Editing Biosensor (section)

===Antibody/antigen interactions===
An [[immunoassay|immunosensor]] utilizes the very specific binding affinity of [[antibodies]] for a specific compound or [[antigen]]. The specific nature of the [[antibody-antigen interaction]] is analogous to a lock and key fit in that the antigen will only bind to the antibody if it has the correct conformation. Binding events result in a physicochemical change that in combination with a tracer, such as fluorescent molecules, enzymes, or radioisotopes, can generate a signal. There are limitations with using antibodies in sensors: 1. The antibody binding capacity is strongly dependent on assay conditions (e.g. pH and temperature), and 2. the antibody-antigen interaction is generally robust, however, binding can be disrupted by [[chaotropic]] reagents, organic solvents, or even ultrasonic radiation.<ref name="High-performance graphene-based bio">{{cite journal |title=High-performance graphene-based biosensor using a metasurface of asymmetric silicon disks |journal=IEEE Sensors Journal |year=2022 |doi=10.1109/JSEN.2021.3134205|last1=Parizi |first1=Mohammad Salemizadeh |last2=Salemizadehparizi |first2=Fatemeh |last3=Zarasvand |first3=Mahdi Molaei |last4=Abdolhosseini |first4=Saeed |last5=Bahadori-Haghighi |first5=Shahram |last6=Khalilian |first6=Alireza |volume=22 |issue=3 |pages=2037–2044 |bibcode=2022ISenJ..22.2037P |s2cid=245069669 }}</ref><ref name=FiberOpticBiosensor>{{Cite journal | last1 = Marazuela | first1 = M.| last2 = Moreno-Bondi | first2 = M.| doi = 10.1007/s00216-002-1235-9 | title = Fiber-optic biosensors – an overview | journal = Analytical and Bioanalytical Chemistry | volume = 372 | issue = 5–6 | pages = 664–682 | year = 2002 | pmid =  11941437| s2cid = 36791337}}</ref>

Antibody-antigen interactions can also be used for [[Serology|serological testing]], or the detection of circulating antibodies in response to a specific disease. Importantly, serology tests have become an important part of the global response to the [[COVID-19]] pandemic.<ref>{{cite journal |last1=Stowell |first1=Sean |last2=Guarner |first2=Jeannette |title=Role of Serology in the Coronavirus Disease 2019 Pandemic |journal=Clinical Infectious Diseases |date=5 November 2020 |volume=71 |issue=8 |pages=1935–1936 |doi=10.1093/cid/ciaa510 |pmid=32357206 |pmc=7197618 }}</ref>