A Whole Blood Immunoassay Using Gold Nanoshells

TLDR

The study presents a rapid immunoassay that detects analytes in complex biological media without sample preparation. The assay uses gold nanoshells whose size‑dependent optical resonance enables spectroscopic detection of antibody/nanoshell aggregation in the near‑infrared. The assay successfully detected immunoglobulins in saline, serum, and whole blood at sub‑nanogram‑per‑milliliter levels within 10–30 minutes.

Abstract

A rapid immunoassay capable of detecting analyte within complex biological media without any sample preparation is described. This was accomplished using gold nanoshells, layered dielectric-metal nanoparticles whose optical resonance is a function of the relative size of its constituent layers. Aggregation of antibody/nanoshell conjugates with extinction spectra in the near-infrared was monitored spectroscopically in the presence of analyte. Successful detection of immunoglobulins was achieved in saline, serum, and whole blood. This system constitutes a simple immunoassay capable of detecting sub-nanogram-per-milliliter quantities of various analytes in different media within 10−30 min.