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Osteoblasts are the functional cells capable of bone formation in the bone microenvironment and play an important role in bone growth, development, and the maintenance of bone mass. The cells cultured in vitro are derived from preosteoblasts in tissues and possess the ability to divide and proliferate. Osteoblasts form the bone matrix by secreting collagen and other matrix proteins, which provides a foundation for the deposition of minerals such as calcium and phosphorus, ultimately resulting in the formation of hard bone tissue. Bone diseases affect the quality of life and the aging of the population. Bone diseases such as osteoporosis, fractures, bone tumours, and arthritis have a significant impact on quality of life, especially among the elderly population. These realities remind us that we should pay more attention to bone and joint health. Therefore, it is particularly important to study the imaging and characterisation of mechanical properties of bone cells, which provides a basis for the research of bone diseases in human beings. [ABSTRACT FROM AUTHOR]

Chromosomal instability (CIN) is a source of genetic variation and is highly linked to the malignance of cancer. Determining the degree of CIN is necessary for understanding the role that it plays in tumor development. There is currently a lack of research on high-resolution characterization of CIN and the relationship between CIN and cell mechanics. Here, a method to determine CIN of breast cancer cells by high resolution imaging with atomic force microscopy (AFM) is explored. The numerical and structural changes of chromosomes in human breast cells (MCF-10A), moderately malignant breast cells (MCF-7) and highly malignant breast cells (MDA-MB-231) were observed and analyzed by AFM. Meanwhile, the nuclei, cytoskeleton and cell mechanics of the three kinds of cells were also investigated. The results showed the differences in CIN between the benign and cancer cells. Also, the degree of structural CIN increased with enhanced malignancy of cancer cells. This was also demonstrated by calculating the probability of micronucleus formation in these three kinds of cells. Meanwhile, we found that the area of the nucleus was related to the number of chromosomes in the nucleus. In addition, reduced or even aggregated actin fibers led to decreased elasticities in MCF-7 and MDA-MB-231 cells. It was found that the rearrangement of actin fibers would affect the nucleus, and then lead to wrong mitosis and CIN. Using AFM to detect chromosomal changes in cells with different malignancy degrees provides a new detection method for the study of cell carcinogenesis with a perspective for targeted therapy of cancer. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cells adherence provides specific information about physiology and pathology, the adhesion measurement between living cells and nanostructures can be measured by atomic force microscopy, but this detection technique is difficult to operate and costly. The adhesion height and effective contact area between cells and substrates are also the key factors affecting measurement value of the overall impedance. These factors change with structural parameters of the substrates, so the adhesion measurement between living cells and substrate can be indirectly reflected by the impedance value. OBJECTIVE: To establish a mapping relationship between the impedance measurement and the adhesion measurement of living cells. The possibility of dynamic measurement of adhesion is realized by this method, and the experimental process is simplified. METHODS: Laser interference technology was used to prepare nanoarray structures with different periods on the surface of silicon wafers for cells culture. Under the same experimental conditions, the impedance of living cells on the substrates of different cycle sizes were measured. The adhesion between cells and different substrates were analyzed by measuring impedance after the interaction between cells and substrate. RESULTS: The adhesion of living cells on the substrates of different sizes be analyzed, and the mapping relationship between the impedance and the adhesion measurement was established. The results showed that, the larger the impedance value between cells and substrate, the larger the effective contact area and the smaller the gap between them. CONCLUSION: The difference of adhesion height and effective adhesion area between living cells and substrates were obtained. This paper, a new method to measure the adhesion properties of living cells is presented, which provides theoretical basis for the related research. [ABSTRACT FROM AUTHOR]

