Related Experiment Video
Updated: Jul 19, 2026
Preparation and Testing of Impedance-based Fluidic Biochips with RTgill-W1 Cells for Rapid Evaluation of Drinking Water Samples for Toxicity
Published on: March 7, 2016
A smartphone-based genetically recombinant whole-cell biosensor for highly sensitive monitoring of polychlorinated
Qiangqiang Luo1, Faying Zhang2, Mengjie Zhang1
1State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, 430062, China.
Background:
Polychlorinated biphenyls (PCBs) are persistent carcinogens widely distributed in ecosystems. Their structural complexity-diverse chlorine numbers and positions-challenges detection using conventional methods like ELISA or instrumental analysis, which are limited to single congeners. Whole-cell biosensors (WCBs) present a promising alternative by enabling multi-congener detection, yet their sensitivity remains constrained by inefficient PCB-sensing proteins. To overcome this limitation, we engineer an Escherichia coli-based WCB that integrates bphAB-mediated PCB degradation with HbpRCBP6-based sensing, exploiting metabolic conversion to enhance detection. This dual-circuit design aims to achieve broad-spectrum PCB recognition while improving sensitivity through chassis optimization and enzymatic pre-processing.
Results:
We developed a BL21(DE3)/HbpRCBP6-bphAB WCB that detects multiple PCB congeners via a two-step mechanism: BphAB enzymes first convert PCBs to hydroxylated derivatives (OH-PCBs), which are then recognized by the HbpRCBP6 transcriptional factor. The biosensor achieved the lowest reported LOD for 2-CBP (2-chlorobiphenyl) and detected 3-CBP, 4-CBP, 2,3-diCBP, and 2,2'-diCBP at low micromolar limits (0.06-1 μM). Structural docking revealed that HbpRCBP6 binds OH-PCBs with higher affinity (binding energy: -6.39 kcal/mol) than native PCBs (-6.14 kcal/mol), validating the critical role of bphAB in enhancing sensitivity. To enable field applications, we immobilized the WCB in a transglutaminase-crosslinked hydrogel and paired it with a smartphone-based detection platform. Dose-response curves showed a linear logarithmic relationship between 2-CBP concentration (1-100 μM) and fluorescence intensity.
Significance:
This study advances PCB monitoring by integrating metabolic pre-processing with sensitive transcriptional activation, overcoming the limitations of single-target assays. The smartphone-compatible hydrogel platform enables real-time, on-site detection. Our strategy, which couples catabolic pathways with optimized sensing proteins, not only advances environmental monitoring capabilities but also provide an innovative strategy for developing metabolic pathway-sensing proteins combined biosensors.
