Caltech associate professor of medical engineering Wei Gao and his team are imagining a futuristic smart bandage—a “laboratory on skin” that not only aids patients and caregivers in tracking the condition of chronic wounds but also administers treatment and accelerates the recovery process for cuts, surgical incisions, abrasions, and burns that tend to heal slowly on their own.
In 2023, Gao’s group surpassed the initial obstacle toward realizing that ambition by demonstrating that a smart bandage they created could offer real-time insights regarding chronic wounds in animal subjects, while also hastening the healing process through the timely administration of medication or electrical fields to promote tissue regeneration.
Now, Gao along with his associates from Caltech and the Keck School of Medicine at USC have overcome another challenge by illustrating that an enhanced version of their bandage, which they refer to as iCares, was capable of continuously sampling fluid that the body directs to wound sites as part of the inflammatory process, in a study involving 20 human patients with chronic wounds. These wounds were unable to heal due to either diabetes or poor blood circulation; the researchers additionally examined more patients both prior to and following surgery.
The smart bandage, equipped with three distinct microfluidic elements—tiny modules that guide and control the flow of liquids—removes excess moisture from wounds while delivering real-time data about the biomarkers present.
“Our advanced microfluidics eliminate moisture from the wound, which aids in healing. They also ensure that the samples examined by the bandage are fresh, rather than a combination of old and new fluids. For precise measurements, we need to capture only the most recent fluid at a wound site,” states Gao, who is also an Investigator at the Heritage Medical Research Institute. “This way, iCares can monitor in real time for crucial biomarkers indicating inflammation and infection.”
Indeed, in a recent paper published in the journal Science Translational Medicine, Gao and his team reveal that the smart bandage can identify molecules such as nitric oxide, which signifies inflammation; and hydrogen peroxide, a marker of infection; potentially one to three days before patients begin to show symptoms.
In a further progression, the team has established a machine-learning algorithm that can effectively categorize the wounds of patients and forecast healing durations with a level of precision comparable to that of an experienced clinician.
The bandage consists of a flexible, biocompatible polymer strip that can be 3D printed cost-effectively. It integrates a nanoengineered biomarker sensor array, designed for disposable hygiene and single-use purposes. The system also features a reusable printed circuit board that manages signal processing and wireless data transfer to a user interface, such as a smartphone. The trio of microfluidic components within iCares includes a membrane that extracts wound fluid from the surface of the wound, a bioinspired module that transports the fluid across the device to a sensor array where it is analyzed, and a micropillar module that directs the collected fluid outside the bandage.
The co-lead authors of the article, “A microfluidic wearable device for wound exudate management and analysis in human chronic wounds,” are Caltech graduate students Canran Wang and Kexin Fan. David G. Armstrong, Distinguished Professor of Surgery and Neurological Surgery at the Keck School of Medicine of USC, is a co-author of the research. Additional contributors from Caltech include Jose A. Lasalde-Ramirez, Wenzheng Heng, Jihong Min (PhD ’24), Samuel A. Solomon, Jiahong Li, Hong Han, Gwangmook Kim, Soyoung Shin, and Alex Seder; former graduate students Minqiang Wang and Ehsan Shirzaei Sani, who now works at the University of Central Florida, are among those credited for their contributions while at Caltech. Authors from the Keck School of Medicine at USC are Chia-Ding Shih (also associated with Casa Colina Hospital and Centers for Healthcare in Pomona, California) and David Armstrong. The research was supported by funding from the National Institutes of Health, the National Science Foundation, the American Cancer Society, the Army Research Office, US Army Medical Research Acquisition Activity, and the Heritage Medical Research Institute. Caltech’s Kavli Nanoscience Institute provided essential support and infrastructure for this project.