Colored XXXX micropillar arrays for high throughput measurements of forces applied by genetic model organisms.

@entity2199 @entity16549 @entity6619 @entity13768 @entity238
Measuring forces applied by multi-cellular organisms is valuable in investigating biomechanics of their locomotion. Several technologies have been developed to measure such forces, for example, strain gauges, micro-machined sensors, and calibrated cantilevers. We introduce an innovative combination of techniques as a high throughput screening tool to assess forces applied by multiple genetic model organisms. First, we fabricated colored @entity13768 ( @entity16549 ) micropillars where the color enhances contrast making it easier to detect and track pillar displacement driven by the organism. Second, we developed a semi-automated graphical user interface to analyze the images for pillar displacement, thus reducing the analysis time for each animal to minutes. The addition of color reduced the Young's modulus of @entity16549 . Therefore, the dye- @entity16549 composite was characterized using Yeoh's hyperelastic model and the pillars were calibrated using a @entity6619 based force sensor. We used our device to measure forces exerted by wild type and mutant @entity2199 moving on an agarose surface. Wild type @entity2199 exert an average force of    1    N on an individual pillar and a total average force of    7.68    N. We show that the middle of @entity2199 exerts more force than its extremities. We find that @entity2199 mutants with defective body wall muscles apply significantly lower force on individual pillars, while mutants defective in sensing externally applied mechanical forces still apply the same average force per pillar compared to wild type animals. Average forces applied per pillar are independent of the length, diameter, or cuticle stiffness of the animal. We also used the device to measure, for the first time, forces applied by @entity238 larvae. Peristaltic waves occurred at 0.4   Hz applying an average force of    1.58    N on a single pillar. Our colored microfluidic device along with its displacement tracking software allows us to measure forces applied by multiple model organisms that crawl or slither to travel through their environment.
