Editing Biosensor (section)

===Organelles===
Organelles form separate compartments inside cells and usually perform functions independently. Different kinds of organelles have various metabolic pathways and contain enzymes to fulfill its function. Commonly used organelles include lysosome, chloroplast and mitochondria. The spatial-temporal distribution pattern of calcium is closely related to ubiquitous signaling pathway. Mitochondria actively participate in the metabolism of calcium ions to control the function and also modulate the calcium related signaling pathways. Experiments have proved that mitochondria have the ability to respond to high calcium concentrations generated in their proximity by opening the calcium channels.<ref>{{Cite journal | last1 = Rizzuto | first1 = R. | last2 = Pinton | first2 = P. | last3 = Brini | first3 = M. | last4 = Chiesa | first4 = A. | last5 = Filippin | first5 = L. | last6 = Pozzan | first6 = T. | doi = 10.1054/ceca.1999.0076 | title = Mitochondria as biosensors of calcium microdomains | journal = Cell Calcium | volume = 26 | issue = 5 | pages = 193–199 | year = 1999 | pmid =  10643557}}</ref> In this way, mitochondria can be used to detect the calcium concentration in medium and the detection is very sensitive due to high spatial resolution. Another application of mitochondria is used for detection of water pollution. Detergent compounds' toxicity will damage the cell and subcellular structure including mitochondria. The detergents will cause a swelling effect which could be measured by an absorbance change. Experiment data shows the change rate is proportional to the detergent concentration, providing a high standard for detection accuracy.<ref>{{Cite journal | last1 = Bragadin | first1 = M. | last2 = Manente | first2 = S. | last3 = Piazza | first3 = R. | last4 = Scutari | first4 = G. | title = The Mitochondria as Biosensors for the Monitoring of Detergent Compounds in Solution | doi = 10.1006/abio.2001.5097 | journal = Analytical Biochemistry | volume = 292 | issue = 2 | pages = 305–307 | year = 2001 | pmid =  11355867| hdl = 10278/16452 | hdl-access = free }}</ref>