Spm 9700

The measurements of mean diameter and particle size distribution were performed by dynamic light scattering in a ZetaPlus (Brookhaven Instruments Co., Holtsville, NY, USA), equipped with a 90Plus/BI-MAS apparatus, at a wavelength of 659 nm with a scattering angle of 90°. The zeta potential of the particles was measured by laser Doppler anemometry using the same equipment. All analyses were performed at 25 °C. Experimental values are given as the mean ± SD for the experiments carried out in triplicate for each sample.
The shape and topographical images of the samples were observed on atomic force microscopy (AFM) images (SPM-9700, Shimadzu, Tokyo, Japan) using a silicon tip probe (Nanoworld, Neuchatel, Switzerland,). The dispersions were freshly diluted with purified water at a ratio of 1:25 (v/v), dropped on a cover slip, dried under a desiccator for 24 h, and then analyzed using an AFM (SPM-9700, Shimadzu, Tokyo, Japan) at room temperature by scanning with a cantilever (non-contact) at 1 Hz.
The physical stability study was performed with cationic nanoparticles with or without BJ venom. Analysis was performed for 45 days, evaluating the mean size, zeta potential and polydispersity index. The particles were stored in a freezer at 5 °C ± 2 °C; before analysis, the samples were stabilized at 25 °C ± 2 °C.

AFM images of the enamel surface after 14 days of pH cycling were captured with an Atomic Force Microscopy (SPM9700; Shimadzu, Kyoto, Japan), which was equipped with an AFM silicon probe (Shimadzu, Kyoto, Japan) and a laser scanner (30 μm × 30 μm × 5 μm). The scanning size rate was 10 µm × 10 µm and 1 Hz, respectively. For each sample, five different fields were randomly selected, and the surface roughness (Ra) of each field was analyzed by the Shimadzu SPM-9700 software (Shimadzu, Kyoto, Japan). Then the average surface roughness of each sample and each group was calculated.

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.