1. Generating overlapping orthogonal gradients in a novel four-port microdevice.
Generating overlapping orthogonal gradients in a novel four-port microdevice. Simply adding two additional diffusion ports provides an enhanced user platform with which one can recreate both an ‘Anteroposterior’ or ‘Dorsoventral’ slice of the neural tube. Introducing PM as a single source (equivalent to the neural tube floor plate) with flanking RA sources and an opposing BMP source induces a similar spatial pattern to that seen with the two-port microdevice. (A-D) Concentration profiles and demonstrated HB9 response for a dorsoventral slice of the notochord using four independent sources. (A) Simulated concentration profile for a single species using one source and three sinks. (B) Experimental demonstration of microdevice concentration profiles using each port as a single source for a colored dye. (C) Experimental HB9+ response to the indicated mediator gradients. (D) Color-coded HB9+ distribution plotted for three separate experiments. Calculated SHH concentration gradient is shown as background. (E-H) Concentration profiles demonstrated for an anteroposterior slice of the notochord using the four-channel device. (E) Computer simulation of concentration profiles using two adjacent inputs as a source. Profiles are approximately linear. (F,G) Experimental demonstration the linear gradient using the fluorescent dyes fluorescein (F) and rhodamine (G). (H) Superposition of linear gradients in F and G. NC, notochord; S, somite.
Christopher J. Demers et al. Development 2016;143:
© Published by The Company of Biologists Ltd