title: 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.
authors.affiliation: Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681, Puerto Rico.
authors.forename: Stephany
authors.initials: S
authors.lastname: Herrera-Posada
authors.affiliation: Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681, Puerto Rico.
authors.forename: Camilo
authors.initials: C
authors.lastname: Mora-Navarro
authors.affiliation: Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681, Puerto Rico.
authors.forename: Patricia
authors.initials: P
authors.lastname: Ortiz-Bermudez
authors.affiliation: Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681, Puerto Rico.
authors.forename: Madeline
authors.initials: M
authors.lastname: Torres-Lugo
authors.affiliation: Department of Materials Science and Engineering, 1509 University Avenue, University of Wisconsin-Madison, WI 53706, USA.
authors.forename: Kyle M
authors.initials: KM
authors.lastname: McElhinny
authors.affiliation: Department of Materials Science and Engineering, 1509 University Avenue, University of Wisconsin-Madison, WI 53706, USA.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Evans
authors.affiliation: Department of General Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681, Puerto Rico.
authors.forename: Barbara O
authors.initials: BO
authors.lastname: Calcagno
authors.affiliation: Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681, Puerto Rico. Electronic address: aldo.acevedo@upr.edu.
authors.forename: Aldo
authors.initials: A
authors.lastname: Acevedo
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D020724:Elastomers / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry; D050866:Liquid Crystals / Q000737:chemistry*; D058185:Magnetite Nanoparticles / Q000737:chemistry / Q000633:toxicity; D051379:Mice; D018613:Microscopy, Confocal; D041681:NIH 3T3 Cells; D053761:Nanocomposites / Q000737:chemistry* / Q000633:toxicity; D013696:Temperature
chemical_list: D020724:Elastomers; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C000499:ferric oxide
keywords: Actuation; Dynamic cell culture; Liquid crystal elastomers; Magnetic composites