Partial filling affinity capillary electrophoresis with cationic poly(vinylpyrrolidone)-based copolymer coatings for studies on human lipoprotein-steroid interactions

Ai Jun Wang, Kati Vainikka, Joanna Witos, Lucia D'Ulivo, Geraldine Cilpa, Petri T. Kovanen, Katariina Öörni, Matti Jauhiainen, Marja-Liisa Riekkola*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

15 Citations (Scopus)

Abstract

Human plasma lipoproteins have strong hydrophobic interactions with steroids and their fatty acyl derivatives such as estradiol fatty acyl esters. In this work, affinity capillary electrophoresis with the partial filling technique was applied to study the hydrophobic interactions between lipoproteins, which are nanometer-sized particles, and nonconjugated steroids. The capillaries were first rinsed with one of two novel poly(vinylpyrrolidone) (PVP)-based cationic copolymers that were strongly adsorbed onto the fused-silica surface via electrostatic interactions. This surface treatment greatly suppressed the adsorption of lipoproteins. Low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles were then employed in the coated capillaries as pseudostationary phase in the partial filling mode. The changes in corrected migration times of steroids increased linearly with the filling time of the lipoproteins. The affinity constants between the steroids and lipoproteins were calculated, and the most hydrophobic steroid studied, progesterone, had stronger affinity than testosterone or androstenedione toward both LDL and HDL. Affinity between steroids and LDL was stronger than that between steroids and HDL. Interactions between the steroids and lipoproteins were mainly nonspecific with particle lipid components, whereas some were site specific with the apolipoproteins. The developed technique has great potential for determination of the affinity of various compounds toward lipoproteins. (C) 2009 Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)93-101
Number of pages9
JournalANALYTICAL BIOCHEMISTRY
Volume399
Issue number1
DOIs
Publication statusPublished - 1 Apr 2010
MoE publication typeA1 Journal article-refereed

Keywords

  • Affinity capillary electrophoresis
  • Affinity constant
  • Copolymers
  • High- and low-density lipoproteins
  • Partial filling technique
  • Steroids

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