Atomic force microscopy-derived nanoscale chip for the detection of human pathogenic viruses.

Native-protein nanolithography (NPNL) was used to fabricate stable bioactive arrays of viral receptor spots. The arrays were specific for the cognate virus and devoid of nonspecific protein and virus adsorption under physiologic conditions. The spot size ranged from 200 nm × 200 nm to 2 μm × 2 μm and up to 3 × 3 spots were arranged per array. With proper force adjustment in the patterning experiments, His₆-tagged bovine serum albumin (BSA) molecules were selectively removed from the underlying self-assembled monolayer (SAM) while leaving the latter intact. Injection of His₆-tagged very low density lipoprotein receptor (VLDLR-HiS₆) constructs resulted in specific, oriented binding to the Ni²⁺ -loaded bis-(nitrolotriacetic acid) (bis-NTA) groups to the re-exposed SAM areas. The arrays of viral receptors were used for the detection of human rhinovirus particles (serotype 2; HRV2) under native conditions by topographical imaging at high signal-to-noise ratio. The kinetic on-rate of the HRV2-VLDLR interaction was derived from the time-dependent binding of the virions to the VLDL receptor spots. No significant binding was observed for the major group virus HRV14 that uses the unrelated receptor ICAM-1.