Use of colloidal quantum dots as a digitally switched swept light source for gold nanoparticle based hyperspectral microscopy.

Kazunori Hoshino,Konstantin V Sokolov,Gauri Bhave,Pratixa P Joshi,Xiaojing Zhang

doi:10.1364/boe.5.001610

Abstract

We propose a method to utilize colloidal quantum dots (QDs) as a swept light source for hyperspectral microscopy. The use of QD allows for uniform multicolor emission which covers visible-NIR wavelengths. We used 8 colors of CdSe/ZnS and CdTe/ZnS colloidal quantum dots with the peak emission wavelengths from 520 nm to 800 nm. The QDs are packed in a compact enclosure, composing a low-cost, solid-state swept light source that can be easily used in most microscopes. Multicolor emission from the QDs is simply controlled by digitally switching excitation UVLEDs, eliminating the use of mechanically-driven gratings or filters. We used gold nanoparticles as optical markers for hyperspectral microscopy. Due to the effect of localized surface plasmon resonance, gold nanoparticles demonstrate size and shape-dependent absorption spectra. Employed in a standard microscope, the QD light source enabled multispectral absorption imaging of macrophage cells labeled with gold nanorods and nanospheres.

Highlights

Hyperspectral imaging is a technique where spectral information is recorded over many wavelengths for each pixel of a high-resolution microscopic image [1,2]
We propose a method to utilize colloidal quantum dots (QDs) as a swept light source for hyperspectral microscopy
The use of QD allows for uniform multicolor emission which covers visible-NIR wavelengths

Summary

Introduction

Hyperspectral imaging is a technique where spectral information is recorded over many wavelengths for each pixel of a high-resolution microscopic image [1,2]. A swept light source is a key element in hyperspectral microscopy It usually consists of a wide band light source coupled with mechanically motorized color wheels or gratings coupled with mechanically scanned stages [1,2], which make the setup complicated and expensive (see Fig. 1(a)). The use of QDs allows for easy construction of a compact swept light source that uniformly covers visible-NIR wavelength range. Another unique advantage of the QD based swept light source is that it does not contain any moving parts.

Gold nanorods and nanospheres

Theoretical analysis

Preparation of macrophage cells

Hyperspectral imaging

Conclusion