Blood sample collection was performed at multiple timepoints post-electrotransfer, as indicated in the figures. Blood was processed to serum and stored at −20 °C for further analysis.
For the PNA studies in mice, TA sites were injected with 20 μL of PNA-labeled pDNA at 0.333 mg/mL, immediately after which the animals were euthanized and the target tissue was excised. Extracted tissues were fixed in 10% paraformaldehyde (HT501128-4L, Sigma-Aldrich, St. Louis, MO, USA) for approximately 72 h, after which they were rinsed with 1x PBS (BM-220, Boston Bioproducts, Milford, MA, USA) and securely stored in 1x PBS in light-resistant containers.
For processing, each sample was placed in a potting mold. A 4% w/v Agarose II (A9918-100G, Sigma-Aldrich, St. Louis, MO, USA) gel was evenly poured over each sample and allowed to set at room temperature for an hour. Agarose blocks were sliced into 0.5–1.0 mm sections and then stored in 1x PBS. Sections were further processed by HistoWiz (Queens, NY, USA) for embedding, sectioning, staining, and imaging. Briefly, samples were paraffin wax-embedded, sectioned to 4 μm, mounted on slides, counterstained with DAPI, and subjected to imaging.
For the PNA studies in mice, TA sites were injected with 20 μL of PNA-labeled pDNA at 0.333 mg/mL, immediately after which the animals were euthanized and the target tissue was excised. Extracted tissues were fixed in 10% paraformaldehyde (HT501128-4L, Sigma-Aldrich, St. Louis, MO, USA) for approximately 72 h, after which they were rinsed with 1x PBS (BM-220, Boston Bioproducts, Milford, MA, USA) and securely stored in 1x PBS in light-resistant containers.
For processing, each sample was placed in a potting mold. A 4% w/v Agarose II (A9918-100G, Sigma-Aldrich, St. Louis, MO, USA) gel was evenly poured over each sample and allowed to set at room temperature for an hour. Agarose blocks were sliced into 0.5–1.0 mm sections and then stored in 1x PBS. Sections were further processed by HistoWiz (Queens, NY, USA) for embedding, sectioning, staining, and imaging. Briefly, samples were paraffin wax-embedded, sectioned to 4 μm, mounted on slides, counterstained with DAPI, and subjected to imaging.