Recently, Circular Dichroism SHG (CD-SHG) microscopy has been implemented to take advantage of collagen chirality to improve 3D visualization.  However, CD-SHG signal is not well characterized yet, and quite different CD-SHG values are reported in the literature.  Here, we identify two major artifacts that may occur in CD-SHG experiments and we demonstrate that thorough optimization and calibration of the experimental setup are required for CD-SHG imaging.  Finally, we successfully record CD-SHG images in human cornea sections and confirm that this technique efficiently reveals collagen fibrils oriented out of the focal plane.
CD-SHG
Implementation of artifact-free circular dichroism SHG imaging of collagen.Second harmonic generation (SHG) enables in situ imaging of fibrillar collagen architecture in connective tissues.  Recently, Circular Dichroism SHG (CD-SHG) microscopy has been implemented to take advantage of collagen chirality to improve 3D visualization.  It measures the normalized difference in the SHG signal obtained upon excitation by left versus right circular polarizations.  However, CD-SHG signal is not well characterized yet, and quite different CD-SHG values are reported in the literature.  Here, we identify two major artifacts that may occur in CD-SHG experiments and we demonstrate that thorough optimization and calibration of the experimental setup are required for CD-SHG imaging.  Finally, we successfully record CD-SHG images in human cornea sections and confirm that this technique efficiently reveals collagen fibrils oriented out of the focal plane.
SHG
Recently, Circular Dichroism SHG (CD-SHG) microscopy has been implemented to take advantage of collagen chirality to improve 3D visualization.  However, CD-SHG signal is not well characterized yet, and quite different CD-SHG values are reported in the literature.  Here, we identify two major artifacts that may occur in CD-SHG experiments and we demonstrate that thorough optimization and calibration of the experimental setup are required for CD-SHG imaging.  Finally, we successfully record CD-SHG images in human cornea sections and confirm that this technique efficiently reveals collagen fibrils oriented out of the focal plane.
CD-SHG