Two École Polytechnique Fédérale de Lausanne (EPFL; Lausanne, Switzerland) scientists have developed a device that can create three-dimensional (3D) images of living cells and track their reaction to various stimuli without the use of contrast dyes or fluorophores. Yann Cotte and Fatih Toy have combined holographic microscopy and computational image processing to observe living biological tissues at the nanoscale.
Using their setup, 3D images of living cells can be obtained in just a few minutes at an incredibly precise resolution of less than 100 nm. And because they’re able to do this without using contrast dyes or fluorescent agents, the experimental results don’t run the risk of being distorted by the presence of foreign substances. The researchers developed, image by image, the film of a growing neuron and the birth of a synapse, caught over the course of an hour at a rate of one image per minute. As a low-intensity laser scans the sample from various angles, numerous images extracted by holography are captured by a digital camera, assembled by a computer, and “deconvoluted” in order to eliminate noise.
To develop their algorithm, the young scientists designed and built a “calibration” system using a thin layer of aluminum that they pierced with 70-nm-diameter “nanoholes” spaced 70 nm apart. The assembled 3D image of the cell, which looks as focused as a drawing in an encyclopedia, can be virtually sliced to expose internal elements such as the nucleus, genetic material, and organelles. In a company that’s in the process of being created and collaborating with startup Lyncée SA, they hope to develop a system that could deliver these kinds of observations in vivo, without the need for removing tissue, using portable devices. They will continue to design laboratory material based on these principles. Contact Yann Cotte at [email protected].
