![\"Photo](\"https:\/\/www.wisconsin.edu\/all-in-wisconsin-new\/wp-content\/uploads\/sites\/378\/2021\/07\/MAD_bone_healing_device1-500x333-1.jpg\")
Researchers know that electricity can help speed up bone healing, but \u201czapping\u201d fractures has never really caught on, since it requires surgically implanting and removing electrodes powered by an external source.<\/p>\n
A major update of that same electrostimulation concept, Wang\u2019s latest invention didn\u2019t come in time to help the 2017 Packers \u2014 however, it may help many others by making electrostimulation a much more convenient option to speed up bone healing.<\/p>\n
His thin, flexible device is self-powered, implantable and bioresorbable, so once the bone is knitted back together, the device\u2019s components dissolve within the body.<\/p>\n
Wang and his collaborators, including Weibo Cai, a UW\u2013Madison professor of radiology and medical physics, described the new device today (July 5, 2021) in the journal Proceedings of the National Academy of Sciences.<\/p>\n
Bone is a piezoelectric material, meaning it produces a tiny bit of electricity when placed under strain. These jolts of electricity stimulate factors that promote bone growth and healing, which is why electrostimulation is an effective therapy.<\/p>\n
While there are external stimulators that create an electric field to accelerate healing indirectly, the ideal solution is stimulating the bone directly. Putting the device inside the body, however, has unique requirements \u2014 not the least of which is powering it, according to Wang.<\/p>\n
\u201cThe ideal case is to have the device be self-generating, which was something that didn\u2019t exist before this,\u201d he says.<\/p>\n To create the new fracture electrostimulation device, or FED, Wang and his team started with a triboelectric nanogenerator, a thin-film device with microstructured surfaces that converts mechanical energy produced by tiny movements into electric power. They coupled the nanogenerator with a pair of electrodes to distribute the electric field to the bone. They built these ultrathin, biodegradable and bioresorbable components on a substrate of poly(lactic-co-glycolic acid), a commonly used FDA-approved biocompatible polymer.<\/p>\n The researchers\u2019 initial tests confirmed that small movements of the device did indeed create an electrical stimulation of about 4 volts, which it could sustain for over six weeks. They then tested the device on rats.<\/p>\n The animals implanted with the device completely recovered from a tibia fracture in about six weeks, much more quickly than animals in a control group. The mineral density and flexural strength of the healed bones also reached the same level as healthy bones in the animals that received the electrostimulation. After the treatment, the devices degraded and absorbed into the rats\u2019 bodies with no complications and no need for surgical removal.<\/p>\n Wang says that it\u2019s possible to fine-tune how long the stimulator will last within the body \u2014 from weeks to months \u2014 by tweaking the properties of the bioresorbable material coating the device.<\/p>\n The thin, flexible device is self-powered, implantable and bioresorbable, so once the bone is knitted back together, the device\u2019s components dissolve within the body.<\/p><\/blockquote>\n Eventually, Wang would like to scale up the fracture electrostimulation device so it will work in humans. But for these self-powered devices, the energy source can be a factor.<\/p>\n \u201cTypically, when someone has a broken bone, they need to restrict their movement,\u201d he explains.<\/p>\n In other words, someone wearing a cast might not produce enough mechanical energy to power the triboelectric nanogenerator.<\/p>\n \u201cThe way a rat moves provides constant stimulation for the device, but for a broken bone in a human that can\u2019t be moved, that\u2019s an issue,\u201d says Wang.<\/p>\n However, the human body provides virtually endless sources of movement that could power the fracture electrostimulation device if the broken bone must remain immobile. \u201cWe may need the device to respond to other types of internal mechanical sources, like blood pressure changes,\u201d says Wang, who\u2019s already looking to the FED\u2019s future.<\/p>\n \u201cIt will be very interesting and impactful to address the development from animal to human,\u201d he says.<\/p>\n Cai is also excited to continue the work.<\/p>\n \u201cOur continued collaborations over the last decade have been very productive and highly synergistic,\u201d says Cai, who has worked with Wang to create a bandage that works along similar principles and an implantable weight loss device, among other projects. \u201cThe Wang group designs and fabricates many intriguing devices, and our group can test those in vivo in various small animal models for subsequent large animal studies and potential clinical translation.\u201d<\/p>\n Other UW\u2013Madison authors include Jun Li, Kangning Zhao and Weina Xu. Guang Yao and Lei Kang of UW\u2013Madison and of Peking University First Hospital; Cuicui Li and Junzhe Yang of Peking University First Hospital; Sihong Chen, Qian Wang and Yuan Lin of the University of Electronic Science and Technology of China, Chengdu; and Yin Long of UW\u2013Madison and the University of Science and Technology of China also contributed.<\/p>\n THIS RESEARCH WAS SUPPORTED BY GRANTS FROM THE NATIONAL INSTITUTES OF HEALTH (R01EB021336 AND P30CA014520).<\/p>\n","protected":false},"excerpt":{"rendered":" In 2017, Green Bay Packers quarterback Aaron Rodgers broke his right collarbone in a game against the Minnesota Vikings. Typically, it takes about 12 weeks for a collarbone to fully heal, but by mid-December fans and commentators were hoping the three-time MVP might recover early and save a losing season. So did Xudong Wang, a […]<\/p>\n","protected":false},"author":15,"featured_media":6655,"comment_status":"closed","ping_status":"closed","template":"","institution":[103],"story_category":[],"class_list":["post-6650","campus_story","type-campus_story","status-publish","has-post-thumbnail","hentry","institution-uw-madison"],"_links":{"self":[{"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/campus_story\/6650","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/campus_story"}],"about":[{"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/types\/campus_story"}],"author":[{"embeddable":true,"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/comments?post=6650"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/media\/6655"}],"wp:attachment":[{"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/media?parent=6650"}],"wp:term":[{"taxonomy":"institution","embeddable":true,"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/institution?post=6650"},{"taxonomy":"story_category","embeddable":true,"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/story_category?post=6650"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Photo](\"https:\/\/www.wisconsin.edu\/all-in-wisconsin-new\/wp-content\/uploads\/sites\/378\/2021\/07\/MAD_bone_healing_Xudong_Wang-333x500-1-200x300.jpg\")