Micromechanics of cellularized biopolymer networks.
Collagen gels are widely used in experiments on cell mechanics because they mimic the extracellular matrix in physiological conditions. Collagen gels are often characterized by their bulk rheology; however, variations in the collagen fiber microstructure and cell adhesion forces cause the mechanical properties to be inhomogeneous at the cellular scale. We study the mechanics of type I collagen on the scale of tens to hundreds of microns by using holographic optical tweezers to apply pN forces to microparticles embedded in the collagen fiber network. We find that in response to optical forces, particle displacements are inhomogeneous, anisotropic, and asymmetric. Gels prepared at 21 °C and 37 °C show qualitative difference in their micromechanical characteristics. We also demonstrate that contracting cells remodel the micromechanics of their surrounding extracellular matrix in a strain- and distance-dependent manner. To further understand the micromechanics of cellularized extracellular matrix, we have constructed a computational model which reproduces the main experiment findings.
Department of Physics, Oregon State University, Corvallis, OR 97331;
Christopher A R
CA
Jones
Department of Physics, Oregon State University, Corvallis, OR 97331;
Matthew
M
Cibula
Center of Theoretical Biophysics, Rice University, Houston, TX 77005; Department of Bioengineering, Rice University, Houston, TX 77005;
Jingchen
J
Feng
Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331.
Emma A
EA
Krnacik
Department of Physics, Oregon State University, Corvallis, OR 97331;
David H
DH
McIntyre
Center of Theoretical Biophysics, Rice University, Houston, TX 77005; Department of Bioengineering, Rice University, Houston, TX 77005; herbert.levine@rice.edu sunb@physics.oregonstate.edu.
Herbert
H
Levine
Department of Physics, Oregon State University, Corvallis, OR 97331; herbert.levine@rice.edu sunb@physics.oregonstate.edu.
Bo
B
Sun
D000818:Animals; D016880:Anisotropy; D001704:Biopolymers / Q000737:chemistry*; D045744:Cell Line, Tumor; D024042:Collagen Type I / Q000737:chemistry*; D018450:Disease Progression; D004548:Elasticity; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D005782:Gels / Q000737:chemistry; D006801:Humans; D051379:Mice; D018613:Microscopy, Confocal; D041681:NIH 3T3 Cells; D009369:Neoplasms / Q000473:pathology; D016011:Normal Distribution; D052898:Optical Tweezers; D055095:Optics and Photonics; D013314:Stress, Mechanical; D013696:Temperature; D014945:Wound Healing
D001704:Biopolymers; D024042:Collagen Type I; D005782:Gels
collagen; fiber network; micromechanics