(556a) Portable Paper-based Biosensors and Novel Artificial Olfaction Biosensors Driven by Cell-free Synthetic Biology

Chemical or biological pollution in rapidly urbanizing cities has become a serious problem that disturbs the lives and livelihoods of millions of people, damaging and restricting potable water supply. Therefore, the rapid detection of pollution molecules will play a significant role in health care as well as environmental management. Many attempts, such as the utilization of diverse biological sensing elements, have been designed to respond to polluted chemicals or bacterial biomarkers for the detection. However, the practical applications of the whole-cell- or cell-element-based biosensors has been restricted by several concerns of biosafety, the hard preparation, and tough storage. For these challenges, cell-free protein synthesis technology, which synthesizes proteins using biological machinery in vitro, could be employed to broaden the applications of synthetic-biology-based biosensors or functional-protein-based biosensors.

For synthetic-biology-based biosensors, we present a portable in vitro biosensing platform for detecting inorganic chemicals or biological organic molecules. The sensing synthetic genetic circuits, coupled with basic cell-free components, were embedded onto papers by freeze-drying, which could be stored and transported at room temperature. These portable testing papers were activated by adding liquid samples for specific inducible reporter expression. To achieve the full availability outside the laboratory, reporter enzymes that could mediate color change by cleaving substrate were selected and demonstrated for in vitro paper-based platform. Synthetic genetic circuits respectively responded to two chemicals arsenic ion and AHLs, which were the common industrial pollutant and bacterial communication signal, were demonstrated to effectively sensing in this in vitro paper-based platform. Besides, combining the smartphone and image analysis software, the visible output could be easily collected and quantified. Without the intact cells, cell-free systems provide an emerging possibility for synthetic biology-based biosensor, which can be practically applied to environmental management or clinical diagnosis outside the laboratory. In the future, more internet technology such as smartphone and internet-of-thing (IoT) technology could be integrated into the detection platform for data sharing, from which people can learn about the environmental condition from a smartphone with the internet.

Moreover, the controllable protein synthesis conditions of cell-free systems also provide an emerging alternative approach for the effective production of complex proteins, such as the membrane olfactory receptor proteins. The nanomaterials can be applied for the functional folding of proteins in cell-free protein synthesis. Combining with the quartz crystal microbalance platform, diverse natural olfactory receptor proteins can be developed into artificial olfaction, which can be potentially employed to detect toxic odors for environmental management and applications.