Atomic force microscopy: High resolution dynamic imaging of cellular and molecular structure in health and disease

et al. 2017

Sensors

The advent of atomic force microscopy (AFM) has provided a powerful tool for investigating the behaviors of single native biological molecules under physiological conditions. AFM can not only image the conformational changes of single biological molecules at work with sub-nanometer resolution, but also sense the specific interactions of individual molecular pair with piconewton force sensitivity. In the past decade, the performance of AFM has been greatly improved, which makes it widely used in biology to address diverse biomedical issues. Characterizing the behaviors of single molecules by AFM provides considerable novel insights into the underlying mechanisms guiding life activities, contributing much to cell and molecular biology. In this article, we review the recent developments of AFM studies in single-molecule assay. The related techniques involved in AFM single-molecule assay were firstly presented, and then the progress in several aspects (including molecular imaging, molecular mechanics, molecular recognition, and molecular activities on cell surface) was summarized. The challenges and future directions were also discussed.

Section: Molecular Activities On Cell Surfacementioning

confidence: 99%

Imaging and Force Recognition of Single Molecular Behaviors Using Atomic Force Microscopy

Dang

et al. 2017

Sensors

“…Although AFM imaging and force spectroscopy can directly image and reveal the unfolding dynamics of single native membrane proteins, the current research has been performed on reconstituted lipid bilayers. Clearly, the mechanistic results derived from an in vitro simulacrum must be addressed at the cellular level [108] . AFM has achieved great success in studies of microbial cells (such as bacteria and fungi) because of the well-defined and rigid nature of the microbial cell envelope [107,109] .…”

Section: Challenge and Outlookmentioning

confidence: 99%

Nanoscale monitoring of drug actions on cell membrane using atomic force microscopy

et al. 2015

Acta Pharmacol Sin

Knowledge of the nanoscale changes that take place in individual cells in response to a drug is useful for understanding the drug action. However, due to the lack of adequate techniques, such knowledge was scarce until the advent of atomic force microscopy (AFM), which is a multifunctional tool for investigating cellular behavior with nanometer resolution under near-physiological conditions. In the past decade, researchers have applied AFM to monitor the morphological and mechanical dynamics of individual cells following drug stimulation, yielding considerable novel insight into how the drug molecules affect an individual cell at the nanoscale. In this article we summarize the representative applications of AFM in characterization of drug actions on cell membrane, including topographic imaging, elasticity measurements, molecular interaction quantification, native membrane protein imaging and manipulation, etc. The challenges that are hampering the further development of AFM for studies of cellular activities are aslo discussed.

“…In recent years, AFM has been used to probe mechanical properties of clinical tumor cells [75,76], which helps develop closer links between laboratory research and clinical requirements. The cell membrane plays an important role in the regulation of membrane proteins and hence SMFS unfolding experiments must be performed on live cells in addition to reconstituted lipid bilayers [77]. In 2009, Alsteens et al [78] used SMFS to unfold Als5p adhesion proteins from purified proteins, and then unfolded the same proteins on live yeast cells, revealing similar unfolding pathways.…”

Section: Challenge and Outlookmentioning

confidence: 99%

Progress in measuring biophysical properties of membrane proteins with AFM single-molecule force spectroscopy

et al. 2014

Chin. Sci. Bull.

Membrane proteins are crucial in cell physiological activities and are the targets for most drugs. Thus, investigating the behaviors of membrane proteins not only provide deeper insights into cell function, but also help disease treatment and drug development. Atomic force microscopy is a unique tool for investigating the structure of membrane proteins. It can both image the morphology of single native membrane proteins with high resolution and, via single-molecule force spectroscopy (SMFS), directly measure their biophysical properties during molecular physiological activities such as ligand binding and protein unfolding. In the context of molecular biomechanics, SMFS has been successfully used to understand the structure and function of membrane proteins, complementing the static three-dimensional structures of proteins obtained by X-ray crystallography. Here, based on the authors' antigen-antibody binding force measurements in clinical tumor cells, the principle and method of SMFS is discussed, the progress in using SMFS to characterize membrane proteins is summarized, and challenges for SMFS are presented.