共查询到20条相似文献,搜索用时 859 毫秒
1.
Sotiris Psilodimitrakopoulos Ivan Amat-Roldan Pablo Loza-Alvarez David Artigas 《Biomedical optics express》2012,3(10):2681-2693
Based on its polarization dependency, second harmonic generation (PSHG) microscopy has been
proven capable to structurally characterize molecular architectures in different biological
samples. By exploiting this polarization dependency of the SHG signal in every pixel of the
image, average quantitative structural information can be retrieved in the form of PSHG image
histograms. In the present study we experimentally show how the PSHG image histograms can be
affected by the organization of the SHG active molecules. Our experimental scenario grounds on
two inherent properties of starch granules. Firstly, we take advantage of the radial
organization of amylopectin molecules (the SHG source in starch) to attribute shifts of the
image histograms to the existence of tilted off the plane molecules. Secondly, we use the
property of starch to organize upon hydration to demonstrate that the degree of structural
order at the molecular level affects the width of the PSHG image histograms. The shorter the
width is the more organized the molecules in the sample are, resulting in a reliable method to
measure order. The implication of this finding is crucial to the interpretation of PSHG images
used for example in tissue diagnostics.OCIS codes: (180.4315) Nonlinear microscopy, (190.2620) Harmonic generation and mixing 相似文献
2.
Chung-Hwan Chen Anupama Venugopalan Nair Shu-Chun Chuang Yi-Shan Lin Mei-Hsin Cheng Chun-Yu Lin Chia-Ying Chang Shean-Jen Chen Chi-Hsiang Lien 《Biomedical optics express》2021,12(5):3050
Collagen of type I (Col I) and type II (Col II) are critical for cartilage and connective tissues in the human body, and several diseases may alter their properties. Assessing the identification and quantification of fibrillar collagen without biomarkers is a challenge. Advancements in non-invasive polarization-resolved second-harmonic generation (PSHG) microscopy have provided a method for the non-destructive investigation of collagen molecular level properties. Here we explored an alternative polarization modulated approach, dual-LC PSHG, that is based on two liquid crystal devices (Liquid crystal polarization rotators, LPRs) operating simultaneously with a laser scanning SHG microscope. We demonstrated that this more accessible technology allows the quick and accurate generation of any desired linear and circular polarization state without any mechanical parts. This study demonstrates that this method can aid in improving the ability to quantify the characteristics of both types of collagen, including pitch angle, anisotropy, and circular dichroism analysis. Using this approach, we estimated the effective pitch angle for Col I and Col II to be 49.7° and 51.6°, respectively. The effective peptide pitch angle for Col II gel was first estimated and is similar to the value obtained for Col I gel in the previous studies. Additionally, the difference of the anisotropy parameter of both collagen type gels was assessed to be 0.293, which reflects the different type molecular fibril assembly. Further, our work suggests a potential method for monitoring and differentiating different collagen types in biological tissues, especially cartilage or connective tissue. 相似文献
3.
Skin cancer incidence has increased exponentially over the last three decades. In 2008 skin cancer caused 2280 deaths in the UK, with 2067 due to malignant melanoma. Early diagnosis can prevent mortality, however, conventional treatment requires multiple procedures and increasing treatment times. Second harmonic generation (SHG) imaging could offer diagnosis and demarcation of melanoma borders non-invasively at presentation thereby short-cutting the excision biopsy stage. To test the efficacy and accuracy of SHG imaging of collagen in skin and to delineate the borders of skin cancers, unstained human melanoma biopsy sections were imaged using SHG microscopy. Comparisons with sister sections, stained with H&E or Melan-A were made for correlation of invasion borders. Fresh ex vivo normal human and rat skin was imaged through its whole thickness using SHG to demonstrate this technique is transferable to in vivo tissues. SHG imaging demonstrated detailed collagen distribution in normal skin, with total absence of SHG signal (fibrillar collagen) within the melanoma-invaded tissue. The presence or absence of signal changes dramatically at the borders of the melanoma, accurately demarcating the edges that strongly correlated with H&E and Melan-A defined borders (p<0.002). SHG imaging of ex vivo human and rat skin demonstrated collagen architecture could be imaged through the full thickness of the skin. We propose that SHG imaging could be used for diagnosis and accurate demarcation of melanoma borders on presentation and therefore potentially reduce mortality rates. 相似文献
4.
