Atomic Force Microscopy on Biological Materials Related to Pathological Conditions

Abstract

Atomic force microscopy (AFM) is an easy-to-use, powerful, high-resolution microscope that allows the user to image any surface and under any aqueous condition. AFM has been used in the investigation of the structural and mechanical properties of a wide range of biological matters including biomolecules, biomaterials, cells, and tissues. It provides the capacity to acquire high-resolution images of biosamples at the nanoscale and allows at readily carrying out mechanical characterization. The capacity of AFM to image and interact with surfaces, under physiologically relevant conditions, is of great importance for realistic and accurate medical and pharmaceutical applications. The aim of this paper is to review recent trends of the use of AFM on biological materials related to health and sickness. First, we present AFM components and its different imaging modes and we continue with combined imaging and coupled AFM systems. Then, we discuss the use of AFM to nanocharacterize collagen, the major fibrous protein of the human body, which has been correlated with many pathological conditions. In the next section, AFM nanolevel surface characterization as a tool to detect possible pathological conditions such as osteoarthritis and cancer is presented. Finally, we demonstrate the use of AFM for studying other pathological conditions, such as Alzheimer’s disease and human immunodeficiency virus (HIV), through the investigation of amyloid fibrils and viruses, respectively. Consequently, AFM stands out as the ideal research instrument for exploring the detection of pathological conditions even at very early stages, making it very attractive in the area of bio- and nanomedicine.

Nanomechanical mapping of soft materials with the atomic force microscope: methods, theory and applications

“…The atomic force microscope (AFM) 1 has greatly contributed to our current understanding of soft materials and their physical, chemical and biomolecular interactions. [2][3][4][5][6][7][8][9][10][11] Mapping at highspatial resolution the mechanical properties of heterogeneous interfaces is one of the key achievements of AFM. In this review nanomechanical mapping and nanomechanical force spectroscopy have the same meaning.…”

Hertz model or Oliver & Pharr analysis? Tutorial regarding AFM nanoindentation experiments on biological samples

“…( )/ will be examined for a wide range of indentation values. The aforementioned factor will be calculated using the approximate (for spherical indenters) equation (1) and the accurate equation (5). It should be noted that equation (5) does not directly relates the applied load to the indentation depth, since it is expressed in terms of contact radius r .…”

“…The aforementioned factor will be calculated using the approximate (for spherical indenters) equation (1) and the accurate equation (5). It should be noted that equation (5) does not directly relates the applied load to the indentation depth, since it is expressed in terms of contact radius r . c For the case of spherical indenters, the contact radius is accurately provided by equation (7).…”

“…Atomic Force Microscopy nanoindentation is a powerful technique for the characterization of biological samples at the nanoscale [1][2][3][4][5][6][7][8][9]. The data processing is usually performed using basic models arising from the contact mechanics theory [7,9].…”

High-Resolution Episcopic Microscopy (HREM): Looking Back on 13 Years of Successful Generation of Digital Volume Data of Organic Material for 3D Visualisation and 3D Display

“…Techniques such as single-photon emission computed tomography (SPECT) and positron emission tomography (PET), micro-computed topography (µCT) and optical coherence tomography (OCT) are already used as routine tools for the diagnosis of pathologies in the clinical routine [4][5][6][7][8][9]. Others, such as micromagnetic resonance tomography (µMRI), atomic force microscopy (AFM) and optical projection tomography (OPT), are still restricted to the scientific analysis and characterisation of biological samples [10][11][12][13][14][15][16]. Their focus rests on the interpretations of the three-dimensional (3D) arrangement of organs, tissues, cells and molecules in healthy and diseased organisms, which is the basis for understanding the genetic, epigenetic and functional aspects of developmental processes, the genesis of pathologies and the effect of strategies to treat diseases.…”