Omcl ac200ts c3

For AFM imaging using an SPM-9700 (Shimadzu, Kyoto, Japan) with a High-Throughput Scanner (Shimadzu, Kyoto, Japan), 0.3 μM DNA was dissolved in 10 mM Tris–HCl buffer (pH 7.5) including 10 μM spermidine or in 0.05% TnT Quick Master Mix (in vitro gene expressions reaction mixture). The DNA solutions were transferred onto a freshly cleaved mica surface and then incubated for 10–30 min at room temperature (24 °C). Subsequently, the samples were rinsed with ultra-pure water, dried with nitrogen gas and imaged by AFM. All measurements were performed in air using the tapping mode. The cantilever, OMCL-AC200TS-C3 (Olympus, Tokyo, Japan), was 200 μm long with a spring constant of 9–20 N/m. The scanning rate was 2 Hz and images were captured using the height mode in a 512 × 512 pixel format. The obtained images were plane-fitted and flattened by the computer program supplied with the imaging module.

For AFM imaging using an SPM-9700 (Shimadzu, Kyoto, Japan), 0.3 µM plasmid DNA was dissolved in Tris-HCl (10 mM) buffer solution (pH 7.5) with various concentrations of polyamines. The DNA solution was incubated for more than 10 min and then transferred onto a freshly cleaved mica surface. After it was allowed to stand for 10 min at room temperature (25 °C), the mica was rinsed with ultra-pure water and dried under nitrogen gas. All measurements were performed in air using the tapping mode. The cantilever (OMCL-AC200TS-C3, Olympus, Tokyo, Japan) was 200 µm long with a spring constant of 9–20 N/m. The scanning rate was 0.4–1.0 Hz and images were captured using the height mode. The obtained images were plane-fitted and flattened by the computer program supplied with the imaging module.

AFM used an SPM-9700 (Shimadzu, Kyoto, Japan) to image and measure 0.6 µM plasmid DNA (4331 bp) or T4 GT7 DNA dissolved in 10 mM Tris-HCl buffer solution at pH 7.5 with various concentrations of DM (0–10 µM) and SP (3.5–60 µM). The DNA solution was incubated for more than 10 min and then transferred onto a freshly cleaved mica surface. Subsequently, the sample was rinsed with ultra-pure water, dried with nitrogen gas and imaged by AFM. All measurements were performed in the air using the tapping mode. The cantilever (OMCL-AC200TS-C3, Olympus, Tokyo, Japan) was 200 µm long with a spring constant of 9–20 N/m. The scanning rate was 0.4 Hz, and images were captured using the height mode in a 512 × 512-pixel format. The obtained images were plane-fitted and flattened by the computer program supplied with the imaging module.