Supernatant: Unlocking potential breakthroughs in medicine and technology

Supernatants are obtained through centrifugation, precipitation and crystallisation
An undated image of supernatant in the laboratory. —Canva
An undated image of supernatant in the laboratory. —Canva

Supernatants are the cell's recovered organelle factions that are obtained through centrifugation, precipitation, crystallisation, or other methods that divide cellular samples. It goes by the name Supernate as well.

Precipitate usually settles in the solution as a layer or pellet, whereas the supernatant is usually transparent, free of precipitate, and has a lower density.

 Decantation is the process through which the supernatant and precipitate separate.

In each given separation reaction, the supernatant is created through a number of successive phases. As the separation process advances, the supernatant usually becomes less complicated.

How is the supernatant formed in precipitation reactions?

The clear liquid that stays above the precipitated material in precipitation reactions is referred to as the supernatant.

A substance undergoes supersaturation during precipitation, which is the point at which the concentration of the solute is greater than its solubility under specific circumstances.

How is supernatant formed in precipitation reactions?

In centrifugation, particles are extracted from a solution by means of centrifugal force. Depending on the rotor's speed and the dimensions, density, and viscosity of the medium, this separation is accomplished.

Less dense components of the mixture travel toward the centrifuge's axis as a result of centrifugation, which causes the denser components to move away from it.

It is possible to raise the effective gravitational force such that the precipitate travels quickly and settles at the tube's bottom. 

The soluble parts of the cell are found in the supernatant, which is the portion of the solution that is left behind.

The initial stage in most fractionations is often centrifugation; at moderate speeds, this process removes cellular debris, leaving behind the supernatant.

The supernatant contains these smaller cell components after the first round of centrifugation. There are several types of centrifugation, but all proceed with the same principle, that is phase separation, during which components of a mixture are converted from a matrix or aqueous medium to a solvent.

There are differential forms of centrifugation:

  • Density gradient centrifugation: macromolecules within a mixture move through a density gradient until they settle at a density equal to their own.
  • Differential centrifugation: A stepwise increase in centrifugation speed is used to separate components of a mixture. Organelles and other sub-cellular particles are separated based on their sedimentation rate.
  • Ultracentrifugation: a stepwise increase in centrifugal force which causes sedimentation of particles as small as 10kDa.

How does the supernatant differ from the precipitate?

The solid medium that settles to the bottom of a solution is called a precipitate. It manifests as a result of the factors surrounding the separation reaction.

 These include modifications to the chemical conditions, such as concentration shifts, temperature swings, changes in pH or ionic strength, or physical procedures like centrifugation.

The chemical species that promotes the formation of precipitates is known as the precipitant; the precipitate is different from it.

Supernatant and precipitate are two different but connected parts of a mixture that are being separated. 

In terms of state, the supernatant is different from the precipitate; it is both liquid and solid.