Chem. J. Chinese Universities ›› 2026, Vol. 47 ›› Issue (9): 20260103.doi: 10.7503/cjcu20260103

• Articles: Inorganic Chemistry • Previous Articles     Next Articles

Visualized Measurement of Self-assembly Efficiency in One-dimensional DNA Nanomaterials

LIU Yuqing1,2,3, CHENG Jie1,2,3, WANG Yue4, JIAO Kai3, ZHU Ying3, LI Jiang3, GUO Linjie3()   

  1. 1.Division of Frontier Applications of Synchrotron Radiation,Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China
    2.University of Chinese Academy of Sciences,Beijing 100049,China
    3.Institute of Materiobiology,College of Sciences,Shanghai University,Shanghai 200444,China
    4.School of Chemistry and Chemical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China
  • Received:2026-03-13 Online:2026-09-10 Published:2026-04-22
  • Contact: GUO Linjie E-mail:guolinjie@shu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22325406, 22525605, 32301185);the National Key Research and Development Program of China(2023YFB3208200)

Abstract:

One-dimensional(1D) DNA nanomaterials exhibit broad potential for applications across multiple fields. However, quantitative evaluation of their self-assembly efficiency remains challenging. In this work, six-helix bundle(6HB) DNA fibers were employed as a model system. Building upon existing image analysis methods, we developed an integrated and parameterized approach to overcome the challenges of single-particle identification and counting in high-aspect-ratio, entangled 1D fibers, and established an AFM image-based method for visualizing and quantifying self-assembly efficiency. In this method, the area coverage ratio and contour length density extracted from AFM images were used as quantitative parameters to characterize 1D DNA fiber networks. Using this method, the effects of buffer pH(5—11) and Mg²⁺ concentration(6.25—87.5 mmol/L) on the assembly behavior of 6HB DNA fibers were investigated. The results show that efficient assembly of 6HB DNA fibers occurs within a well-defined window of conditions. Continuous long fibers are preferentially formed in the pH range of 6—8, with the highest assembly efficiency at pH=8, where the area coverage ratio reaches ca. 36%, and the contour length density is ca. 8 μm/μm². When the pH value deviates from this range, the continuous 1D network gradually transforms into fragmented or disordered aggregates, and both parameters decrease to background levels. Fiber assembly also shows a clear threshold response to Mg²⁺ concentration: the assembly efficiency increases rapidly above 25 mmol/L, and stable long fibers form at concentrations above 50 mmol/L, corresponding to area coverage ratios >20% and contour length densities >4 μm/μm². These results quantitatively demonstrate the strong dependence of DNA nanostructure self-assembly on environmental conditions such as pH and ionic strength. The analytical framework established here provides a useful quantitative tool for the design, assembly, and application of 1D DNA nanomaterials.

Key words: Six-helix bundle DNA fibers, AFM image analysis, Self-assembly efficiency

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