Sam Sia, professor of biomedical engineering, and Ken Shepard, Lau Family Professor 0f Electrical Engineering and professor of biomedical engineering, have won a $16.4 million four-year grant from DARPA for their proposal, "Treatment and Recovery Augmented with Electrical and Ultrasound?Mediated Actuation and Sensing."
With the funding, the Columbia Engineering researchers are developing an "active" bandage together with active implanted components that, guided by a machine-learning framework to monitor and modulate the healing progression, will accelerate the recovery of the wound. Their proposed patch device, several centimeters long and wide, will enable active sensing of the wound healing process through a wide range of sensors integrated into wound dressings for various physical and chemical indicators, including pH, temperature, oxygen level, moisture, mechanical, and electrical signals.
While wound bandages and dressings are one of the most common clinical tools for acute and chronic wound care, most are passive and cannot actively respond to variations in the wound environment. Active sensing of the wound healing process would be a major advance for clinicians and patients alike."
Ken Shepard, Lau Family Professor 0f Electrical Engineering and professor of biomedical engineering
The wound healing device consists of five components:
- an active patch device that acts as an ultrasound imager, a focused ultrasound actuator, and sensor and stimulator;
- injectable sub-500-μm "motes" (very small integrated circuits) that are powered by the patch and appear in the ultrasound image, enabling sensing of biomarkers deeper in the wound;
- injectable hydrogel beads that allow drug delivery;
- active implantable scaffolds that sense the wound and delivery drugs; and
- a machine-learning framework that communicates wirelessly with the patch device and that closes the loop, connecting imaging recognition, surface sensing, and mote interrogation to drive actuation decisions.
The active patch device will contain a 2D array of both piezoelectric transducers and electrodes, in both acoustic and electrical contact with the wound within the bandage. The researchers are designing the device on a polyimide flexible printed circuit board incorporating custom complementary metal-oxide-semiconductor application-specific integrated circuits (IC) mounted on the same patch for control. They are thinning the IC chips to be flexible enough to conform to the patch. The flexible printed circuit board connects to a small wearable control box, containing batteries and a Bluetooth wireless interface.
"Each physical and chemical signal from the sensors can provide a wealth of information on the status of the wound healing processes," says Sia, PI of this multi-institutional project and a leader in point-of-care blood tests, wearable sensors, and implantable devices. "Since every wound is different, continuous sensing enables monitoring of the healing process in real time, and sets the stage for timely individualized interventions to accelerate healing."
In addition to developing innovative sensing capabilities, the researchers are incorporating precise actuation functions, such as drug delivery in response to wound environments, into the wound dressings.
Sia and Shepard are working on the project with colleagues from Columbia Engineering (Helen Lu and Clark Hung) and Columbia University Irving Medical Center (Sergei Rudchenko), MIT (Xuanhe Zhao and Ed Boyden), Harvard Medical School/Beth Israel Deaconess Medical Center (Aris Veves), George Mason University (Parag Chitnis), Northwestern University (John Rogers), IBM, and the University of Utah.
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