Nanoprobe Based on Novel NIR‐II Quinolinium Cyanine for Multimodal Imaging

Abstract NIR‐II imaging has the advantages of high sensitivity, spatiotemporal resolution, and high penetration depth, thereby serving as a potential alternative to conventional imaging methods. Herein, a novel NIR‐II dye IR‐1010 ( λ ex / λ em = 1010/1058 nm) is reported with high quantum yield (3.08%) and good stability, by incorporating p‐methoxyphenyl groups into a quinolinium cyanine dye. Then a multifunctional nanoprobe, termed IUFP NPs , is developed by the incorporation of upconversion (UC) nanoparticles (NPs), perfluoro‐15‐crown‐5‐ether (PFCE), and IR‐1010, to display the novel performance of multimodal imaging. Under the single‐wavelength excitation (980 nm), IUFP NPs simultaneously emit the NIR‐II fluorescence of IR‐1010 and visible UC luminescence of UCNPs, and thus realize the UC imaging for cells, and NIR‐II fluorescence/photoacoustic/ 19 F magnetic resonance imaging for blood vessels, lymph nodes and tumor in mice. This work affords a novel approach to NIR‐II dyes and a general strategy for the design of multimodal imaging probes.