Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter. Our current focus is on detection and sensing/imaging with an emphasis on the development of integrated photonics. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.

 

VISCOELASTICITY OF LIVING CELLS ALLOWS HIGH-RESOLUTION IMAGING BY TAPPING MODE ATOMIC-FORCE MICROSCOPY


PUTMAN CAJ, VANDERWERF KO, DEGROOTH BG, VANHULST NF, GREVE J
BIOPHYSICAL JOURNAL
vol 67 issue 4: p1749-p1753 OCT 1994

Application of atomic force microscopy (AFM) to biological objects and processes under physiological conditions has been hampered so far by the deformation and destruction of the soft biological materials invoked. Here we describe a new mode of operation in which the standard V-shaped silicon nitride cantilever is oscillated under liquid and damped by the interaction between AFM tip and sample surface. Because of the viscoelastic behavior of the cellular surface, cells effectively ''harden'' under such a tapping motion at high frequencies and become less susceptible to deformation. Images obtained in this way primarily reveal the surface structure of the cell. It is now possible to study physiological processes, such as cell growth, with a minimal level of perturbation and high spatial resolution (similar to 20 nm).
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