Magnetic domain wall tweezers: a new tool for mechanobiology studies on individual target cells

Abstract

In vitro tests are of fundamental importance for investigating cell mechanisms in response to mechanical stimuli or the impact of the genotype on cell mechanical properties. In particular, the application of controlled forces to activate specific bio-pathways and investigate their effects, mimicking the role of the cellular environment, is becoming a prominent approach in the emerging field of mechanobiology. Here, we present an on-chip device based on magnetic domain wall manipulators, which allows the application of finely controlled and localized forces on target living cells. In particular, we demonstrate the application of a magnetic force in the order of hundreds of pN on the membrane of HeLa cells cultured on-chip, via manipulation of 1 μm superparamagnetic beads. Such a mechanical stimulus produces a sizable local indentation of the cellular membrane of about 2 μm. Upon evaluation of the beads' position within the magnetic field originated by the domain wall, the force applied during the experiments is accurately quantified via micromagnetic simulations. The obtained value is in good agreement with that calculated by the application of an elastic model to the cellular membrane.

Biocompatibility of a Magnetic Tunnel Junction Sensor Array for the Detection of Neuronal Signals in Culture

“…The first SiO 2 layer is used as adhesive layer, while Si 3 N 4 film protects the sensor from the liquid environment, due to its low porosity and high chemical resistance (Vanhove et al, 2013). The final layer of SiO 2 is used to promote the adhesion of the extracellular matrix proteins used for the cell growth (Monticelli et al, 2016).…”

The Role of Nanomechanics in Healthcare

“…Optical tweezer is a single‐molecule manipulation technique used for application of calibrated forces and measurement of resultant displacements of the particles . As a result, it is an extremely useful tool to unravel mechanical properties and dynamics of biological molecules to gain insight into mechanical functions performed by these entities …”

“…Application of optical tweezers to investigate dynamic interactions between biological objects has been demonstrated . A study on virus–cell adhesion employed two independently controlled optical tweezers for examining probability of adhesion under biologically relevant conditions .…”

“…Nanotribological investigations to probe wear properties of specimens has resulted in enhanced understanding of contact mechanics in biospecies, such as cell adhesion on scaffold surface, abrasion of implants due to body fluids and neighboring tissues, and friction between surgical instruments and organs/tissues they make contact with during surgery . Noninvasive characterization techniques such as optical tweezers and magnetic tweezers are powerful methods to probe mechanics and dynamics of biological macromolecules . In recent years, these techniques have been clubbed with other microscopic and spectroscopic tools, such as fluorescence microscopy, Raman spectroscopy, digital holographic microscopy etc.…”

A numerical model suggests the interplay between nuclear plasticity and stiffness during a perfusion assay

“…From experimentation to mechanical modelling A wide range range of experimental techniques are available to investigate mechanical properties of various components of the cell and of the nucleus at various scales [10]. They include perfusion [11], micropipette aspiration -possibly coupled with relaxation experiments - [12], Atomic Force Microscopy (AFM), active or passive micro-rheology through magnetic or optical tweezers with local information [13], microplate compression [14], substrate strain, micro-needle manipulation [15], shear flow and cytoindentation [16]. The first experimental setups focused on getting the mechanical behaviour of the overall nucleus.…”