(a) IVIS and (b) Odyssey imaging show that, while naked siRNA is primarily cleared through the kidneys, 304O13 mediates accumulation in the liver and spleen. (c) Confocal microscopy of 304O13-treated liver shows siRNA (red) delivery throughout the tissue, including Kupffer cells (magenta) and hepatocytes (nuclei in blue and actin cytoskeleton in green). Three animals were tested per condition for experiments depicted in a–c and the images shown are representative. Scale bar, 50 μm. (d) 304O13 LNPs were rapidly eliminated from the bloodstream after tail vein injection. Error bars represent s.d. (n=3).