by Michael D’Agati ’18

Infections caused by wounds are a health concern for many people around the world. If treated incorrectly, these infections can cause major health problems for those affected. Treatments that can reduce the severity of the infections depend on rapid and timely detection of the infection-causing bacteria. In the past decade, previous attempts at creating biosensors for detecting wound bacteria have suffered from limitations, such as low sensitivity and molecular labels. These labels, which are chemicals attached to larger molecules that can bind to the target to be detected, require complicated fabrication methods and suffer from short shelf-life and stability; they can also cause local toxicity and sensitization.

Professor Anita Shukla and Dr. Roya Sheybani of Brown University developed sensors to detect bacterial wound infections that have high sensitivity and do not rely on molecular labels. An interdigitated thin film gold electrode was used to directly sense the adsorption of bacteria on the sensor. This design allows for greater surface area for sensing and doesn’t corrode as readily as carbon electrodes would. When bacteria attach to the sensor surface, the impedance, or resistance of the device in an electrical circuit, increases, indicating that the wound could be infected. Their biosensor also monitors the local pH level and attachment of bacterial cells across a potentially infected wound.

The results of the project show that a highly sensitive biosensor for determining infections can be created without the use of molecular labels. By measuring pH and bacterial attachment directly, the device utilizes simple development methods, while still maintaining high sensitivity. The team also mentioned that the methods and materials used could be repurposed on flexible substrates, so they can additionally be used on clinically relevant materials, including bandages, sutures, and catheters. This type of device could be the future for detecting infections in wounded patients.

References:

1. R. Sheybani, A. Shukla. Highly sensitive label-free dual sensor array for rapid detection of wound bacteria. Biosensors and Bioelectronics, (2016). doi: 10.1016/j.bios.2016.10.084.
2. Image retrieved from: https://commons.wikimedia.org/wiki/File:E._coli_Bacteria_(16578744517).jpg.