In 2010, Shinya Yamanaka, the winner of the Kyoto Prize, had discovered pluripotent stem cells. At the University of Berkeley, bioengineers used these stem cells to create living, beating hearts on-a-chip. Their aim is to reproduce organs of the human body on-a-chip and then interconnect them with channels carrying micro-fluidics, ultimately creating a complete human being on-a-wafer.
According to Professor Kevin Healy, bioengineers have mastered the art of deriving almost any type of human tissue for skin stem cells. Yamanaka was the discoverer of this process. Healy wants to use this in drug screening applications, since that can be done without actually testing on animals. Ultimately, by generating organs-on-a-chip using the stem cells of the patient would be beneficial as this could help with study of genetic diseases as well.
At present, the heart on-a-chip beats each time it pumps blood through micro-fluidic veins within its polymer and silicone chamber. By connecting the various organs via micro-fluidic channels that carry natural biological fluids and blood between them, bioengineers plan to study the interaction of drugs among the various organs.
For example, by solving a heart problem with a drug, the liver might start retaining toxins. It would be much better to find this out beforehand prior to administering the drug to the patient.
The UC Berkeley developed heart-on-a-chip uses human heart tissues that have been derived from adult stem cells. Researchers hope someday to replace the animal models currently used for drug safety testing. However, Professor Healy clarified that creating living robots by the process was not their mission. Their funding comes from the Tissue Chip for Drug Screening Initiative of the National Institute of Health. This being an interagency collaboration aimed specifically at developing 3D human tissue chips solely for drug screening.
Nonetheless, this technology of creating organs-on-a-chip and interconnecting them via micro-fluidic channels, might someday lay the foundation for making robot-like creatures. For example, a single 4-inch wafer can house about 24 artificial heart chips.
However, making robot-like creatures requires sensors and actuators. Although sensors are easier, actuators pose more problems. According to Professor Healy, MIT is working on developing artificial muscles to serve as actuators.
Professor Healy along with his colleagues has created an inch-long artificial heart, which is housed in silicone, and contains real cardiac muscle cells. Once the heart cells are inserted within the device, it takes about 24 hours for the cells to begin spontaneously beating at the normal rate of 55-80 times per minute. Simultaneously, the heart cells pump blood through the micro-fluidics channels. Administering drugs known to slowdown or speed up the heart’s frequency, causes the artificial heart to respond normally.
Currently, the micro-fluidics channels carry only nutrients. However, the same channels might someday be used to carry away waste products as well. Professor Healy’s lab has managed to keep the cells viable over several weeks. They plan to put hundreds of organs-on-a-chip and spread them across a wafer, interconnecting them all with micro-fluidics channels carrying blood and other essential bodily fluids. Very soon, using animals for drug screening would end.
