Membrane chromatography is considered a promising method for the purification and separation of diverse biomolecules such as proteins and antibodies. Membrane chromatography combines the procedures of membrane filtration and chromatography and is generally independent of the feed-flow. Thus, it is a recognized as an effective alternative compared to packed bed chromatography.
Ion-exchange membranes represent a major segment of media used in membrane chromatography. Various biomolecules with a different charge, but similar molecule weight, can be easily separated as a result of electrostatic interactions between the surface charge of the ion-exchange membrane and the charged groups. In addition to ion exchange membranes, affinity membranes allow specific binding of an analyte of interest through ligands, such as protein A. This allows analytes, such as monoclonal antibodies, to be purified. However, the biomolecules are recovered by pH shifts or/and high salt concentrations from ion exchange membranes or affinity membranes, which minimizes the yield and maximizes the cost of the process.
i3 Membrane offers a clean, fast, and cost-effective alternative: digital membrane chromatography.
By functionalization of the ion-exchange membrane with a nanometer-sized layer of gold, the chemical binding capacity of biomolecules can be switched when it is connected to an electrical source. Desorption takes place through simple regulation of the electrical potential. The electrical voltage can be continuously controlled so that the species of interest can be separated at defined time intervals. The process of adsorption and electrical desorption can be repeated several times, resulting in an enormous increase in separation capacity. Digitization of membrane adsorbers replaces the need for pH shifts or/and high salt concentrations without affecting the molecular structure of the target molecules.
The digital desorption works with AEX Membrane (use of BSA protein) as well as with affinity chromatographic membranes. Antibodies (Trastuzumab) bound at a Protein A membrane could be gained from the membrane by more than 95% using a certain voltage without shifting the pH-value. This have been covered by a patent application. The results show that digital membrane chromatography can be used for all different kinds of chromatography.
Digital i3 syringe filter units include a 25mm Au100/100 coated polyamide membrane with a membrane volume of 0,04 mL and pore size of 0,22 µm. Each unit contains one to three layers of our AEX membranes. This variable assembly of membrane layers enables for higher flow rates and dynamic binding capacity. Digital i3 syringe filter units are equipped with contact elements that allow an electrical potential to be applied to the membrane by an external voltage source. The female Luer lock inlet and male Luer lock outlet simplifies connection to typical low-pressure chromatography systems.
