Light‐Responsive Hierarchically Structured Liquid Crystal Polymer Networks for Harnessing Cell Adhesion and Migration

Abstract

Extracellular microenvironment is highly dynamic where spatiotemporal regulation of cell-instructive cues such as matrix topography tightly regulates cellular behavior. Recapitulating dynamic changes in stimuli-responsive materials has become an important strategy in regenerative medicine to generate biomaterials which closely mimic the natural microenvironment. Here, light responsive liquid crystal polymer networks are used for their adaptive and programmable nature to form hybrid surfaces presenting micrometer scale topographical cues and changes in nanoscale roughness at the same time to direct cell migration. This study shows that the cell speed and migration patterns are strongly dependent on the height of the (light-responsive) micrometer scale topographies and differences in surface nanoroughness. Furthermore, switching cell migration patterns upon in situ temporal changes in surface nanoroughness, points out the ability to dynamically control cell behavior on these surfaces. Finally, the possibility is shown to form photoswitchable topographies, appealing for future studies where topographies can be rendered reversible on demand.

Light-Triggered Formation of Surface Topographies in Azo Polymers

“…Recent advances have already led to interesting applications outside the field of optics, especially for living cell adhesion and friction [14]. This work combined with the recent demonstration of dynamics and oscillations in surface topographies will lead the azobenzene-containing polymeric coatings in a new field of research.…”

“…LCs allow for a high degree of control over molecular alignment, which is important in forming topographies. LCNs are created from reactive LC monomeric mixtures that can be aligned by a variety of techniques (among them are various interfacial techniques, mechanical [14,94,95], optical [96][97][98][99][100] and electrical [101]). These mixtures typically contain an azobenzene moiety (molecule 4 in Figure 9c) acting both as a cross-linker and deformation trigger molecule.…”

“…This technique was recently used to investigate cell adhesion and migration behavior to different sized surface topographies [14]. Here, UV irradiation of a planar cholesteric azo-LCN coating through a hexagonal dotted mask resulted in pillars.…”

“…Outside nature-inspired applications, textured surfaces show promising optical properties, both as transmissive and reflective diffraction gratings [4,5]. Designing topographies on a surface can lead to applications in photonics (such as nanostructured polarizers and/or wave plates [6,7] and antireflection coatings [8][9][10][11]), friction control (including robotic fingerprints [12,13]), (de)wetting of surfaces and even control over cellular adhesion and mobility [14].…”

Compliance‐Mediated Topographic Oscillation of Polarized Light Triggered Liquid Crystal Coating

“…These large topographies were only reported for chiral nematic liquid crystal (LC) coatings. [2,12] For other glasssupported azopolymers, topographies are smaller, reaching up to only a few hundred nanometers. [13,14] We have shown before that oscillations in glass-supported coatings are achievable by changing the polarization state of incident ultraviolet (UV) light.…”