Integrated circuit biosensors using living whole-cell bioreporters

A low-power CMOS bioluminescent bioreporter integrated circuit (BBIC) is designed and fabricated for use in electronic/biological chemical sensing. The bioreporters are placed on a CMOS integrated circuit (IC) that detects bioluminescence, performs signal processing and produces a digital output pulse with a frequency that is proportional to the concentration of the target substance. The digital output pulse that contains the sensor information can then be transmitted to a remote location either wirelessly or via a data cable. The basic building blocks of the integrated circuit are the microlumninometer and the transmitter. The microluminometer includes an integrated photodetector and a signal processor and is housed in a rugged inexpensive package that can be used in many remote applications in hazardous environmental monitoring. The total power consumption of the entire signal processing circuitry including the photodiodes is 3 mW from a 3.3-V power supply. This is lowered by a factor of 3 when compared to previous versions of the BBIC. In addition, it also integrates all features of detection, processing and data transmission into one small element. The bioreporter typically contains the luxCDABE reporter genes. The close proximity of the bioreporter and the sensing element eliminates the need for complex instrumentation to channel light from the bioreporters to the microluminometer. This paper presents an integrated CMOS microluminometer realized in 0.35-mu m CMOS process and optimized for the detection of low-level bioluminescence as part of the BBIC. A flow-through test system was designed to expose the BBIC system composed of the microluminometer and the bioreporter Pseudomonas fluorescens 5RL to salicylate for determination of analytical benchmark data. The results obtained from the experiment are currently being used to study enclosures and micro-environment configurations for field-deployable BBICs for environmental monitoring.