Transdermal administration of chemo therapeutics into burn healing may be an effective treatment to reduce toxic side effects and improve patient compliance for burns. As a transdermal delivery system, Camelina lipid droplets (CLDs) have received great attention due to their biocompatibility, high drug payload, and rapid absorption. However, the absorbed-related mechanisms of Camelina lipid droplets have not yet been reported. Thus, this paper not only demonstrated that CLD can accelerate skin burn healing through promoting hFGF2 absorption, but also elucidated the mechanism between the skin tissue and keratinocytes using Franz, HE staining, DSC, FTIR spectroscopy, and atomic force microscopy with the presence of CLD-hFGF2 freeze-dried powder. We found that the cumulative release rate of CLD-hFGF2 freeze-dried powder was significantly higher than that of free hFGF2 freeze-dried powder into the skin. At the same time, CLD can change the structure and content of lipids and keratin to increase the permeability of hFGF2 freeze-dried powder in skin tissue. Unlike the free state of hFGF2, the biophysical properties of single cells, including height and adhesion force, were changed under CLD-hFGF2 freeze-dried powder treatment. Meanwhile, CLD-hFGF2 freeze-dried powder was more easily taken up through keratinocytes without damaging cell integrity, which provided a new viewpoint for understanding the absorption mechanism with the CLD system for cellular physiology characteristics. Overall, our findings demonstrated that CLD could break through the stratum corneum (SC) barrier and elucidated the transport mechanism of lipid droplets in skin tissue, which provides a crucial guideline in drug delivery applications for future engineering. [ABSTRACT FROM AUTHOR]

Many diseases are related to changes in the biomechanical properties of cells; their study can provide a theoretical basis for drug screening and can explain the internal working of living cells. In this study, the biomechanical properties of nephrocytes (VERO cells), hepatocytes (HL‐7702 cells), and hepatoma cells (SMCC‐7721 cells) in culture were detected by atomic force microscopy (AFM) to analyse the side effects of colchicine at different concentrations (0.1 μg/mL (A) and 0.2 μg/mL (B)) at the nanoscale for 2, 4 and 6 h. Compared with the corresponding control cells, the damage to the treated cells increased in a dose‐dependent manner. Among normal cells, the injury of nephrocytes (VERO cells) was markedly worse than that of hepatocytes (HL‐7702 cells) in both colchicine solutions A and B. Based on the analyses of biomechanical properties, the colchicine solution reduced the rate of division and inhibited metastasis of SMCC‐7721 cells. By comparing these two concentrations, we found that the anticancer effect of colchicine solution A was greater than that of solution B. Studying the mechanical properties of biological cells can help understand the mechanism of drug action at the molecular level and provide a theoretical basis for preventing the emergence and diagnosis of diseases at the nanoscale. LAY DESCRIPTION: In this study, the biomechanical properties of nephrocytes (VERO cells), hepatocytes (HL‐7702 cells), and hepatoma cells (SMCC‐7721 cells) in culture were detected by atomic force microscopy (AFM) to analyse the side effects of colchicine at different concentrations (0.1 μg/mL (A) and 0.2 μg/mL (B)) at the nanoscale for 2, 4 and 6 h. Where A is the concentration in the instruction manual. Compared with the two different concentrations of colchicine solution, it was found that both concentrations cause damage to nephrocytes (VERO cells), and the damage to the treated cells increased in a dose‐dependent manner within 6 h. Low concentrations had nearly no effect on hepatocytes (HL‐7702 cells), but there is also damage when the concentration raises. In other words, for hepatocytes, it may have an impact only when the concentration of colchicine exceeds the dosage specified in the instructions. For hepatocellular carcinoma cells, the anticancer effect of colchicine at a concentration close to the specification is more marked. Studying the mechanical properties of biological cells can help understand the mechanism of drug action at the molecular level and provide a theoretical basis for preventing the emergence and diagnosis of diseases at the nanoscale. [ABSTRACT FROM AUTHOR]

Alcoholic liver disease is an important cause of death worldwide. Hepatocyte apoptosis is commonly observed in alcoholic liver disease. In this study, we investigated the effect of ginsenoside Rg1 (G‐Rg1), an organic component of ginseng, on the alcohol‐induced morphological and biophysical properties of hepatocytes. Human hepatocytes (HL‐7702) were treated in vitro with alcohol and G‐Rg1. The cell morphology was observed using scanning electron microscopy. Cell height, roughness, adhesion, and elastic modulus were detected using atomic force microscopy. We found that alcohol significantly induced hepatocyte apoptosis, whereas G‐Rg1 attenuated the alcohol‐induced hepatocyte damage. Scanning electron microscopy revealed that alcohol‐induced significant morphological changes in hepatocytes, including decreased cell contraction, roundness, and pseudopods, whereas G‐Rg1 inhibited these negative changes. Atomic force microscopy revealed that alcohol increased the cell height and decreased the adhesion and elastic modulus of hepatocytes. Following treatment with G‐Rg1, the cell height, adhesion, and elastic modulus of alcohol‐injured hepatocytes were all similar to those of normal cells. Thus, G‐Rg1 can attenuate the alcohol‐induced damage to hepatocytes by modulating the morphology and biomechanics of the cells. Research Highlights: In this study, the morphological characteristics of hepatocytes were observed using SEM.The changes in hepatocyte three‐dimensional images and biomechanical action caused by alcohol and G‐Rg1 were examined at the nanoscale using AFM under near‐physiological conditions.Alcohol‐induced hepatocytes showed abnormal morphology and biophysical properties. G‐Rg1 attenuated the alcohol‐induced damage to hepatocytes by modulating the morphology and biomechanics of the cells. [ABSTRACT FROM AUTHOR]

