Magneto-responsive liquid crystalline elastomer nanocomposites as potential candidates for dynamic cell culture substrates

Abstract

Recently, liquid crystalline elastomers (LCEs) have been proposed as active substrates for cell culture due to their potential to attach and orient cells, and impose dynamic mechanical signals through the application of external stimuli. In this report, the preparation of anisotropic and oriented nematic magnetic-sensitized LCEs with iron oxide nanoparticles, and the evaluation of the effect of particle addition at low concentrations on the resultant structural, thermal, thermo-mechanical, and mechanical properties is presented. Phase transformations produced by heating in alternating magnetic fields were investigated in LCEs in contact with air, water, and a common liquid cell culture medium was also evaluated. The inclusion of nanoparticles into the elastomers displaced the nematic-to-isotropic phase transition, without affecting the nematic structure as evidenced by similar values of the order parameter, while reducing the maximum thermomechanical deformations. Remote and reversible deformations of the magnetic LCEs were achieved through the application of alternating magnetic fields, which induces the nematic-isotropic phase transition through nanoparticle heat generation. Formulation parameters can be modified to allow for remote actuation at values closer to the human physiological temperature range and within the range of deformations that can affect the cellular behavior of fibroblasts. Finally, a collagen surface treatment was performed to improve compatibility with NIH-3T3 fibroblast cultures, which enabled the attachment and proliferation of fibroblasts on substrates with and without magnetic particles under quiescent conditions. The LCEs developed in this work, which are able to deform and experience stress changes by remote contact-less magnetic stimulation, may allow for further studies on the effect of substrate morphology changes and dynamic mechanical properties during in vitro cell culture.

Advances in Cell Scaffolds for Tissue Engineering: The Value of Liquid Crystalline Elastomers

“…Electric field sensitive LCEs are generally prepared by inorganic nanoparticle doping (such as carbon powder) leading to conductive materials . In magneto‐responsive LCEs, the inorganic dopants are usually magnetic iron oxide nanoparticles, allowing for nanocomposite in which materials heating can be triggered by application of an alternating magnetic fields . However, light is definitely the more interesting activation stimulus because it enables a rapid, punctual, and wireless control of the material properties, in addition to being a clean, cheap and environmental friendly energy source.…”

Photoreversible Soft Azo Dye Materials: Toward Optical Control of Bio‐Interfaces

“…Phase transition temperatures in LCEs are typically much higher than physiological temperature; so their implementation as cell culturing substrates has been so far modest and restricted to nondynamic applications. However, advances in their application as biomaterials in the near future are foreseeable both for their anisotropy, as well as for their photoactuation capabilities …”

An Untethered Magnetic‐ and Light‐Responsive Rotary Gripper: Shedding Light on Photoresponsive Liquid Crystal Actuators

“…Liquid crystal networks (LCNs) are attractive materials for fabricating soft actuators since they operate in dry environments, and their deformation can be programmed within the LC network by the 3D organization of the molecular building blocks. The versatility of liquid crystal (LC) networks has allowed for the development of several functional, responsive actuators with diverse fabrication techniques, such as 3D printing, and operating with a variety of triggers, including light, heat, humidity, and magnetic, and electric fields. Among the triggers studied in the development of LC actuators, light is highly appealing for untethered motion as it provides instantaneous stimulus, resulting in a fast response with a high degree of control.…”