Compositions and methods for determining mechanical properties of cells

Abstract

Provided herein are systems and method for measuring cell stiffness. In particular, provided herein are microelectrode configuration and systems for measuring platelet deformation and stiffness.

We claim: 
     
         1 . A device that induces a dimensional change in a cell, a cell component, or a cell fragment, comprising:
 a microelectrode chip comprising a plurality of parallel microelectrodes arranged in a triangular tip orientation, wherein said microelectrode is configured to deliver a varying electric field to a cell, a cell component, or a cell fragment.   
     
     
         2 . The device of  claim 1 , wherein said varying electrical fields is induced by or applied via oscillations of voltage. 
     
     
         3 . The device of  claim 1 , wherein said varying electric field is electric filed oscillations generated by dielectrophoresis. 
     
     
         4 . The device of  claim 1 , wherein said device is fabricated by one or more of photolithography, laser ablation or electron beam patterning. 
     
     
         5 . A system for measuring mechanical properties of a cell, a cell component, or a cell fragment, comprising:
 a) a microelectrode chip comprising a plurality of parallel microelectrodes arranged in a triangular tip orientation;   b) a power supply; and   c) a visualization means.   
     
     
         6 . The system of  claim 5 , wherein said microelectrode chip further comprises a fluid chamber on top of said chip. 
     
     
         7 . The system of  claim 5 , wherein said microelectrode has an electrode gap distance of approximately 10 μm 
     
     
         8 . The system of  claim 5 , wherein said microelectrode has a surface coating of a Ti—Au—Ti sandwich. 
     
     
         9 . The system of  claim 5 , wherein said microscope is a bright field microscope. 
     
     
         10 . The system of  claim 5 , further comprising a digital camera in operable combination with said microscope. 
     
     
         11 . The system of  claim 5 , wherein said visualization means is selected from the group consisting of a microscope, a camera, and a CCD device. 
     
     
         12 . The system of  claim 5 , wherein said microelectrodes induce varying electrical fields via oscillations of voltage. 
     
     
         13 . The system of  claim 5 , wherein said microelectrodes induce varying electrical fields generated by dielectrophoresis. 
     
     
         14 . A method, comprising:
 a) trapping a plurality of cells, cell components, or cell fragments in the microelectrode of the device or system of  claim 5 ;   b) measuring at least one mechanical property of said cells, cell components, of cell fragments along the axis of maximum extension.   
     
     
         15 . The method of  claim 14 , wherein said cell is a non-adherent cell. 
     
     
         16 . The method of  claim 14 , wherein said cell is selected from the group consisting of platelets, white blood cells, red blood cells, circulating tumor cells, bone marrow cells, stem cells, progenitor cells, and endothelial progenitor cells. 
     
     
         17 . The method of  claim 14 , wherein said cell components are selected from the group consisting of microparticles, mitochondria, golgi, lusosomes, and peroxisomes. 
     
     
         18 . The method of  claim 14 , wherein said cell fragments are selected from the group consisting of budded vesiculated, vacuolated, or membrane-containing cellular constituents. 
     
     
         19 . The method of  claim 14 , wherein said mechanical property is selected from the group consisting of stiffness, deformation, elasticity, and bending. 
     
     
         20 . The method of  claim 14 , wherein the magnitude of deformation of said cells is proportional to cell stiffness.