Molecule self-assembly/disassembly is a common phenomenon in nature and plays an important role in many biological events. By studying the molecule assembly/disassembly, a lot of life-sustaining underlying mechanisms could be realized.

Till now, a variety of techniques have been reported to characterize the morphology and structures of the molecular self-assembly/disassembly. However, these biophysical methods either are destructive to samples or require rigorous sample preparations, and more importantly, they are confined within the static characterization of the structures.

Using a homebuilt liquid-phase Scanning Tunneling Microscopy (L-STM), Dr. LU Qingyou’s group and Dr. WANG Junfeng’s group in High Magnetic Field Laboratory, Chinese Academy of Sciences (CHMFL), joined hands with LIANG Gaolin’ group in department of Chemical Physics, University of Science and Technology of China (USTC) to study the molecular arrangement structure of supramolecular nanofibers under solution conditions.

STM images clearly showed the inner molecular packing details of the nanofiber and the diameter of the nanofiber (2.9 ± 0.1 nm) was consistent with that of cryo transmission electron microscopy.

More importantly, they have directly visualized the phosphokinase-instructed small molecule self-assembly dynamic process and EGFR-instructed disassembly dynamic process.

This is the first time that small molecule assembly/disassembly dynamic process in solution was directly imaged with scanning tunneling microscopy, proving the correctness of small molecule assembly/disassembly mechanism. Besides, the self-healing dynamic process of nanofibers also has been observed for the first time.

This work unprecedentedly sheds new light on nature-mimic self-assembly and disassembly at the molecular level. It also illustrates the potential of homebuilt L-STM in studying delicate biological processes in physiological solution with high resolution.

The findings were published in Nanoscale entitled Using L-STM to directly visualize enzymatic self-assembly/disassembly of nanofibers.

This work was supported by the Chinese national high magnetic field facilities, the National Natural Science Foundation of China and the "Hundred Talent Program" of the Chinese Academy of Sciences.

Cartoon illustration of enzymatic self-assembly/disassembly of nanofibers in aqueous solution. (Image by WANG Jihao) 

L-STM images of EGFR-instructed molecular disassembly of nanofibers.  

(a)Cartoon illustration of enzymatic self-assembly/disassembly of nanofibers in aqueous solution. (b) L-STM images of EGFR-instructed molecular disassembly of nanofibers.(Image by WANG Jihao)