Micro Sensor for cell force measurement
|Wojciech Swieszkowski 1, Waldemar T. Smolik 1, Norbert Danz 2, Erik Forester 2, Jean-Pierre Kaiser 3, Arie Bruinink 3, Krzysztof J. Kurzydlowski 1|
1. Warsaw University of Technology, Faculty of Materials Science and Engineering (InMat), Wołoska 141, Warszawa 02-507, Poland
Cell elasticity, motility and migration are very important for understanding various biological processes. Currently, monitoring cellular traction forces is desired as new marker to monitor cell functionality. We developed a sensor system for cell force measurement based upon a polymer microchip covered with a micro pillar matrix. The spring constant is chosen to enable pillar bending by forces in the range of 10..100 nN. The pillars bend in response to cellular forces that are transmitted via cellular focal adhesion points. The micro chip is read out optically. Besides a transmission image to analyze pillar bending, two different fluorescence images of dye markers can be taken sequentially. Matrix with the cells is illuminated bys spatially homogenized LED radiation. The focal position during long term experiments can be maintained by means of a piezo stage in order to obtain highly resolved images from the CCD imager. Sophisticated software controls the optical system and performs image registration. First, one transmission (red) as well as two fluorescence images (blue & green) are taken using appropriate CCD gain and integration times. Fluorescence information yields those pillar positions that are at least covered by a cell. The transmission image is used to calculate the magnitude and direction of pillars deflection. Therefore, detection of single pillar position and its deviation from a hexagonal grid is analyzed automatically, enabling a mapping of traction forces.In summary, this system containing transducer polymer chip, optics, and dedicated software analysis is a complete imaging system for image registration, single cell visualization and cellular force measurement. First results of cellular force measurements obtained are presented.
Presentation: Poster at E-MRS Fall Meeting 2009, Symposium F, by Wojciech Swieszkowski
See On-line Journal of E-MRS Fall Meeting 2009
Submitted: 2009-08-19 14:01 Revised: 2009-08-26 09:23