Bio Sample Preparation for TEM

Bio MA-Tek provides professional and high quality services on sample preparations of different bio-samples for electron microscopic observation.

In bio application, there’re many things including nano-drugs, blood, cell, tissue till even medical devices need to be observed or analyzed. As you may know, biological samples are usually high water content with low contrast under TEM. So, a proper sample preparation for keeping the sample with original feature will be the key and the main challenge. We can provide the solutions for bio sample preparation, such like Native staining, CPD, unltr-microtome, cryo-treatment, and also a unique wet cell for liquid TEM.

Negative Staining
Many organic or biological samples are composed of light atoms (such as carbon, hydrogen, oxygen etc), thus result in low contrast in their EM images; negative staining with heavy elements (metals) could enhance the contrast for these samples; this is called “negative staining”.
(Example) Biomaterial samples _ PLGA nanoparticles	(Example) Biomaterial samples_ Influenza Virus
(Example) Biomaterial samples _ Liposomes	(Example) Biomedical samples_Abraxane

Resin Embedding and Ultramicrotome
Biological samples with high water content, such as cells, bacteria, tissues, organs, as well as many synthetic biomaterials have to be undergoing the procedure of fixation, dehydration, resin embedding and ultramicrotomy; then the slices can be collected and placed on copper grid for TEM observation.
(Example) Biological samples _ Muscle	(Example) Biological samples – Bacteria
(Example) Biological samples –Rat Liver	(Example) Biological samples – Leukocytes
(Example) Biomaterials (Facial mask): gold nanoparticles on the fiber surface can be clearly visualized. Left figure shows gold nanoparticles on the surface of the facial mask fiber edge; Right figure shows EDX result from the marked position in left figure.
(Example) Biomaterials (cosmetics) Ultrathin slice of cosmetic cake under TEM, particle morphology including the aggregation/agglomeration can be observed, and the elements can be identified by EDX.

Critical Point Drying
Biological samples with high water content would need to be fixed (by glutaraldehyde), dehydrated (by ethanol), critical point dried (with carbon dioxide supercritical fluids), sputter coated with Pt or Au prior to be observed with SEM.
					Critical Point Drier K850  Supercritical drying is a process to remove liquid from specimen without subject to surface tension, which is usually detrimental to the structure. The liquid is first completely replaced by CO2 in liquid phase, at high pressure. Then, CO2 is brought beyond critical point and then allowed to lower pressure, converting to gas phase. The specimen is dried preserving original morphology.
(Example) Biological Samples_ Cells are being fixed, dehydrated, and coated with Pt thin film and imaged by the SEM; gold nanoparticles of ~ 200 nm can be visualized.

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 Bio-EM Analysis (EN) 2017-09-04
 Material Structures (EN) 2017-09-04