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Thermoresponsive N,N ‐dialkylacrylamide copolymer blends as DNA sieving matrices with a thermally tunable mesh size
Author(s) -
Kan CheukWai,
Doherty Erin A. S.,
Buchholz Brett A.,
Barron Annelise E.
Publication year - 2004
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200305785
Subject(s) - copolymer , materials science , dna , chemical engineering , polymer chemistry , chemistry , polymer , composite material , biochemistry , engineering
In an earlier study we showed that a blend of thermoresponsive and nonthermoresponsive hydroxyalkylcelluloses could be used to create a thermally tunable polymer network for double‐stranded (ds) DNA separation. Here, we show the generality of this approach using a family of polymers suited to a wider range of DNA separations: a blended mixture of N , N ‐dialkylacrylamide copolymers with different thermoresponsive behaviors. A mixture of 47% w/w N , N ‐diethylacrylamide (DEA)/53% w/w N , N ‐dimethylacrylamide (DMA) (DEA47; thermoresponsive, transition temperature = 55°C in water) and 30% w/w DEA/70% w/w DMA (DEA30; nonthermoresponsive, transition temperature > 85°C in water) copolymers in the ratio of 1:5 w/w DEA47:DEA30 was used to separate a dsDNA restriction digest (ΦX174‐ Hae III). We investigated the effects of changing mesh size on dsDNA separation, as controlled by temperature. We observed good DNA separation performance with the copolymer blend at temperatures ranging from 25°C to 48°C. The separation selectivity was evaluated quantitatively for certain DNA fragment pairs as a function of temperature. The results were compared with those obtained with a control matrix consisting only of the nonthermoresponsive DEA30. Different DNA fragment pairs of various sizes show distinct temperature‐dependent selectivities. Over the same temperature range, no significant temperature dependence of selectivity is observed for these DNA fragment pairs in the nonthermoresponsive control matrix. Overall, the results show similar trends in the temperature dependency of separation selectivity to what was previously observed in hydroxyalkylcellulose blends, for the same DNA fragment pairs. Finally, we showed that a ramped temperature scheme enables improved separation in the blended copolymer matrix for both small and large DNA fragments, simultaneously in a single capillary electrophoresis (CE) run.