中文摘要：

原子力显微术（Atomic force microscopy,AFM）的力学成像模式可在高分辨成像的同时，定量测量材料的力学性质。然而，对尺度小、质地薄而软的生物分子的弹性模量的测量仍然是一个挑战。本文以脱氧核糖核酸（Deoxyribonucleic acid，DNA）折纸为检测样品，将峰值力定量纳米力学模式（Peak Force Quantitative Nanomechanical Mapping，PF—QNM）作为测量手段研究了DNA分子的力学性质，探索不同作用力对DNA折纸弹性模量的影响。结果表明，当峰值力控制在80—100pN时，峰值力成像稳定，获得的杨氏模量维持在约10MPa。与传统力曲线阵列模式（Force volume mapping，FV）＊N比较，在小力区（〈100pN），两种方法符合性较好。这种峰值力定量纳米力学模式为DNA分子定量力学性质研究提供了一种简便而有效的研究方法。

英文摘要：

Background： The mechanical mapping mode of atomic force microscopy （AFM） enables to measure mechanical properties of materials while imaging with high-resolution. However, to measure the elastic Young＇s modulus of biomolecules is still a challenge because they are so small, soft and thin. Purpose： This study aims to explore the compression elasticity of DNA origami and the different forces on the effect of Young＇s measurement on the deoxyribonucleic acid （DNA） origami sample. Methods： The peak force imaging mode （Peak Force Quantitative Nanomechanical Mapping, PF-QNM） was used to measure the Young＇s modulus of DNA origami under various activing forces. Results： It was found that by using of 80-100pN peak forces, the elastic Young＇s modulus measurement results were relatively stable, keeping about 10 MPa for the peak force measurement on DNA origami. Compared with the traditional force volume contract mode （Force volume mapping, FV）, the values obtained consisted well with that of FV when the force were limited below 100 pN. Conclusion： This method provided a simple and effective way for quantitative measuring the elasticity of DNA molecules.