Gold nanoparticle interaction with proteins is characterized by using scattering correlation spectroscopy. Protein orientation and binding affinity regarding the nanoparticle surface are discussed.

HydrophobinVmh2 is a small amphiphilic protein, which self-assembles on different surfaces and naturally interacts with glucose. Here, we report on the synthesis of a nanobiocomplex made of polyethylene glycol, Vmh2 and gold nanoparticles by a one-step process and on its ability to recognise glucose in an aqueous solution at 0.3–0.6–1.2 mg ml⁻¹ concentrations. Even though the Vmh2 proteins are intrinsically bonded to the gold core, effective glucose interaction monitoring was demonstrated by using dynamic light scattering, ultraviolet–visible, polarization-modulated infrared reflection–absorption and x-ray photoelectron spectroscopies. Experimental results highlighted an affinity constant of 7.3 ± 0.3 mg ml⁻¹ between the nanobiosystem and the sugar, and a detection sensitivity of 0.13 ± 0.06 a.u./mg ml⁻¹.

We investigate the characteristics and fate of spheroid- and rod-shaped TiO₂ nano-crystals in aqueous solutions and provide a proper evaluation of their reactivity.