Xiaoyun Xu Jie Cheng Michael J. Thrall Zhengfan Liu Xi Wang Stephen T.C. Wong 《Biomedical optics express》2013,4(12):2855-2868
Lung carcinoma is the leading cause of cancer-related death in the United States, and non-small cell carcinoma accounts for 85% of all lung cancer cases. One major characteristic of non-small cell carcinoma is the appearance of desmoplasia and deposition of dense extracellular collagen around the tumor. The desmoplastic response provides a radiologic target but may impair sampling during traditional image-guided needle biopsy and is difficult to differentiate from normal tissues using single label free imaging modality; for translational purposes, label-free techniques provide a more promising route to clinics. We thus investigated the potential of using multimodal, label free optical microscopy that incorporates Coherent Anti-Stokes Raman Scattering (CARS), Two-Photon Excited AutoFluorescence (TPEAF), and Second Harmonic Generation (SHG) techniques for differentiating lung cancer from normal and desmoplastic tissues. Lung tissue samples from patients were imaged using CARS, TPEAF, and SHG for comparison and showed that the combination of the three non-linear optics techniques is essential for attaining reliable differentiation. These images also illustrated good pathological correlation with hematoxylin and eosin (H&E) stained sections from the same tissue samples. Automated image analysis algorithms were developed for quantitative segmentation and feature extraction to enable lung tissue differentiation. Our results indicate that coupled with automated morphology analysis, the proposed tri-modal nonlinear optical imaging technique potentially offers a powerful translational strategy to differentiate cancer lesions reliably from surrounding non-tumor and desmoplastic tissues.OCIS codes: (170.3880) Medical and biological imaging, (300.6230) Spectroscopy, coherent anti-Stokes Raman scattering, (170.2520) Fluorescence microscopy, (270.4180) Multiphoton processes, (170.4580) Optical diagnostics for medicine, (190.1900) Diagnostic applications of nonlinear optics 相似文献
5.
Dionysios Xydias Georgios Ziakas Sotiris Psilodimitrakopoulos Andreas Lemonis Eleni Bagli Theodore Fotsis Achille Gravanis Dimitrios S. Tzeranis Emmanuel Stratakis 《Biomedical optics express》2021,12(2):1136
In this study, we use non-linear imaging microscopy to characterize the structural properties of porous collagen-GAG scaffolds (CGS) seeded with human umbilical vein endothelial cells (HUVECs), as well as human mesenchymal stem cells (hMSCs), a co-culture previously reported to form vessel-like structures inside CGS. The evolution of the resulting tissue construct was monitored over 10 days via simultaneous two- and three-photon excited fluorescence microscopy. Time-lapsed 2- and 3-photon excited fluorescence imaging was utilized to monitor the temporal evolution of the vascular-like structures up to 100 µm inside the scaffold up to 10 days post-seeding. 3D polarization-dependent second harmonic generation (PSHG) was utilized to monitor collagen-based scaffold remodeling and determine collagen fibril orientation up to 200 µm inside the scaffold. We demonstrate that polarization-dependent second harmonic generation can provide a novel way to quantify the reorganization of the collagen architecture in CGS simultaneously with key biomechanical interactions between seeded cells and CGS that regulate the formation of vessel-like structures inside 3D tissue constructs. A comparison between samples at different days in vitro revealed that gradually, the scaffolds developed an orthogonal net-like architecture, previously found in real skin. 相似文献
6.
