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Microscopic “optical-staining” strategies to visualize living cells


By appropriately modifying microscope’s optical path, unstained living cells can be optically contrasted at negligible cost.

MODULATION RELIEF CONTRAST MICROSCOPY (also referred to as “schlieren contrast”)

is a 150­ years-old, nearly forgotten imaging modality (Töpler 1866). By employing an asymmetric “relief” diaphragm (RD) in the condenser and an asymmetric modulator (M) just above the objective lens it is capable of competing with much more complex and costly differentical interference contrast (DIC) Nomarski microscopy.

Thus far, modulation relief contrast microscopy functioned well only with small-power objective lenses (x20 and less). We are now modifying it (design not shown) so that it performs well at any magnification. As we have demonstrated earlier (Pelc et al. 2008) for its more simple variant (standard relief contrast [off-axis illumination] employing no modulator) it is also complementary to phase-contrast imaging (cf. bottom part of the image plate).

Jointly, these two modalities are capable of visualizing cellular structures ranging from very thin (filopodia, lamellipodia) to very thick ones (large cells, cell clusters), yet requiring no staining (Pelc et al. 2014 @ Intnl. Microsc. Congr., Prague).