Cell behaviour on micropatterned substrata: limits of extracellular matrix geometry for spreading and adhesion

TLDR

Cell adhesion, spreading and migration depend on dynamic contacts with the extracellular matrix, whose number, availability and spatial distribution shape cell morphology and mobility. The study aimed to determine the geometrical limits of ECM binding sites necessary for cell attachment and spreading by microcontact printing regular ECM protein dot patterns. Using microcontact printing, cells were cultured on substrata with ECM protein dots as small as 0.1 μm² and spaced less than 5 μm apart, allowing them to adhere and spread on these regions. Cells spread and migrate on ECM dots ≥1 μm² only when dot separation is <30 μm; spacing of 5–25 μm forces cells to conform to the pattern, while the extent of spreading correlates with total ECM coverage and peaks at >15 % coating, highlighting critical geometrical limits for designing surfaces that optimally interact with cells.

Abstract

Cell adhesion, spreading and migration require the dynamic formation and dispersal of contacts with the extracellular matrix (ECM). In vivo, the number, availability and distribution of ECM binding sites dictate the shape of a cell and determine its mobility. To analyse the geometrical limits of ECM binding sites required for cell attachment and spreading, we used microcontact printing to produce regular patterns of ECM protein dots of defined size separated by nonadhesive regions. Cells cultured on these substrata adhere to and spread on ECM regions as small as 0.1 μm2, when spacing between dots is less than 5 μm. Spacing of 5-25 μm induces a cell to adapt its shape to the ECM pattern. The ability to spread and migrate on dots ≥1 μm2 ceases when the dot separation is ≥30 μm. The extent of cell spreading is directly correlated to the total substratum coverage with ECM-proteins, but irrespective of the geometrical pattern. An optimal spreading extent is reached at a surface coating above 15%. Knowledge of these geometrical limits is essential for an understanding of cell adhesion and migration, and for the design of artificial surfaces that optimally interact with cells in a living tissue.