WHAT WE MAKE ...
KEEPS PEOPLE HEALTHY
MINUTE MEDICAL SENSOR
Babak Ziaie is harnessing the science of small. Among his most recent prototypes is a minute medical sensor that could be implanted in the body to monitor aneurysms.
Babak Ziaie, professor of electrical and computer engineering and biomedical engineering, developed a minute pressure sensor that could be used to monitor aneurysms and other medical conditions. Among his other concepts is an implantable wireless dosimeter designed for use as a radiation detector to ensure accurate dose monitoring in radiation oncology.
WHEN SMALL IS VERY
Acoustic waves from music, particularly the driving bass rhythm of rap, cause a component in the device to vibrate, and this vibration is harvested to generate electricity. The resulting electric charge enables the device to transmit data to a receiver, which could be placed several inches from the patient.
The implantable pressure sensor is tested (video) inside a balloon that represents a urinary bladder while music is played as a researcher monitors the device's performance. The prototype (bottom picture) is shown next to a quarter for size perspective.
ONE DEVICE, MANY USES
The new acoustically charged sensor is capable of monitoring pressure in the urinary bladder and in the sac of a blood vessel damaged by an aneurysm. It could one day be used to curb incontinence in people with paralysis by checking bladder pressure and stimulating the spinal cord to close a sphincter that controls urine flow from the bladder.
This graphic illustrates the principles behind the operation of a new type of miniature medical sensor designed to be implanted in the body. The device is powered by acoustic waves capable of penetrating tissue.
The design offers potential benefits over conventional implantable technologies, which either require batteries or receive power through “induction” coils on the device and an external transmitter. Both approaches have downsides. Batteries have to be replaced periodically, requiring surgery, and data are difficult to retrieve from devices that use coils.
Ziaie is pictured holding a dime-size prototype of a wireless device designed to be implanted in tumors to tell doctors the precise dose of radiation received and locate the exact position of tumors during treatment. "Currently, there is no way of knowing the exact dose of radiation received by a tumor," Ziaie says. "And, because most organs shift inside the body depending on whether a patient is sitting or lying down, for example, the tumor also shifts. This technology will allow doctors to pinpoint the exact position of the tumor to more effectively administer radiation treatments." The device eventually will be reduced to the size of a rice grain.
The device is an example of a microelectromechanical system, or MEMS. The research team would like to further miniaturize the sensor. "If it were smaller it could be used in the brain to, for example, measure pressure in the skull for patients who have hydrocephalus," Ziaie says.
The sensor is one in a long line of novel ideas springing from Ziaie’s lab in the Birck Nanotechnology Center at Purdue’s Discovery Park.
AMONG ZIAIE'S OTHER CONCEPTS:
- Devices that might be implanted in tumors to generate oxygen, boosting the killing power of radiation and chemotherapy.
- A magnetic “ferropaper” to fashion low-cost “micromotors” for surgical instruments, tiny tweezers to study cells and miniature speakers.
- A wireless device the size of a rice grain that could be injected into tumors to tell doctors the precise dose of radiation received and locate the exact position of tumors during treatment.
- A new type of pump for drug-delivery patches having arrays of “microneedles” to deliver a wider range of medications than now possible with conventional patches.
- Stretchable electrodes to study how cardiac muscle cells, neurons and other cells react to mechanical stresses from heart attacks, traumatic brain injuries and other diseases.
- A technique that uses inexpensive paper to make “microfluidic” devices for rapid medical diagnostics and chemical analysis.