Sotiris Psilodimitrakopoulos Pablo Loza-Alvarez David Artigas 《Biomedical optics express》2014,5(12):4362-4373
Fast imaging of molecular changes under high-resolution and label-free conditions are essential for understanding in-vivo processes, however, current techniques are not able to monitor such changes in real time. Polarization sensitive second harmonic generation (PSHG) imaging is a minimally invasive optical microscopy technique capable of quantifying molecular conformational changes occurring below the diffraction limit. Up to now, such information is generally retrieved by exciting the sample with different linear polarizations. This procedure requires the sample to remain static during measurements (from a few second to minutes), preventing the use of PSHG microscopy from studying moving samples or molecular dynamics in living organisms. Here we demonstrate an imaging method that is one order of magnitude faster than conventional PSHG. Based on circular polarization excitation and instantaneous polarimetry analysis of the second harmonic signal generated in the tissue, the method is able to instantaneously obtain molecular information within a pixel dwell time. As a consequence, a single scan is only required to retrieve all the information. This allowed us to perform PSHG imaging in moving C. elegans, monitoring myosin’s dynamics during the muscular contraction and relaxation. Since the method provides images of the molecular state, an unprecedented global understanding of the muscles dynamics is possible by correlating changes in different regions of the sample.OCIS codes: (180.4315) Nonlinear microscopy, (190.2620) Harmonic generation and mixing 相似文献
7.
David Sevrain Matthieu Dubreuil Grace Elizabeth Dolman Abed Zaitoun William Irving Indra Neil Guha Christophe Odin Yann Le Grand 《Biomedical optics express》2015,6(4):1209-1218
In this paper we analyze a fibrosis scoring method based on measurement of the fibrillar collagen area from second harmonic generation (SHG) microscopy images of unstained histological slices from human liver biopsies. The study is conducted on a cohort of one hundred chronic hepatitis C patients with intermediate to strong Metavir and Ishak stages of liver fibrosis. We highlight a key parameter of our scoring method to discriminate between high and low fibrosis stages. Moreover, according to the intensity histograms of the SHG images and simple mathematical arguments, we show that our area-based method is equivalent to an intensity-based method, despite saturation of the images. Finally we propose an improvement of our scoring method using very simple image processing tools.OCIS codes: (180.4315) Nonlinear microscopy, (170.1610) Clinical applications, (170.3880) Medical and biological imaging, (170.4580) Optical diagnostics for medicine, (110.2960) Image analysis 相似文献
8.
Sushant P. Sahu Qianglin Liu Alisha Prasad Syed Mohammad Abid Hasan Qun Liu Maria Ximena Bastidas Rodriguez Orna Mukhopadhyay David Burk Joseph Francis Supratik Mukhopadhyay Xing Fu Manas Ranjan Gartia 《Biomedical optics express》2021,12(1):604
We utilized collagen specific second harmonic generation (SHG) signatures coupled with correlative immunofluorescence imaging techniques to characterize collagen structural isoforms (type I and type III) in a murine model of myocardial infarction (MI). Tissue samples were imaged over a four week period using SHG, transmitted light microscopy and immunofluorescence imaging using fluorescently-labeled collagen antibodies. The post-mortem cardiac tissue imaging using SHG demonstrated a progressive increase in collagen deposition in the left ventricle (LV) post-MI. We were able to monitor structural morphology and LV remodeling parameters in terms of extent of LV dilation, stiffness and fiber dimensions in the infarcted myocardium. 相似文献
9.
Danielle Tokarz Richard Cisek Ahmad Golaraei Sylvia L. Asa Virginijus Barzda Brian C. Wilson 《Biomedical optics express》2015,6(9):3475-3481
Changes in collagen ultrastructure between malignant and normal human thyroid tissue were investigated ex vivo using polarization second harmonic generation (SHG) microscopy. The second-order nonlinear optical susceptibility tensor component ratio and the degree of linear polarization (DOLP) of the SHG signal were measured. The ratio values are related to the collagen ultrastructure, while DOLP indicates the relative amount of coherent signal and incoherent scattering of SHG. Increase in ratio values and decrease in DOLP were observed for tumor tissue compared to normal thyroid, indicating higher ultrastructural disorder in tumor collagen.OCIS codes: (180.4315) Nonlinear microscopy, (170.3880) Medical and biological imaging, (170.4730) Optical pathology, (170.6935) Tissue characterization 相似文献
10.
