Our Bioartificial Future

Sixty years ago, room sized computers for extremely specific applications were an impressive technology demonstration. We all know how that evolved. At a comparable stage in the advance of biotechnology, today we see that bioartificial implants - cells combined with microscale and chemical engineering - can perform one of the tasks of a pancreas:

Encapsulating a large collection of islets has been difficult, he says, because the material to make that capsule has never been designed for that purpose.

"This device differs because its polymer membrane has been designed to have the optimal properties for encapsulating islets," Rosenthal tells C&EN. "It allows for free movement of insulin and glucose but restricts access of immune molecules that might attack the encapsulated islets." Likewise, any viruses that might be piggybacking on the islets are trapped behind the membrane.

"Because of that, we can use pig cells, and the only thing that communicates between them and the patient are the small molecules and small proteins," Rosenthal notes.

The polymer can also sequester oxygen from the environment, thanks to its silicone-based components. This oxygen nourishes the encapsulated islets cells. "These membranes are biocompatible, flexible, transparent, autoclavable, and they're easily synthesized and relatively inexpensive," Rosenthal says.

Those room sized computers were pretty clunky and dedicated; the real challenge was in integrating such a beast with the processes and organization it was intended to help. The same is true of medical implants and helper devices, as we're just not very good at putting things in the body yet, measured on the grand scale of what is possible. It's tough, expensive and often damaging to the patient. But take a look at the computer you're using to read this post. Sixty years ago, you'd have had to build a city of rooms to match its power. Integration of that power for use in specific tasks is easy now, and an entire infrastructure exists to handle the tasks that are beyond one person's time and energy.

So to the future of bioartificial organs. A computer doesn't look much like a brain, a slide-rule, or a typewriter. The bioartificial pancreas of the future won't look a whole lot like the pancreas you're carrying around with you at the moment. In parallel to work on regenerative medicine and repair of aging - aiming to maintain the body we have - we will see a great breadth of development in semi-organic prostheses and other functional replacements, and the growth of support infrastructure for that technology.

There is a certain logic here that suggests bioartificial bodies as an end-point: consider that researchers can build a bioartificial pancreas, but it's still that case that long-term use of implants is a burden in the best cases, and simply impossible in most others. The problem is the integration between systems we have built and evolved systems in the body: everything from matching blood vessels to dealing with the immune system response is a challenge. So instead of hooking your new bioartificial organ up to a body, wouldn't it be easier to hook it up to another collection of bioartificial organs, where it is perfectly feasible to control all the interactions? The end of that line of thinking is a comprehensive support machinery for the human brain, an entirely different form of body and technology base in beneficial competition with regenerative medicine. Choice is good; mix and match.

It's a challenge to say what will be hard and will be easy 20 years from now, never mind further out. Maybe controlling the body to accept long-term implant use is trivial in 2030, and everyone queues up for the latest blood filter device from a Japanese fashion house, as it's substantially better than the one you were born with. But if you're interested in living for a long time, it's a benefit to keep up with what is happening today, and think about what is plausible in the years ahead.

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