In situ mechanical characterization of mouse oocytes using a cell holding device

Abstract

This paper presents a cellular force measurement technique that allows for mechanical characterization of mouse oocytes during microinjection (i.e., in situ) without requiring a separate characterization process. The technique employs an elastic cell holding device and a sub-pixel computer vision tracking algorithm to resolve cellular forces in real time with a nanonewton force measurement resolution (2 nN at 30 Hz). Mechanical properties (i.e., stiffness) of both healthy and defective mouse oocytes are characterized. The experimental results suggest that the in situ obtained force-deformation data are useful for distinguishing healthy mouse oocytes from those with aging-induced cellular defects, promising an approach for oocyte quality assessment during microinjection. Biomembrane and cytoskeleton structures of the healthy and defective oocytes are also investigated in an attempt to correlate the measured subtle mechanical difference to cellular structure changes.

Paper-based piezoresistive MEMS sensors

“…Soft materials, such as polydimethylsiloxane (PDMS) and polyacrylamide (PAA), have been widely used for constructing micro devices [13][14][15][16] and in mammalian cell culture. 17 Mechanical properties (e.g., Characterization of the mechanical properties of soft materials is based primarily on tensile testing and nanoindentation, both of which require access to expensive equipment.…”

Deformation of a single mouse oocyte in a constricted microfluidic channel

“…Nevertheless, at the two different channel heights of 100 μm and 150 μm, the deformation degree of oocytes showed similar increasing tendency with time and the maximum value of oocyte deformation were close, i.e., D = 0.43 at H c = 100 μm and D = 0.42 at H c = 150 μm. Previous studies on mechanical behavior of oocytes focus on oocytes under no-flow conditions using microinjector, 16, 25, 26 while it is hard to use microinjector for studying mechanical behavior of oocytes under flow conditions. Here, we demonstrated a simple platform that can be used to study the flow effects on a single oocyte during external shear flow, which can be helpful for manipulating oocytes in microfluidic flow.…”

“…11-15 Confined micro-scale reservoirs were used to entrap oocytes and perform force measurements during microinjection. 16 However, these devices do not allow the study of shape deformation and spindle structure change of oocytes under flow. In the present study, we demonstrate a simple microfluidic device for the controlled entrapment of oocytes.…”

Silicon Nanotweezers with double actuation and extended stroke for single cell studies

“…It thus both of fundamental importance and of practical interest to develop tools and methods to efficiently and quantitatively probe mechanical properties of cells. Several tools have been developed in the past to probe cells mechanical properties [5]- [8].…”