Simple immobilization of antibody in organic/inorganic hybrid thin films for immunosensing

Simple method to immobilize antibody in organic/inorganic hybrid thin films, prepared easily by using liquid phase deposition (LPD), was proposed to enhance the sensitivity, reproducibility and stability of immunosensing chips. The LPD method could embed a monoclonal antibody of C-reactive protein (Anti-CRP), which is mixed with poly(l-lysine) (PL) as an organic binder, on/in titanium oxide thin layer deposited onto a surface plasmon resonance (SPR) sensing chip (F(Anti-CRP-PL)), allowing simple immobilization of anti-CRP capable of CRP detection. As a control, anti-CRP was non-covalently immobilized after preparing the titanium oxide layer containing PL (SIF(Anti-CRP-PL)). Binding experiments of CRP on the prepared sensor chips were performed by SPR measurements. The CRP binding capacity of anti-CRP on F(Anti-CRP-PL) was 54% greater than that of anti-CRP on SIF (Anti-CRP-PL), suggesting that the immobilization method could retain good antigen-binding activity of anti-CRP. Reproducibility of the antigen-antibody interaction was estimated by SPR using 10mM HCl as the regeneration regent. CRP was repeatedly detected, and the detection limit was calculated to be 19.9ngmL(-1) (CV: 8.9%). By using this method, antibodies could be simply immobilized to various kinds of sensing chips for the development of immunosensing systems.