This paper describes a pneumatic balloon actuator (PBA) composed of polydimethylsiloxane (PDMS) for cellular aggregate manipulation. We evaluated the ability of the microdevice to manipulate a tiny and sensitive cellular aggregate without causing serious damage. We used human mesenchymal stem cells (hMSCs) for the cellular aggregate. We describe the design, fabrication, characterization and operation of the soft microfingers to pinch and release a spherical hMSC aggregate (φ200 μm), and we employed a PBA to serve as an artificial muscle to drive the microfingers. A design of the microfingers in terms of dimensions, generated force and contact conditions was accomplished. The designed dimensions of a single finger were 560 μm×900 μm. In summary, we demonstrate the utility of the surface modification of a fingertip for pinching and releasing a cellular aggregate and describe a manipulation system that was constructed to drive and control the microfingers. The implemented manipulation system, which is composed of microfingers and a positioning mechanism, was tested and verified in a series of operations.
Keywords: cellular aggregate; manipulation; pinching; pneumatic balloon actuator; positioning; releasing; soft MEMS; surface modification.