Screening of the binding properties of molecularly imprinted nanoparticles via capillary electrophoresis
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In response to the need for straightforward analytical methods to assess the affinity of molecularly imprinted nanoparticles (MIP NPs) for ligands, capillary electrophoresis (CE) was exploited using MIP NPs targeting the iron-regulating hormone hepcidin. In this work, MIP NPs were challenged with their template peptide, i.e., the N-terminal 5-mer of hepcidin, in comparison to unrelated ligand peptides. A CE separation method was developed ex novo achieving, after optimization of the background electrolyte (150 mM sodium phosphate pH 7.4) and of the running temperature (35 °C), the full separation of the free ligand from the complexed MIP NPs. The CE binding isotherm allowed the estimation of a micromolar dissociation constant for the 5-mer template–MIP NPs complex, in agreement with independent measurements. The CE offered the advantages of a direct injection of the MIP NPs/ligand incubation mix, without preliminary fractionation steps, requiring only minimal sample volumes and short analysis times. In conclusion CE proved to be a valid technique for characterizing the interactions of MIP NP libraries for selected target compounds.
KeywordsMolecularly imprinted nanoparticles Capillary electrophoresis Binding isotherm Affinity Hepcidin
AMB, LC, and GM thank Italian Ministry of Education, Research and University for the grant FIRB2012 RBFR12LD0W_003; The research leading to these results has received funding from the People Programme (Marie Curie Actions, PINP project awarded to EA) of the European Union’s Seventh Framework Programme FP7/2007-2013/ under REA grant agreement no. 327165. Authors are grateful to Dr. Andrea Anesi for the mass spectrometry analyses.
Compliance with ethical standards
Conflict of interests
The authors declare no conflict of interests.
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