Delivery of femtolitre droplets using surface acoustic wave based atomisation for cryo-EM grid preparation

Dariush Ashtiani, Hari Venugopal, Matthew Belousoff, Bradley Spicer, Johnson Mak, Adrian Neild, Alex de Marco

Research output: Contribution to journalArticleResearchpeer-review

18 Citations (Scopus)

Abstract

Cryo-Electron Microscopy (cryo-EM) has become an invaluable tool for structural biology. Over the past decade, the advent of direct electron detectors and automated data acquisition has established cryo-EM as a central method in structural biology. However, challenges remain in the reliable and efficient preparation of samples in a manner which is compatible with high time resolution. The delivery of sample onto the grid is recognized as a critical step in the workflow as it is a source of variability and loss of material due to the blotting which is usually required. Here, we present a method for sample delivery and plunge freezing based on the use of Surface Acoustic Waves to deploy 6–8 µm droplets to the EM grid. This method minimises the sample dead volume and ensures vitrification within 52.6 ms from the moment the sample leaves the microfluidics chip. We demonstrate a working protocol to minimize the atomised volume and apply it to plunge freeze three different samples and provide proof that no damage occurs due to the interaction between the sample and the acoustic waves.

Original languageEnglish
Pages (from-to)94-101
Number of pages8
JournalJournal of Structural Biology
Volume203
Issue number2
DOIs
Publication statusPublished - Aug 2018

Keywords

  • Atomization
  • Blot-free sample preparation
  • Cryo-EM
  • Microfluidics
  • Surface acoustic waves

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