Fig. 3. Binding of E4 nanoformulations is DLL4-specific. (A) Binding of fluorescently labelled NP 11, NP 12 and corresponding blank NP controls 9 and 10 (50 μg polymer mL–1) to DLL4 was analysed by modified ELISA ± pre-incubation with DLL4 (10 μg mL–1). (B) Binding of fluorescently labelled NP 12 (250 μg polymer mL–1) to DLL4 was analysed by modified ELISA ± competition with DLL4 antibody (165–40 000 ng mL–1). (C) Enhanced DLL4 binding by NP 12 is dependent upon site-specific “click” coupling. VNAR conjugate 7 and VNAR E4 6 were incubated with fluorescently labelled NP composed of (1) PLGA-502H, (2) a 75 : 25 blend of PLGA-502H : PLGA-PEG-NHS or (3) a 75 : 25 blend of PLGA-502H : PLGA-PEG-azide. Binding of these nanoformulations and corresponding blank NP controls (500 μg polymer mL–1) to DLL4 was analysed by modified ELISA. Data expressed as mean ± SEM.