A cardiomyocyte is the basic structural and functional unit of the heart, which is the actual executor of the systolic function. The study of the contraction and relaxation characteristics of cardiomyocyte is of great significance to the physiological behavior and pathology of the heart. How to dynamically express its contraction and relaxation behaviors in 3D has become a challenging issue. Although the video analysis method under the optical microscope can observe the changes in the horizontal direction, it is difficult to describe the changes in the vertical direction. The atomic force microscope (AFM) can accurately express the mechanical and morphological characteristics of the changes in the vertical direction, but it cannot be fully expressed in real time because it is acquired by scanning with a single probe. In order to express the contraction and relaxation characteristics of cardiomyocyte accurately and three dimensionally, a dynamic imaging method in this study is proposed using the periodicity of AFM acquisition and the periodicity of cardiomyocyte contraction. Compared with the optical experiment, it is proven that this method can dynamically represent the contraction and relaxation processes of cardiomyocyte and solve the problem of how to express it in 3D. It brings a new way for the study of physiological characteristics of cardiomyocytes and dynamic imaging by AFM. [ABSTRACT FROM AUTHOR]

Cell viability detection plays a crucial role in apoptosis and anticancer drug research. Compared with conventional colorimetric assays and organic fluorescent probe-based imaging, it is greatly desired to develop a simple and facile fluorescent probe for in situ real-time detection of cell viability. Herein, MoS2 nanoflakes are employed as fluorescent probes for detecting cancer cell viability by using their inherent tunable photoluminescence (PL) properties by ion intercalation. The appropriate amount of MoS2 nanoflakes for A549 lung cancer cells was firstly determined by MTT assay. After MoS2 nanoflakes successfully covered cells, the effects of the nanoflakes on cell morphology and mechanical properties were studied by atomic force microscopy (AFM). Then, the modulation of PL by potassium ions (K+) from cells was investigated at different cell viabilities. The results showed that PL intensity increased as cell viability decreased. Finally, the nanoflakes were further used as fluorescent probes to assess the cell viability change induced by anticancer drugs. The results showed that with the increase of drug concentration, the fluorescence intensity increased, indicating a decrease in cell viability. The ion-modulated PL of MoS2 nanoflakes makes MoS2 a promising candidate for applications in anticancer drug screening. [ABSTRACT FROM AUTHOR]

The phase image of tapping‐mode atomic force microscopy (TM‐AFM) contains energy dissipation, which is related to the sample information on the physical properties such as the sample Young's modulus, adhesion, surface morphology and subsurface morphology. When TM‐AFM is used for sample measurement, the frequency near the first resonance peak of probe is usually selected to drive the probe vibration. When the probe vibration is driven by the frequency, the probe has a high amplitude sensitivity, but the phase sensitivity is relatively low. In this paper, the frequency at the probe phase resonance peak was selected for driving the probe vibration to measure the sample, which improved the image resolution. Phase imaging was performed on three uniform photoresist samples with different thicknesses and the same structure. When the scanning parameters were fixed and the probe setpoint value was changed alone, it was found that with the decrease of setpoint value the horizontal resolution of the phase subsurface image was decreased, and the depth sensitivity was increased first and then decreased. The result shows that TM‐AFM working at the phase resonance peak can better realise the subsurface imaging of samples at different depths. Phase subsurface imaging at the resonance can be used to quantitatively obtain subsurface phase images of different depths. [ABSTRACT FROM AUTHOR]

