Detect-to-warn cell based sensing technology: Chemical sensing of multiple agents in a cascade

Techniques to develop highly sensitive biosensors are largely dependant upon the properties of the material and its associated interactions. A novel challenge is the development of effective biosensors based on fundamental research in biotechnology, genetics and information technology, which will change the existing axiom of "detect -to-treat" to "detect -to-warn". Current biosensor technologies encompass antibody-antigen interactions, hormone-receptor interactions, and nucleic acid based assays. These sensors are useful in narrow band applications requiring high specificity for agent identification. Mammalian cells have excitable cell membranes that function as novel sensing platforms by producing a variation in the extracellular potential based on the chemical stimulus. Here we report a method of developing single cell based sensors by integrating the biological tool of dielectrophoresis with the micro fabrication technology. We display its ability to detect a large number of chemical agents, reject false alarms, characterize the chemical agent functionality and determine the associated sensitivity limit, and the physiological response in terms of the calcium transients for each specific chemical agent that produces synergistic effects on humans. We finally demonstrate the capability of a single cell based sensor to identify general chemical agents in cascade.