Tamara P. Martin Greg Norris Gail McConnell Susan Currie 《The international journal of cardiovascular imaging》2013,29(8):1733-1740
To determine whether second harmonic generation (SHG) can be used as a novel and improved label-free technique for detection of collagen deposition in the heart. To verify whether SHG will allow accurate quantification of altered collagen deposition in diseased hearts following hypertrophic remodelling. Minimally invasive transverse aortic banding (MTAB) of mouse hearts was used to generate a reproducible model of cardiac hypertrophy. Physiological and functional assessment of hypertrophic development was performed using echocardiography and post-mortem analysis of remodelled hearts. Cardiac fibroblasts were isolated from sham-operated and hypertrophied hearts and proliferation rates compared. Multi-photon laser scanning microscopy was used to capture both two-photon excited autofluorescence (TPEF) and SHG images simultaneously in two channels. TPEF images were subtracted from SHG images and the resulting signal intensities from ventricular tissue sections were calculated. Traditional picrosirius red staining was used to verify the suitability of the SHG application. MTAB surgery induced significant hypertrophic remodelling and increased cardiac fibroblast proliferation. A significant increase in the density of collagen fibres between hypertrophic and control tissues (p < 0.05) was evident using SHG. Similar increases and patterns of staining were observed using parallel traditional picrosirius red staining of collagen. Label-free SHG microscopy provides a new alternative method for quantifying collagen deposition in fibrotic hearts. 相似文献
11.
Kennedy Brittain MacAulay Harvey Richard Cisek Saranyan Pillai Sean D Christie Danielle Tokarz 《Biomedical optics express》2022,13(6):3593
The origin of second harmonic generation (SHG) signal in otoconia was investigated. SHG signal intensity from otoconia was compared to pure calcite crystals, given calcite is the primary component of otoconia and is known to emit surface SHG. The SHG intensity from calcite was found to be ∼41× weaker than the SHG intensity from otoconia signifying that the SHG signal from otoconia is likely generated from the organic matrix. Furthermore, the SHG intensity from otoconia increased when treated with a chelating agent known to dissolve calcite which confirms that calcite is not the source of SHG. Additionally, polarization-resolved SHG microscopy imaging revealed that the arrangement of the SHG emitters is radial and can form highly ordered domains. 相似文献
12.
Maxime Rivard Mathieu Laliberté Antony Bertrand-Grenier Catalin Harnagea Christian P. Pfeffer Martin Vallières Yves St-Pierre Alain Pignolet My Ali El Khakani Fran?ois Légaré 《Biomedical optics express》2011,2(1):26-36
Fascia tissue is rich in collagen type I proteins and can be imaged by second harmonic generation (SHG) microscopy. While identifying the overall alignment of the collagen fibrils is evident from those images, the tridimensional structural origin for the observation of SHG signal is more complex than it apparently seems. Those images reveal that the noncentrosymmetric (piezoelectric) structures are distributed heterogeneously on spatial dimensions inferior to the resolution provided by the nonlinear optical microscope (sub-micron). Using piezoresponse force microscopy (PFM), we show that an individual collagen fibril has a noncentrosymmetric structural organization. Fibrils are found to be arranged in nano-domains where the anisotropic axis is preserved along the fibrillar axis, while across the collagen sheets, the phase of the second order nonlinear susceptibility is changing by 180 degrees between adjacent nano-domains. This complex architecture of noncentrosymmetric nano-domains governs the coherent addition of 2ω light within the focal volume and the observed features in the SHG images taken in fascia.OCIS codes: (180.4315) Nonlinear microscopy, (190.4160) Multiharmonic generation 相似文献
13.
