Rice University Engineers Develop Chitosan Hydrogel System Turning Probiotic Bacteria into Safe Bioelectrical Environmental Sensors

Rice University researchers use crustacean-derived hydrogels to trap bacteria on electrodes, creating safe and stable bioelectrical sensors for milk and water.

By: AXL Media

Published: Mar 15, 2026, 7:11 AM EDT

Source: Information for this report was sourced from Rice University

Overcoming Connectivity Barriers in Microbial Electronics

The integration of living bacteria into electronic devices has long been hindered by the difficulty of maintaining a stable electrical connection in fluid environments. While microbial sensors offer the ability to regenerate and survive harsh conditions, the chemical mediators required to transport electrons from the bacteria to an electrode are often swept away by liquid flow. According to Rafael Verduzco, a professor at Rice University, previous iterations of these sensors also faced challenges regarding the toxicity of the mediators used. By developing a specialized containment system, researchers have now found a way to bridge the gap between biological activity and electronic detection without compromising environmental safety.

The Architectural Role of Modified Chitosan

The breakthrough relies on a hydrogel made from chitosan, a renewable polymer sourced from the shells of crustaceans. This material acts as a physical "shell" that traps bacteria in close proximity to an electrode while remaining porous enough to allow target substances to enter. Verduzco noted that the chitosan was chemically modified to serve as a series of "anchor points" for electron mediators. This modification ensures that the components necessary for signal transmission remain fixed within the gel, providing a flexible and low-cost framework for consistent electronic communication between the living microbes and the hardware.

Engineering a Redox Active Polymer Network

To solve the dual problem of bacterial containment and electron transport, doctoral student Xinyuan Zuo proposed the use of a redox-active polymer. This material acts as a biological wire, capable of accepting electrons from the bacteria and passing them along a chain until they reach the electrode to be recorded as an electrical current. By attaching these mediators directly to the chitosan backbone, the team produced a biohybrid material that generates a stable current. This innovation transforms a standard hydrogel into a functional circuit component that remains effective even when submerged in moving liquids like wastewater or food products.