Robust Micromechanical Neurite Elicitation in Synapse-Competent Neurons Via Magnetic Bead Force Application

Abstract

The ability to engineer living networks of interconnected neurons with specified connectivity would facilitate the study of synaptogenesis and information processing in the nervous system. Previously, we found that a neurite can be elicited from embryonic chick forebrain neurons by direct mechanical means using magnetic bead force application (MBFA); however, our previous studies and others focused on young, synapse-incompetent neurons. To address this issue, we tested cultures of embryonic chick forebrain neurons of varying age and found that neurites could be micromechanically elicited via MBFA at all ages tested, which ranged between 7 and 22 embryonic equivalent (EE) days (days in ovo plus days in vitro). The probability of neurite initiation was at least 40% for all ages, with a maximum of approximately 80% after 2-4 days in vitro, and a decrease to approximately 60% by day 10 in vitro. The force required to elicit a neurite was approximately 1500 pN with a minimum of approximately 700 pN at embryonic equivalent day 14. The probability of success was similar for two rates of force application (10 and 500 pN/s). Neurite initiation via micromechanical force is robust with respect to cell age, and micromechanical force can induce neurites in synapse-competent neurons.

Optical neuronal guidance in three-dimensional matrices

“…Fromherz, 2002). Micromechanical forces from glass microneedles (Lamoureux et al, 2002) or magnetic microbeads (Fischer et al, 2005) can elicit neurites by applying forces on the cell surface, but these techniques are not easily adapted to 3D environments.…”

“…Fromherz, 2002). Micromechanical forces from glass microneedles (Lamoureux et al, 2002) or magnetic microbeads (Fischer et al, 2005) can elicit neurites by applying forces on the cell surface. All of these techniques have some limitations (Fromherz, 2002), and, for the most part, cannot be easily extended to three dimensions (for a review, see Seidlits et al, 2008).…”

Signalling effect of NIR pulsed lasers on axonal growth

“…Several methods have thus been suggested. These include the use of electric fields (Patel and Poo, 1982), use of micropatterned substrate structures (Fromherz et al, 1991;Lee et al, 2007;Kaehr et al, 2004) or mechanical forces (Fischer et al, 2005;Lamoureux et al, 1992). In addition to all the aforementioned a number of works have highlighted the use of light as a potential tool to achieve control on axon guidance.…”

Magnetic micro-device for manipulating PC12 cell migration and organization

“…Physical forces play a key role in shaping neuronal structures. 8,9 Magnetic particles on the nanoscale can also mediate magnetic manipulations if a sufficient amount is incorporated into the cells. [1][2][3][4][5] It has been demonstrated that mechanical pulling of neuronal branches has the ability to modify branches fate and role within the cell.…”