live tissue imaging (cornea) optical imaging of tissue cells histology and electron microscopy can...
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Live tissue imaging (cornea)
Optical imaging of tissue cells
Histology and Electron Microscopy can image ECM.•Requires sectioning and staining.
Stroma Extracellular Matrixcollagen is ubiquitous
Light scattering Cellular fluorescence
nonlinear microscopy endogenous nonlinear optical signals
High Resolution Imaging
Cornea (Rabbit)
Epithelium
Stroma
Endothelium
100 m
14 m
Corneal Stroma
30 m
xy z
y
x
z
xyz
28 x 32 x 33 m
Inte
nsit
y (a
.u.)
Wavelength (nm)
750 nm
Inte
nsit
y (a
.u.) 800 nm
8 m
0
350 400 450 500 550 600
0
Corneal imaging signals
Spectral filtering of imaging signals
520 nm 400 nm
8 m
keratocytes 30 m
TPEF + SHG TPEF SHG
SHG in Collagen
Collagen fiberquaternarystructure
tertiarystructure
~
Polarization dependence of SHG
Ex(t)
Ey(t)
P(t)
xy
z Collagen fiber
Fundamental SHG
SHG Polarization Dependence
Incident laserpolarization
8 m
Optical characterization of tissue
Polarization dependence of SHG in collagen
Endogenous nonlinear optical signals to characterize tissue
Linear (circular) polarization
Spectroscopy of nonlinear optical signals to enhance contrast
constituent specific imaging
sensitive to long range order of collagen molecules
Cornea(diagnosis window to the
eye)
Wilmer Eye Institute, Johns Hopkins University
U.S. 3 million cases of glaucomaU.S. 1.5 million diagnosed OHT and treated to reduce IOP
Applanation Tonometry
Corneal tissue properties affectIOP measurement
central cornea thickness
low tensionglaucoma
OHT56%
NLOM: characterize tissue material properties dependence on IOP