Propeller-shaped molecules diphenyldibenzofulvene (1) and (4-methoxyphenyl)phenyldibenzofulvene (2) were nonemissive when dissolved in good solvents but became luminescent when aggregated in poor solvents or in the solid state, showing a novel phenomenon of aggregation-induced emission (AIE). 8-Phenylbenzo[e]-acephenanthrylene (3), a ring-closed form of 1 with one of its phenyl blades locked, was emissive in the solutions, suggesting that the AIE effects of 1 and 2 are caused by the restrictions of intramolecular rotations of their aromatic blades in the aggregation state. The crystals of 1 and 2 emitted stronger, bluer lights than their amorphous powders, possibly due to the structural rigidification and conformational twisting of the dye molecules in the crystalline phase. The light-emitting diodes with a device configuration of ITO/NPB/dye/ BCP/Alq 3 /LiF/Al were fabricated, which emitted bluish-green and yellow lights with maximum luminance and current efficiency up to 5000 Cd/m 2 and 1.90 Cd/A, respectively.

Second near-infrared (NIR-II, 1000−1700 nm) fluorescence bioimaging has attracted tremendous scientific interest and already been used in many biomedical studies. However, reports on organic NIR-II fluorescent probes for in vivo photoinduced imaging and simultaneous therapy, as well as the longterm tracing of specific biological objects, are still very rare. Herein we designed a single-molecular and NIR-II-emissive theranostic system by encapsulating a kind of aggregation-induced emission luminogen (AIEgen, named BPN-BBTD) with amphiphilic polymer. The ultra-stable BPN-BBTD nanoparticles were employed for the NIR-II fluorescence imaging and photothermal therapy of bladder tumors in vivo. The 785 nm excitation triggered photothermal therapy could completely eradicate the subcutaneous tumor and inhibit the growth of orthotopic tumors. Furthermore, BPN-BBTD nanoparticles were capable of monitoring subcutaneous and orthotopic tumors for a long time (32 days). Single-molecular and NIR-II-emitted aggregation-induced emission nanoparticles hold potential for the diagnosis, precise treatment, and metastasis monitoring of tumors in the future.

Rationale: Cerebrovascular diseases, together with malignancies, still pose a huge threat to human health nowadays. With the advantages of its high spatial resolution and large penetration depth, fluorescence bioimaging in the second near-infrared spectral region (NIR-II, 900-1700 nm) and its related imaging-guided therapy based on biocompatible fluorescence dyes have become a promising theranostics method.Methods: The biocompatibility of IR-820 we used in NIR-II fluorescence bioimaging was verified by long-term observation. The model of the mouse with a cranial window, the mouse model of middle cerebral artery occlusion (MCAO) and a subcutaneous xenograft mouse model of bladder tumor were established. NIR-II fluorescence cerebrovascular functional imaging was carried out by IR-820 assisted NIR-II fluorescence microscopy. Bladder tumor was treated by NIR-II fluorescence imaging-guided photothermal therapy.Results: We have found that IR-820 has considerable NIR-II fluorescence intensity, and shows increased brightness in serum than in water. Herein, we achieved real time and in vivo cerebrovascular functional imaging of mice with high spatial resolution and large penetration depth, based on IR-820 assisted NIR-II fluorescence microscopy. In addition, IR-820 was successfully employed for NIR-II fluorescence imaging and photothermal therapy of tumor in vivo, and the subcutaneous tumors were inhibited obviously or eradicated completely.Conclusion: Due to the considerable fluorescence intensity in NIR-II spectral region and the good photothermal effect, biocompatible and excretable IR-820 holds great potentials for functional angiography and cancer theranostics in clinical practice.