The physical properties of tumor-derived exosomes have gained much attention because they are helpful to better understand the exosomes in biomedicine. In this study, the conductive atomic force microscopy (C-AFM) was employed to perform the electrical characterizations of exosomes, and it obtained the topography and current images of samples simultaneously. The exosomes were absorbed onto the mica substrates coated with a gold film of 20 nm thick for obtaining the current images of samples by C-AFM in air. The results showed that the single exosomes had the weak conductivity. Furthermore, the currents on exosomes were measured at different bias voltages and pH conditions. It illustrated that the conductivity of exosomes was affected by external factors such as bias voltages and solutions with different pH values. In addition, the electrical responses of low and high metastatic potential cell-derived exosomes were also compared under different voltages and pH conditions. This work is important for better understanding the physical properties of tumor-derived exosomes and promoting the clinical applications of tumor-derived exosomes. [ABSTRACT FROM AUTHOR]

Cancer is now responsible for the major leading cause of death worldwide. It is noteworthy that lung cancer has been recognised as the highest incidence (11.6%) and mortality (18.4%) for combined sexes among a variety of cancer diseases. Therefore, it is of great value to investigate the mechanical properties of lung cancerous cells for early diagnosis. This paper focus on the influence of measurement parameters on the measured central Young's moduli of single live A549 cell in vitro based on the force spectroscopy mode of atomic force microscopy (AFM). The effects of the measurement parameters on the measured central Young's moduli were analysed by fitting the force–depth curves utilising the Sneddon model. The results revealed that the Young's moduli of A549 cells increased with the larger indentation force, higher indentation speed, less retraction time, deeper Z length and lower purity percentage of serum. The Young's moduli of cells increased first and then decreased with the increasing dwell time. Hence, this research may have potential significance to provide reference for the standardised detection of a single cancerous cell in vitro using AFM methodologies. Lay description: Cancer is now responsible for the majority leading cause of death worldwide and it is noteworthy that lung cancer has been recognised as the highest incidence (11.6%) and mortality (18.4%) for combined sexes among a variety of cancer diseases. Therefore, it is of great value to investigate the mechanical properties of lung cancerous cells for early diagnosis. This paper primarily investigated the morphological properties and the influence of measurement parameters on the measured local elastic moduli of single live A549 cell in vitro using the AFM‐based force spectroscopy mode. In practice, there are many factors for incorrect or inaccurate experimental results using AFM to measure the characteristics of live cells, such as non‐homogeneous nature of cells, probe geometry and size, mechanical analysis model, substrate stiffness and different measurement parameters. The various measurement parameters have become the huge impact factor to influence the measurement result. Hence, this research may have potential significance to provide reference for the standardised detection of a single cancerous cell in vitro using AFM methodologies. [ABSTRACT FROM AUTHOR]

Conductive atomic force microscopy (C-AFM) is a powerful tool used in the microelectronics analysis by applying a certain bias voltage between the conducting probe and the sample and obtaining the electrical information of sample. In this work, the surface morphological information and current images of the lambda DNA (λ DNA) molecules with different distributions were obtained by C-AFM. The 1 and 10 ng ÎĽ lâˆ'1 DNA solutions were dripped onto mica sheets for making randomly distributed DNA and DNA network samples, and another 1 ng ÎĽ lâˆ'1 DNA sample was placed in a DC electric field with a voltage of 2 V before being dried for stretching the DNA sample. The results show that the current flowing through DNA networks was significantly higher than the stretched and random distribution of DNA in the experiment. The I â€" V curve of DNA networks was obtained by changing the bias voltage of C-AFM from âˆ'9 to 9 V. The currents flowing through stretched DNA at different pH values were studied. When the pH was 7, the current was the smallest, and the current was gradually increased as the solution became acidic or alkaline. [ABSTRACT FROM AUTHOR]

