Encapsulation Technology for Increased Portability of Cell‐based Biosensors

Mammalian cell‐based biosensors (CBBs) have become a powerful way to detect pathogens, toxins and toxicants. CBBs can serve as a sentinel for a broad range of agents, including unknown or complex combinations of agents, and report a physiologically relevant endpoint. Despite CBBs advantages over conventional detection methods, they suffer from poor efficacy outside of the laboratory environment because cells are sensitive to changes in their environment including pH, temperature, and media composition. Advances in cell‐encapsulating hydrogels may solve some of the challenges with transitioning CBBs into commercial products. In collaboration with Luna Innovations Incorporated, sol‐gels were investigated for their cell stabilization activity. A well‐developed water toxicant sensor based on impedance sensing of confluent cell monolayers after chemical challenge was used to evaluate the sol gels. A variety of sol‐gel formulations and application protocols were evaluated to stabilize a confluent cell layer adherent to gold electrodes which is the sensing element of the impedance CBB. The data show that a saccharide modified sol‐gel was able to stabilize the impedance of a confluent layer of mammalian cells on the sensing platform for 50 days at room temperature with no medium replacement, whereas non‐encapsulated cells quickly died in this uncontrolled environment. Furthermore, encapsulated cells were still able to detect toxicants by exhibiting a decrease in impedance after treatment. These findings show that cell‐encapsulation may allow CBBs to transition from the laboratory into viable products. SBIR with ERDC‐CERL, #W9132T‐14‐C‐0016