Ultrahigh-Throughput Single-Particle Hyperspectral Imaging of Gold Nanoparticles

Abstract

Gold nanoparticles (AuNPs) have become increasingly useful in recent years for their roles in nanomedicine, cellular biology, energy storage and conversion, photocatalysis, and more. At the single-particle level, AuNPs have heterogeneous physical and chemical properties which are not resolvable in ensemble measurements. In the present study, we developed an ultrahigh-throughput spectroscopy and microscopy imaging system for characterization of AuNPs at the single-particle level using phasor analysis. The developed method enables quantification of spectra and spatial information on large numbers of AuNPs with a single snapshot of an image (1024 × 1024 pixels) at high temporal resolution (26 fps) and localization precision (sub-5 nm). We characterized the localized surface plasmonic resonance (SPR) scattering spectra of gold nanospheres (AuNSs) of four different sizes (40–100 nm). Comparing to the conventional optical grating method which suffers low efficiency in characterization due to spectral interference caused by nearby nanoparticles, the phasor approach enables high-throughput analysis of single-particle SPR properties in high particle density. Up to 10-fold greater efficiency of single-particle spectro-microscopy analysis using the spectra phasor approach when compared to a conventional optical grating method was demonstrated.

Hyperspectral microscopy as a particle exposure assessment tool

“…However, only gold nanoparticle detection is addressed. Only this last work 25 shows different material discrimination of 2 or 3 different material types. Our work also focuses on individual mineral particle discrimination but for bright-field imaging.…”

“…While optical microscopy is not able to detect nanoscale particles (< 200 nm) due to its diffraction-limited resolution, dark field microscopy overcomes this diffraction limit and offers a faster, effective, and cheaper alternative than other expensive techniques such as electron microscopy to image nanoparticles. Finally, a high-throughput spectroscopy and microscopy imaging system has been proposed for characterization of gold nano particles at the single-particle level 25 , enabling a single snapshot image of 1024x1024 pixels at high temporal resolution (26 fps) in the visual spectral range of 400-700 nm. The developed method enables quantification of spectra and spatial information.…”