Technology: How it Works
PrIME
stands for:
Preparative
Isolation by
Membrane
Electrophoresis.
The PrIME system separates uses electrical potential. Every biological component has a natural size and charge. Based on these characteristics can selectively move one biological component across a membrane away from other biological contaminants can be removed. This very powerful separation process uses the natural charge of the target molecule to selectively drive its transfer across the membrane. The existing membrane separation processes use pressure to achieve a separation. Pressure is indiscriminate as it pushes all of the biological components equally thus making the membrane do all the work. This is one reason why existing separation processes are less efficient than the PrIME.
Below is a picture of the PrIME separation cartridge and the other clinical NuSep product, the SpermSep IVF cartridge.
The PrIME system separates on the basis
of both size and charge. The target
protein's net charge is determined by the separation buffer. The charge on the
protein determines the direction of movement and the amount of this charge
determines the speed of this movement. Simultaneously the size of the holes in
the membrane determine if the protein can move across into the collection
stream. In effect the PrIME system provides a simultaneous 2 dimensional separation.
This is a unique capability of the PrIME system.
PrIME’s disposable single use cartridge
(see above) is designed to provide the separation of a particular molecular
weight. For example a nominal 70,000 molecular weight cartridge would be used in
an appropriate pH buffer to separate albumin. The nominal 70,000 molecular
weight cut off means that biological components larger than 70,000 will not be
able to transfer across the membrane but smaller molecules, such as albumin are
able to transfer.
The PrIME membrane is a unique polyacrylamide
membrane which provides a tortuous path for the biological components to travel
through from one side of the membrane to the other. This path allows the system
to selectively separate the molecules based on its size and charge and the
speed at which these particles travel through the membrane. In comparison, standard membranes used in the
current technologies such as micro-, ultra- and nanofiltration have physical
pores that traverse the membrane thickness. These membranes are manufactured with
a particular pore-size distribution that allows pressure to force larger particles
through than the nominal molecular weight cut off.
Additionally, the pressure applied can
cause fowling as it pushes all the components against the membrane and they
have to sort themselves out or be squeezed through the holes in the membranes. By comparison, in the PrIME system, only the
biological components that have the appropriate size and charge will travel
through the membrane and into the collection stream. This reduces membrane
fowling and increases the recovery of the target component. The use of dual
properties of size and charge allows the enhanced selection of the target
molecules compared with the use of pressure for separation.
