Fig. 5.
In vivo delivery and bioactivity of tethered IGF-1. (A) Quantitative delivery of human IGF-1 to the myocardium of rats after 5 min and 7, 14, 28, and 84 days. Twenty-five nanograms of free nonbiotinylated IGF-1 (negative control), biotinylated IGF-1 bound to streptavidin in nonbiotinylated peptides (untethered b-IGF-1; negative control), or tethered b-IGF-1 with streptavidin coupled to biotinylated self-assembling peptides was injected into the myocardium of rats (n ≥ 4 for each group per time point). (B) Immunohistochemistry showing phospho-Akt-specific staining in untethered b-IGF-1 (Left) and tethered b-IGF-1 (Right) samples. Arrows denote areas staining positive for phospho-Akt (brown staining). (Scale bars: 20 μm.)