High‐Fidelity NIR‐II Multiplexed Lifetime Bioimaging with Bright Double Interfaced Lanthanide Nanoparticles

Abstract Fluorescence lifetime imaging provides more possibility of in vivo multiplexing in second near infrared (NIR‐II) window. However, it still faces the obstacle that fluorescent probes with differentiable lifetime often exhibit quite different fluorescence intensity, especially the short lifetime usually accompanies with a weak fluorescence intensity, resulting in the difficulty for simultaneously decoding multiplexed lifetime information due to the interference of background noise. To facilitate high‐fidelity lifetime multiplexed imaging, we developed a series of Er 3+ doped double interface fluorescent nanoprobes (Er‐DINPs): α‐NaYF 4 @NaErF 4 : Ce@NaYbF 4 @NaErF 4 : Ce@NaYF 4 with strong fluorescence intensity and easily distinguishable fluorescence lifetime. Both in vitro and in vivo experimental results confirmed the advantage of these probes with comparable fluorescence intensity for high‐fidelity multiplexed lifetime bioimaging.