Optic nerve degeneration is a major cause of irreversible blindness worldwide with glaucoma being the most common optic neuropathy,affecting approximately 76 million people worldwide in 2020.The optic nerve comprises ...Optic nerve degeneration is a major cause of irreversible blindness worldwide with glaucoma being the most common optic neuropathy,affecting approximately 76 million people worldwide in 2020.The optic nerve comprises axons of retinal ganglion cells(RGCs),the output neurons of the inner retina.Protecting RGCs and axons from degeneration and regenerating RGC axons to preserve and recover vision in patients with progressive optic neuropathy is an unmet need.Unlike embryonic neurons,mature neurons of the mammalian central nervous system fail to regenerate their axons following injury.The age-related loss of axon regenerative capacity of RGCs over time renders vision loss from optic neuropathy irreversible.The failure of injured RGCs to regenerate axons is largely attributed to inhibitory molecules in the extrinsic environment and a change in the intrinsic molecular makeup of aging cells.Early studies have demonstrated that RGCs require specific molecular signals for the stimulation of axon growth even without inhibitory molecules in the extrinsic environment,leading successive efforts to focus on uncovering the intrinsic signaling pathways that control axon extension during RGC development.展开更多
Resolving three-dimensional morphological features in thick specimens remains a significant challenge for label-free imaging.We report a new speckle diffraction tomography(SDT)approach that can image thick biological ...Resolving three-dimensional morphological features in thick specimens remains a significant challenge for label-free imaging.We report a new speckle diffraction tomography(SDT)approach that can image thick biological specimens with~500 nm lateral resolution and~1μm axial resolution in a reflection geometry.In SDT,multiple-scattering background is rejected through spatiotemporal gating provided by dynamic speckle-field interferometry,while depth-resolved refractive index maps are reconstructed by developing a comprehensive inverse-scattering model that also considers specimen-induced aberrations.Benefiting from the high-resolution and full-field quantitative imaging capabilities of SDT,we successfully imaged red blood cells and quantified their membrane fluctuations behind a turbid medium with a thickness of 2.8 scattering mean-free paths.Most importantly,we performed volumetric imaging of cornea inside an ex vivo rat eye and quantified its optical properties,including the mapping of nanoscale topographic features of Dua’s and Descemet’s membranes that had not been previously visualized.展开更多
文摘Optic nerve degeneration is a major cause of irreversible blindness worldwide with glaucoma being the most common optic neuropathy,affecting approximately 76 million people worldwide in 2020.The optic nerve comprises axons of retinal ganglion cells(RGCs),the output neurons of the inner retina.Protecting RGCs and axons from degeneration and regenerating RGC axons to preserve and recover vision in patients with progressive optic neuropathy is an unmet need.Unlike embryonic neurons,mature neurons of the mammalian central nervous system fail to regenerate their axons following injury.The age-related loss of axon regenerative capacity of RGCs over time renders vision loss from optic neuropathy irreversible.The failure of injured RGCs to regenerate axons is largely attributed to inhibitory molecules in the extrinsic environment and a change in the intrinsic molecular makeup of aging cells.Early studies have demonstrated that RGCs require specific molecular signals for the stimulation of axon growth even without inhibitory molecules in the extrinsic environment,leading successive efforts to focus on uncovering the intrinsic signaling pathways that control axon extension during RGC development.
基金S.K.,Y.L.,P.T.C.S.,and Z.Y.acknowledge support from National Institutes of Health(NIH)funding 5-P41-EB015871-27 and Hamamatsu CorporationP.T.C.S.further acknowledges support from the Singapore-Massachusetts Institute of Technology Alliance for Research and Technology(SMART)Center,Critical Analytics for Manufacturing Personalized-Medicine IRG.P.T.C.S.and Z.Y.further acknowledge support from NIH R01DA045549,R21GM140613-02,R01HL158102.R.Z.acknowledges support from Croucher Innovation Awards 2019(Grant No.CM/CT/CF/CIA/0688/19ay)+2 种基金Hong Kong Innovation and Technology Commission(ITS/148/20 and ITS/178/20FP)Hong Kong General Research Fund(14209521)The Chinese University of Hong Kong Research Sustainability of Major RGC Funding Schemes-Strategic Areas.
文摘Resolving three-dimensional morphological features in thick specimens remains a significant challenge for label-free imaging.We report a new speckle diffraction tomography(SDT)approach that can image thick biological specimens with~500 nm lateral resolution and~1μm axial resolution in a reflection geometry.In SDT,multiple-scattering background is rejected through spatiotemporal gating provided by dynamic speckle-field interferometry,while depth-resolved refractive index maps are reconstructed by developing a comprehensive inverse-scattering model that also considers specimen-induced aberrations.Benefiting from the high-resolution and full-field quantitative imaging capabilities of SDT,we successfully imaged red blood cells and quantified their membrane fluctuations behind a turbid medium with a thickness of 2.8 scattering mean-free paths.Most importantly,we performed volumetric imaging of cornea inside an ex vivo rat eye and quantified its optical properties,including the mapping of nanoscale topographic features of Dua’s and Descemet’s membranes that had not been previously visualized.
