Volume EM: a quiet revolution takes shape

The vEM community consists of imaging scientists who develop and deliver vEM and end users who apply vEM to answer their research questions. The goal of the grassroots vEM community initiative is to build a coherent international community of vEM experts and users to facilitate science delivery, and to build capacity to meet the vEM needs of the bioscience research community.

In the 2000s, the ‘volume revolution’ gathered pace and so too did the growth of the vEM expert community. Despite local collaboration and networking by vEM experts, it was initially difficult to communicate the exciting advances being made in vEM to the wider life sciences community in the shadow of the burgeoning ‘resolution revolutions’ in both light microscopy and single-particle cryo-EM. Taking inspiration from the UK cryo-EM community, a vEM town hall meeting was organized by some of authors of this Comment (L.M.C., G.J.K., A.P. and P.V.), supported by and held at the Wellcome Trust in London, UK in October 2019. Sixty members of the expert vEM community attended, representing biologists, microscopists, technologists, facility managers, hardware and software engineers, image analysts, public image archivists and commercial suppliers. Although there were international attendees, the meeting was driven by and focused on the UK vEM community, and from this meeting came the first formal proposal for a vEM infrastructure capable of meeting UK bioscience demand. The proposal suggested the formation of multiple centers of excellence for established vEM techniques (SBF-SEM, FIB-SEM and array tomography) housed close to key end-user communities in universities or research institutes, and a national facility that would host newly developed vEM techniques that were not yet user-friendly enough for broader rollout (for example, plasma FIB, multibeam SEM and GridTape TEM). All facilities would have the supporting hardware and expertise for sample preparation, correlative multimodal workflows (light microscopy, SEM, TEM and X-ray microscopy) and advanced data handling and analysis.

The proposal was submitted to UK funders who provided positive feedback, but requested further development of the concept. Before further progress could be made, the COVID-19 pandemic swept across the world. As with much of science, the vEM community continued their work online and held town hall meetings in October 2020 (60 attendees) and October 2021 (200 attendees). In August 2020, at a vEM microlaboratory workshop organized by another author of this Comment (K.N.), around 50 domain experts identified current issues in vEM, which were articulated as key ‘how can we?’ questions. These questions were:

• How can we retrieve, preserve and prepare large-volume biological samples to obtain appropriate information?

• How can we accelerate end-to-end sample throughput and interpretation?

• How can we improve software to transform vEM from a qualitative to a quantitative method, enabling user-friendly extraction of insights from biological samples?

• How can we share vEM data quickly and efficiently for viewing and analysis without overburdening local storage and computing capacity?

• How can we set up an efficient vEM facility?

• How can we improve communication and information exchange within the vEM community and across disciplines?

From these meetings emerged two goals: to build (1) a coherent international community of vEM experts and users to facilitate science delivery and (2) a vEM infrastructure that can serve the needs of the international bioscience research community. To achieve these aims, six working groups (focusing on infrastructure, community, outreach, sample preparation, data and training) were formed, each of which was co-chaired by two volunteers from the vEM community (Table 1). As of early 2023, there are almost 80 international imaging scientists who are volunteering their time and enthusiasm across the working groups (Fig. 3). As well as increasing the global representation of the working groups and networking colleagues across disciplines, the groups have delivered resources that include:

• A website to link the community and share resources

• A mailing list for the vEM community

• A vEM Twitter account and hashtag (#volumeEM)

• A vEM community logo

• Blog posts from the working group co-chairs on the community site FocalPlane

• An edition of Methods in Cell Biology focused on vEM methods

• A special issue of Frontiers in Cell and Developmental Biology, focused on methods and applications in correlative light microscopy and vEM

• A Nature Reviews Methods Primer article on vEM for those new to the field¹

• Case studies showing the impact of vEM in the biosciences

• A new Gordon research conference focused on vEM, starting in 2023

• A list of volunteer vEM expert reviewers for journal editors and funders (available from the corresponding authors on request)

• A database of vEM-related resources set up in collaboration with Microlist

• A vEM-focused virtual seminar series in collaboration with Euro-BioImaging

• A sample preparation widget in collaboration with the European Molecular Biology Laboratory European Bioinformatics Institute (EMBL-EBI)

• Training videos to explain complex vEM workflows

• Explainers of the toolkit required to get started with vEM workflows.

vEM community working group membership by country in 2022.