Scanning Probe Microscopies: Imaging and Biomechanics in Reproductive Medicine Research

Abstract

Basic and translational research in reproductive medicine can provide new insights with the application of scanning probe microscopies, such as atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM). These microscopies, which provide images with spatial resolution well beyond the optical resolution limit, enable users to achieve detailed descriptions of cell topography, inner cellular structure organization, and arrangements of single or cluster membrane proteins. A peculiar characteristic of AFM operating in force spectroscopy mode is its inherent ability to measure the interaction forces between single proteins or cells, and to quantify the mechanical properties (i.e., elasticity, viscoelasticity, and viscosity) of cells and tissues. The knowledge of the cell ultrastructure, the macromolecule organization, the protein dynamics, the investigation of biological interaction forces, and the quantification of biomechanical features can be essential clues for identifying the molecular mechanisms that govern responses in living cells. This review highlights the main findings achieved by the use of AFM and SNOM in assisted reproductive research, such as the description of gamete morphology; the quantification of mechanical properties of gametes; the role of forces in embryo development; the significance of investigating single-molecule interaction forces; the characterization of disorders of the reproductive system; and the visualization of molecular organization. New perspectives of analysis opened up by applying these techniques and the translational impacts on reproductive medicine are discussed.

Probing Italy: A Scanning Probe Microscopy Storyline

“…During the last 20 years, the laboratory provided services and participated in R&D projects in collaboration with several Italian universities, public laboratories, and private laboratories. It has resulted in several publications, some of which are pioneering applications of SPM (especially SNOM) to biology and biomedicine [164][165][166][167][168].…”

Atomic force spectroscopy‐based essay to evaluate oocyte postovulatory aging

“…Recently, there is a growing attention to the cellular mechanical properties for their relation to the physiological or pathological cell status 18–21 . Biomechanical parameters, evaluated through different techniques, have already been proven to be good noninvasive predictors for embryo and zygote viability, as well as for the detection of the maturation phases of the oocytes 22 .…”

“…Recently, there is a growing attention to the cellular mechanical properties for their relation to the physiological or pathological cell status. 18 , 19 , 20 , 21 Biomechanical parameters, evaluated through different techniques, have already been proven to be good noninvasive predictors for embryo and zygote viability, as well as for the detection of the maturation phases of the oocytes. 22 Microtactile sensors and micropipette aspiration of whole oocytes were used to investigate the phenomenon called “zona hardening” after fertilization, which involves a ZP stiffening after fertilization.…”