Transmission Electron Microscope (TEM)-based Exosome Characterization

In the field of exosome research, the application of Transmission Electron Microscopy (TEM) is undoubtedly the gold standard for identifying the characteristics of exosomes. This technique not only provides intuitive information on the morphology, size, and integrity of exosomes, but also plays a crucial role in exploring the biological functions of exosomes and their potential in clinical applications. Creative Biolabs is capable of assisting clients in identifying exosomes using TEM or Cryogenic Transmission Electron Microscopy (Cryo-TEM).

Principle of Exosome Identification by TEM

TEM generates images by scanning the sample with a high-energy electron beam, based on the interaction between the sample and the electron beam. When the electron beam penetrates the sample, areas of different densities cause varying degrees of electron absorption or scattering, thus forming different levels of brightness in the image and revealing the structure and morphology of the sample. For exosomes, TEM can particularly reveal their size (typically between 30nm to 150nm) and unique morphology (e.g., the typical cup-shaped appearance).

TEM vs Cryo-TEM

Feature	TEM	Cryo-TEM
Principle	Uses a high-energy electron beam to penetrate the sample, generating an image based on the interaction between electrons and the sample.	Similar to TEM, but the sample is rapidly frozen at extremely low temperatures to preserve its original state.
Sample Preparation	The sample requires a multi-step preparation process, including fixation, dehydration, and slicing.	The sample is rapidly frozen, avoiding dehydration and chemical fixation, thus preserving the natural state of the sample.
Image Resolution	High resolution, capable of clearly observing the morphology of exosomes.	Provides similar or higher resolution, able to capture the native structure and details of the sample.
Sample Integrity	Chemical fixation and dehydration may alter the original physical and chemical state of the sample.	Since chemical processing is not required, the sample is closer to its physiological state, reducing sample damage.
Applicability	Suitable for routine observation of exosome morphology and size.	Especially suitable for studying the original state and functional structures of exosomes and their payloads.
Operational Complexity	Relatively simple.	Requires specialized equipment and techniques, more complex in operation.
Price	Relatively lower.	Higher due to the need for cryogenic equipment and materials.

Process of Observing Exosomes by TEM

Sample Preparation:
- Pre-treatment in TEM: Distribute the exosome sample on the TEM grid at the appropriate concentration and use negative staining to enhance image contrast.
- Pre-treatment in Cryo-TEM: Place the exosome sample directly on the TEM grid, then rapidly freeze.
Sample Loading: Load the prepared sample onto a slide and insert it into the TEM device.
Adjustment and Focusing: Fine-tune and focus through the TEM control system to ensure high clarity and accuracy of the images.
Image Acquisition: Collect images at different magnifications, including low magnification (1μm field of view) to observe the overall distribution of exosomes, medium magnification (500nm and 200nm field of view) to observe the details of exosome colonies, and high magnification (100nm field of view) to precisely observe the morphological features of individual exosomes.

Fig.1. Exosome TEM characterization at different magnifications. (Creative Biolabs) Fig.1. Observing exosomes at different magnifications using TEM.

Advantages of Choosing Creative Biolabs

Advanced Instrumentation: Given the high cost of TEM equipment and the need for professional operation and maintenance, many research institutions find it difficult to equip themselves. Creative Biolabs has introduced cutting-edge TEM technology, capable of providing unmatched high-resolution images of exosomes.
Professional Operation Team: Operating TEM requires deep professional knowledge and extensive technical experience. Compared to individual operations by clients, the technical team at Creative Biolabs not only possesses professional operational skills but also has extensive experience in sample preparation and image analysis.

Creative Biolabs has accumulated rich experience and knowledge in the field of exosome research and application. Our TEM-based exosome characterization service is designed to help you obtain intuitive, accurate information on the morphology, size, and integrity of exosome samples. If you are looking for professional exosome identification services, do not hesitate to contact us immediately.

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