By Mariah Quintanilla
Exceptionally talented athletes and hard working people are often described as “machines” because of their seemingly super-human abilities. To many scientists who study biological processes, however, the “human machine” metaphor is not a metaphor at all, but a scientific truth.
The emerging field of biological engineering research utilizes our own cells as potential building blocks for machine-like capabilities, said researchers from the University of Illinois and the Georgia Institute of Technology. These future biological machines may be “hyper organs” that are more efficient than our own organs, or insulin-releasing implants made entirely of cells, they said at the American Association for the Advancement of Sciences (AAAS) conference in Boston.
Why build with cells?
Rashid Bashir and Taher Saif, a bioengineer and mechanical engineer at the University of Illinois at Urbana-Champaign, have been experimenting with “self-emerging” structures formed from stem cells. The cells are placed in a petri dish and genetically programmed to form natural structures.
“In biology, we talk a lot about structure and function,” Bashir said. “We want to get to a point where the cell cluster knows how to form a shape.” Instead of making cells adhere to a fabricated structure, Bashir and Saif hope to train the cells to form a structure and carry out certain functions on their own.
Our body fixes itself when it sustains a minor injury, continually regulates its internal pH and temperature, and protects itself against outside invaders, such as pathogens, to avoid getting sick. Our cells also interact with each other to form muscle, and coagulate to stop bleeding. Cell-based machines are promising because they are so unlike traditional machines, which must be constructed, and then fixed when broken, Bashir said.
In one experiment, the researchers placed cardiac muscle cells and a string together on a petri dish, and observed the resulting interactions. “We are throwing (cells) on this scaffold … and the cells organized themselves to form a muscle ring,” Saif said.
The muscle cells used the string as a sort of backbone, and formed a moving structure, similar in function and appearance to the “tail,” or flagella, of a bacterium. If replicated, no two swimmers will be alike, said Saif. Each cluster of cells arranges themselves into unique structures that perform the same swimming movements.
The ethical questions and future of bio machines
Researchers are experimenting with a variety cells, from neurons, found in the brain, to epithelial cells that make up our skin. They hope to “harness the intelligence” of neurons, drawing on the millions of years of evolutionary knowledge built into them.
“If you knew how to put those building blocks together, you could design anything,” Bashir said.
The endless possibilities in the realm of biological engineering evoke an equally endless list of ethical concerns, said Lizanne DeStefano, associate dean in the College of Sciences at Georgia Institute of Technology, who contributed to the panel discussion. The parameters of organ and tissue donation must be carefully discussed with patients, so that they are aware of the exact way in which their body parts are being used. Some positive ethical advances, however, are likely to emerge from new biotechnology.
Animal testing has been a hallmark of pharmaceutical research, DeStefano said. Mice and monkeys are frequently used to judge efficacy of drugs, and the resulting data is never directly designed for humans. Biological machines may bypass the need for animal testing, and lead to more specificity in drug and organ development.
Bashir and Saif recognize that ethics are an integral factor in their research goals, and have integrated ethical workshops into their current research.
“We have to be very careful. We are dealing with living entities,” Bashir said. Engaging in public dialogues on the ethics of biological machines is critical as they continue with their research, he said.