Purpose.: To investigate the depth-dependent mechanical anisotropy of the @entity1 @entity2687 at the tissue (stroma) and molecular (collagen) level by using atomic force microscopy (AFM). Methods.: Eleven @entity1 donor corneas were dissected at different stromal depths by using a microkeratome. Mechanical measurements were performed in 15% dextran on the surface of the exposed stroma of each sample by using a custom-built AFM in force spectroscopy mode using both microspherical (38- m diameter) and nanoconical (10-nm radius of curvature) indenters at 2- m/s and 15- m/s indentation rates. Young's modulus was determined by fitting force curve data using the Hertz and Hertz-Sneddon models for a spherical and a conical indenter, respectively. The depth-dependent anisotropy of stromal elasticity was correlated with images of the @entity2687 acquired by two-photon microscopy. Results.: The force curves were obtained at stromal depths ranging from 59 to 218  m. At the tissue level, Young's modulus (ES) showed a steep decrease at approximately 140- m stromal depth (from 0.8 MPa to 0.3 MPa; P = 0.03) and then was stable in the posterior stroma. At the molecular level, Young's modulus (EC) was significantly greater than at the tissue level; EC decreased nonlinearly with increasing stromal depth from 3.9 to 2.6 MPa (P = 0.04). The variation of microstructure through the thickness correlated highly with a nonconstant profile of the mechanical properties in the stroma. Conclusions.: The @entity2687 exhibits unique anisotropic elastic behavior at the tissue and molecular levels. This knowledge may benefit modeling of @entity146 and help in the development of biomimetic materials.

Multiscale Investigation of the Depth-Dependent Mechanical Anisotropy of the XXXX Corneal Stroma.

@entity1 :: ('9606', 'Species') :: ['human'] @entity2687 :: ('MESH:D003316', 'Disease') :: ['corneal stroma'] @entity146 :: ('MESH:D001523', 'Disease') :: ['corneal behavior']
@entity1 :: (9606,Species) :: ['Human']