Although nanopillars (NPs) provide a promising tool for capturing tumor cells, the effect of mixing NPs with other nanopatterns on cell behavior remains to be further studied. In this paper, a method of fabricating silicon nanoscale topographies by combining laser interference lithography with metal assisted chemical etching was introduced to investigate the behaviors and pseudopodia of A549 cells on the topologies. It was found that cells had a limited manner in spreading with small cell areas on the silicon nanopillar (SiNP) arrays, but a good manner in spreading with large cell areas on the silicon nanohole (SiNH) arrays. When on the hybrid SiNP/SiNH arrays, cells had medium cell areas and they arranged orderly along the boundaries of SiNPs and SiNHs, as well as 80% of cells displayed a preference for SiNPs over SiNHs. Furthermore, the lamellipodia and filopodia are dominant in the hybrid SiNP/SiNH and SiNP arrays, respectively, both of them are dominant in the SiNH arrays. In addition, the atomic force acoustic microscopy was also employed to detect the subsurface features of samples. The results suggest that the hybrid SiNP/SiNH arrays have a targeted trap and elongation effect on cells. The findings provide a promising method in designing hybrid nanostructures for efficient tumor cell traps, as well as regulating the cell behaviors and pseudopodia. [ABSTRACT FROM AUTHOR]

Trypsin is playing an important role in the processes of cancer proliferation, invasion and metastasis which require the precise information of morphology and mechanical properties on the nano‐scale for the related research. In this work, living human hepatoma (SMCC‐7721) cells were treated with different concentrations of trypsin solution. The morphology and mechanical properties of the cells were measured via atomic force microscope (AFM). Statistical analyses of measurement data indicated that with the increase of trypsin concentration, the average cell height and the surface roughness were both increased, but the cell viability, the cell surface adhesion and the elasticity modulus were decreased significantly. The force required to puncture the cells was also gradually reduced. It indicates that trypsin not only hydrolyses the proteins between the cell and the substrate but also the membrane proteins. The results offer valuable clues for the cancerous process study, pathological analysis and trypsin inhibitor drug development. And this work provides an effective way for overcoming the cell membrane in drug injection for cell‐targeted therapy. [ABSTRACT FROM AUTHOR]

As a model of neurodegenerative disease, the study on SH-SY5Y cells is of great significance due to the complexity of cause and difficulty in cure. Based on this reality, we studied the influence of culture duration on the morphology and mechanical properties of living SH-SY5Y cells by atomic force microscopy (AFM). A comparative analysis was made to characterize the cell size and tip-cell adhesion, and their increased trends with the increase of cell culture duration were obtained, providing a guideline for the physiological characteristics of the cells. As the culture time increased from 24 h to 48 h, the measured average height and width of cells were increased by 0.59 μ m and 1.38 μ m, respectively. As for cell elasticity, statistical analysis showed that the difference between different parts of the cell was obvious. Additionally, the electrophysiological characteristic as an important indicator for measuring the functional activities of SH-SY5Y cells was investigated. Here, a homemade conductive atomic force microscope (C-AFM) provided an effective way for membrane potential recordings. It was successfully used to study the real-time responses of living SH-SY5Y cells to mechanical insertions, and a membrane potential with an amplitude of − 0. 1 0 1 V was obtained without losing cell viability. The conductive probe equipped on a homemade C-AFM was isolated with dielectric material except for the tip apex, which enabled it to act as a nanoelectrode. As the sharp tip moves towards the target cell, the noise caused by liquid disturbance about 2 mV amplitude was captured. Right after the tip was inserted into the cell surface, a membrane potential spike with an amplitude of −0.101 V was successfully recorded. [ABSTRACT FROM AUTHOR]

Changes in mechanical properties of cells are closely related to a variety of diseases. As an advanced technology on the micro/nano scale, atomic force microscopy is the most suitable tool for information acquisition of living cells in human body fluids. AFMs are able to measure and characterize the mechanical properties of cells which can be used as effective markers to distinguish between different cell types and cells in different states (benign or cancerous). Therefore, they can be employed to obtain additional information to that obtained via the traditional biochemistry methods for better identifying and diagnosing cancer cells for humans, proposing better treatment methods and prognosis, and unravelling the pathogenesis of the disease. In this report, we review the use of AFMs in cancerous tissues, organs, and cancer cells cultured in vitro to obtain cellular mechanical properties, demonstrate and summarize the results of AFMs in cancer biology, and look forward to possible future applications and the direction of development. [ABSTRACT FROM AUTHOR]

