Editing Urea (section)

===Laboratory uses===
Urea in concentrations up to 10&nbsp;[[molar concentration#Units|M]] is a powerful [[protein]] [[denaturation (biochemistry)|denaturant]] as it disrupts the noncovalent bonds in the proteins. This property can be exploited to increase the solubility of some proteins. A mixture of urea and [[choline chloride]] is used as a [[deep eutectic solvent]] (DES), a substance similar to [[ionic liquid]]. When used in a deep eutectic solvent, urea gradually denatures the proteins that are solubilized.<ref>{{cite journal | first1 = Erwann | last1 = Durand | first2 = Jérôme | last2 = Lecomte | first3 = Bruno | last3 =Baréa | first4 = Georges | last4 = Piombo | first5 = Éric | last5 = Dubreucq | first6 = Pierre | last6 = Villeneuve | title = Evaluation of deep eutectic solvents as new media for ''Candida antarctica'' B lipase catalyzed reactions | journal = Process Biochemistry | publisher = [[Elsevier]] | volume = 47 | issue = 12 | date = 2012-12-01 | pages = 2081–2089 | doi = 10.1016/j.procbio.2012.07.027 | issn = 1359-5113 | df = dmy-all}}.</ref>

Urea in concentrations up to 8&nbsp;M can be used to make fixed brain tissue transparent to visible light while still preserving fluorescent signals from labeled cells. This allows for much deeper imaging of neuronal processes than previously obtainable using conventional one photon or two photon confocal microscopes.<ref>{{cite journal | vauthors = Hama H, Kurokawa H, Kawano H, Ando R, Shimogori T, Noda H, Fukami K, Sakaue-Sawano A, Miyawaki A | title = Scale: a chemical approach for fluorescence imaging and reconstruction of transparent mouse brain | journal = Nature Neuroscience | volume = 14 | issue = 11 | pages = 1481–8 | date = August 2011 | pmid = 21878933 | doi = 10.1038/nn.2928 | s2cid = 28281721 }}</ref>