Creating a robophysical model to study how malaria infiltrates human skin

Malaria remains a serious health concern worldwide, especially in developing countries. Understanding how malaria parasites (sporozoites) infiltrate skin (a complex matrix of collagen fibers immersed in water) to reach bloodstreams will facilitate the cure for the disease. However, it is challenging to understand the complex interaction between the elongate organism and the complex environments, as the equations of motion are too complicated to solve directly. Here, based on recent biological observations, we created a robophysical model that mimics the movement of sporozoites along collagen fibers. We designed and manufactured a segmented robot to model a sporozoite and used elastic rods immersed in a viscous fluid (with Reynolds number matched to the biological system) to model collagen fibers in skin. The robot's segments has actuated wheels to allow it to crawl on the rod. Additionally, to replicate the sporozoites' curved shape and enable steering, the segments are daisy-chained with cables on both sides which can be shortened by motors. We will use this robophysical model to study how sporozoite locomotion varies with its mechanical properties and actuation and the parameters of the environment. This will provide a ground truth for future computational modeling.