These devices make house calls in the body
Implantable medical devices are designed to repair, replace, rehabilitate, and ultimately restore lost bodily function, but a newer class of these devices is focused on diagnosis. The emerging devices provide information about what’s happening in the body, and include things like glucose monitors, heart pressure sensors, brain-tissue oxygenation sensors, and neural recording devices. In addition, we are now seeing multifunctional, “smart” implants that not only sense but also treat conditions in a closed-loop response, leading to personalized, precise treatments that target individual needs.
My lab works with clinical partners at Indiana University School of Medicine, Purdue College of Veterinary Medicine, and other basic science researchers to develop smarter, more reliable implantable devices to improve healthcare’s diagnostic and therapeutic capabilities around such chronic diseases as neurodegeneration, metabolic diseases and inflammatory disorders.
Our research pursues three main avenues: 1) microscale devices to reduce invasiveness, 2) multifunctional devices for closed-loop treatments, and 3) reliable devices for chronic in vivo functionality. Examples of our work include a self-clearing shunt system for better treatment of intraventricular hemorrhage and hydrocephalus, smart shunts for glaucoma treatment, self-clearing biosensors for continuous neurodegeneration monitoring, microscale neural interfaces for neurorehabilitation, and a closed-loop antidote delivery system for opioid overdose.
In the self-clearing shunt system, we’ve created a smart catheter with microfabricated magnetic actuators that can reduce the size of blood clots following a hemorrhagic stroke so the blood can be removed more rapidly and clinical outcomes can be improved. We’ve integrated a multifunctional sensor to help us detect when the catheter is flowing freely or obstructed; it can also tell when the microdevice is activated and whether the catheter is placed correctly.
In our glaucoma device, microscale actuator arrays clean the microtube to help reduce high-pressure buildup in glaucoma patients. Our implantable biosensors can measure glucose, lactate and glutamate in vivo. Our innovation to treat opioid overdose detects respiratory failure via a wearable sensor, triggering a drug-delivery device that has been placed beneath the skin and can release the life-saving antidote naloxone within 10 seconds.
Reliability is one of the biggest challenges in implantable devices. Many implantable devices and biosensors don’t last very long due to the body’s anti-inflammatory response. A large area of my research is working on ways to restore functionality to these biosensors so clinicians can better track how the body changes as disease progresses; provide continuous, uninterrupted treatment; and note changes before a disease produces symptoms.
Our research could have an enormous impact on treating many chronic illnesses, like neurodegeneration and diabetes. To create long-lasting implantable biosensors, we are investigating novel conductive polymer, bioinspired designs, new nanomanufacturing techniques, and other microscale transducers to minimize immune response and add regenerative properties.
I believe the future of implantable devices lies in implanted distributed sensors that track how the body changes before a person has any problems. There are a lot of opportunities for improving devices around a multidisciplinary approach that involves novel materials, manufacturing techniques, and designs. With these advances, we can realize futuristic visions of such things as chronically reliable brain-machine interfaces and continuous monitoring biosensor arrays.
The sci-fi of implantable devices and biosensors — like downloading consciousness — that you see in media like the television series “Black Mirror” are not yet possible. There are certainly ethical questions to be addressed regarding these potential developments. But with careful consideration and guidance, we can push the boundaries of future medicine to significantly improve the quality of medical care, using smarter and more reliable implantable devices for more personalized, automatic and preventive treatments.
Hyowon “Hugh” Lee, PhD
Associate Professor, Weldon School of Biomedical Engineering
Birck Nanotechnology Center
Center for Implantable Devices
College of Engineering, Purdue University
Related Links
Purdue’s giant leap toward personalized medicine helps eyes drain themselves for glaucoma patients
Millions with neurological diseases could find new option in implantable neurostimulation devices
Opioid addicts become ‘first responders’ to their own overdose
Engineering critical solutions for the opioid epidemic
Laboratory of Implantable Microsystems Research — Research projects
Laboratory of Implantable Microsystems Research — Journal Publications
