Lensless imaging of cells and bacteria
Jan 31, 2012
from 01:00 PM to 02:00 PM
|Where||Tesla Room 53-125 Engineering IV Building|
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Lensless imaging has recently attracted a lot of attention as a compact, easy-to-use method to image or detect biological objects over large field of view.
We will report our latest work on lensless imaging applied to cells, i.e. eukaryote (10µm) and prokaryote (1µm).
The application of lensless imaging to the monitoring of cells culture is not straightforward. One has to face several problems, e.g. contamination of the cell culture, temperature stability and poor illumination condition due to diffusion in the culture medium. Yet we managed to perform acquisitions good enough to perform holographic reconstruction and measure relevant cell and colonies features.
In order to detect individual bacteria, we have introduced a method based on a thin wetting film imaging that produces a micro-lens effect on top of each bacterium when the sample dries up. The imaging using a high-end CMOS sensor is combined with an in-line holographic reconstruction to improve positive detection rate up to 95% with micron-sized beads at high density of ~103 objects/mm2. The system allows detecting from single bacterium to densely packed objects (103 bacteria/μl) within 10μl sample. As an example, E.coli, Bacillus subtilis and Bacillus thuringiensis, have been successfully detected with strong signal to noise ratio across a 24mm2 FOV.
Cédric ALLIER, born in 1972, received his Ph.D in Nuclear Physics from the University of TU Delft (NL) in May 2000. From 2001 to 2009, he worked for the company Cyberstar (industrial and scientific instrumentation). Since May 2009 he is a project leader at the CEA-LETI/DTBS/LISA group working on innovative bio-imaging solutions.