Electron microscopy services
Vironova is a service provider specialized in transmission electron microscopy (TEM) analysis of vaccines, gene therapy and drug delivery particles such as viruses and liposomes. Vironova offers a complete GMP-compliant TEM analysis package that includes both negative stain (nsTEM) analysis and cryogenic (cryoTEM) analysis, each providing powerful image datasets, quantitative data, and conclusions from the analysis.
TEM – unmatched technology
Sample purity, particle size, shape and overall morphology are often directly correlated to the efficacy and safety of the end drug product. TEM is an unmatched technology for visualizing and understanding particle characteristics and seeing what actually happens when conditions are changed in upstream and downstream processes or product formulations.
Gene therapy & Viral based Vaccines
MiniTEM automates imaging, AAV particle detection and measurements to present accurate size distribution data
MiniTEM™ can reveal contaminants in AAV samples, for example proteosomes in the figure below.
In the above graph an overlay of the results from MiniTEM and DLS analysis of the same sample is shown. DLS was in this case not able to distinguish between AAV particles and the proteasomes.
Size distribution study with MiniTEM can also reveal small size debris and aggregates
The size distribution graph shows the number of particles of expected size as well as smaller size debris and aggregates – the data is easily correlated to what is revealed in the acquired images.
Automated size distribution analysis can be used to detect level of debris and compare the purity of different AAV samples
The box-plot shows purity measurement of the two samples calculated as the ratio of the total area of debris to Adenovirus particles.
MiniTEM can be used to automatically quantify disrupted empty AAV particles
TEM analysis of negatively stained AAV samples (nsTEM) is a reproducible method for revealing particles with disrupted capsid structure. Disrupted particles take in stain and can therefore be identified by their darker centres.
Comparing particle integrity of two AAV samples in MiniTEM:
Comparing particle integrity of Adenovirus samples in MiniTEM:
Below is an analysis of MuLV (murine leukemia virus). The numbers of circular intact particles with preserved morphology, of non-circular particles morphologically affected by the processing, and of debris, are compared.
Examples of details in virus morphology revealed with nsTEM
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| Rotavirus | Influenza |
Influenza virus protein
The VAS software in combination with cryoTEM accurately distinguishes between full and empty AAV particles
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The output of VAS analysis is a report with quantitative data.
Packaging
Drug delivery
Size distribution of liposomes detected with VAS
Shape (circularity) distribution analysis of liposomes detected by VAS
VAS software allows objective determination of drug content of liposomes
The VAS software measures whether the liposomes contain the drug or not. The program then presents a bar chart. The output of VAS analysis is a report with quantitative data.
VAS is employed to quantify lamillarity classes
High magnification cryoTEM of liposomes supports measurements of bilayer thickness
The graph shows the thickness distribution in nm.
Biologics
MiniTEM is employed for size distribution analysis of recombinant proteins to detect deviations in size
The size distribution graph shows the number of particles of expected size as well as smaller size debris and aggregates – the data is easily correlated to the content of the acquired images.
TEM imaging of different samples of monoclonal antibodies (mAbs)
Single mAbs in a monolayer can be observed as well as stress induced aggregates.
