Separation of ofloxacin enantiomers by capillary electrophoresis with fluorescence detection using deoxyribonucleic acid oligonucleotides as chiral selectors.

This study used capillary electrophoresis with fluorescence detection- and a partial-filling mode-based method for chiral separation of ofloxacin. The deoxyribonucleic acid oligonucleotides with different base sequences were studied as potential chiral selectors including deoxyribonucleic acid tetrahedron, G-quadruplex, and G-riched double-strand deoxyribonucleic acid. Under the optimized conditions, all the deoxyribonucleic acid chiral selectors exhibited excellent chiral separation capabilities with a resolution higher than 1.5. The electrophoretic behavior of the ofloxacin enantiomer might result from the intermediate conjugate with different stabilities between chiral selectors and analytes by a combination of the hydrogen bond and spatial recognition structure. Moreover, satisfactory repeatability regarding run-to-run and interday repeatability was obtained, and all the relative standard deviation values of migration times and resolutions were below 4% (n = 6). Conclusively, both spatial structure and arrangement of the G bases potentiated the chiral separation capability of deoxyribonucleic acid for ofloxacin enantiomer. This work offered a stepping stone for enantioseparation using deoxyribonucleic acid as chiral selectors.

Fluorescence coupled capillary electrophoresis as a strategy for tetrahedron DNA analysis.

A strategy based on fluorescence coupled capillary electrophoresis (CE-FL) was developed for analyzing tetrahedron DNA (TD) and TD-doxorubicin (DOX) conjugate. Capillary gel electrophoresis exhibited desirable performance for separating TD and DNA strands. Under the optimized conditions, satisfactory repeatability concerning run-to-run and interday repeatability was obtained, and relative standard deviation value of resolution (n = 6) was 0.64%. Furthermore, the combination of CE and fluorescence detection provided a sensitive platform for quantifying TD concentration and calculating the damage degree of TD. The electrophoretograms indicated that CE-FL was a suitable TD assay method with high specificity and sensitivity. In addition, the application of CE-FL for TD fluorescence resonance energy transfer (FRET) research was also explored. Two types of DNA strands were utilized to interfere the formation of TD. The impact of partially complementary chain and completely complementary chain on FRET signal was explored, and the influence mechanism was discussed. After applying CE-FL for characterizing TD, we also combine CE and FRET to analyze TD-DOX conjugate. CE presented a favourable technique to monitor DOX loading and releasing processes. These noteworthy results offered a stepping stone for DNA nanomaterials assay by using CE-FL.