Biosensors can be thought of as any device which is capable of sensing an analyte (e.g. a molecule or compound) or certain condition (e.g. pH or temperature) through the use of a biological component (Turner, 2013). One example of this would be a canary in a coal mine, where in the presence of carbon monoxide, the canary dies. A perhaps less morbid and more advanced biosensor example are those which have been developed by synthetic biologists. All organisms use native biosensing devices to monitor molecules of interest and initiate cell responses. For example, maintenance of cell homeostasis requires the sensitive detection and subsequent regulation of many molecules, such as metals, fatty acids and hydrogen peroxide (Rensing & Grass, 2003, Zhang & Rock, 2009 and Marinho et al., 2014). Two-component systems are common biosensing systems in bacteria. These systems allow bacteria to respond to extracellular signals by the phosphorylation of a sensor kinase in the presence of a target molecule, which subsequently phosphorylates further response regulator proteins. These response regulators can alter cell behaviour through protein interactions, transcriptional regulation, or RNA binding (Gao et al., 2007).
In recent years, there has been a substantial increase the number biosensors produced using synthetic biology methods. Synthetic biology involves the application of engineering principles to the manipulation of biological systems. Biosensors constructed using these methods adapt the native cellular biosensing processes discussed previously, such as protein or RNA binding, and use these interactions to induce transcription of a reporter gene, such as a fluorescent protein.
These sensors may be expressed as living whole-cell sensors, but are also increasingly being expressed in cell-free protein synthesis systems. However, thus far, the costs of these systems has been prohibitive to wide-spread use in synthetic biology (Smith et al., 2017).
Why are Biosensors Useful?
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What Problems do Biosensor Developers Face?
The Sensynova Framework
References:
Turner, A. P. F., 2013, Biosensors: sense and sensibility, Chem. Soc. Rev., DOI: 10.1039/C3CS35528D
