Preparation of DNA Origami Belt and Effect of pH on Its Stability

Abstract The long single-stranded DNA containing multiple copy units prepared by rolling circle amplification technique was used as a scaffold strand. The scaffold strands were hybridized to three short staple strands by molecular self-assembly and produced DNA origami belt. Using the principle of SYBR Green real-time fluorescence quantitative PCR method and atomic force microscopy (AFM) imaging technology, the formation of double-stranded structure was examined by the change of fluorescence signal intensity in the reaction solution while the morphology of DNA belts was observed by AFM intuitively. The effect of pH value on the stability of DNA belt was studied, and its performance of pH-resistant in the wide pH range of 3–11 was obtained. DNA belts exhibited the best stability in neutral pH enviroment (pH = 7), which showed a significantly higher fluorescence signal than that of other groups within 24 h. DNA belts had poor resistance to acid and alkali environment, especially to extreme pH conditions (pH = 3, pH = 11). At extreme pH, even instantaneous treatments (