Immunoglobulin G immobilization on PVDF surface

• PVDF requires functionalization prior to surface attaching proteins.
• Grafting is a key step in protein-A and IgG immobilization onto PVDF surface.
• Achieving ends-on orientation of IgG on N2/H2 plasma treated PVDF via grafted protein-A.

Immobilization of antibody molecules onto hydrophobic polymeric surfaces with disordered orientation is something unwanted in many applications. To overcome this drawback, controlled immunoglobulin G (IgG) immobilization onto poly(vinylidene fluoride) surface was investigated in this paper. A two-step process involving radiofrequency plasma pretreatment for polymer surface functionalization, followed by coupling reaction was developed, after which immunoglobulin G was immobilized onto the surface directly or via protein-A. IR and XPS data proved that the process is more efficient when the radiofrequency plasma pretreatment was performed using N2 and N2/H2 as discharge gases. NIR-CI, AFM and XPS surface evaluation revealed that immobilization of IgG onto N2/H2 plasma-treated PVDF via grafted protein-A was achieved with an ends-on orientation, leaving available the antigen binding sites of IgG. This procedure could be a promising route for the preparation of oriented IgG assembly onto PVDF, useful in biomedical, membranes or sensors applications. QCM results showed a better antibody–antigen interaction when IgG immobilization onto PVDF substrate is mediated by protein A.

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