biostudies-literatureEltony AMNIBIB NIH HHSNEI NIH HHSU.S. Department of Health & Human Services | National Institutes of Health1354https://www.ebi.ac.uk/biostudies/studies/S-EPMC8924229biostudies-literatureUnknown13(1)Load-bearing tissues are typically fortified by networks of protein fibers, often with preferential orientations. This fiber structure imparts the tissues with direction-dependent mechanical properties optimized to support specific external loads. To accurately model and predict tissues' mechanical response, it is essential to characterize the anisotropy on a microstructural scale. Previously, it has been difficult to measure the mechanical properties of intact tissues noninvasively. Here, we use Brillouin optical microscopy to visualize and quantify the anisotropic mechanical properties of corneal tissues at different length scales. We derive the stiffness tensor for a lamellar network of collagen fibrils and use angle-resolved Brillouin measurements to determine the longitudinal stiffness coefficients (longitudinal moduli) describing the ex vivo porcine cornea as a transverse isotropic material. Lastly, we observe significant mechanical anisotropy of the human cornea in vivo, highlighting the potential for clinical applications of off-axis Brillouin microscopy.Nature communicationsMeasuring mechanical anisotropy of the cornea with Brillouin microscopy.PMC8924229R01-EY025454R41 EY028820R41-EY028820R01 EY025454R01-EB027653P41-EB015903P41 EB015903R01 EB027653Yun SHShao PEltony AMfalseMeasuring mechanical anisotropy of the cornea with Brillouin microscopy.Load-bearing tissues are typically fortified by networks of protein fibers, often with preferential orientations. This fiber structure imparts the tissues with direction-dependent mechanical properties optimized to support specific external loads. To accurately model and predict tissues' mechanical response, it is essential to characterize the anisotropy on a microstructural scale. Previously, it has been difficult to measure the mechanical properties of intact tissues noninvasively. Here, we use Brillouin optical microscopy to visualize and quantify the anisotropic mechanical properties of corneal tissues at different length scales. We derive the stiffness tensor for a lamellar network of collagen fibrils and use angle-resolved Brillouin measurements to determine the longitudinal stiffness coefficients (longitudinal moduli) describing the ex vivo porcine cornea as a transverse isotropic material. Lastly, we observe significant mechanical anisotropy of the human cornea in vivo, highlighting the potential for clinical applications of off-axis Brillouin microscopy.2022-01-01T00:00:00Z2022 Mar2024-10-18T09:57:51.852Z2024-10-18T09:57:51.852ZS-EPMC89242293529338810.1038/s41467-022-29038-5