Abstract 4305: Biodistribution and clearance of non-targeted DyLight dyes in tumor-free nude mice for in vivo imaging

Abstract

Abstract Far red to near infra red (NIR) fluorophores are commonly used in cell-based assays and for deep tissue in vivo imaging. The light emitting and physico-chemical characteristics of these fluorophores, e.g. excitation and emission spectra, relative hydrophilicity/hydrophobicity and molecule size, can significantly influence their performance in these applications. Currently there are no guidelines for selection of fluorophores optimal for targeted in vivo imaging. To address this issue we have designed a panel of DyLight dyes with maximum excitation wavelength in the range of 650 -785 nm, maximum emission wavelength in the range of 670 - 800 nm and different levels of sulfonation and/or PEGylation. We studied the kinetic of tissue distribution and clearance of these fluorophores as well as their effect on morphology of different tissues in mice after intravenous injection. Briefly, nude mice were anesthetized, injected with a dye (100 µL of dye at 0.5mg/ml in PBS) into retro-orbital plexus, and imaged using Carestream MSFX or Carestream XTREME Imager. Images were generated before dye injection, immediately after injection (0 hours) and 3, 6, 12 and 24 hours post injection. At the end of the experiment, animals were sacrificed; internal organs were collected and used for ex vivo analysis. The results of in vivo imaging experiments demonstrated that: hydrophobic fluorophores have a relatively slow kinetic of distribution and clearance, and often cleared via a hepatic pathway. Introduction of the negatively charged groups and or PEG chains increased dye solubility affected the kinetics of both fluorophore distribution and its clearance. In addition, negatively charged fluorophores had a tendency to be cleared predominantly via renal pathway. A histological analysis of the internal organs showed no detectable tissue damage. These results provide guidelines for the selection of optimal NIR dyes for in vivo imaging. Citation Format: Marie C. NLEND, Surbhi Desai, Suk J. Hong, Mary Beth Anderson, Georgyi V. Los, Greg T. Hermanson, Justin M. Diener, Warren M. Leevy, Peter A. Bell. Biodistribution and clearance of non-targeted DyLight dyes in tumor-free nude mice for in vivo imaging. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4305. doi:10.1158/1538-7445.AM2014-4305