Conjugation of hydroxyapatite nanocrystals with human immunoglobulin G for nanomedical applications.
Inorganic nanosized drug carriers are a promising field in nanomedicine applied to cancer. Their conjugation with antibodies combines the properties of the nanoparticles themselves with the specific and selective recognition ability of the antibodies to antigens. Biomimetic carbonate-hydroxyapatite (HA) nanoparticles were synthesized and fully characterized; human IgGs, used as model antibodies, were coupled to these nanocrystals. The maximum loading amount, the interaction modelling, the preferential orientation and the secondary structure modifications were evaluated using theoretical models (Langmuir, Freundlich and Langmuir-Freundlich) spectroscopic (UV-Vis, Raman), calorimetric (TGA), and immunochemical techniques (ELISA, Western Blot). HA nanoparticles of about 30 nm adsorbed human IgGs, in a dose-dependent, saturable and stable manner with micromolar affinity and adsorption capability around 2.3 mg/m(2). Adsorption isotherm could be described by Langmuir-Freundlich model, and was due to both energetically homogeneous and heterogeneous binding sites on HA surface, mainly of electrostatic nature. Binding did not induce secondary structure modification of IgGs. A preferential IgG end-on orientation with the involvement of IgG Fc moiety in the adsorption seems most probable due to the steric hindrance of their Fab domains. Biomimetic HA nanocrystals are suitable substrates to produce nanoparticles which can be functionalized with antibodies for efficient targeted drug delivery to tumours.
Dipartimento di Scienze Mediche, Università del Piemonte Orientale A. Avogadro, Novara, Italy.
Michele
M
Iafisco
Elena
E
Varoni
Michele
M
Di Foggia
Stefano
S
Pietronave
Milena
M
Fini
Norberto
N
Roveri
Lia
L
Rimondini
Maria
M
Prat
D000327:Adsorption; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D001665:Binding Sites; D015153:Blotting, Western; D004337:Drug Carriers / Q000737:chemistry* / Q000378:metabolism; D017886:Durapatite / Q000737:chemistry / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D018796:Immunoconjugates / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D007074:Immunoglobulin G / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D058990:Molecular Targeted Therapy / Q000379:methods*; D050997:Nanomedicine / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry; D009369:Neoplasms / Q000276:immunology / Q000628:therapy*; D010316:Particle Size; D011485:Protein Binding; D017433:Protein Structure, Secondary; D013057:Spectrum Analysis; D055672:Static Electricity; D013499:Surface Properties
D000970:Antineoplastic Agents; D004337:Drug Carriers; D018796:Immunoconjugates; D007074:Immunoglobulin G; D017886:Durapatite