摘要
研究了不同pH环境对2种使用M13链作为骨架链的常见DNA折纸折叠与稳定性的影响,获得了其在pH=4~11这一广泛范围内的耐受性数据.首先观察了在不同pH缓冲液中的三角形DNA折纸自组装折叠行为,发现其合适pH范围为6~9,过高或过低的pH都不能退火形成折纸结构.另一方面,又研究了在标准pH缓冲液中预先制备的DNA折纸,对不同pH环境的耐受性.研究发现,在pH值为5~10的溶液环境中,DNA折纸均保持一定稳定.比较以上2种研究方法获得的结果,可以发现,相比在不同pH缓冲液中从头退火制备,已形成的DNA折纸对酸碱有较好耐受性.另外,研究也发现,长方形折纸和三角形折纸稳定性相似,都能在pH=5~10的环境中保持至少12 h的稳定性.据此,还提出了pH对折纸稳定性的可能影响机理,认为其对氢键的破坏及对DNA链造成的断裂共同导致了DNA折纸结构的破碎.
The response of DNA origami nanostructures to pH is systematically investigated from two aspects in this work. At first, self-assembly of DNA origami triangle in different pH buffer was tested by putting M13 scaffold and staple strands into a series of sodium citrate buffer （10 mmol/L with 12.5 mmol/L Mg^2＋）, the as-prepared sample was characterized by AFM. The formation of the origami structure was affected by pH and the structure was observed only in the pH range of 6 - 9. Tolerance of DNA origami to pH in the external environment was investigated by immersing them （pH = 8） into acidic and basic solutions for 2 h at room temperature, followed by characterization of the samples by AFM and 0.5% agarose gel respectively. The AFM results showed that the DNA origami triangle maintained the original structure at pH range of 5 - 10, and the structure was broken at higher or lower pH. The agarose gel suggested that the most stable state of DNA origami triangle was in pH range of 7 - 8, where the intensity and mobility of the sample band remained the same. Compared with the origami self-assembled in different pH buffers, the pre-prepared origami showed better resistance to acidic and alkali environments. In order to test the long time-stability of DNA origami, pH value of the prepared triangle origami was adjusted in the range of 5 - 10 and the reaction time was extended to 12 h. AFM test results indicated that the DNA origami could maintain its original structure for at least 12 h. Another common origami nanostructure was also tested; like origami triangle, rectangle structure showed a similar pH tolerance which could keep the stability at pH range of 5 - 10 for at least 12 h. The long time pH stability experiment of the triangle and the rectangle structures indicated that the origami structure based on M13 owned a relatively high pH tolerance. Based on the above results, possible mechanism of pH effect on DNA origami stability was also proposed. In the process of the origami preparation, excess H^＋ or OH-
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2017年第12期1993-2000,共8页
Acta Polymerica Sinica
基金
国家重点基础研究发展计划(973计划
项目号2013CB932803)
国家自然科学基金(基金号21473236
31371015)
中国科学院青年创新促进会资助项目
