Procipient® (Dimethyl Sulfoxide USP, Ph. Eur.) is the most widely used medium for the cryopreservation of living cells and tissue. DMSO also plays a role in synthesis of proteins. DMSO has various functions in the Biotechnology segment. DMSO is useful in cryopreservation of cells and can be used to purify proteins. The solvent properties may be useful for synthesis or drug delivery of proteins, peptides or carbohydrates.
A unique combination of physical properties has established DMSO as the standard in cell preservation. In 1959, it was discovered that dimethyl sulfoxide (DMSO), which passes through cell membranes more readily than glycerol, is also useful as a cryoprotectant. When combined with water, DMSO exhibits unique and interesting thermodynamic properties. The eutectic mixture of the combination results in a liquid at minus 80°C!
DMSO penetrates cell membranes and depresses the freezing point of contained water. As the temperature decreases in the cryopreservation cycle, the cell is protected from freezing and the deleterious effects of ice crystals.
DMSO is used in the cryopreservation of cells and biological tissue for a variety of end use applications. These include tissue banks, vaccines, drug delivery applications, cell culture and in laboratory cell testing.
Histology and cytology
Histological and cytological procedures are multi-stepped and time consuming. Dimethyl sulfoxide is added to proprietary blends of plastic polymer paraffin waxes. The DMSO reduces infiltration times and facilitates thin sectioning (Culling CFA. Handbook of Histopathological and Histochemical Techniques. 3rd ed. Sydney: Butterworths. 1974) DMSO is thought to scavenge residual transition solvent and probably alter tissue permeability by substituting for or removing bound water thus improving infiltration.
One example on the market is Paraplast Plus® that is similar to the original product except that Plus has added to it a low level (<0.1%) of dimethyl sulfoxide (DMSO) for faster tissue penetration. According to the manufacturer’s claims, this slight variation in composition typically results in a shortening of infiltration times by one third.
DMSO is also used in stains for nucleic acid where degree and intensity of staining is improved with the use of DMSO.
DMSO is used as a reaction solvent in the solid phase synthesis of peptides, during coupling operations between resin-bound fragments and activated carboxyl groups on the incoming fragment. A variety of coupling agents have been reported in this step, including TBTU/HOBt/DIPEA, DIC/DHBt, and HBTU/ HOBt/DIPEA.
In a recent review of strategies for the convergent synthesis of proteins, it was reported that performing the coupling step in DMSO using a DCC/HOBt coupling system resulted in a low degree of product epimerization:
Adapted from Barlos, K.; Gatos, D. Biopolymers (Peptide Science), Vol. 51, 266-278 (1999)
Solubilizing Peptides and Proteins
DMSO is widely used to dissolve proteins / peptides for purification via preparative HPLC in reverse-phase mode. It is also used as a reaction solvent for protein modification reactions due to the ability to dissolve high molecular weight peptides when other solvents fail.