Titan Krios vs. Glacios: Which Do You Need?
Head-to-head comparison of the two most popular cryo-EM microscopes for structural biology.
Overview
The Titan Krios G4 (300 kV) and Glacios 2 (200 kV) are both manufactured by Thermo Fisher Scientific and represent the high-end and mid-range of the cryo-EM market. While the Krios has long been the gold standard for high-resolution single particle cryo-EM, the Glacios 2 with Selectris energy filter has narrowed the resolution gap significantly.
Resolution and Performance
The Titan Krios G4 routinely achieves sub-2Å resolution for well-behaved samples and holds most of the highest-resolution cryo-EM records. The Glacios 2, at 200 kV, can achieve 2.5-3Å resolution for many targets, which is sufficient for drug design and mechanistic studies. For small proteins (<100 kDa) or samples requiring the absolute best resolution, the Krios remains the better choice.
Cost and Accessibility
Krios time is expensive ($150-$500/hr external) and often booked weeks in advance. Glacios time is typically 30-50% cheaper and more readily available. Many facilities now use the Glacios for routine screening and initial datasets, reserving the Krios for final high-resolution collection. This two-microscope workflow optimizes both cost and throughput.
When to Choose Each
Choose the Titan Krios when: you need sub-2.5Å resolution, your target is small (<150 kDa), you need cryo-ET with thick samples, or you're working on a high-impact publication. Choose the Glacios when: 3Å resolution is sufficient, you're screening many conditions, your budget is limited, or you need faster turnaround.
Frequently Asked Questions
Can the Glacios 2 replace the Titan Krios?
For many projects, yes. The Glacios 2 with Selectris energy filter achieves 2.5-3Å resolution routinely, which is sufficient for most drug design and mechanistic studies. However, for sub-2.5Å or very challenging samples, the Krios remains superior.
Which is better for cryo-tomography?
The Titan Krios is preferred for cryo-ET due to its 300 kV beam (better penetration through thick ice) and stage stability. The Glacios can be used for thin lamellae but is suboptimal for cellular tomography.
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