OTE Stain (Oolong Tea Extract) in Cacodylate buffer

21,29 90,00 

  • 0.2% OTE solution – 0.1M Na cacodylate buffer
  • microfiltered 0.45µ – pH around 7
  • 20ml Airless opaque bottle or 200ml brun bottle
  • store at 4-8°C
  • made in France
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SKU: GC500270-20 Category:


Product description :

Uranyl acetate, a contrast agent used in electron microscopy for over 40 years, has faced strict regulations since 2014 due to its toxicity. As a result, researchers have sought less toxic alternatives, leading to the development of non-toxic and non-radioactive contrasting agents like UAR, Uranyless, and OTE.

OTE (Oolong Tea Extract) is derived from Oolong tea and acts as a tannin, enabling etching completion through a lead citrate post-contrast process. Positioned between green tea (non-oxidized) and black tea (fully oxidized), OTE offers a unique contrast-enhancing solution.

Application :

To prepare the OTE solution, dissolve OTE powder in 70°C water at a concentration of 0.2% using a magnetic stirrer. Complete dissolution occurs within 15 to 30 minutes under agitation, followed by filtering the solution at 0.45µ or preferably at 0.22µ. Store the solution in a small Eppendorf tube or an AirLess Black bottle in the refrigerator, ensuring darkness at 4°C. Before use, allow the solution to return to room temperature.

When contrasting grids with OTE, immerse them in the solution for 15 to 20 minutes at room temperature in darkness. After contrast, drain the grids without rinsing or with a very brief wash (1 to 2 seconds). For post-staining, treat the samples with lead citrate according to Reynolds (Ref # 11300) for 1 to 2 minutes. Subsequently, drain, rinse briefly, dry the samples, and they are ready for observation.

Additional information :

The prepared aqueous OTE solution has a slightly acidic pH of 6, which can be adjusted by replacing water with a phosphate or cacodylate Na buffer.

OTE, being a food product, does not require a Material Safety Data Sheet (MSDS). For visual guidance on the OTE preparation process, refer to the tutorial video: OTE Preparation Video.

Additional information