Abstract

Cell-based biosensors have great potential to detect various toxic and pathogenic contaminants in aqueous environments. However, frequently they cannot meet practical requirements due to insufficient sensing performance. Here, we investigated a modular, cascaded signal amplifying methodology to address this issue. We first tuned intracellular receptor densities of the sensory module to increase sensitivity, and then engineered ultrasensitive activator-based multi-layered transcriptional amplifiers to sequentially amplify the transduced sensor signal and boost output expression level. We demonstrated these strategies by engineering ultrasensitive bacterial cell-based sensors for arsenic and mercury. We next developed an encapsulated microbial sensor cell array for low-cost, portable and precise field monitoring, where the analyte concentration can be readily visualized via displaying an easy-to-interpret volume bar-like pattern. The ultrasensitive signal amplifying methodology along with the sensing platform will be widely applicable to many other cell-based sensors, paving the way for their real world applications in the environment and healthcare. Further, new low-cost cell-free expression system based biosensors are being developed to facilitate their stable and reliable performance in the field.

Biography

Dr Baojun Wang is Group Leader of the Synthetic Biological Circuit Engineering Lab at the University of Edinburgh. He is a tenured Principal Investigator in the School of Biological Sciences and Edinburgh SynthSys Centre for Synthetic and Systems Biology. He received a PhD in Bioengineering from Imperial College London (2011) and was a Research Associate at Imperial College before joined the faculty of University of Edinburgh in 2013. His research interests include building novel customized genetic circuits for sensing, information processing and computing of multiple cellular and environmental signals with applications in diverse areas, for example, biosensing, biomanufacturing and biotherapies. His research has been funded by BBSRC (New Investigator Award), Gates Foundation (Grand Challenges Explorations Award) among others in addition to leading industry partners including Microsoft Research, Huawei Technologies and DSTL.