# Cryo-correlative light and electron microscopy (cryo-CLEM) transfer holder for high-resolution imaging

> **NIH NIH R43** · HUMMINGBIRD PRECISION MACHINE COMPANY · 2020 · $251,880

## Abstract

Project Summary
Project Title: Cryo-correlative light and electron microscopy (cryo-CLEM) transfer holder for high-
resolution imaging
Company Name: Hummingbird Precision Machine Co., dba Hummingbird Scientific
Principal Investigator: Khim Karki, Ph.D.
Summary:
Cryogenic transmission electron microscopy (cryo-TEM) technique has enabled important
structural and dynamic information of complex cells or macro-molecules by freezing the samples
in their native environment. However, biological materials suffer from poor contrast in TEM and
requires pre-screening of the regions of interest (ROI) using fluorescence marker and/or beads.
The sample grid is transferred into the TEM without disturbing the pre-mapped coordinates for
correlative imaging – the workflow commonly referred to as cryogenic cross-correlative light and
electron microscopy (cryo-CLEM) technique. Currently, there is no commercial solution that
allows interrupted transfers of sample between different cryo-CLEM tools such as focused ion
beam (FIB), light microscopy (LM) and TEM, all while maintaining the cryogenic temperatures (<
-140°C) of the sample. High-yield and high-throughput analysis is also key to identifying structures
in several dimensions and orientations (e.g. proteins), especially when using conventional TEM
approaches. The use of multiple sample transfer tools in existing cryo-CLEM makes the workflow
tedious and time consuming – requiring additional training and yielding lower success rate.
This proposal aims to develop a cryo-TEM transfer holder with a modular correlative tip containing
cryo-sample that allows a single workflow where the sample can be transferred between the
vitrification tool, FIB, LM and the TEM. The developed holder tip will have a built-in cryo shutter
to prevent the sample from frosting. The correlative tip will interface across all cryo-CLEM tools
in the workflow to allow undistorted transfer of sample for high resolution TEM imaging. The
developed transfer holder and workflow will be validated onsite at Hummingbird facility as well as
using real-world examples with our collaborators – for example looking at host-pathogen
interactions. Research groups focused on soft/biological materials interested in accurate and
high-resolution analyses of the macromolecular structures are the main customer of this product.

## Key facts

- **NIH application ID:** 10140792
- **Project number:** 1R43EB030894-01
- **Recipient organization:** HUMMINGBIRD PRECISION MACHINE COMPANY
- **Principal Investigator:** Daan Hein Alsem
- **Activity code:** R43 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $251,880
- **Award type:** 1
- **Project period:** 2020-09-30 → 2022-09-29

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10140792

## Citation

> US National Institutes of Health, RePORTER application 10140792, Cryo-correlative light and electron microscopy (cryo-CLEM) transfer holder for high-resolution imaging (1R43EB030894-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10140792. Licensed CC0.

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