Ultra-Soft PDMS-Based Magnetoactive Elastomers as Dynamic Cell Culture Substrata

Abstract

Mechanical cues such as extracellular matrix stiffness and movement have a major impact on cell differentiation and function. To replicate these biological features in vitro, soft substrata with tunable elasticity and the possibility for controlled surface translocation are desirable. Here we report on the use of ultra-soft (Young’s modulus <100 kPa) PDMS-based magnetoactive elastomers (MAE) as suitable cell culture substrata. Soft non-viscous PDMS (<18 kPa) is produced using a modified extended crosslinker. MAEs are generated by embedding magnetic microparticles into a soft PDMS matrix. Both substrata yield an elasticity-dependent (14 vs. 100 kPa) modulation of α-smooth muscle actin expression in primary human fibroblasts. To allow for static or dynamic control of MAE material properties, we devise low magnetic field (≈40 mT) stimulation systems compatible with cell-culture environments. Magnetic field-instigated stiffening (14 to 200 kPa) of soft MAE enhances the spreading of primary human fibroblasts and decreases PAX-7 transcription in human mesenchymal stem cells. Pulsatile MAE movements are generated using oscillating magnetic fields and are well tolerated by adherent human fibroblasts. This MAE system provides spatial and temporal control of substratum material characteristics and permits novel designs when used as dynamic cell culture substrata or cell culture-coated actuator in tissue engineering applications or biomedical devices.

Influence of the geometry on magnetic interactions in a retina fixator based on a magnetoactive elastomer seal

“…Magnetoactive elastomers (MAEs) are polymer composite materials that have magnetically sensitive filler particles embedded in the polymer matrix [1][2][3][4][5][6][7][8][9][10][11][12][13]. The main property that characterizes these smart materials is their high responsiveness to external magnetic fields.…”

“…the changes to viscoelastic properties that occur in an MAE sample under the influence of external magnetic fields [1][2][3][4][5], and magnetodeformational effect, i.e. spontaneous deformation in magnetic field [6][7][8][9][10][11], serve as a basis for using MAEs as elements of tunable damping devices [12] and cell substrates [13]. This paper is dedicated to studying the MAEs for medical purposes, namely a surgical treatment of complicated retinal detachment cases [14][15][16].…”

Dynamic bioengineered hydrogels as scaffolds for advanced stem cell and organoid culture

“…In addition to polyacrylamide-based systems, PDMS [poly(dimethylsiloxane)] was used to develop magnetoactive hydrogels. [34] Notably, these hydrogels required extensive post-fabrication treatment to produce cell adhesive surfaces suitable for cell culture. Thus, magnetoactive materials provide an interesting platform for reversible mechanical changes, but their compatibility with biologic systems must be further improved in order to use this technology for organoid culture.…”

Dynamic and biocompatible thermo-responsive magnetic hydrogels that respond to an alternating magnetic field

“…In the growing field of dynamic, stimuli-responsive cell substrates there are only a few which involve the use of magnetic hydrogels [27][28][29] and none rely on AMF stimulation. In particular, acrylamide gels loaded with nickel micro-wires were shown to alter their surface roughness upon the application of a static magnetic field and to induce changes in the adhesion area of vascular smooth cells [27].…”

“…In particular, acrylamide gels loaded with nickel micro-wires were shown to alter their surface roughness upon the application of a static magnetic field and to induce changes in the adhesion area of vascular smooth cells [27]. Another study focused on the development of a magneto-active elastomer that changes stiffness and topography after application of static and oscillating field [29]. This substrate was used to study migration and morphology of human fibroblasts.…”