Label-Free Liposome & Exosome Hyperspectral Microscopy

HSI System
Post publication date: 
Thursday, February 17, 2022

Research of nano-scale vesicles such as liposomes and exosomes as drug delivery vectors has progressed significantly leading to increasing numbers of FDA clinical trials. Most of these early clinical trial efforts have focused on engineered liposomes carrying a drug or gene therapy load. However, rapid progress is now being made with natural exosomal vectors.

Key challenges remain in understanding the efficacy of tumor cell targeting with these nanoscale carriers, which most often happens through endocytic events or direct cell membrane fusion for eventual release of the drugs to the cell. Since fluorescent labeling of the vesicle can interfere with its task, a label-free, in-vitro imaging method is required to confirm this efficacy with a variety of vesicle-drug load combinations. The imaging method should also help determine proper drug load across the vesicle sample and confirm its interaction and uptake with live cells.

CytoViva's Enhanced Darkfield Hyperspectral Microscope is proving to be highly effective in helping researchers understand both the targeting of vesicle carriers to cells as well as the timed release of their drug cargo. With this label free imaging technique it is possible to:

  • Image label-free exosomes and liposomes < 100 nm in-vitro and in solution
  • Distinguish vesicles with differing payloads as well as empty vesicles
  • Conduct label-free cell trafficking of the vesicle-drug construct with spectral mapping to identify interaction with live or fixed cells

A specific example of the CytoViva system being used for this application is shown in the images above. In this example, a prostate cancer-specific peptide is added to a doxorubicin-loaded liposome. With the CytoViva Enhanced Darkfield Hyperspectral Microscope system, the researcher is able to create a reference spectral library (figure 1) unique to the doxorubicin-loaded liposome (figure 2). Note that the reference spectra illustrated in figure 1 has a very distinct peak at ~575nm that is consistent with the spectral properties of doxorubicin. Figure 3 shows a label-free tumor cell that has been incubated with the liposome construct. The red pixels in figure 4 demonstrate the spectral mapping of the reference spectrum confirming the presence and location of the liposomal construct within the tumor cell.

A key benefit of the CytoViva system is that it does not require fluorescent labeling or other alteration of the cell structure or the liposomes for effective imaging and analysis. Additionally, these samples can be imaged as live cells using the SynVivo for CytoViva live-cell microfluidics chamber. With this system, the nano-drug delivery construct can be added to the live cell culture and images can be captured over time, recording the dynamic interaction. This system can also be used as a "simulated in-vivo" system for observing nanoparticle fate in the biological environment.

With the ability to provide both high-resolution spatial imaging and spectral characterization, CytoViva's Enhanced Darkfield Hyperspectral Microscope system can significantly impact your nano-drug delivery development work. Please contact us at info@schaefer-tec.it to learn more about the technique or to discuss test imaging of your samples. 

Related products 

Cytoviva HSI Darkfield Hyperspectral Microscope
Visible Near Infrared (VNIR) and Short Wave Infrared (SWIR)
SynVivo environmental chamber.
Real-Time Visualization of Live Cell-Nanoparticle Interactions

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Cytoviva