Fabricated cantilever for AFM measurements and manipulations: pre-stress analysis of stress fibers.
The atomic force microscope (AFM) is a highly successful instrument for imaging of nanometer-sized samples and measurement of pico- to nano-Newton forces acting between atoms and molecules, especially in liquid. Generally, commercial AFM cantilevers, which have a sharp tip, are used for AFM experiments. In this review, we introduce micro-fabricated AFM cantilevers and show several applications for cell biology. In manipulation of samples on a cellular scale with a force of tens to hundreds of nano-Newtons, attempts have been made to secure the formation of covalent/non-covalent linkages between the AFM probe and the sample surface. However, present chemistry-based modification protocols of cantilevers do not produce strong enough bonds. To measure the tensile strength and other mechanical properties of actin-based thin filaments in both living and semi-intact fibroblast cells, we fabricated a probe with a hooking function by focused ion beam technology and used it to capture, pull and eventually break a chosen thin filament, which was made visible through fusion with fluorescent proteins. Furthermore, we fabricated a microscoop cantilever specifically designed for pulling a microbead attached to a cell. The microscoop cantilevers can realize high-throughput measurements of cell stiffness.
Innovation Laboratory, Tokyo Institute of Technology, 4259-S2-8, Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan. smachida@bio.titech.ac.jp
Shinichi
S
Machida
Takahiro
T
Watanabe-Nakayama
Masakazu
M
Saito
Rehana
R
Afrin
Atsushi
A
Ikai
D000818:Animals; D003584:Cytological Techniques / Q000379:methods*; D005347:Fibroblasts / Q000502:physiology; D018625:Microscopy, Atomic Force / Q000379:methods*; D051381:Rats; D022502:Stress Fibers / Q000502:physiology*; D013718:Tensile Strength