Cell traction forces on soft biomaterials. I. Microrheology of type I collagen gels.
A laser-trap microrheometry technique was used to determine the local shear moduli of Type I collagen gels. Embedded 2.1 microm polystyrene latex particles were displaced 10-100 nm using a near-infrared laser trap with a trap constant of 0.0001 N/m. The trap was oscillated transversely +/- 200 nm using a refractive glass plate mounted on a galvanometric scanner. The displacement of the microspheres was in phase with the movement of the laser trap at frequencies less than 1 rad/s, indicating that at least locally, the gels behaved as elastic media. The local shear modulus was measured at various positions throughout the gel, and, for gels at 2.3 mg/mL and 37 degrees C, values ranged from G = 3 to 80 Pa. The average shear modulus G = 55 Pa, which compares well with measurements from parallel plate rheometry.
Velegol
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Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA. velegol@psu.edu
Lanni
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D001672:Biocompatible Materials / Q000378:metabolism*; D002448:Cell Adhesion; D003094:Collagen / Q000378:metabolism*; D004548:Elasticity; D017276:Friction; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000378:metabolism*; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D011137:Polystyrenes; D012212:Rheology / Q000295:instrumentation / Q000379:methods*; D013055:Spectrophotometry, Infrared / Q000295:instrumentation / Q000379:methods
D001672:Biocompatible Materials; D011137:Polystyrenes; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D003094:Collagen