In vivo fluorescence lifetime imaging differentiates the bound versus unbound status of a cell surface receptor targeted ligand.

摘要: In vivo fluorescence lifetime imaging allows for the isolation of probe-specific fluorescence lifetime from surrounding tissue auto-fluorescence. Fluorescence lifetime is not affected by agent concentration or depth, or image acquisition parameters. However, fluorescence lifetime can be affected by the in vivo tissue microenvironment, e.g. pH or hypoxia. In this work, fluorescence lifetime is used to characterize the presence and fate of a high-affinity peptidyl delta opioid receptor (δOR) ligand conjugated to the near-infrared fluorescent IRDye800CW (Li-Cor). HCT116 colorectal cancer cells engineered to over-express the δOR and parental non-expressing HCT116 cells were bilaterally xenografted subcutaneously into the flanks of athymic nude mice. At a series of time-points following tail vein injection of the ligand, in vivo fluorescence images images were acquired using the Optix MX3 scanner (Advanced …