Editing Differential centrifugation (section)

{{Short description|Method of separating particles in a mixture}}
{{More citations needed|date=October 2009}}

[[File:Differentielle_zentrifugation.png|thumb|right|Differential centrifugation]]

In [[biochemistry]] and [[cell biology]], '''differential centrifugation''' (also known as '''differential velocity centrifugation''') is a common procedure used to separate [[organelle]]s and other sub-cellular particles based on their [[Svedberg|sedimentation rate]]. Although often applied in biological analysis, differential centrifugation is a general technique also suitable for crude purification of non-living suspended particles (e.g. [[nanoparticles]], [[colloidal]] particles, [[viruses]]). In a typical case where differential centrifugation is used to analyze cell-biological phenomena (e.g. organelle distribution), a [[Tissue (biology)|tissue]] sample is first [[Lysis|lysed]] to break the [[cell membrane]]s and release the organelles and [[cytosol]]. The lysate is then subjected to repeated [[centrifugation]]s, where particles that sediment sufficiently quickly at a given centrifugal force for a given time form a compact "pellet" at the bottom of the centrifugation tube.<ref>{{cite journal |last1=Ohlendieck |first1=Kay |last2=Harding |first2=Stephen E. |title=Centrifugation and Ultracentrifugation |journal=Wilson and Walker's Principles and Techniques of Biochemistry and Molecular Biology |date=19 April 2018 |pages=424–453 |doi=10.1017/9781316677056.014|isbn=9781107162273 }}</ref>

After each centrifugation, the ''supernatant'' (non-pelleted solution) is removed from the tube and re-centrifuged at an increased [[centrifugal force (fictitious)|centrifugal force]] and/or time. Differential centrifugation is suitable for crude separations on the basis of sedimentation rate, but more fine grained purifications may be done on the basis of density through [[equilibrium density-gradient centrifugation]].<ref name="darnell">{{Cite journal | url=https://www.ncbi.nlm.nih.gov/books/NBK21492/ |title = Purification of Cells and Their Parts|year = 2000|last1 = Darnell|first1 = James|last2 = Baltimore|first2 = David|last3 = Matsudaira|first3 = Paul|last4 = Zipursky|first4 = S. Lawrence|last5 = Berk|first5 = Arnold|last6 = Lodish|first6 = Harvey}}</ref> Thus, the differential centrifugation method is the successive pelleting of particles from the previous supernatant, using increasingly higher centrifugation forces.<ref>{{cite book |last1=Griffith |first1=Owen Mitch |title=Practical Techniques for Centrifugal Separations – Application Guide |date=2010 |publisher=Principles & Techniques of Biochemistry and Molecular Biology |pages=1–27 |url=https://thermofisher.co.nz/Uploads/file/Scientific/Applications/Equipment-Furniture/Practical-Techniques-for-Centrifugal-Separations.pdf |access-date=2020-10-14 |archive-date=2023-02-07 |archive-url=https://web.archive.org/web/20230207165352/https://thermofisher.co.nz/Uploads/file/Scientific/Applications/Equipment-Furniture/Practical-Techniques-for-Centrifugal-Separations.pdf |url-status=dead }}</ref> Cellular organelles separated by differential centrifugation maintain a relatively high degree of normal functioning, as long as they are not subject to denaturing conditions during isolation.<ref>{{cite book|author=Gerald Karp|title=Cell and Molecular Biology: Concepts and Experiments|url=https://books.google.com/books?id=arRGYE0GxRQC&q=%22Differential+centrifugation%22&pg=PR28|date=19 October 2009|publisher=John Wiley & Sons|isbn=978-0-470-48337-4|pages=28–}}</ref><ref>{{cite journal |last1=Livshits |first1=Mikhail A. |last2=Khomyakova |first2=Elena |last3=Evtushenko |first3=Evgeniy G. |last4=Lazarev |first4=Vassili N. |last5=Kulemin |first5=Nikolay A. |last6=Semina |first6=Svetlana E. |last7=Generozov |first7=Edward V. |last8=Govorun |first8=Vadim M. |title=Isolation of exosomes by differential centrifugation: Theoretical analysis of a commonly used protocol |journal=Scientific Reports |date=30 November 2015 |volume=5 |issue=1 |pages=17319 |doi=10.1038/srep17319 |pmid=26616523 |pmc=4663484 |bibcode=2015NatSR...517319L |s2cid=14200669 |language=en |issn=2045-2322|doi-access=free }}</ref>