Engineering Minute

Engineering Minute – Weight Loss Implant

Engineers at University of Wisconsin-Madison have developed a battery-free, implantable weight-loss device to combat obesity. The implantable device is about a third the size of a penny and can be inserted using a minimally invasive procedure. It acts by generating electrical pulses from the stomach's natural movements during digestion, and delivers those pulses to the vagus nerve that communicates signals from the stomach to the brain. The pulses trick the brain into thinking the stomach is full after only a few bites of food. In animal models, the device helped rats to shed almost 40 percent of their body weight. The results of this study were recently published in Nature Communications.

implantable weight-loss device
Graduate student Guang Yao (left) and Xudong Wang (right) hold a small implantable device that helped rats lose 40 percent of their body weights. Photo credit: University of Wisconsin-Madison.


“The pulses correlate with the stomach’s motions, enhancing a natural response to help control food intake,” stated Xudong Wang, a University of Wisconsin–Madison professor of materials science and engineering. “It’s automatically responsive to our body function, producing stimulation when needed."


From the University of Wisconsin-Madison article "Wang’s device has several advantages over an existing unit that stimulates the vagus nerve for weight loss. That existing unit, “Maestro,” approved by the Food and Drug Administration in 2015, administers high-frequency zaps to the vagus nerve to shut down all communication between the brain and stomach. It requires a complicated control unit and bulky batteries which frequently must be recharged.

That ongoing maintenance can be a big barrier to use, says Dr. Luke Funk, a surgery professor in UW–Madison’s Division of Minimally Invasive, Foregut and Bariatric Surgery who was not involved in the research. 'One potential advantage of the new device over existing vagus nerve stimulators is that it does not require external battery charging, which is a significant advantage when you consider the inconvenience that patients experience when having to charge a battery multiple times a week for an hour or so,' he says."


Read more about the implantable weight loss device at the University of Wisconsin-Madison