Transmission electron micrographs of (A) TAT/DNA, (B) TAT/DNA-Ca, (C) TAT-PEG/DNA, (D) TAT-PEG/DNA-Ca, (E) 25% TAT-PEG-LABL/DNA, (F) 25% TAT-PEG-LABL/DNA-Ca (G) 50% TAT-PEG-LABL/DNA, and (H) 50% TAT-PEG-LABL/DNA-Ca complexes. Complexes were formed at an N/P ratio of 30 without CaCl2 (left panel) or with 75 mM of CaCl2 (right panel). Scale bars are 500 nm.