RE nanoparticles for surgical guidance with NIR imaging. (A) Schematic illustration of excretable RE nanoparticle for multifunctional biomedical imaging and ICG in the NIR-II window. (B) SEM images of multimodal probes enabled by red blood cell coated with NIR-II emissive lanthanide nanoparticles. Adapted with permission from 151, Copyright 2019, John Wiley & Sons, Inc. (C, D) NIR II fluorescence bioimaging results (12 h PI) of epidermal tumors with sizes of 7 mm3 (C) and 3 mm3 (D) and NIR II fluorescence bioimaging results after the surgical resection of tumors. Adapted with permission from 152, Copyright 2019, Ivyspring International Publisher.