Introduction
Biological samples typically contain nanomaterials that scatter light significantly, and these samples are usually studied with dark field illumination. When dark field illumination is combined with hyperspectral imaging, it becomes a unique tool that can be used for identifying the location and composition of nanomaterials embedded in cells. To this end, the IMA hyperspectral imager supplied by Photon etc can be used for this application. A high-efficient dark field condenser can be fitted to this hyperspectral imager to produce high contrast images of biological samples.
High Throughput
Photon etc’s hyperspectral filter delivers excellent throughput and helps in acquiring high resolution images easily and quickly. Both spectral and spatial data can be collected in real time because the camera is capable of capturing the entire area in the field of view. Spectrally resolved videos can also be recorded to track the dynamics of cells and luminescent nanoscale components. In addition, Photon etc’s software, PHySpec, enables principal component analysis (PCA) to identify the smallest changes in both single and collective nanoparticles.
Experimental Framework
Figure 1. Dark-field image of human breast cancer cells tagged with gold nanoparticles (60nm size).
To demonstrate the capabilities of the IMA hyperspectral imager for studying nanomaterials in biological samples, 60nm gold nanoparticles (GNPs) were used to tag a sample of MDA-MB-23 human breast cancer cells. The cells were then exposed to a dark field illumination on the whole field of view (Figure 1). A 60× objective was used to image an area of 150×112μm, with an exposition time of 2s per wavelength and a step of 2nm. The entire analysis was completed within a fraction of minutes for over one million spectra, with each covering the entire visible spectrum.
Figure 2. Monochromatic image at 550nm; GNPs marked in green after PCA.
Cells usually exhibit a flat scattering spectrum, whist GNPs have a sharp peak of approximately 550nm. The 550nm image taken from the dark field hyperspectral cube of the breast cancer is shown in Figure 2. After PCA software processing, the GNPs were highlighted with a green colouring. Figure 3a shows the magnification of a breast cancer cell and Figure 3b displays the spectra of the areas containing GNPs. These images confirm the presence of single 60nm nanoparticles (peak at 550 nm) and their aggregates (peaks red-shifted). No GNPs were detected in the regions between the cells.
Figure 3. Magnification of a breast cancer cell (a) and spectra of GNPs in different areas (b).
Conclusion
The above experiment confirms that Photon etc’s IMA hyperspectral imager equipped with a dark field condenser can be effectively used for producing high contrast images of biological samples.
About Photon etc
Photon etc. offers state-of-the-art photonic and optical research instrumentation, from laser line tunable filters to widefield and microscopy hyperspectral imaging systems. Its patented spectral imaging and optical sensing technologies provide solutions for a wide variety of scientific and industrial applications. From material analysis to medical imaging, Photon etc.’s expertise and spirit of innovation allow the exploration of uncharted territories.
Photon etc. aims to provide each researcher, engineer and technician with access to the latest innovations in optical and photonic instrumentation. As pioneers in Bragg-based hyperspectral imaging, Photon etc. offers state-of-the-art instruments, driven by its clients’ desires to surpass limitations in measurement and analysis.
Inspired by the scientific creativity found in Montreal and Quebec, Photon etc. promotes open and collaborative innovation and excellence. The dynamic team of this company is proud to offer to its clients innovative and reliable instruments, based on the latest scientific advances in photonics and optics. At Photon etc., the primary wish is to develop a long term relationship with the clients by providing products adapted to their specific needs, combined with personalized service and support.
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