4.2.2 Characterization.
Agarose gel electrophoresis. A 1% (w/v) agarose gel was prepared with EtBr. A total of 5 μL prepared Td mixed with loading buffer was loaded and run at 95 V for 35 min. To identify the Td with ASOs, a 2% (w/v) agarose gel was used.
AFM imaging. All samples were diluted to 2.5 nM in TM buffer (12.5 mM Tris, 5 mM MgCl2). Then, 10 μL of Td was dropped onto freshly cleaved mica and incubated for 5 min to allow strong absorption onto the surface. Then, the mica was rinsed using filtered deionized water and gently dried with compressed nitrogen. Next, the samples were scanned in tapping mode on an Agilent 5500 SPM.
Dynamic light scattering. A 2 μM solution of Td was prepared based on the above-mentioned protocols and then diluted to 0.2 μM with ultrapure water. After passing through a 0.22 μm filter, samples were analyzed by a Malvern Zetasizer Nano ZS to measure the hydrodynamic size and size distribution.
TEM. LP-Td was dropped on a grid and incubated for 4 min, then remaining solution was absorbed by filter paper. The TEM images were obtained by JEM-2100Plus with 80 kV.