Percoll
Encyclopedia
Percoll was first formulated by Pertoft et al. as a tool for more efficient density separation. It is used for the isolation of cell
s, organelle
s, and/or virus
es by density centrifugation
. Percoll consists of colloidal silica particles of 15-30 nm diameter (23% w/w in water) which have been coated with polyvinylpyrrolidone (PVP).
Percoll is well suited for density gradient experiments because it possesses a low viscosity compared to alternatives, a low osmolarity and no toxicity towards cells and their constituents.
Percoll is a registered trademark of GE Healthcare
.
(ART) to select sperm
from semen
by density gradient centrifugation, for use in techniques such as in vitro fertilization or intrauterine insemination. However, in 1996, Pharmacia
sent out a letter to laboratories stating that Percoll should be used for research purposes only, not clinical. Pharmacia had not marketed it as a sperm preparation product; it had been repackaged and sold as such by third-party manufacturers. The FDA Warning Letter
was due to concerns that PVP might cause damage to sperm (an unknown issue), and also that some batches of Percoll contained high levels of endotoxin
(a known issue). The latter concern also applies to the use of Percoll with any other cells that might be injected back into a patient, since endotoxin can cause severe inflammation and fever. Since then it has been replaced with other colloids in the ART industry.
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
s, organelle
Organelle
In cell biology, an organelle is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own lipid bilayer....
s, and/or virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es by density centrifugation
Centrifugation
Centrifugation is a process that involves the use of the centrifugal force for the sedimentation of mixtures with a centrifuge, used in industry and in laboratory settings. More-dense components of the mixture migrate away from the axis of the centrifuge, while less-dense components of the mixture...
. Percoll consists of colloidal silica particles of 15-30 nm diameter (23% w/w in water) which have been coated with polyvinylpyrrolidone (PVP).
Percoll is well suited for density gradient experiments because it possesses a low viscosity compared to alternatives, a low osmolarity and no toxicity towards cells and their constituents.
Percoll is a registered trademark of GE Healthcare
GE Healthcare
GE Healthcare is a division of GE Technology Infrastructure, which is itself a division of General Electric . It employs more than 46,000 people worldwide and is headquartered in Little Chalfont, Buckinghamshire, United Kingdom. GE Healthcare is the first GE business segment to be headquartered...
.
Past use in artificial reproduction
Percoll was previously used in assisted reproductive technologyAssisted reproductive technology
Assisted reproductive technology is a general term referring to methods used to achieve pregnancy by artificial or partially artificial means. It is reproductive technology used primarily in infertility treatments. Some forms of ART are also used in fertile couples for genetic reasons...
(ART) to select sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
from semen
Semen
Semen is an organic fluid, also known as seminal fluid, that may contain spermatozoa. It is secreted by the gonads and other sexual organs of male or hermaphroditic animals and can fertilize female ova...
by density gradient centrifugation, for use in techniques such as in vitro fertilization or intrauterine insemination. However, in 1996, Pharmacia
Pharmacia
Pharmacia was a pharmaceutical and biotechnological company in Sweden.-History:Pharmacia was founded in 1911 in Stockholm, Sweden by pharmacist Gustav Felix Grönfeldt at the Elgen Pharmacy. The company is named after the Greek word φαρμακεία, transliterated pharmakeia, which means 'sorcery'...
sent out a letter to laboratories stating that Percoll should be used for research purposes only, not clinical. Pharmacia had not marketed it as a sperm preparation product; it had been repackaged and sold as such by third-party manufacturers. The FDA Warning Letter
FDA Warning Letter
The United States Food and Drug Adminstration defines a Warning Letter as "...a correspondence that notifies regulated industry about violations that FDA has documented during its inspections or investigations...
was due to concerns that PVP might cause damage to sperm (an unknown issue), and also that some batches of Percoll contained high levels of endotoxin
Endotoxin
Endotoxins are toxins associated with some Gram-negative bacteria. An "endotoxin" is a toxin that is a structural molecule of the bacteria that is recognized by the immune system.-Gram negative:...
(a known issue). The latter concern also applies to the use of Percoll with any other cells that might be injected back into a patient, since endotoxin can cause severe inflammation and fever. Since then it has been replaced with other colloids in the ART industry.