Using Biological Organisms as Chemical Sensors: The MicRoboCop Project

The MicRoboCop project introduces chemistry students to the concepts and protocols of synthetic biology. MicRoboCop is a biosensor that has been designed for unique applications in forensic chemistry. The lab is carried out in collaboration with an instructor teaching a genetics course. Students in the biology course synthesize biosensors using Escherichia coli (E. coli), and students in the chemistry course evaluate the effectiveness of the biosensors using analytical chemistry methods. Chemistry students learn basic microbiological techniques to culture the bacteria, and they analyze the expression of red fluorescent protein (RFP) using fluorescence spectroscopy. Students in upper-division (third- and fourth year) chemistry courses evaluated one part of the MicRoboCop system for its response to arsenic(III) and antimony(III) ions using fluorescence spectroscopy. The limits of detection for the biosensor were estimated using a spectrofluorimeter fitted with a 96-well plate reader, and were found to be less than 1 ppb for antimony and arsenic. Additionally, the biosensor was shown to respond similarly to both antimony and arsenic. Several different variations on the analysis of RFP expressing biosensors are presented, as well as different instrumental options for fluorescence analysis.