Micro Transportation Systems: A Review

This paper summarized and reviewed recent studies of micro transportation systems (MTS) in the MEMS (Micro Electro-Mechanical System) field. Micro transportation systems can be identified and classified into three categories based on the contact types between the objects and the actuators (i.e. liquid-based, solid- based and air-bearing type). Their advantages and disadvantages were also analyzed and compared. The au- thors have proposed and developed three types of solid-based MTS utilizing electrostatic comb-drive actua- tors and ratchet mechanisms to drive the micro container in straight and curved paths. These MTSs have been fabricated with silicon-on-insulator (SOI)-MEMS technology and tested successfully. In the near future, MTSs can be applied in different fields such as medicine (to classify and test blood cells), in bioengineering (to capture, sort and combine bio-cells, DNA), or in micro robot systems.