Patent ID: 8075780
Filing Date: 2011-12-13
Classification: B01D,C07K

Abstract:
1. A system for the purification by ultrafiltration of target synthetic biological molecules including oligonucleotides, synthetic DNA and synthetic RNA from a solution each molecule having a molecular weight from about 0.5 KD to less than 5 KD comprising: a filtration holder having an inlet, a filtrate outlet and a retentate outlet, and a surface modified ultrafiltration membrane having a charged coating on the surface of the membrane, wherein the ultrafiltration membrane is located in the holder and separates the holder into an upstream compartment and a downstream compartment such that all filtrate must enter the inlet and pass through the surface modified ultrafiltration membrane before exiting the holder through the filtrate outlet, the surface modified ultrafiltration membrane has a nominal molecular weight cutoff (NMWCO) from about 0.5 KD to less than 5 KD when the modified membrane surface has a negative charge, or a nominal molecular weight cutoff (NMWCO) from about 0.5 KD to about 20 KD when the modified membrane surface has a positive charge; wherein the NMWCO of the ultrafiltration membrane is larger than the molecular weight of the target synthetic biological molecules.