Multi-material and multi-module freestanding microrobot for cargo transportation

Microrobots play an essential role in early diagnosis and precision medicine with the increasing demands for controllability in bio-medicine and micromanipulation, which can complete the pre-designed behavior under external stimulation. However, most microrobots are currently made of a single material system and focus on fabricating a driving module as the main structure of microrobots. This hinders the integration of diverse functions in one microrobot to fulfill the complex application. Here, a multi-material and multi-module hand-microrobot based on femtosecond laser direct writing technology is proposed, which has a pH-responsive capturing module and a magnetic-responsive transportation module (MRTM). This microrobot can not only respond to pH for capturing and releasing objects, but also respond to magnetic fields for cargo delivery even with obstacles. The two responding modules of the hand-microrobot are fabricated independently, and can collaborate with each other to achieve the delivery of target objects like polystyrene (PS) microsphere (10 µm) or 786-O cell by capturing, transporting, and spatial rolling. Besides, the MRTM can be locally fabricated on any prefabricated static structure, so that the whole microrobot can achieve controllable motion. This strategy is expected to be used to manipulate cells, deliver drugs for precise treatment, and environmental treatment.