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.

Surface states of carbon dots (CDs) are critical to the photoemission properties of CDs. By carefully adjusting the reaction conditions in a hydrothermal synthesis route, we have prepared a series of CDs with excitation-dependent emission (EDE) and excitation-independent emission (EIE) properties by controlling the content of nitrogen elements, confirming that the characteristic optical properties of CDs originate from their energy levels. It has been found that surface-passivation of the as-prepared CDs by nitrogen doping can improve the emission efficiency and be beneficial to EIE features due to the single electron transition resulting from the single functional groups. And the as-prepared CDs can specifically bind with Hg(2+) with the emission quenched because of the electron transfer from the LUMO levels of CDs to Hg(2+).