Nanoparticle Biosensor Imaging in Tissue Using Darkfield Hyperspectral Microscopy

Blog Post

Immagine iperspettrale di nanoparticelle d'oro nei tessuti

Immagine iperspettrale di nanoparticelle d'oro nei tessuti

Post publication date:

Friday, June 23, 2023

The development of plasmonic nanoparticles as effective biosensors for disease detection is growing rapidly. These new nanoparticle diagnostic markers are being targeted for diseases not easily detected through PCR, or traditional pathology staining.

Using these new nanoparticle biosensors requires a new imaging and diagnostic capability. Traditional brightfield pathology or fluorescent microscopy techniques are not an option for imaging these nanoparticle biosensors. To fill this need, CytoViva Inc. has developed an Enhanced Darkfield Hyperspectral Microscopy system. This imaging system has been demonstrated to accurately image and map nanoparticles over large areas of ex-vivo tissue or in-vitro cells. This system utilizes patented darkfield microscopy optics, which create a high signal-to-noise ratio image, enabling the scatter from these nanoparticle biosensors to be imaged in a biological matrix. When combined with hyperspectral imaging, each pixel of the captured image contains the VNIR 400nm-1,000nm optical spectral response of that pixel’s spatial area. This allows the nanoparticles to be spectrally identified and spectrally mapped quickly and an accurately in a biological matrix.

Moreover, the non-destructive CytoViva technique requires no labeling, special fixation, or other alteration of the sample prior to imaging. It can identify most types of nanomaterials in either stained or unstained tissue and can be easily operated right from your benchtop.

Figure 1: Hyperspectral Image of AuNPs in Tissue

Figure 2: Spectral Response of AuNPs and Tissue

Figure 3: AuNP Spectra Mapped (red) in the Tissue

Figure 4: Class Distribution of the Tissue Area Mapped for AuNPs

See the example above illustrating CytoViva's ability to accurately identify and map the distribution of AuNPs targeted to lymph node tissue. Figure 1 is an enhanced darkfield hyperspectral image of an unstained ex-vivo lymph node tissue section containing targeted AuNPs (image area is 100 x 150 μm). Note the obvious areas of AuNP aggregation, which appear gold in the image. In Figure 2, the spectral response from a representative pixel area of the AuNP is shown in red, and the tissue spectral response is shown in green. These spectra have been normalized to an intensity of one for easy comparison. Using the reflectance spectral response of the AuNPs, a spectral mapping algorithm identifies all pixels containing AuNPs as red in Figure 3. It is important to note that both aggregated and dispersed areas of AuNPs are present and mapped in the tissue. Finally, Figure 4 provides the class distribution confirming that 2.836% of the total tissue area in the full image contained AuNPs.

Whether your research requires identifying a single nanoparticle in cells or nanoparticle aggregates across large areas of tumor tissue, polymer thin films, or other matrixes, CytoViva's Enhanced Darkfield Hyperspectral Microscopy is a proven technique to support your efforts. It can be operated right from your benchtop in a fraction of the time and cost of other techniques such as EDS and SEM.

Please contact us to learn more about the instrument or to arrange a demonstration with your samples.