Development of a Cell-Loading Microrobot with Simultaneously Improved Degradability and Mechanical Strength for Performing In Vivo Delivery Tasks

Microrobots with simultaneously improved degradability and mechanical strength are highly demanded in performing in vivo delivery tasks in clinical applications. The properties of degradability and mechanical strength are contradictory for many materials used to make microrobots. This article proposes a new design that can result in 3D cell culture microrobots with improved degradability and mechanical strength from the following perspectives. First, the mechanical strength of a microrobot is improved using triangle patterns to replace hexagon pattern in the microrobot structure, which can provide more supporting grids to obtain increased mechanical strength. Second, the relationship between structural design and material composition in relation to the mechanical strength of microrobot is investigated. The study reveals that triangle-patterned microrobots have increased mechanical strength compared with hexagon-patterned microrobots, thereby allowing high composition of degradable material that leads to the fast degradation of the microrobot. It is also shown that the triangle-patterned microrobots can maintain the same structural integrity and cell capacity as hexagon-patterned microrobots. Finally, the demonstration shows that the triangle-patterned microrobot can be precisely navigated in microfluidic channels. This article successfully demonstrates that the degradability and mechanical strength can be improved simultaneously through the microrobot structural design.