Pluronic F-127 formed uniform fluorescent platelets, inducing a significant enhancement in PLQY. These results decipher the stimuli-triggered structural variation of organic aggregates with concurrent sensitive fluorescence response and pave the way for a deep understanding of the evolutionary events of biogenic aggregates.

The aggregation-induced emission photosensitizer (AIEPS) has stoodout as an alternative and competent candidate in bacterial theranostics,particularly with the use of cationic AIE PS in bacterial discriminationand elimination. Most reported work emphasizes the role of electrostaticinteraction between cationic AIE PS and negatively charged bacterialsurfaces, enabling broad applications from bacterial discriminationto bacterial killing. However, the underlying targeting mechanismand the design rationale of the cationic AIE PS for effective bacteriallabeling remain poorly investigated. In this Article, we designedand synthesized a series of cationic amphiphilic AIE PSs with differentcalculated log P values. Then, we systemically studiedthe relationship between the hydrophobicity variation of AIE PS andbacterial targeting outcomes, the dose of AIE PS needed to label variousspecies of bacteria, and their photodynamic antibacterial efficiency.The findings in this work provide a better understanding of the unclearAIE PS-bacterial interaction mechanism and some insights intothe structural design strategies of cationic amphiphilic AIE PS forbetter development in bacterial theranostics.