Bioactivated and PEG-Protected Circa 2 nm Gold Nanoparticles for in Cell Labelling and Cryo-Electron Microscopy
Nadja Groysbeck1, Victor Hanss2, Mariel Donzeau1
1Université de Strasbourg - CNRS, UMR 7242, Biotechnologie et Signalisation Cellulaire, Boulevard Sebastien Brant, Illkirch, F-67400, France.
Small Methods
|April 10, 2023
Summary
Researchers developed 2 nm gold nanoparticles (AuNPs) for cryo-electron microscopy (EM) labeling. Functionalized AuNPs successfully targeted intracellular components, enabling visualization of macromolecules within human cells using cryo-EM.
Area of Science:
- Cellular biology
- Nanotechnology
- Microscopy
Background:
- Cryo-electron microscopy (EM) advances allow near-native imaging of cellular structures.
- Specialized labeling techniques are needed to complement cryo-EM progress.
- Intracellular labeling requires targeted delivery and detection of nanoparticles.
Purpose of the Study:
- To develop and validate 2 nm gold nanoparticles (AuNPs) as intracellular labels for cryo-EM.
- To functionalize AuNPs for targeted delivery to specific cellular compartments.
- To assess the utility of biofunctionalized AuNPs in live human cells.
Main Methods:
- Synthesis and functionalization of 2 nm AuNPs with peptides and polyethylene glycols (PEGs).
- Delivery of AuNPs into living human cells via electroporation.
- Cryo-electron microscopy of vitreous cell sections for nanoparticle visualization.
Main Results:
- PEG-coated AuNPs diffused in the cytoplasm but did not enter the nucleus.
- AuNPs functionalized with Nuclear Localization Signals (NLS) were rapidly imported into the nucleus.
- Cryo-EM confirmed the presence of single 2 nm AuNPs within the cell nucleus.
Conclusions:
- Biofunctionalized 2 nm AuNPs are effective tools for labeling intracellular targets.
- Live-cell electroporation combined with AuNP functionalization enables targeted cellular cryo-EM.
- This approach facilitates the identification of macromolecules within cells using cryo-EM.
