Researchers Develop Lens-Free Imaging Technique to Monitor Living Cells

Researchers Develop Lens-Free Imaging Technique to Monitor Living Cells

30 July 2013

Researchers in France have developed an innovative imaging technique without using lenses that could prove extremely helpful in time-lapse imaging of biological systems.

The technology was developed by a team at CEA-Leti, a Grenoble-based institute which is part of the French government's CEA research organisation. The technique gave the researchers the chance to monitor micron-size objects across a wide field of view. They believe it might help scientists study biological systems more effectively, since it allows live imaging of cells, bacteria and viruses, ensuring greater visibility, capacity to differentiate between them and the chance to study their behavior.

The researchers initially managed to detect single bacteria and later single viruses over an extended field of view using the lens-free imaging technique. The team is now working to enable live imaging of 2D and 3D cell cultures.

The latest version of the CEA-Leti method, presented in late June, images objects at a two-micron resolution over a field of view spanning 24 square millimeters while enabling time-lapse imaging of cell cultures over extended periods. The new technique adds to work currently underway at the University of California, Los Angeles (UCLA), where researchers have been successful with experiments using lens-free holographic microscopy.

In order to address the challenges of applying the optical principle to small biological structures, the researchers used a thin wetting film that created liquid micro-lenses on top of each object monitored while sharpening their contrast for detection. The use of the technique in combination with lens-free imaging is the first robust application of the wetting film, combining optics and fluidics at the nano- or micro-scale, Allier commented.

This method was first developed by CEA-Leti three years ago and allowed for the detection of single bacteria over square-millimeter areas only, but the team has now managed to enhance the technology in collaboration with UCLA, making it able to detect single viruses.