In situ control of cell substrate microtopographies using photolabile hydrogels

Abstract

Substratum topography can play a significant role in regulating cellular function and fate. To study cellular responses to biophysical cues, researchers have developed dynamic methods for controlling cell morphology; however, many of these platforms are limited to one transition between two predefined substratum topographies. To afford the user additional control over the presentation of microtopographic cues to cell populations, a photolabile, PEG-based hydrogel system is presented in which precisely engineered topographic cues can be formed in situ by controlled erosion. Here, the ability to produce precisely engineered static microtopographies in the hydrogel surface is first established. Human mesenchymal stem cell (hMSC) response to topographies with features of subcellular dimensions (∼5 to 40 μm) and with various aspect ratios increasing from 1:1 to infinity (e.g., channels) are quantified, and the dynamic nature of the culture system is demonstrated by sequentially presenting a series of topographies through in situ modifications and quantifying reversible changes in cell morphology in response to substratum topographies altered in real time. Photolabile hydrogels provide a platform for cell culture where multiple manipulations of surface topography can be controlled both spatially and temporally in situ. In this way it is possible to maintain cell cultures under standard conditions while altering the surface. The system can be exploited to create various topographies and topographic interfaces that are not predetermined by the substrate material through multiple, sequential alterations. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.