In Stock
SKU: 687-200-AU Series | Category: Cryo-EM Consumables
UltrAuFoil® Holey Gold Films
The Gold Standard for Stability: UltrAuFoil® are ultra-stable holey gold films on gold grids designed specifically for high-resolution cryo-electron microscopy (Cryo-EM). Developed to eliminate differential contraction, these Cryo-EM gold grids significantly reduce beam-induced motion, allowing for sharper images and improved 3D reconstruction data.
Material: 400-500Å Polycrystalline Gold Foil
Stability: Reduces Beam-Induced Drift
Biocompatible: Chemically Inert & Non-Oxidizing
Available in 200 & 300 Mesh Sizes
Revolutionizing Cryo-EM Specimen Preparation
UltrAuFoil® Gold Films address one of the most persistent challenges in cryo-EM: specimen movement. Traditional carbon foils on copper grids suffer from differential thermal contraction when frozen, causing the foil to "drum" or move when hit by the electron beam.
By using a gold foil on a gold grid, UltrAuFoil eliminates this mechanical strain. The result is a support structure that remains ultra-stable during imaging, minimizing radiation-induced motion to less than 1 Å in optimal conditions. This technology was originally developed by Drs. Christopher J. Russo and Lori A. Passmore at the MRC Laboratory of Molecular Biology.
Technical Specifications & Configurations
The grids consist of a 400-500 Å thick polycrystalline gold foil with a regular square array of micrometer-sized holes. They are chemically inert, highly conductive, and biocompatible, making them ideal for sensitive biological samples.
| Mesh Size | Hole Size / Spacing | Film Type | Common Application |
|---|---|---|---|
| 200 Mesh Gold | 2 µm Hole / 2 µm Space (R 2/2) | UltrAuFoil (Gold) | Larger complexes, viruses |
| 300 Mesh Gold | 1.2 µm Hole / 1.3 µm Space (R 1.2/1.3) | UltrAuFoil (Gold) | High-resolution single particle |
| 300 Mesh Gold | 0.6 µm Hole / 1 µm Space (R 0.6/1) | UltrAuFoil (Gold) | Small proteins, dense packing |
Advantages Over Carbon Films
Compared to traditional Quantifoil carbon grids, UltrAuFoil offers distinct advantages for data collection efficiency:
- No Differential Contraction: Gold foil on gold grid means the geometry remains unchanged at cryogenic temperatures.
- Conductivity: Superior electrical conductivity reduces charging effects.
- Durability: Less fragile than thin carbon films and does not oxidize over time.
- Drift Correction: Reduces reliance on complex software drift correction, allowing for faster data acquisition.
Frequently Asked Questions
1. Do UltrAuFoil grids require glow discharging?
While the gold foil is naturally more hydrophilic than carbon, it is recommended to use a glow discharge cleaning system (like the PELCO easiGlow™) to ensure optimal wetting and ice distribution immediately before use.
2. What is the shelf life of these grids?
UltrAuFoil grids do not have a strict expiration date due to gold's inert nature, but it is generally recommended to use them within two years of purchase to ensure surface cleanliness.
3. Can I use these for automated data collection?
Yes. Because the beam-induced motion is so low, you can often use beam tilt to focus, which speeds up automated data collection significantly compared to traditional methods.
4. Why is gold preferred over carbon?
Gold is dense, conductive, and chemically inert. The primary benefit in Cryo-EM gold grids is that the support film and the grid bar contract at the same rate when frozen, preventing the "crinkling" effect seen in carbon-on-copper grids.
5. Are these grids compatible with standard Vitrobots?
Yes, UltrAuFoil grids fit standard 3.05mm TEM holders and are fully compatible with vitrification devices like the Vitrobot, Leica EM GP, and manual plungers.
