Figure 1
From: Engineering aligned human cardiac muscle using developmentally inspired fibronectin micropatterns
Approach to engineer a biomimetic 2D micropattern based on fibronectin ECM in the left ventricle of the embryonic chick heart. (A) Darkfield image of a 6-day-old embryonic chick heart. (B) Representative confocal 3D image (top down) of embryonic chick myocardium stained for nuclei (blue) and fibronectin (red). (C) The region of image in (B) used for the pattern generation, removing the nuclei and the high-intensity fibronectin areas on the edges corresponding to forming blood vessels. (D) Image in (C) processed to remove any features less than 1 µm in length, which are below the resolution of the photomask to be made. (E) Max intensity projection of the fibronectin ECM in (D) and conversion to a binary image. (F) The biomimetic pattern unit cell used in this study, composed of parts of four separate images combined into a single image, where each color represents the features from a specific image. The red region corresponds to the red pattern in (E), with the green arrow showing an example of a transferred feature. (G) The biomimetic unit cell in (F) is arrayed in 2D to create large area patterns in the photomask. (H) Representative image of the biomimetic micropattern microcontact printed using fluorescently-labeled fibronectin on PDMS-coated coverslips, confirming the fidelity of the protein transfer. (I and J) Representative images of the control micropatterns consisting of fibronectin (I) 20 × 20 and (J) 2 × 2 line patterns. Scale bars are (A) 500 µm, (B-F) 50 µm, (G) 100 µm, and (H-J) 50 µm. GIMP software was used to generate and edit the pattern (https://www.gimp.org/downloads/.).
