Receptor Arrays for the Selective and Efficient Capturing of Viral Particles, Proteins and Nanoparticles

Abstract

We describe microarrays of receptor molecules that capture viral particles with high specificity and at high density. Patches of viral receptors were generated by first modifying microscale gold squares on glass substrates with alkanethiol derivatives and then immobilizing the His -tagged very-low-density lipoprotein 6 (VLDL) receptor ligand binding domain via metal-chelate complexes to the gold surfaces. Free glass areas surrounding the gold squares were passivated with a dense film of poly(ethylene glycol) (PEG). As assessed by atomic force microscopy, human rhinovirus particles were captured onto the VLDL-receptor patches with a high surface coverage but were effectively repelled by the PEG layer, resulting in a 330 000-fold higher density of the particles on the gold as compared to the glass surfaces. The metal chelate-based coupling strategy was found to be superior to two alternative routes, which used the covalent coupling of viral particles or viral receptors to the substrate surface. The high density receptor arrays were employed for sensing and characterizing viral particles with so far unprecedented selectivity.Furthermore, an alternative route to create arrays in the nanometer range for the site specific binding of proteins, nanoparticles and pathogens is shown. These arrays are results of AFM based nanolithography performed on Mica substrates passivated by repellent protein- or PEG films. We could show that with the help of this method we are able to create nanometer-sized structures in the range of an AFM tip radius. The structures created in this manner were subsequently refilled with proteins which serve as a basis for the specific binding of other proteins, particles or pathogens of interest and could furthermore be analyzed by AFM under near physiological conditions.