Fig. 1.

Micropatterning strengths. (A) Experiments in embryos can be limited by a number of factors including ethical considerations, low material accessibility and difficulty in disentangling biological variables. (B) Reconstituting developmental processes in vitro is an attractive and complementary approach. However, a rationalised control of the in vitro microenvironment is required to avoid variable cell behaviours, which confound analysis and may hide important biological processes. (C) Micropatterns offer opportunities to control and uncouple several aspects of the environment including substrate composition, mechanics, geometry and topography. Certain micropatterning techniques can also modulate these variables dynamically. These attributes offer key advantages. For example, careful experimental design with micropatterns enable the precise spatio-temporal perturbation of individual variables, while standardisation facilitates quantitative approaches. Furthermore, as micropatterned cultures are scalable and easy to image, they are compatible with high-throughput applications. Micropatterns range from the nanometre (nm) to the millimetre (mm) scale and thus afford a certain agility to interrogate processes across multiple biological scales. Overall micropatterns can be used to bring biological processes to a manageable yet meaningful level of complexity, offering opportunities to test biological paradigms quantitatively and inform targeted experiments in embryos for validation. ECM, extracellular matrix; FOV, field of view.