Development of a Regenerable Cell Culture Material System That Senses and Releases Dead Cells
Takeo Yamaguchi1, Shuhei Okajima1, and Yasuyuki Sakai2. (1) Chemical System Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan, (2) Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
We developed a rapidly regenerable cell culture system in which the cell culture substrate detects cell death and selectively releases the dead cells. This culture material was achieved by combining a detector that responds to the signal from the dead cells and an actuator to release the dead cells. Benzo-18-crown-6-acrylamide (BCAm) with a pendant crown ether receptor was used as the sensor to recognize cellular signals and N-isopropylacrylamide (NIPAM) was used as the actuator. This copolymer of NIPAM and BCAm can respond to potassium ions and change its nature from hydrophobic to hydrophilic at the culture temperature of 37 °C. Living cells concentrate potassium ion internally; when cells die, potassium ions are released. The polymer surface recognizes the potassium ions released from the dead cells, the NIPAM hydrates, and the dead cells are selectively detached. This in vitro culture system is a novel one in which artificial culture materials work cooperatively with cellular metabolism by responding to this signal from the cells, thereby realizing in vitro tissue regeneration partly mimicking the mechanisms of in vivo homeostasis. By releasing dead cells rapidly, surrounding living cells were not affected by diffusion of cellular contents and cytokines, and rapid tissue repair was observed. This material system would increase the overall lifetime of bioreactors or bioartificial organs. Furthermore, this material will be used as the cell culture substrates for specific cells that are difficult to cultivate due to quick cell death in vitro.