Smart Bandage Monitors Chronic Wounds in Human Patients

A future smart bandage, envisioned as a "lab on skin," could assist both patients and caregivers by not only monitoring chronic wounds but also delivering treatment and accelerating the healing process for slow-healing cuts, incisions, scrapes, and burns.

In 2023, a research team at California Institute of Technology (Caltech, Pasadena, CA, USA) took an important step toward realizing this concept by demonstrating that a smart bandage they developed could provide real-time data on chronic wounds in animal models. This bandage also facilitated faster healing by applying medication or electrical fields to promote tissue growth. Building on this success, the team has now made further progress by showing that an enhanced version of their bandage, known as iCares, could continuously sample fluid from chronic wounds in 20 human patients. These patients suffered from wounds that failed to heal due to conditions like diabetes or poor blood circulation. The research also included additional patients both before and after surgical procedures.

The smart bandage is equipped with three distinct microfluidic components—miniature modules that control the flow of liquids—to manage excess moisture in wounds while providing real-time data on biomarkers. In a recent study published in Science Translational Medicine, the team demonstrated that the bandage could detect molecules such as nitric oxide (which signals inflammation) and hydrogen peroxide (a marker of infection). This capability allows the bandage to identify these biomarkers one to three days before symptoms appear in patients. Additionally, the researchers have developed a machine-learning algorithm that classifies patients' wounds and predicts healing times with accuracy comparable to that of expert clinicians.

The bandage is made from a flexible, biocompatible polymer strip that can be 3D printed at a low cost. It includes a nanoengineered biomarker sensor array that is disposable for hygiene and single-use applications. The system also features a reusable printed circuit board for signal processing and wireless data transmission to a user interface, such as a smartphone. iCares’ microfluidic system is composed of a membrane that extracts wound fluid, a bioinspired component that moves the fluid to a sensor array for analysis, and a micropillar module that carries the fluid out of the bandage for analysis.

"Our innovative microfluidics remove moisture from the wound, which helps with healing,” said Wei Gao, Caltech professor of medical engineering, who led the research team. “They also make sure that samples analyzed by the bandage are fresh, not a mixture of old and new fluid. To get accurate measurements, we need to sample only the newest fluid at a wound site. In this way, iCares can watch in real time for important biomarkers of inflammation and infection."