Grow Your Own: How Artificial Organs Will Change the Face of Medicine

Back in June I entered the University of the West of England and BBC Focus Magazine’s science writing competition, which had the theme “the Science that will transform our future”. I didn’t win anything of course, but thought I’d share the article. You can read the winners’ entries here.

Grow Your Own: How Artificial Organs Will Change the Face of Medicine

A human ear growing out of the back of a mouse. In 1997 this astonishing image led to speculation that one day organs for human transplantation might be obtained this way. Since then the field of body part and organ creation has seen real progress, and the new direction it has taken appears to bring us much closer to a future where organ donors and animal testing are obsolete.

Printing To Order

According to NHS Blood and Transplant there have been almost 7,000 patients awaiting a solid organ transplant in the UK in 2014. Compare this figure with the 708 transplants which took place in the same year and the problem is clear. One solution is to create organs for each patient.

The use of engineered tissue is not new. In 2001 Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine, led a pioneering procedure in which patients with poor bladder function received replacement organs formed from their own cells. Since then other structures have also been grown by sowing cells and growing them on either a protein or synthetic scaffold, such as skin, bone marrow and even a whole trachea. However moving onto complex organs such as the lungs or liver is not a simple matter.

A newer development which has helped in artificial organ formation is the use of three dimensional printing. 3D printing of tissue is now possible, albeit mainly small samples for research purposes. Cells are used as the “ink”, and layers of different cells are built up to form the required structures. The biggest hindrance to perfecting organs has been the vasculature conundrum – how could a stable network of tiny blood vessels, vital for delivering oxygen and nutrients and removing waste, be created? The answer was found by American and Australian university researchers who 3D-printed a mould using agarose fibres (a sugar extracted from seaweed). The mould formed microchannels in a cell and protein mixture which was then solidified using light, allowing the fibres to be removed. A layer of endothelial cells then lined the channel walls to form blood vessels.

With the ability to vascularise organs formed from patients’ own cells, we may see an end to long transplant waiting lists, organ rejection and the need for immune system-suppressing anti-rejection drugs within the next few decades.

A Whole Body On A Chip

The main reason why animal testing remains part of the drug development process is because they contain entire interlinked organ systems which cannot be replaced by a human cell layer in a petri dish. Those at Harvard’s Wyss Institute have developed organs-on-chips as a potential answer. Flat, plastic pieces, only a few centimetres long, contain channels lined with different cells depending on the organ being emulated. Layering various cell types creates an organ model which can be supplied with blood or air depending on the organ, and then bacteria or drugs to mimic various conditions. Linking chips together could potentially recreate an entire body, So far only the liver and lung chips have been successfully linked.

The end of animal testing is not the only benefit. These chips could simulate illnesses or the organ systems of the very young or elderly – all groups which are excluded from initial stage clinical trials – for more representative results.

Cyborg Body Parts

Teaming 3D printed biological material with electronics could be a way to ensure that they function normally, or even better. A team from Princeton University was able to create a bionic ear using a mixture of 3D-printed molecules: calf cells mixed with hydrogel to form the ear structure, and silver nanoparticles which would become a coiled antenna to act as the cochlea. This printed structure could pick up radio frequencies beyond normal human hearing, and two such ears could “hear” in stereo.

While this is ear is unlikely to used therapeutically, the methods used in it’s formation proved 3D printing can allow the full integration of electronic parts into tissue. Biocybernetic technology could pave the way for the internal monitoring of organs, provide novel treatments for organ dysfunction and even lead to superhuman senses. The creation of customised body parts, although controversial, will open up a world of possibilities.

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