Purely organic room temperature phosphorescence (RTP) has attracted wide attention recently due to its various application potentials. However, ultralong RTP (URTP) with high efficiency is still rarely achieved. Herein, by dissolving 1,8-naphthalic anhydride in certain organic solid hosts, URTP with a lifetime of over 600 ms and overall quantum yield of over 20% is realized. Meanwhile, the URTP can also be achieved by mechanical excitation when the host is mechanoluminescent. Femtosecond transient absorption studies reveal that intersystem crossing of the host is accelerated substantially in the presence of a trace amount of 1,8-naphthalic anhydride. Accordingly, we propose that a cluster exciton spanning the host and guest forms as a transient state before the guest acts as an energy trap for the RTP state. The cluster exciton model proposed here is expected to help expand the varieties of purely organic URTP materials based on an advanced understanding of guest/host combinations.

Multimodality imaging is highly desirable for accurate diagnosis by achieving high sensitivity, spatial-temporal resolution, and penetration depth with a single structural unit. However, it is still challenging to integrate fluorescent and plasmonic modalities into a single structure, as they are naturally incompatible because of significant fluorescence quenching by plasmonic noble-metal nanoparticles. Herein, we report a new type of silver@AIEgen (aggregation-induced emission luminogen) core-shell nanoparticle (AACSN) with both strong aggregated-state fluorescence of the AIEgen and distinctive plasmonic scattering of silver nanoparticles for multimodality imaging in living cells and small animals. The AACSNs were prepared through a redox reaction between silver ions and a redox-active AIEgen, which promoted synergistic formation of the silver core and self-assembly of the AIEgen around the core. The resulting AACSNs exhibited good biocompatibility and high resistance to environmental damage. As a result, excellent performance in fluorescence imaging, dark-field microscopy, and X-ray computed tomography-based multimodality imaging was achieved.

The targeting and long-term imaging of the Golgi apparatus have been realized via l-cysteine functionalized nanoprobes.

An OFF-ON red-emitting phosphorescent thiol probe is designed by using the (3)MLCT photophysics of Ru(II) complexes, i.e., with Ru(II) as the electron donor. The probe is non-luminescent because the MLCT is corrupted by electron transfer from Ru(II) to an intramolecular electron sink (2,4-dinitrobenzenesulfonyl). Thiols cleave the electron sink, and the MLCT is re-established. Phosphorescence at 598 nm was enhanced by 90-fold, with a 143 nm (5256 cm(-1)) Stokes shift and a 1.1 mus luminescent lifetime.

Sensitive and accurate detection of highly contagious virus is urgently demanded for disease diagnosis and treatment. Herein, based on a multifunctional aggregation-induced emission luminogen (AIEgen), a dual-modality readout immunoassay platform for ultrasensitive detection of viruses has been successfully demonstrated. The platform is relied on virions immuno-bridged enzymatic hydrolysis of AIEgen, accompanying with the in situ formation of highly emissive AIE aggregates and shelling of silver on gold nanoparticles. As a result, robust turn-on fluorescence and naked-eye discernible plasmonic colorimetry composed dual-signal is achieved. By further taking advantage of effective immunomagnetic enrichment, EV71 virions, as an example, can be specifically detected with a limit of detection down to 1.4 copies/μL under fluorescence modality. Additionally, semiquantitative discerning of EV71 virions is realized in a broad range from 1.3 × 10 to 2.5 × 10 copies/μL with the naked eye. Most importantly, EV71 virions in 24 real clinical samples are successfully diagnosed with 100% accuracy. Comparing to the gold standard polymerase chain reaction (PCR) assay, our immunoassay platform do not need complicated sample pretreatment and expensive instruments. This dual-modality strategy builds a good capability for both colorimetry based convenient preliminary screening and fluorescence based accurate diagnosis of suspect infections in virus-stricken areas.

The catalyzed luminol chemiluminescence (CL) in a strongly alkaline environment has been rarely induced by singlet oxygen (1O2). This paper reports that cetyltrimethyl ammonium bromide passivated carbon nanodots (CTAB-CDs), prepared by the hydrothermal treatment of fullerene in the presence of CTAB, can be used as excellent catalysts to dramatically enhance the CL intensity of the luminol–H2O2 system in NaOH medium owing to their unique surface property. More importantly, this CL enhancement takes place mainly through the intermediate of 1O2, which follows a different mechanism from traditional reports. The CL spectra, UV–vis spectra, electron paramagnetic resonance (EPR) spectra, transmission electron microscopy (TEM) images before and after the CL reaction, and the effects of various free radical scavengers on the CL intensity were conducted to identify the possible 1O2-participating CL enhancement mechanism. It was demonstrated that the CL enhancement by CTAB-CDs originated from the processes of the catalysis of CDs on the electron-transfer and the breakdown of H2O2. Both processes produced a great amount of 1O2 on the surface of CTAB-CDs, and then the reaction of 1O2 with luminol resulted in an unstable endoperoxide, which could rapidly decompose into the excited state 3-aminophthalate anions (3-APA*), leading to the enhanced CL at 440 nm. The important features of this CDs-catalyzed CL will not only enrich traditional luminol CL mechanism in strongly alkaline conditions but also open up a new route to study this novel carbon nanomaterial, which may broaden the applications in a large variety of fields.

Now and in the future, with the development of artificial biomolecules as well as nanomaterials, targeted drug delivery based on elegant biomolecule–nanomaterial conjugation approaches is being developed to achieve great versatility, additional functions, and further advances.

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