Preparation and characterization of nickel nanoparticles for binding to his-tag proteins and antigens

• Published in: Pharmaceutical research 2007-02, Vol.24 (2), p.343-352
• Main Authors: PATEL, Jigna D, O'CARRA, Ronan, JONES, Julia, WOODWARD, Jerold G, MUMPER, Russell J
• Format: Article
• Language: English
• Subjects: Antigens - chemistry; Binding sites; Biological and medical sciences; Blotting, Western; CD4 Lymphocyte Count; Cell Proliferation - drug effects; Chemistry, Pharmaceutical; Emulsions; Enzyme-Linked Immunosorbent Assay; General pharmacology; Green Fluorescent Proteins - chemistry; Histidine - chemistry; HIV Core Protein p24 - chemistry; Human immunodeficiency virus 1; Hydrogen-Ion Concentration; Immunoglobulin G - biosynthesis; Interferon-gamma - metabolism; Medical sciences; Nanoparticles; Nickel; Nickel - chemistry; Pharmaceutical technology. Pharmaceutical industry; Pharmacology; Pharmacology. Drug treatments; Polyethylene Glycols; Protein Binding; Proteins - chemistry; Spectrophotometry, Atomic; Spleen - cytology; Virus Replication - drug effects; Waxes
• ISSN: 0724-8741; 1573-904X
• DOI: 10.1007/s11095-006-9154-7

The purpose of these studies was to prepare nanoparticles (NPs) with a small amount of surface-chelated nickel for obtaining enhanced binding of histidine-tagged (his-tag) proteins compared to non-histidine-tagged protein binding to charged nanoparticles. NPs were prepared from oil-in-water microemulsion precursors using emulsifying wax, 3 mM Brij 78 and 0.1 mM DOGS-NTA-Ni lipid (referred to as Ni-NPs). The amount of lipid entrapped in the NPs was quantitated by atomic emission spectroscopy (AES). The Ni-NPs were investigated for binding to two his-tag proteins, green fluorescent protein (GFP) and his-tag HIV-1 Gag p24. In vivo studies in mice were carried out to evaluate the immune responses obtained to his-tag Gag p24 bound to Ni-NPs. AES studies demonstrated that approximately 5% of the DOGS-NTA-Ni lipid used was entrapped in the NPs. The optimal binding ratio his-tag GFP and his-tag Gag p24 to Ni-NPs was found to be 1:33.7 and 1:35.4 w/w, respectively. This interaction was stable at 37 degrees C in PBS, pH 7.4 over 4 h and the interaction of his-tag GFP with the Ni-NPs was enhanced compared to control NPs prepared with no Ni on the surface (NTA-NPs). The in vivo studies demonstrated enhanced serum IgG and IgG2a responses to his-tag Gag p24 bound to Ni-NPs compared to protein adjuvanted with Alum or adsorbed on the surface of control NTA-NPs. Ni-NPs can be used to bind strongly to his-tag proteins. This system was demonstrated to have potential applications in vaccine delivery for enhancing immune responses to protein-based vaccines.