Effect of experimental conditions on the binding abilities of ciprofloxacin-imprinted nanoparticles prepared by solid-phase synthesis

Imprinted nanoparticles present several advantages respect to bulk imprinted materials, but, when prepared by traditional methods, their usefulness is limited as the approaches are costly or require complex optimization steps, while the purification from template molecules is challenging. An innovative approach is the solid-phase synthesis. It consists in the covalent immobilization of the template onto a solid support, the polymerization of nanoparticles around the template, the clean-up from unproductive components and the final release of the imprinted nanoparticles, which are free of template and demonstrate high affinity for the target molecule. Here we report the use of ciprofloxacin as immobilized template to evaluate the effect of different experimental conditions in the solid phase polymerization (template scaffolding, polymerization mixtures, polymerization medium) and different rebinding conditions (buffer pH) on the binding properties. The results confirm that the solid phase synthesis approach is a flexible approach, where the experimental conditions are decisive for the binding properties. The results show that this approach is a powerful technique to easily prepare nanoparticles fully compatible with the aqueous environment, with reduced non specific binding (≈104 mol L-1), high equilibrium binding constants (105-107 mol L-1) and fast association rate constants (≈106 mol L-1min-1), values which are comparable to those of natural antibodies