The prototype CryoWriter from CryoWrite AG (Basel, Switzerland)

Our lab received the first prototype of the CryoWriter. This device uses microfluidic technology to:

- Observe a biological sample with an inverted light microscope (fluorescense, phase contrast), to identify a location of interest, e.g., in a tissue section.
- Use a microfluidic capillary of 50 micrometer inner diameter to aspire a few nanoliters of sample from a specified location.
- Optionally dilute the sample in the capillary, or
- Optionally purify the sample with the help of antibodies coupled to magnetic beads within the capillary.
- "Write" a few nanoliters of the sample onto an electron microscopy grid, while the grid is kept at dew-point temperature (ca. 2ºC) under a humid atmopshere.
- Plunge-freeze the grid within 100 miliseconds to LN2 temperature.


The CryoWriter also features automated grid picking, automated glow-discharging of the grids, automated plunging in liquid ethane, automated storage of the grids under liquid nitrogen, and the machine documents the entire process including video recordings of all processes.


This technology was developed by the Team of Dr. Thomas Braun at the Biozentrum of the University of Basel. The company CryoWrite AG is based on several patents from that work. The CryoWriter in our lab is the prototype of the commercial version.

Application to Nanoliters of biological sample+-

We use the cryoWriter to vitrify single particle cryo-EM samples, using only nanoliters of sample solution at a time. Sample requirements are

  • Protein concentration: approx. 1 mg/ml or lower
  • Sample quantity: approx. 1 microliter, from which a few nanoliters will be used. The remainder can be used for other purposes.
  • Buffer requirements: As usual for conventional cryo-EM

Application to human brain slices+-

We plan to use the CryoWriter on tissue sections of human brain. For this reason, it is installed in a BSL-2 laboratory.

The fluorescent light microscope will be used to identify Lewy bodies, which are plaques in the neuronal cells of brain tissue of patients who died from Parkinson's disease and donated their body to this research.

Once an individual Lewy body is localised, the microfluidic capillary will be used to aspire the fibrillar (or other?) content of the Lewy body, dilute the contents slightly, and write the resulting nanoliters of sample onto a cryo-EM grid, which will be plunge frozen and later imaged by cryo-EM or cryo-electron tomography. The goal is to determine the high-resolution (atomic) structure of the fibrils that were present in a single Lewy body.

Alternatively, this method will be applied to tau tangles from Alzheimer's disease patient tissue, or to plaques in human brain tissue from patients who suffered from other neurodegenerative diseases, such as DLB, MSA, FTLD, or others.