Understanding the cell–substrate interactions has great significance in tissue regeneration therapies. However, the cell–substrate interactions are not well understood because the interface of cell–substrate is typically buried beneath the cells. This research investigated the subsurfaces of fibroblasts cultured on hybrid nanoarrays using atomic force acoustic microscopy (AFAM). We fabricated hybrid silicon nanowires (SiNWs) and silicon nanoholes (SiNHs) on Si substrates to serve as biomimetic nanoarrays by employing laser interference lithography and the metal-assisted chemical etching (MacEtch) method. After the L929 cells were cultured on the nanoarrays, scanning electron microscopy (SEM) and AFAM were employed to investigate the surface and subsurface of L929 cells. It was suggested that fibroblasts could sense the morphology of the hybrid nanoarrays and membrane damage of fibroblasts on the hybrid nanoarrays were related to the nanostructures. This study can help guide the design of biointerfaces and provide a useful tool for the study of cell subsurfaces in diverse biological fields. [ABSTRACT FROM AUTHOR]

In the manipulation of nanoparticles for precise placement, the relatively low adhesion of the nanoparticles to the substrate surface has emerged as a problem. Owing to the fact that nanoparticles manipulated using atomic force microscopy (AFM) often cannot be accurately placed at their predetermined destinations or may even go astray, becoming "lost," the success rate of manipulation attempts is low. We investigated the possibility of enhancing the adhesion between magnetic nanoparticles and a substrate surface by modifying a mica substrate with a solution of 3-aminopropyltriethoxysilane (APTES). The morphology of the mica surface before and after modification was analyzed, and the adhesive force was calculated by using AFM in contact mode. The effect of different APTES-solution concentrations on the adhesive force was analyzed as well. The results demonstrate that the adhesion of the nanoparticles to the modified substrate was substantially stronger than their adhesion to an unmodified surface, a finding that can be used to improve the success rate of nanoparticle manipulation. [ABSTRACT FROM AUTHOR]

Conductive atomic force indentation (CAFI) was proposed to study the self‐repair behaviour of the neuronal cell membrane here. CAFI was used to detect the changes of membrane potentials by performing the mechanical indentation on neurons with a conductive atomic force microscope. In the experiment, a special insulation treatment was made on the conductive probe, which turned out to be a conductive nanoelectrode, to implement the CAFI function. The mechanical properties of the neuronal cell membrane surface were tested and the membrane potential changes of neurons cultured in vitro were detected. The self‐repair behaviour of the neuronal cell membrane after being punctured was investigated. The experiment results show that CAFI provides a new way for the study of self‐repair behaviours of neuronal cell membranes and mechanical and electrical properties of living cells. [ABSTRACT FROM AUTHOR]

Since the invention of the atomic force microscope (AFM), it has been widely applied in biomedicine. One of the most important applications is used as an indenter tool to do the indentation experiment in order to get the mechanical properties of cells. In this paper, SW480 cells were used as the test subjects. Through the analysis of the contact and indentation, Young's modulus ( E), which is an important parameter of cancer cells, has been estimated. Experimental results show that different mechanical models should be chosen to calculate the E in different indentation depths. Here, the E of SW480 cells was (2.5 ± 0.8) KPa at the indentation depth of 99 nm. [ABSTRACT FROM AUTHOR]

Vascular endothelial cells form a barrier that blocks the delivery of drugs entering into brain tissue for central nervous system disease treatment. The mechanical responses of vascular endothelial cells play a key role in the progress of drugs passing through the blood–brain barrier. Although nanoindentation experiment by using AFM (Atomic Force Microscopy) has been widely used to investigate the mechanical properties of cells, the particular mechanism that determines the mechanical response of vascular endothelial cells is still poorly understood. In order to overcome this limitation, nanoindentation experiments were performed at different loading rates during the ramp stage to investigate the loading rate effect on the characterization of the mechanical properties of bEnd.3 cells (mouse brain endothelial cell line). Inverse finite element analysis was implemented to determine the mechanical properties of bEnd.3 cells. The loading rate effect appears to be more significant in short-term peak force than that in long-term force. A higher loading rate results in a larger value of elastic modulus of bEnd.3 cells, while some mechanical parameters show ambiguous regulation to the variation of indentation rate. This study provides new insights into the mechanical responses of vascular endothelial cells, which is important for a deeper understanding of the cell mechanobiological mechanism in the blood–brain barrier. [ABSTRACT FROM AUTHOR]

