• Analysis of the mechanical properties of chromosomes in air and liquid by AFM

      Wang, Bowei; Yang, Fan; Dong, Jianjun; Li, Jiani; Wang, Ying; Qu, Kaige; Wei, Huimiao; Wang, Zuobin; Changchun University of Science and Technology; Changli Nano Biotechnology Ltd; et al. (IEEE, 2021-11-18)
      Chromosomes contain all the genomic information thus making the study of chromosomes practical and significant. Herein, the morphologies of chromosomes prepared with different methods were monitored by atomic force microscopy (AFM). Moreover, the mechanical properties of chromosomes in air and liquid were investigated quantitatively through AFM-based force spectroscopy. The differences of chromosome morphologies and mechanical properties caused by sample preparations indicated that the chromosome characterization in liquid was more meaningful to reveal the physiological characteristics of chromosomes.
    • A dynamic feedback algorithm of AFM based on cell morphology changes

      Cheng, Can; Wang, Xinyue; Dong, Jianjun; Liu, Zimin; Wang, Zuobin; Changchun University of Science and Technology; University of Bedfordshire (IEEE, 2021-11-18)
      The atomic force microscope (AFM) used in biological research as a powerful tool has been for many years. However, the imaging of living cells is still a problem as the sample is too high and too soft to obtain their accurate morphologies. Especially in the high-speed scanning mode, AFM does not have enough judgments to make accurate measurements at the down part of the sample. In this study, we propose an improved control method to improve the image quality of living human colon cancer cells (SW480) especially in the down part during the scanning.
    • Effect of astragalus polysaccharides on cancer cells studied by AFM

      Lu, Zhengcheng; Wang, Zuobin; Li, Dayou; Zhu, Wenyu; Wang, Rui; Qu, Kaige; Yan, Jin; University of Bedfordshire; Changchun University of Science and Technology (IEEE, 2021-11-18)
      As a traditional Chinese medicine, astragalus and its products are used in cancer treatment aiming to reduce the side effects of chemotherapy. Cells are the most basic unit of living organisms, and AFM directly obtains information from living cells on the micro/nano scale. Therefore, the use of AFM to study the interaction between astragalus and cells is conducive to a full range of drug efficacy evaluation and provides a new way for drug development. In this paper, astragalus polysaccharides were extracted from astragalus, which were diluted into solutions of different concentrations. Combined with the MTT experiment, the effects of Astragalus polysaccharide on cancer cells and benign cells were studied by AFM.
    • Effect of SMMC-7721-derived exosomes on hepatocytes studied by AFM

      Ju, Tuoyu; Yang, Fan; Wang, Ying; Song, Zhengxun; Xu, Hongmei; Chen, Yujuan; Wang, Zuobin; Changchun University of Science and Technology; University of Bedfordshire (IEEE, 2021-11-18)
      Exosomes play an important role in the early diagnosis and development of hepatocellular carcinoma (HCC). In the past, researchers mainly studied the contents of exosomes and the biological mechanism on cells, but the changes of mechanical properties of cells caused by exosomes are not clear. In this study, the changes of mechanical properties of hepatocytes (L-02) co-cultured with exosomes (7721-exos) derived from HCC (SMMC-7721) with low metastatic ability were studied. The 7721-exos were able to promote the proliferation and rearrange the cytoskeleton of L-02 cells. The atomic force microscopy measurement results showed that the height was increased, the adhesion and the elastic modulus were reduced. The effect was concentration dependent. The changes of cell mechanical properties induced by exosomes were of great significance for further studying the mechanism of exosomes.
    • Self-assembly of DNA molecules in magnetic fields

      Gao, Mingyan; Hu, Jing; Wang, Jianfei; Liu, Mengnan; Zhu, Xiaona; Saeed, Sadaf; Hu, Cuihua; Song, Zhengxun; Xu, Hongmei; Wang, Zuobin; et al. (IOP Publishing, 2021-11-18)
      In this work, a rich variety of self-assembled DNA patterns were obtained in the magnetic field. Herein, atomic force microscopy (AFM) was utilized to investigate the effects of the concentration of DNA solution, intensity and direction of magnetic field and modification of mica surface by different cations on the self-assembly of DNA molecules. It was found that owning to the change of the DNA concentration, even under the same magnetic field, the DNA self-assembly results were different. The in situ test results showed that the DNA self-assembly in an magnetic field was more likely to occur in liquid phase than in gas phase. In addition, whether in a horizontal or vertical magnetic field, a single stretched dsDNA was obtained in a certain DNA concentration and magnetic field intensity. Besides, the modification of cations on the mica surface significantly increased the force between the DNA molecules and mica surface, and further changed the self-assembly of DNA molecules under the action of magnetic field.