The brightness of organic fluorescence materials determines their resolution and sensitivity in fluorescence display and detection. However, strategies to effectively enhance the brightness are still scarce. Conventional planar π-conjugated molecules display excellent photophysical properties as isolated species but suffer from aggregation-caused quenching effect when aggregated owing to the cofacial π–π interactions. In contrast, twisted molecules show high photoluminescence quantum yield (ΦPL) in aggregate while at the cost of absorption due to the breakage in conjugation. Therefore, it is challenging to integrate the strong absorption and high solid-state ΦPL, which are two main indicators of brightness, into one molecule. Herein, we propose a molecular design strategy to boost the brightness through the incorporation of planar blocks into twisted skeletons. As a proof-of-concept, twisted small-molecule TT3-oCB with larger π-conjugated dithieno­[3,2-b:2′,3′-d]­thiophene unit displays superb brightness at the NIR-IIb (1500–1700 nm) than that of TT1-oCB and TT2-oCB with smaller thiophene and thienothiophene unit, respectively. Whole-body angiography using TT3-oCB nanoparticles presents an apparent vessel width of 0.29 mm. Improved NIR-IIb image resolution is achieved for femoral vessels with an apparent width of only 0.04 mm. High-magnification through-skull microscopic NIR-IIb imaging of cerebral vasculature gives an apparent width of ∼3.3 μm. Moreover, the deeply located internal organ such as bladder is identified with high clarity. The present molecular design philosophy embodies a platform for further development of in vivo bioimaging.

Huanglongbing (HLB) is one of the most destructive diseases of citrus, which has posed a serious threat to the global citrus production. This research was aimed to explore the use of chlorophyll fluorescence imaging combined with feature selection to characterize and detect the HLB disease. Chlorophyll fluorescence images of citrus leaf samples were measured by an in-house chlorophyll fluorescence imaging system. The commonly used chlorophyll fluorescence parameters provided the first screening of HLB disease. To further explore the photosynthetic fingerprint of HLB infected leaves, three feature selection methods combined with the supervised classifiers were employed to identify the unique fluorescence signature of HLB and perform the three-class classification (i.e., healthy, HLB infected, and nutrient deficient leaves). Unlike the commonly used fluorescence parameters, this novel data-driven approach by using the combination of the mean fluorescence parameters and image features gave the best classification performance with the accuracy of 97%, and presented a better interpretation for the spatial heterogeneity of photochemical and non-photochemical components in HLB infected citrus leaves. These results imply the potential of the proposed approach for the citrus HLB disease diagnosis, and also provide a valuable insight for the photosynthetic response to the HLB disease.

or completely in the state of aggregation, impeding the progress of some specific applications. [2] In 2001, the uncommon luminogen system noted as aggregationinduced emission (AIE) [3] broke down the captivity of Förster's discovery named aggregation-caused quenching (ACQ), which brought a new wonderland for organic fluorophores. The intrinsic tendency to form aggregates in concentrated solutions or the solid state actively promotes the emission intensity of the fluorophores with AIE characteristics. Years of unremitting exploration has accumulated design experience of diverse AIEgens [4] and shaped plentiful innovated applications for stimuli sensing, [5] optoelectronic systems, [6] molecular detection, [7] bio-imaging, [8,9] and so on. Taking advantages of AIE dots with high resistance to photobleaching and excellent reliability, multifarious specific bio-sensing modes, including bio-imaging, launched on a grand. [8,10] The development of the AIE universe provides potential diagnostic and therapeutic means in clinic. Nowadays, efforts of AIEgens for fluorescence imaging in mice have already been

Lymph node metastasis is a major metastatic route of cancer and significantly influences the prognosis of cancer patients. Radical lymphadenectomy is crucial for a successful surgery. However, iatrogenic normal organ injury during lymphadenectomy is a troublesome complication. Here, this paper reports a kind of organic nanoprobes (IDSe-IC2F nanoparticles (NPs)) with excellent second near-infrared (NIR-II) fluorescence and photothermal properties. IDSe-IC2F NPs can effectively label lymph nodes and helped achieve high-contrast lymphatic imaging. More importantly, by jointly using IDSe-IC2F nanoparticles and other kinds of nanoparticles with different excitation/emission properties, a multichannel NIR-II fluorescence imaging modality and imaging-guided lymphadenectomy is proposed. With the help of this navigation system, the iatrogenic injury can be largely avoided. In addition, NIR-II fluorescence imaging-guided photothermal treatment ("hot" strategy) can ablate those metastatic lymph nodes which are difficult to deal with during resection ("cold" strategy). Nanoprobes-assisted and multichannel NIR-II fluorescence imaging-guided "cold" and "hot" treatment strategy provides a general new basis for the future precision surgery.