DNA sequencing by capillary electrophoresis using copolymers of acrylamideand N,N-dimethyl-acrylamide

Copolymers of acrylamide (AM) and N,N-dimethylacrylamide (DMA) with AM to D MA molar ratios of 3:1, 2:1 and 1:1 and molecular weights of about 2.2 MDa were synthesized. The polymers were tested as separation media in DNA seque ncing analysis by capillary electrophoresis (CE). The dynamic coating abili ty of polydimethylacrylamide (PDMA) and the hydrophilicity of polyacrylamid e (PAM) have been successfully combined in these random copolymers. A separ ation efficiency of over 10 million theoretical plates per meter has been r eached by using the bare capillaries without the additional polymer coating step. Under optimized separation conditions for longer read length DNA seq uencing, the separation ability of the copolymers decreased with decreasing AM to DMA molar ratio from 3:1, 2:1 and 1:1. In comparison with PAM, the c opolymer with a 3:1 AM:DMA ratio showed a higher separation efficiency. By using a 2.5% w/v copolymer with 3:1 AM:DMA ratio, one base resolution of 0. 55 up to 699 bases and 0.30 up to 963 bases have been achieved in about 80 min at ambient temperatures.