Piperazine-based buffers for liposome coating of capillaries for electrophoresis

Abstract

Anionic liposomes can be coated on fused-silica capillaries for electrophoresis in the presence of N-(hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) (HEPES) as background electrolyte (BGE) solution. In this work, the interaction of various compounds with zwitterionic and anionic phospholipid coatings was studied with HEPES at pH 7.4 as BGE solution. The chromatographic and electrophoretic behavior of three test sample solutions (anionic, cationic, and neutral) was investigated for evaluation of the phospholipid coatings. Our results show that hydrophobic interactions between analytes and the phospholipid coating are important for the migration of charged analytes. In addition, the performances of other piperazine-based buffers, i.e., N-(2-hydroxyethyl)piperazine-N'-(2-hydroxypropanesulfonic acid), piperazine-N,N'-bis(2-ethanesulfonic acid), and piperazine-N,N'-bis(hydroxypropane sulfonic acid), at pH 7.4, as liposome solvent and BGE solution were evaluated and compared with the performance of HEPES at pH 7.4. The anionic liposome solution comprised 80/20 mol% phosphatidylcholine/phosphatidylserine. A simple test solution was selected and the chromatographic and electrophoretic migration behavior of the analytes was evaluated. The results show that, in addition to HEPES, other piperazine-based buffers at pH 7.4 are suitable for coating of fused-silica capillaries with anionic liposomes.

Dynamic coating of SU‐8 microfluidic chips with phospholipid disks

“…1). In the previous studies, HEPES and other piperazine-based buffers have been found superior to other organic and inorganic buffer ions as BGEs [42,43]. Here, the stability of the POPC/DSPEG3000 coating was investigated at varying pH conditions in the presence of HEPES or, alternatively, inorganic borate buffer.…”

Effect of ionic liquids on the interaction between liposomes and common wastewater pollutants investigated by capillary electrophoresis

“…(2) for systems containing liposomes. Some buffer compositions may enhance the adsorption of liposomes to the fused silica capillary wall [27], however, phosphate buffers are known to minimize such adsorption [28] and therefore it was selected as the buffer compound for this study. The retention factors of the selected wastewater compounds in the presence of liposomes are shown in Fig.…”

Capillary electrophoresis of liposomes functionalized for protein binding

“…However, in most cases they exhibit electric charges. For this reason, they can be analyzed by CE, and they proved useful as anionic pseudostationary phases in EKC ( ; for recent reviews see [23,24]. It was found that, besides the pH, the kind of the electrolytes [6,25] and its ionic strength [5,18], and the preparation procedure of the vesicles influences the electrophoretic properties of the particles [23,26].…”