A platform for assessing chemotactic migration within a spatiotemporally defined 3D microenvironment.

While the quantification of cell movement within defined biochemical gradients is now possible with microfluidic approaches, translating this capability to biologically relevant three-dimensional microenvironments remains a challenge. We introduce an accessible platform, requiring only standard tools (e.g. pipettes), that provides robust soluble factor control within a three-dimensional biological matrix. We demonstrate long-lasting linear and non-linear concentration profiles that were maintained for up to ten days using 34.5 muL solute volume. We also demonstrate the ability to superimpose local soluble factor pulses onto existing gradients via defined dosing windows. The combination of long-term and transient gradient characteristics within a three-dimensional environment opens the door for signaling studies that investigate the migratory behavior of cells within a biologically representative matrix. To this end, we apply temporally evolving and long-lasting gradients to study the chemotactic responses of human neutrophils and the invasion of metastatic rat mammary adenocarcinoma cells (MtLN3) within three-dimensional collagen matrices.