A bioreporter bioluminescent integrated circuit for very low-level chemical sensing in both gas and liquid environments

We report a compact biosensor using genetically engineered whole-cell bioreporters on a CMOS based integrated circuit, also called the microluminometer, for accurately sensing low concentrations of a wide range of toxic substances in both gas and liquid environments. The bioluminescent bioreporters are bacteria that can be genetically altered to achieve bioluminescence when in contact with a targeted substance. The bioreporters are placed in close proximity to the microluminometer thus obviating the need for complex instrumentation to channel light from the bioreporters to the microluminometer. The microluminometer presented here is a more robust design and consumes lower power when compared to the one presented in Bolton et al.'s work [E.K. Bolton, G.S. Sayler, D.E. Nivens, J.M. Rochelle, S. Ripp, M.L. Simpson, Integrated CMOS photodetectors and signal processing for very low-level chemical sensing with the bioluminescent bioreporter integrated circuit, Sens. Actuators B 85 (2002) 179–185]. The microluminometer includes integrated photodiodes and signal processor and is realized using a standard 0.35 μm CMOS process. The photodiode array is operated with a reverse bias of a few mV and demonstrates a leakage current of 45–60 fA and a minimum detectable signal (MDS) of 0.15 fA while operating at room temperature. We present results from both liquid based and air based testing with salicylate and naphthalene as the analytes, respectively, and genetically altered bacteria, Pseudomonas fluorescens 5RL, as the bioreporter.