• Dynamic mechanics of HK-2 cell reaction to HG stimulation studied by atomic force microscopy

      Yang, Fan; Wang, Jiajia; Qu, Kaige; Yang, Xue; Liu, Chuanzhi; Wang, Ying; Song, Zhengxun; Xu, Hongmei; Chen, Yujuan; Wang, Zuobin; et al. (Royal Society of Chemistry, 2020-10-02)
      Renal tubular cell injury by exposure to high glucose (HG) stimulation mainly accounts for diabetic nephropathy (DN). To understand the mechanism of injury by HG, quantitative characterization has commonly focused on the cells that are already impaired, which ignores the signals for the process of being injured. In this study, the architecture and morphology of HK-2 cells were observed dynamically by multiple imaging methods. AFM (atomic force microscopy)-based single-cell force spectroscopy was employed to investigate the dynamic mechanics quantitatively. The results showed that the Young's modulus increased continuously from 2.44 kPa up to 4.15 kPa for the whole period of injury by HG, while the surface adhesion decreased from 2.43 nN to 1.63 nN between 12 h and 72 h. In addition, the actin filaments of HK-2 cells exposed to HG depolymerized and then nucleated with increasing Young's modulus. The absence of cell pseudopodia coincided with the reduced cell adhesion, strongly suggesting close relationships between the cell architecture, morphology and mechanical properties. Furthermore, the stages of cell reactions were identified and assessed. Overall, the dynamic mechanics of the cells facilitate the identification of injured cells and the assessment of the degree of injury for accurate diagnoses and treatments.
    • Evaluations of 5-fluorourcil treated lung cancer cells by atomic force microscopy

      Jiang, Xiaolin; Ma, Ke; Hu, Cuihua; Gao, Mingyan; Zhang, Jiashuo; Wang, Ying; Chen, Yujuan; Song, Zhengxun; Wang, Zuobin; Changchun University of Science and Technology; et al. (The Royal Society of Chemistry, 2019-09-06)
      Atomic force microscopy (AFM) can be used to obtain the physical information of single live cancer cells; however, the physical changes in live cells with time based on AFM remain to be studied, which play a key role in the evaluation of the efficacy and side effects of drugs. Herein, the treatment of the A549 cell line with the anticarcinogen 5-fluorouracil has been discussed based on the AFM analysis of their continuous physical changes, including their surface morphology, height, adhesion and Young's modulus, with time. In comparison, the African green monkey kidney (Vero) cell line was tested as normal cells to determine the side effects of 5-fluorouracil. The results show that the optimal concentration of 5-fluorouracil is about 500 μM, which presents the best anticancer effect and mild side effects.
    • The influence of different liquid environments on the atomic force microscopy detection of living bEnd.3 cells

      Jin, Yan; Sun, Baishun; Xie, Chenchen; Liu, Yan; Song, Zhengxun; Xu, Hongmei; Wang, Zuobin; Changchun University of Science and Technology; University of Bedfordshire (Royal Society of Chemistry, 2021-05-10)
      Atomic force microscopy (AFM) is one of the most important tools in the field of biomedical science, and it can be used to perform the high-resolution three-dimensional imaging of samples in liquid environments to obtain their physical properties (such as surface potentials and mechanical properties). The influence of the liquid environment on the image quality of the sample and the detection results cannot be ignored. In this work, quantitative imaging (QI) mode AFM imaging and mechanical detection were performed on mouse brain microvascular endothelial (bEnd.3) cells in different liquid environments. The gray-level variance product (SMD2) function was used to evaluate the imaging quality of the cells in liquids with different physical properties, and the variations in cell mechanical properties were quantitatively analyzed. An AFM detection liquid containing less ions and organics compared with the traditional culture medium, which is beneficial for improving the imaging quality, is introduced, and it shows similar mechanical detection results within 3 h. This can greatly reduce the detection costs and could have positive significance in the field of AFM living-cell detection.
    • Study of NSCLC cell migration promoted by NSCLC-derived extracellular vesicle using atomic force microscopy

      Wang, Shuwei; Wang, Jiajia; Ju, Tuoyu; Yang, Fan; Qu, Kaige; Liu, Wei; Wang, Zuobin; Jilin University; Changchun University of Science and Technology; University of Bedfordshire (Royal Society of Chemistry, 2021-02-16)
      Extracellular vesicles (EVs) secreted by cancer cells play a key role in the cancer microenvironment and progression. Previous studies have mainly focused on molecular functions, cellular components and biological processes using chemical and biological methods. However, whether the mechanical properties of cancer cells change due to EVs remains poorly understood. This work studies the effects of mechanical changes in non-small cell lung cancer (NSCLC) cells after treatment with EVs on migration by atomic force microscopy (AFM). Different concentrations of EVs were added into the experimental groups based on co-culture experiments, while the control group was cultured without EVs for 48 h. Cellular migration was evaluated by wound healing experiments. The cellular morphology, cell stiffness and surface adhesion were investigated by AFM. Cytoskeleton changes were detected by fluorescence staining assay. By comparison to the control group, the cell migration was enhanced. After treatment with EVs, the cell length and height show an upward trend, and the adhesion force and Young's modulus show a downward trend, and filopodia were also detected in the cells. Overall, the EVs promoted the migration of NSCLC cells by regulating cells' physical properties and skeletal rearrangement.
    • A study on the effects of tumor-derived exosomes on hepatoma cells and hepatocytes by atomic force microscopy

      Ju, Tuoyu; Wang, Shuwei; Wang, Jiajia; Yang, Fan; Song, Zhengxun; Xu, Hongmei; Chen, Yujuan; Zhang, Jingran; Wang, Zuobin; Changchun University of Science and Technology; et al. (Royal Society of Chemistry, 2020-12-07)
      Tumor-derived exosomes (exos) are closely related to the occurrence, development and treatment of tumors. However, it is not clear how the exosomes affect the physical properties, which lead to the deterioration of the target cells. In this paper, atomic force microscopy (AFM) was used to study the effects of exosomes in HCC-LM3 cells and other cells (SMMC-7721 and HL-7702). The results showed that the HCC-LM3-exos (the exosomes secreted by HCC-LM3 cells, 50 μg mL-1) significantly promoted the proliferation and migration of HCC-LM3 cells. HCC-LM3-exos also promoted the proliferation and migration of SMMC-7721 and HL-7702 cells at 1000 and 1500 μg mL-1, respectively. With an increase in time and concentration, the proliferation effect was more significant. On comparing the mechanical properties of the three types of cells (HCC-LM3, SMMC-7721 and HL-7702 cells), the degradation degree and migration ability of the cells were from high to low in the above order. In turn, the surface roughness of the cells decreased, and adhesion and elastic modulus increased. With an increase in treatment time, surface roughness increased, while adhesion and elastic modulus decreased. These suggested that the HCC-LM3-exos could change the mechanical properties of cells, leading to their deterioration, and enhance their migration and invasion ability. In this paper, the effects of exosomes were analyzed from the perspective of the physical parameters of cells, which provide a new idea to study cancer metastasis and prognosis.