Microfluidic wound scratching platform based on an untethered microrobot with magnetic actuation

Cell migration is closely associated with various pathological conditions such as tumor invasion and metastasis as well as cell proliferation. The in vitro wound healing assay involves a simple and affordable technique and is used to examine the migration abilities of cells in a wound area created on confluent cell culture. Although this technique is easy to implement, it is not suitable for microfluidic chips. Microfluidic systems offer advantages such as examining the microenvironment of the cells and performing an analysis closer to the living system in a continuous flow setting. However, they are not compatible with the classical wound healing assay since they are closed systems, and their small channels are not suitable for wound creating via a micropipette tip. This work presents a functional system, which can be used to create wounds in a microfluidic platform without causing any negative effects on the cells and requiring the use of any chemicals. In this system, an untethered magnetic microrobot, which can be manipulated in 4 degrees of freedom (DOF) to create wounds with uniform sizes and different shapes within a closed microfluidic system was used. In addition, the effect of different wound geometries on wound healing was investigated. According to the results, triangle-shaped wound healed the slowest, while the plus-shaped wound healed the fastest. This study could open new lanes in the use of microrobots in lab-on-a-chip devices and can be extended to 3D cell cultures in the near future.