Combining Digital Holographic Microscopy with Microfluidics: A New Tool in Biotechnology - Biomedical Optical Phase Microscopy and Nanoscopy - page 194

for d D r . Moreover, we adopted the subtraction approach of the double exposure to remove
aberrations in the phase map [56] .

With the aim to test the proposed holographic configuration, we performed different
experiments with two kinds of micro-objects, a latex 9.7 m sized microsphere and in vitro

cells. Figure 10.5A shows the amplitude reconstruction of a latex particle, where a good
lateral circular cross-section of the sphere can be observed. Instead, Figure 10.5B represents
the phase of the complex wavefield coming from the microparticle. In the case of latex
beads, the phase map is not a quantitative measurement but it is reported to demonstrate the
capability of our setup. Quantitative phase contrast maps are obtained for transparent
biological samples as it is shown in Figures 10.6 and 10.7 . Figure 10.6 is the phase
distribution of a mouse cell; the peaks in the phase maps indicate the presence of lipid
particles into the cell, as already shown in a previous study [57] .

μ

The cell was driven against the upper glass wall of the chamber and maintained in this
position until it attached to the surface. After some hours, the cell entered mitosis as
indicated by a continuous change in cell shape that occurs in anaphase and telophase, that
was captured by the DH microscope. In Figure 10.6A D , some frames showing the final
stage of the evolution during the duplication process are illustrated. The lateral as well as

Figure 10.7
Phase map of a bull spermatozoon obtained with the same optical configuration.