The rise of the cyborgs: Scientists reveal new method to 'grow' electronic sensors inside human tissue

* Researchers say breakthrough is 'first step' towards an artificial heart
* Could be used to implant sensors into patients to monitor medical issues
* Can also be used in labs to study the effects of new drugs

By Mark Prigg

Cyborgs melding human and robotic technology together have finally come a step closer to reality.

Researchers at MIT in Boston have revealed a new technique that can place sensors inside human tissue.

To control the three-dimensional shape of engineered tissue, researchers grow cells on tiny, sponge-like scaffolds.

These devices can be implanted into patients or used in the lab to study tissue responses to potential drugs.

A team of researchers from MIT, Harvard University and Boston Children’s Hospital has now added a new element to tissue scaffolds: electronic sensors.

These sensors, made of silicon nanowires, could be used to monitor electrical activity in the tissue surrounding the scaffold, control drug release or screen drug candidates for their effects on the beating of heart tissue. 

'We are very excited about this study,' Robert Langer, the David H. Koch Institute Professor at MIT and a senior author of the paper said.

'It brings us one step closer to someday creating a tissue-engineered heart, and it shows how novel nanomaterials can play a role in this field.'

The researchers built their new scaffold out of epoxy, a nontoxic material that can take on a porous, 3-D structure.

Silicon nanowires embedded in the scaffold carry electrical signals to and from cells grown within the structure.

'The scaffold is not just a mechanical support for cells, it contains multiple sensors.

'We seed cells into the scaffold and eventually it becomes a 3-D engineered tissue,' Tian says.
The team chose silicon nanowires for electronic sensors because they are small, stable, can be safely implanted into living tissue and are more electrically sensitive than metal electrodes.

The nanowires, which range in diameter from 30 to 80 nanometers (about 1,000 times smaller than a human hair), can detect voltages less than one-thousandth of a watt, which is the level of electricity that might be seen in a cell.

In the Nature Materials study, the researchers used their scaffolds to grow cardiac, neural and muscle tissue.

Using the engineered cardiac tissue, the researchers were able to monitor cells’ response to noradrenalin, a stimulant that typically increases heart rate.

Gordana Vunjak-Novakovic, a professor of biomedical engineering at Columbia University, says the work could help address a great need to engineer cells that respond to electrical stimuli, which may advance the treatment of cardiac and neurological disease.

'This is a beautiful example of how nanoelectronics can be combined with tissue engineering to monitor the behavior of cells,' says Vunjak-Novakovic.

The team also grew blood vessels with embedded electronic sensors and showed that they could be used to measure pH changes within and outside the vessels.

Such implantable devices could allow doctors to monitor inflammation or other biochemical events in patients who receive the implants.

Ultimately, the researchers would like to engineer tissues that can not only sense an electrical or chemical event, but also respond to it appropriately - for example, by releasing a drug.

VIDEO: See the scaffolds in action before being fixed with electronic sensors...