“Are Thunderbirds Go?”; Another Swimming Robot May Propel Itself Through Bloodstream








In short

We seem to be frequently coming back to the topic of insertable or injectable, self-propelling, steerable “minisubmarines”, and it seems Stanford University is not to be left out in the quest with this project which they have been talking about this week.


We’ve covered endoscopic robots quite extensively in recent weeks, including one intended for internalisation in the intestine which is to be driven by external MRI and can apparently be “steered”, or at least somewhat orientated.  Find that one here. Then there was the endoscopically inserted crab-like gizmo which could be seen grasping and excising suspicious lesions on the intestinal wall. Of course we covered the swallowable endoscopic camera recently with a piece of research that rather suggested it missed too many lesions.

Now researchers at Stanford’s Engineering department have come up with what they describe in a press release as a tiny, wirelessly powered, self-propelled medical device capable of controlled motion through a fluid-blood more specifically.

The device was presented this week by assistant professor Ada Poon at the International Solid-State Circuits Conference (ISSCC). Her concept is similar (as far as we understand it) to the MRI-driven gizmo mentioned earlier in that it can be powered wirelessly using electromagnetic radio waves. No batteries to wear out. No cables needed to provide power.

From the Stanford press release, Poon comments “Such devices could revolutionize medical technology. Applications include everything from diagnostics to minimally invasive surgeries.”

While potential applications seem numerous we’re rather taken with the idea of a family of devices with specific purposes, rather like mini Thunderbirds (showing our age). Imagine the one with the drill on the front to penetrate the toughest plaque (The “Mole”), or the one like Thunderbird 3 capable of delivering a payload like for example a stent.. or a dose of a particular drug to a particular locale.

Avoiding bulky batteries

“While we have gotten very good at shrinking electronic and mechanical components of implants, energy storage has lagged in the move to miniaturize,” said co-author Teresa Meng, a professor of electrical engineering and of computer science at Stanford.

The Stanford release states that the idea of implantable medical devices is not new, but most of today’s implements are challenged by power because of the required battery size.  Large, heavy batteries must be replaced periodically. Fully half the volume of most of these devices is consumed by battery. One idea, covered recently here for application to a static device such as a pacemaker, was to use the body’s own energy to provide drive.

Poon’s devices however consist of a radio transmitter outside the body sending signals to an independent device inside the body that picks up the signal with an antenna of coiled wire. The transmitter and the antenna are magnetically coupled such that any change in current flow in the transmitter produces a voltage in the coiled wire — or, more accurately, it induces a voltage. The power is transferred wirelessly. The electricity runs electronics on the device and propels it through the bloodstream, if so desired.

Clever stuff, deliberately dumbed down to schoolboy level for our bit of friday fun.

Source: Stanford University