1 research outputs found
Digital Microarrays: Single-Molecule Readout with Interferometric Detection of Plasmonic Nanorod Labels
DNA
and protein microarrays are a high-throughput technology that
allow the simultaneous quantification of tens of thousands of different
biomolecular species. The mediocre sensitivity and limited dynamic
range of traditional fluorescence microarrays compared to other detection
techniques have been the technology’s Achilles’ heel
and prevented their adoption for many biomedical and clinical diagnostic
applications. Previous work to enhance the sensitivity of microarray
readout to the single-molecule (“digital”) regime have
either required signal amplifying chemistry or sacrificed throughput,
nixing the platform’s primary advantages. Here, we report the
development of a digital microarray which extends both the sensitivity
and dynamic range of microarrays by about 3 orders of magnitude. This
technique uses functionalized gold nanorods as single-molecule labels
and an interferometric scanner which can rapidly enumerate individual
nanorods by imaging them with a 10× objective lens. This approach
does not require any chemical signal enhancement such as silver deposition
and scans arrays with a throughput similar to commercial fluorescence
scanners. By combining single-nanoparticle enumeration and ensemble
measurements of spots when the particles are very dense, this system
achieves a dynamic range of about 6 orders of magnitude directly from
a single scan. As a proof-of-concept digital protein microarray assay,
we demonstrated detection of hepatitis B virus surface antigen in
buffer with a limit of detection of 3.2 pg/mL. More broadly, the technique’s
simplicity and high-throughput nature make digital microarrays a flexible
platform technology with a wide range of potential applications in
biomedical research and clinical diagnostics