Silicon photomultiplier (SPM) detection of low-level bioluminescence for the development of deployable whole-cell biosensors: possibilities and limitations.
Whole-cell bacterial bioreporters await miniaturized photon counting modules with high sensitivity and robust compatible hardware to fulfill their promise of versatile, on-site biosensor functionality. In this study, we explore the photon counting readout properties of the silicon photomultiplier (SPM) with a thermoelectric cooler and the possibilities of detecting low-level bioluminescent signals. Detection performance was evaluated through a simulated LED light source and the bioluminescence produced by the genetically engineered Pseudomonas fluorescens bacterial bioreporter 5RL. Compared with the conventional photomultiplier tube (PMT), the results revealed that the cooled SPM exhibits a wider linear response to inducible substrate concentrations (salicylate) ranging from 250 to 5000 ppb. Although cooling of the SPM lowered dark count rates and improved the minimum detectable signal, and the application of a digital filter enhanced the signal-to-noise ratio, the detection of very low light signals is still limited and remains a challenge in the design of compact photon counting systems.
The Center for Environmental Biotechnology and the Department of Microbiology, The University of Tennessee, Knoxville, TN 37996, USA.
Huaqing
H
Li
Nicholas
N
Lopes
Scott
S
Moser
Gary
G
Sayler
Steven
S
Ripp
D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D008163:Luminescent Measurements / Q000295:instrumentation* / Q000379:methods; D017785:Photons; D012825:Silicon
D012825:Silicon