The Sensor Revolution: Health

In the iRevive system, tiny wireless sensors monitor an emergency patient’s heart rate, blood oxygen level, and other vital signs. The sensor data is captured in a record that can be accessed via a secure wireless network, aiding medical decision-makers at every stage, from first responders to ambulance technicians to emergency room physicians.

Credit: Matt Welsh, Harvard University

Sensors have applications in every phase of health care and diagnostics. Doctors now perform tests in their offices that were sent out to laboratories just a few years ago. The results are available immediately, and at lower cost. Wireless, wearable sensors can provide continuous monitoring of the elderly or chronically ill in their own homes. And in an emergency situation, networks of wireless patient monitors can ensure the quick and accurate transfer of information between first responders and hospital emergency rooms, even when there are multiple casualties.

Imaging Below the Surface

At the NSF’s Center for Subsurface Sensing and Imaging Systems (CenSSIS) at Northeastern University in Boston, researchers are using a “physics-based imaging” approach to extract the maximum available information from subsurface sensing technologies. Scientists and engineers from Northeastern University, Boston University, and Rensselaer Polytechnic Institute combine state-of-the-art fabrication techniques with sophisticated physical modeling to create instruments that “see” through skin, water, or other tissues and fluids. They are using this approach to improve mammography and to raise the success rate of in vitro fertilization through internal examination of embryos. It works equally well for non-medical problems like land mine detection and monitoring of coral reefs—an application being pursued with partners at the University of Puerto Rico-Mayaguez.

Restoring Failing Vision

At Wayne State University, Loren Schwiebert and his colleagues at the Networking Wireless Sensors laboratory are using their technology to help the visually impaired. Their designs for artificial retinas and cortical implants transmit signals from external cameras to stimulators within the eye. The NEWS team uses retinal prosthetics to aid patients suffering from retinitis pigmentosa, macular degeneration, or other diseases in which the eyes' own sensors—the rods and cones—are destroyed, but the underlying retinal structure is sound. When the retina itself is damaged and will not respond to electrical stimulation, they use a cortical implant instead. Schwiebert is researching network protocols and power management for the systems, which can’t rely on an internal power source—power for the implanted electronics must be supplied over the radio link together with high bandwidth video data.

Catching Heart Attacks Early

University of Louisville researcher Kyung Kang and his colleague Chang Ahn, at the University of Cincinnati, use MEMS machining methods to make microfluidic devices that can simultaneously perform four separate biochemical assays. By measuring four cardiac markers rapidly and simultaneously, they hope to improve care for suspected heart attack patients.

Case Western Reserve University electrical engineer Darrin Young has another approach to bettering cardiac health. Young’s team is working on pill-sized implantable sensors for heart rate, blood pressure and temperature. Initially, the devices will report the vital signs of a lab mouse to an external computer. Working with geneticist Joseph Nadeau at the Case School of Medicine, Young eventually hopes to identify at-risk patients and detect the onset of heart attacks or epileptic seizures before they reach a critical stage.

Comprehending Alzheimer’s Disease

(Left) This biosensor is made from an array of silver nanoparticles deposited on glass. The nanoparticles are surrounded by strong electric and magnetic fields (right) that change when molecules from the environment bind to the sensor.

Credit: Amanda J. Haes, Richard P. Van Duyne, Department of Chemistry, Northwestern University (left). K. Lance Kelly, George C. Schatz, Nanoscale Science and Engineering Center, Northwestern University (right)

Alzheimer’s patients may benefit from sensor research by Northwestern University chemist Richard van Duyne and neurobiologist William Klein. Van Duyne’s group uses surface plasmon resonances to detect small shifts in the electronic properties of their sensors as molecules attach. By fine-tuning the surface chemistry of the sensor, the attachment properties of different molecules can be studied. Klein has a theory that small proteins called amyloid β-derived diffusible ligands (ADDLs) are key agents in Alzheimer’s pathology, so he worked with researchers in van Duyne’s lab to develop SPR sensors that monitor the binding of ADDLs with their antibodies.