Hexadimethrine bromide (commercial brand name Polybrene) is a

cationic An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

polymer A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...

with several uses. Currently, it is primarily used to increase the efficiency of transduction of certain cells with

retrovirus A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. Once inside the host cell's cytoplasm, the virus uses its own reverse transcriptase ...

cell culture Cell culture or tissue culture is the process by which cells are grown under controlled conditions, generally outside of their natural environment. The term "tissue culture" was coined by American pathologist Montrose Thomas Burrows. This te ...

. Hexadimethrine bromide acts by neutralizing the charge repulsion between

virion A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1 ...

s and

sialic acid Sialic acids are a class of alpha-keto acid sugars with a nine-carbon backbone. The term "sialic acid" (from the Greek for saliva, - ''síalon'') was first introduced by Swedish biochemist Gunnar Blix in 1952. The most common member of this gr ...

on the

cell surface The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment ( ...

. Use of Polybrene can improve transduction efficiency 100-1000 fold although it can be toxic to some cell types. Polybrene in combination with DMSO shock is used to transfect some cell types such as NIH-3T3 and CHO. It has other uses, including a role in

protein sequencing Protein sequencing is the practical process of determining the amino acid sequence of all or part of a protein or peptide. This may serve to identify the protein or characterize its post-translational modifications. Typically, partial sequencing o ...

. Hexadimethrine bromide also reverses heparin anticoagulation during open-heart surgery, and it was the original reversal agents used in the 1950s and 1960s. It was replaced by

protamine sulfate Protamine sulfate is a medication that is used to reverse the effects of heparin. It is specifically used in heparin overdose, in low molecular weight heparin overdose, and to reverse the effects of heparin during delivery and heart surgery. ...

in 1969, after it was shown that hexadimethrine bromide could potentially cause

kidney failure Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...

in dogs when used in doses in excess of its therapeutic range. It is still used as an alternative to protamine sulfate for patients who are sensitive to protamine, and at least one surgical center has gone back to using it as their standard reversal agent, since protamine sulfate causes at least a mild hypotensive reaction in most or all patients Hexadimethrine bromide is also used in enzyme kinetic assays in order to reduce spontaneous activation of zymogens that are prone to auto activation.

References

Organic polymers {{polymer-stub