Sequence-specific nucleic acid mobility using a reversible block copolymer gel matrix and DNA amphiphiles (lipid-DNA) in capillary and microfluidic electrophoretic separations

Reversible noncovalent but sequence-dependent attachment of DNA to gels is shown to allow programmable mobility processing of DNA populations. The covalent attachment of DNA oligomers to polyacrylamide gels using acrydite-modified oligonucleotides has enabled sequence-specific mobility assays for DNA in gel electrophoresis: sequences binding to the immobilized DNA are delayed in their migration. Such a system has been used for example to construct complex DNA filters facilitating DNA computations. However, these gels are formed irreversibly and the choice of immobilized sequences is made once off during fabrication. In this work, we demonstrate the reversible self-assembly of gels combined with amphiphilic DNA molecules, which exhibit hydrophobic hydrocarbon chains attached to the nucleobase. This amphiphilic DNA, which we term lipid-DNA, is synthesized in advance and is blended into a block copolymer gel to induce sequence-dependent DNA retention during electrophoresis. Furthermore, we demonstrate and characterize the programmable mobility shift of matching DNA in such reversible gels both in thin films and microchannels using microelectrode arrays. Such sequence selective separation may be employed to select nucleic acid sequences of similar length from a mixture via local electronics, a basic functionality that can be employed in novel electronic chemical cell designs and other DNA information-processing systems.