Development of a highly specific and sensitive cadmium and lead microbial biosensor using synthetic CadC-T7 genetic circuitry

• Published in: Biosensors & bioelectronics 2016-05, Vol.79, p.701-708
• Main Authors: Kim, Hyun Ju, Lim, Ji Won, Jeong, Haeyoung, Lee, Sang-Jae, Lee, Dong-Woo, Kim, Taesung, Lee, Sang Jun
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacteria - chemistry; Bacteria - genetics; Bacteria - metabolism; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Base Sequence; Biosensing Techniques - methods; Biosensors; CadC; Cadmium; Cadmium - analysis; Cadmium - metabolism; Devices; Electric circuits; Flow cytometry; Gene Expression Regulation, Bacterial; Genetics; Heavy metal ions; Heavy metals; Lead - analysis; Lead - metabolism; Microbial biosensor; Microfluidic Analytical Techniques - methods; Microfluidic device; Microfluidics; Molecular Sequence Data; T7 RNA polymerase; Transcription Factors - chemistry; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2015.12.101

Multiple copies of a cadC homolog encoding a heavy metal-responsive transcription factor were found in the genome of a bacterium isolated from ocean sediment, and the heavy metal responses of the encoded proteins were characterized using a fluorescence reporter assay. Each CadC regulator exhibited distinct specificity in response to heavy metal ions, indicating their potential use as modular heavy metal biosensors. Next, we constructed CadC-controlled T7 RNA transcription systems for intracellular signal amplification, i.e., higher sensitivity. Flow cytometry revealed that cadmium and lead ions could be recognized specifically by CadC-T7 biosensors, which could be combined with a microfluidic platform to generate heavy metal biosensor devices with increased sensitivity. Our results demonstrate the successful development of synthetic CadC-T7 genetic circuitry for use in improved heavy metal biosensor microfluidic devices. •CadC regulators and cadO operators were excavated from genome information.•T7 signal amplification modules were assembled with cadC and cadO.•CadC-T7 Microbial biosensors showed distinct heavy metal specificities.•Microfluidic platform enhanced the sensitivity of heavy metal biosensors.