How to choose the best cryo-loop for your crystal

There are many different shapes, sizes and varieties of cryo-loop. Choosing the one best suited to your experiment is a vital first step in getting the best data from your crystal.

There are some simple rules to follow:
  • Check out the size and shape of your crystals and choose your loop to match:

  • Round loops will work for most crystals, and come in an extensive range of sizes.
  • If your crystals are needle-like, we recommend an elliptical shape, which allows you to get a more complete dataset.
  • For very fragile (eg. thin plates), or extremely small crystals, try a mesh loop to support the crystal and prevent mechanical stress.

We supply two types of loop: Actiloops and Litholoops. Both varities come as full cryomount sets, labelled with size and a datamatrix and cryovial, or simply mounted on pins. They all strictly follow SPINE specifications.

Which you choose depends on what you are looking for. But here is a summary of their features to help you choose:


  • Made from etched cured polyamide resin for zero background (left).
  • Low hydrophobicity for lower volumes of mother liquor retained in loop, further reducing background scatter.
  • Rigid in beam - reducing cryostream flow-induced motion, increasing spot position consistency and resulting in significant improvement in merging statistics.
  • Maximum strength to prevent loop and crystal motion in the cold stream, increasing spot position consistancy and improving data merging statistics. Best in field (see Alkire et al, 2013 )
  • High resistance to mechanical stress to resist loop breaking.


  • Active-Drain™ construction with drainage groove and reservoir removes excess mother liquor from the crystal reducing background.
  • Enhanced with hydrophilic polymer surface treatment further reducing mother liquor and background.
  • Technically superior 3D polymer film for minimal background and superior resolution.
  • Maximum strength to prevent loop and crystal motion in the cold stream, increasing spot position consistency and improving data merging statistics (see Alkire et al, 2013 ).
  • Round, elliptical, mesh and elliptical mesh shapes available to optimize fit to crystal.

Remember whatever loop you choose, it's important to choose a size that matches your crystal as closely as possible. Our elliptical loops make this much easier for needle crystals! To lengthen your loop's lifetime and so further improve their value, please follow the recommended cleaning method below.


Whichever loop you choose, cleaning them correctly will extend their lifetime. Our recommended cleaning routine is as follows:

  1. Fill a sonicator bath with a 1% solution of tergazyme (Sigma).
  2. Place loops upside down on Eppendorf racks and sonicate for ~3 minutes.
  3. Rinse with dionised water from tap.
  4. Shake off the excess of water and let the loop dry on Eppendorf racks overnight (but can be sped up in 37°C incubator).
  5. Inspect under microscope – if anything still adheres soak for around 20 minutes in ethanol.
  6. Under microscope, use a paper wick, microprobe or needle to gently dislodge softened material.

If you don't have access to a sonicator bath, soaking in detergent for 15-20 minutes and then dislodging material under a microsope is effective.

You'll also need all those other bits and bobs such as marker pens that work on cryoware, magnetic wands, and other tools for crystal manipulation.


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