Colchicine is a drug commonly used for the treatment of gout, however, patients may sometimes encounter side-effects induced by taking colchicine, such as nausea, vomiting, diarrhea and kidney failure. In this regard, it is imperative to investigate the mechanism effects of colchicine on biological cells. In this paper, we present a method for the detection of mechanical properties of nephrocytes (VERO cells), hepatocytes (HL-7702 cells) and hepatoma cells (SMCC-7721 cells) in culture by atomic force microscope (AFM) to analyze the 0.1 μg/mL colchicine-induced effects on the nanoscale for two, four and six hours. Compared to the corresponding control cells, the biomechanical properties of the VERO and SMCC-7721 cells changed significantly and the HL-7702 cells did not considerably change after the treatment when considering the same time period. Based on biomechanical property analyses, the colchicine solution made the VERO and SMCC-7721 cells harder. We conclude that it is possible to reduce the division rate of the VERO cells and inhibit the metastasis of the SMCC-7721 cells. The method described here can be applied to study biomechanics of many other types of cells with different drugs. Therefore, this work provides an accurate and rapid method for drug screening and mechanical analysis of cells in medical research. [ABSTRACT FROM AUTHOR]

[Display omitted] Cell recognition methods are in high demand in cell biology and medicine, and the method based on atomic force microscopy (AFM) shows a great value in application. The difference in mechanical properties or morphology of cells has been frequently used to detect whether cells are cancerous, but this detection method cannot be a general means for cancer cell detection, and the traditional artificial feature extraction method also has its limitations. In this work, we proposed an analytic method based on the physical properties of cells and deep learning method for recognizing cell types. The residual neural network used for recognition was modified by multi-scale convolutional fusion, attention mechanism and depthwise separable convolution, so as to optimize feature extraction and reduce operation costs. In the method, the collected cells were imaged by AFM, and the processed images were analyzed by the optimized convolutional neural network. The recognition results of two groups of cells (HL-7702 and SMMC-7721, SGC-7901 and GES-1) by this method show that the recognition rate of dataset with the combination of cell surface morphology, adhesion and Young's modulus is higher, and the recognition rate of the dataset with optimal resolution is higher. Our study indicated that the recognition of physical properties of cells using deep learning technology can serve as a universal and effective method for the automated analysis of cell information. [ABSTRACT FROM AUTHOR]

In an atomic force microscope (AFM) system, the measurement accuracy in the scan images is determined by the displacement accuracy of piezo scanner. The hysteresis model of piezo scanner displacement is complex and difficult to correct, which is the main reason why the output displacement of the piezo scanner does not have high precision. In this study, an image pixel hysteresis model of the piezo scanner displacement in the AFM system was established. An AFM was used to scan a two-dimensional (2D) grating in the 0 ° and 90 ° directions and a polynomial fitting method was employed to obtain the image pixel hysteresis model parameters of the piezo scanner displacement in the X-direction and Y-direction. The image pixel hysteresis model was applied to correct the AFM scan image of regular octagons. The results showed that the relative measurement error in the X-direction was decreased from 12.47% to 0.52% after the correction and that in the Y-direction decreased from 28.57% to 0.35%. The image pixel hysteresis model can be applied in the post-processing software of a commercial AFM system. The model solves the hysteresis problem of the AFM system and improves the measuring accuracy of AFM in 2 degrees of freedom (2 DOF). [ABSTRACT FROM AUTHOR]

Tubule epithelial cell is a complex element that not only exhibits elasticity behaviour, but also presents nonlinear and time-dependent behaviour during any stage of its life cycle. Responses of tubule epithelial cells to physical stimuli are influenced by their mechanical properties. However, accurately constitution of their mechanical properties is still a challenge and the characterisation mechanism is far from sophisticated. In addition, the particular mechanism that determines the mechanical response is still unclear. In order to overcome this limit, an approach combined with AFM nanoindentation experiment and computation modelling by a viscohyperelastic model is developed to describe the complex behaviour in the current study. Viscohyperelastic parameters of tubule epithelial cells treated and untreated with drug Cytochalasin D are obtained by the optimization algorithm applied in this approach. The comparison between treated and untreated results indicate that larger amount of relaxation was observed due to the disruption of cytoskeleton when using drug Cytochalasin D. Our results demonstrate the feasibility of this approach to monitor the variation of these viscohyperelastic parameters, which can be used as an effective index for renal disease diagnosed and drug evaluation. [ABSTRACT FROM AUTHOR]