Digital Optical and Scanning Probe Microscopy for Inspection and Manipulation of Biocells - Bioanalysis Advanced Materials Methods and Devices - page 85

Chapter 7
Digital Optical and Scanning Probe Microscopy
for Inspection and Manipulation of Biocells
Sergei Chizhik, Lizaveta Drozd, and Nikita Fomin
Abstract As biomedical interest has progressed to the study of biological tissues
and single cells investigations of the different biomaterials involved require very
careful use of fine-scale measurement methods, Atomic Force Microscopy (AFM)
and Dynamic Laser Speckle (DLS) being reported here. AFM and DLS are complex
experimental systems with the functions of scanning probe and optical microscopy.
A special optical system makes it possible to visualize the objects and position the
probe within microscale dimensions. AFM is used both for visualization and
identification of the local adhesion and viscoelastic properties of biological cells,
and for manipulation of the cell by means of varying the load being applied to it.
Additional information about cellular activity could be obtained by laser probing
via DLS of the living tissues being studied. These techniques, AFM and DLS,
greatly enhance the potential for measurements and open a new field of experiments
in cell biology. The purpose of this chapter is to show the application of AFM and
DLS to studies of biological cells, namely measurement of the motility of general
cells in living tissues and the elastic modulus of a single cell membrane, as well as
identifying the forces causing membrane damage. The time-space cross-correlation
analysis of the temporal evaluation of the dynamic biospeckle patterns is shown to
be a means of real time flow visualization of the microcirculation of blood in living
tissue. Digital processing of biospeckle pattern records yields 2D maps exhibiting
the temporal and spatial variations in subskin blood flow. This could be used for
biomedical diagnostic purposes, e.g., for detecting microscale deviations from the
normal case. Three methods of evaluating dynamic speckle patterns are described.
Both decorrelation and autocorrelation analyses have been realized in real time
mode, when a total digital specklegram treatment was performed during the time
interval between successive frames (40 ms). Results in the form of 2D maps of
subskin blood flux were visualized on the PC monitor with a frequency of 25 Hz.
S. Chizhik • L. Drozd ( * ) • N. Fomin
A.V. Likov Heat and Mass Transfer, Institute of National Academy of Sciences of Belarus,
P. Brovki Str. 15, Minsk 220072, Belarus
e-mail: [e-mail]