"More than  million adults and children worldwide are obese according to a  study that called the growing number and weightrelated health problems a rising pandemic. New batteryfree easily implantable weightloss devices developed by engineers at the University of WisconsinMadison could offer a promising new weapon for battling the bulge. In laboratory testing the devices helped rats shed almost  percent of their body weight. Results of the study were published today Dec.   in the journal Nature Communications. Measuring less than  centimeter across or about a third of the area of a U.S. penny the tiny devices  which are safe for use in the body and implantable via a minimally invasive procedure  generate gentle electric pulses from the stomachs natural churning motions and deliver them to the vagus nerve which links the brain and the stomach. That gentle stimulation dupes the brain into thinking that the stomach is full after only a few nibbles of food. The pulses correlate with the stomachs motions enhancing a natural response to help control food intake says Xudong Wang a UWMadison professor of materials science and engineering. Unlike gastric bypass which permanently alters the capacity of the stomach the effects of the new devices also are reversible. When Wang and his collaborators removed the devices after  weeks the studys rats resumed their normal eating patterns and weight bounced right back on. Wangs 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  administers highfrequency 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 Luke Funk a surgery professor in UWMadisons Division of Minimally Invasive Foregut and Bariatric Surgery. 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. In fact Wangs device contains no batteries no electronics and no complicated wiring. It relies instead on the undulations of the stomach walls to power its internal generators.  That means the device only stimulates the vagus nerve when the stomach moves. Its automatically responsive to our body function producing stimulation when needed says Wang. Our body knows best. Wang is a world expert in wearable and implantable capacitive electricitygenerating devices having previously created implantable nanogenerators that harvest energy from peoples beating hearts and breathing a motionpowered bandage for wound healing and other such devices. He and his collaborators patented the weightloss device through the Wisconsin Alumni Research Foundation and are moving forward with testing in larger animal models. If successful they hope to move toward human trials. Our expectation is that the device will be more effective and convenient to use than other technologies says Wang.  UWMadison radiology professor Weibo Cai is also a senior author on the study.  This research was supported by grants from the National Institutes of Health REB and PCA.  Sam MillionWeaver   millionweavewisc.edu mailtomillionweavewisc.edu  DOWNLOAD PHOTOS httpsuwmadison.box.comvweightloss"