Biosensor
BIOSENSORS
ADVANCED BIOREPORTER TECHNOLOGIES FOR TARGETED SENSING OF CHEMICAL AND BIOLOGICAL AGENTS
Steven Ripp and Gary S. Sayler
Introduction
Bioreporters refer to intact, living microbial cells that have been genetically engineered to produce a measurable signal in response to a specific chemical or physical agent in their environment (Figure 1). Bioreporters contain two essential genetic elements, a promoter gene and a reporter gene. The promoter gene is turned on (transcribed) when the target agent is present in the cell’s environment. The promoter gene in a normal bacterial cell is linked to other genes that are then likewise transcribed and then translated into proteins that help the cell in either combating or adapting to the agent to which it has been exposed. In the case of a bioreporter, these genes, or portions thereof, have been removed and replaced with a Signal reporter gene. Consequently, turning on the promoter gene Transcription Translation Promoter now causes the reporter gene to be turned on. Activation of Reporter mRNA the reporter gene leads to Reporter Gene Protein production of reporter proteins that ultimately generate some type of a detectable signal. Analyte Therefore, the presence of a Figure 1. Anatomy of a bioreporter organism. Upon exposure to a signal indicates that the specific analyte, the promoter/reporter gene complex is transcribed bioreporter has sensed a into messenger RNA (mRNA) and then translated into a reporter particular target agent in its protein that is ultimately responsible for generating a signal. environment. Originally developed for fundamental analysis of factors affecting gene expression, bioreporters were early on applied for the detection of environmental contaminants1 and have since evolved into fields as diverse as medical diagnostics, precision agriculture, food-safety assurance, process monitoring and control, and bio-microelectronic computing. Their versatility stems from the fact that there exist a
ADVANCED BIOREPORTER TECHNOLOGIES FOR TARGETED SENSING OF CHEMICAL AND BIOLOGICAL AGENTS
Steven Ripp and Gary S. Sayler
Introduction
Bioreporters refer to intact, living microbial cells that have been genetically engineered to produce a measurable signal in response to a specific chemical or physical agent in their environment (Figure 1). Bioreporters contain two essential genetic elements, a promoter gene and a reporter gene. The promoter gene is turned on (transcribed) when the target agent is present in the cell’s environment. The promoter gene in a normal bacterial cell is linked to other genes that are then likewise transcribed and then translated into proteins that help the cell in either combating or adapting to the agent to which it has been exposed. In the case of a bioreporter, these genes, or portions thereof, have been removed and replaced with a Signal reporter gene. Consequently, turning on the promoter gene Transcription Translation Promoter now causes the reporter gene to be turned on. Activation of Reporter mRNA the reporter gene leads to Reporter Gene Protein production of reporter proteins that ultimately generate some type of a detectable signal. Analyte Therefore, the presence of a Figure 1. Anatomy of a bioreporter organism. Upon exposure to a signal indicates that the specific analyte, the promoter/reporter gene complex is transcribed bioreporter has sensed a into messenger RNA (mRNA) and then translated into a reporter particular target agent in its protein that is ultimately responsible for generating a signal. environment. Originally developed for fundamental analysis of factors affecting gene expression, bioreporters were early on applied for the detection of environmental contaminants1 and have since evolved into fields as diverse as medical diagnostics, precision agriculture, food-safety assurance, process monitoring and control, and bio-microelectronic computing. Their versatility stems from the fact that there exist a