Cameron P. Brown Marie-Andree Houle Konstantin Popov Mischa Nicklaus Charles-Andre Couture Matthieu Laliberté Thomas Brabec Andreas Ruediger Andrew J. Carr Andrew J. Price Harinderjit S. Gill Lora Ramunno Francois Légaré 《Biomedical optics express》2014,5(1):233-243
The collagen meshwork plays a central role in the functioning of a range of tissues including cartilage, tendon, arteries, skin, bone and ligament. Because of its importance in function, it is of considerable interest for studying development, disease and regeneration processes. Here, we have used second harmonic generation (SHG) to image human tissues on the hundreds of micron scale, and developed a numerical model to quantitatively interpret the images in terms of the underlying collagen structure on the tens to hundreds of nanometer scale. Focusing on osteoarthritic changes in cartilage, we have demonstrated that this combination of polarized SHG imaging and numerical modeling can estimate fibril diameter, filling fraction, orientation and bundling. This extends SHG microscopy from a qualitative to quantitative imaging technique, providing a label-free and non-destructive platform for characterizing the extracellular matrix that can expand our understanding of the structural mechanisms in disease.OCIS codes: (170.0170) Medical optics and biotechnology, (190.0190) Nonlinear optics 相似文献
14.
Rivard M Laliberté M Bertrand-Grenier A Harnagea C Pfeffer CP Vallières M St-Pierre Y Pignolet A El Khakani MA Légaré F 《Biomedical optics express》2010,2(1):26-36
Fascia tissue is rich in collagen type I proteins and can be imaged by second harmonic generation (SHG) microscopy. While identifying the overall alignment of the collagen fibrils is evident from those images, the tridimensional structural origin for the observation of SHG signal is more complex than it apparently seems. Those images reveal that the noncentrosymmetric (piezoelectric) structures are distributed heterogeneously on spatial dimensions inferior to the resolution provided by the nonlinear optical microscope (sub-micron). Using piezoresponse force microscopy (PFM), we show that an individual collagen fibril has a noncentrosymmetric structural organization. Fibrils are found to be arranged in nano-domains where the anisotropic axis is preserved along the fibrillar axis, while across the collagen sheets, the phase of the second order nonlinear susceptibility is changing by 180 degrees between adjacent nano-domains. This complex architecture of noncentrosymmetric nano-domains governs the coherent addition of 2ω light within the focal volume and the observed features in the SHG images taken in fascia. 相似文献
15.
Viet-Hoan Le Seunghun Lee Bumju Kim Yeoreum Yoon Calvin J. Yoon Wan Kyun Chung Ki Hean Kim 《Biomedical optics express》2015,6(7):2542-2551
Both polarization sensitive optical coherence tomography (PS-OCT) and second harmonic generation (SHG) microscopy are 3D optical imaging methods providing information related to collagen in the skin. PS-OCT provides birefringence information which is due to the collagen composition of the skin. SHG microscopy visualizes collagen fibers in the skin based on their SHG property. These two modalities have been applied to the same skin pathologies associated with collagen changes, but their relationship has not been examined. In this study, we tried to find the relationship by imaging the same skin samples with both modalities. Various parts of the normal rat skin and burn damaged skin were imaged ex vivo, and their images were analyzed both qualitatively and quantitatively. PS-OCT images were analyzed to obtain tissue birefringence. SHG images were analyzed to obtain collagen orientation indices by applying 2D Fourier transform. The skin samples having higher birefringence values had higher collagen orientation indices, and a linear correlation was found between them. Burn damaged skin showed decreases in both parameters compared to the control skins. This relationship between the bulk and microscopic properties of skin may be useful for further skin studies.OCIS codes: (260.1440) Birefringence, (170.3890) Medical optics instrumentation, (180.4315) Nonlinear microscopy, (170.4500) Optical coherence tomography, (170.2655) Functional monitoring and imaging 相似文献
16.
Tseng JY Ghazaryan AA Lo W Chen YF Hovhannisyan V Chen SJ Tan HY Dong CY 《Biomedical optics express》2010,2(2):218-230
Tissue glycation from diabetes and aging can result in complications such as renal failure, blindness, nerve damage and vascular diseases. In this work, we applied multiphoton microscopy for imaging and characterizing the extent of tissue glycation. The characteristic features of multiphoton autofluorescence (MPAF) and second harmonic generation (SHG) images as well as MPAF spectra of glycated bovine skin, cornea and aorta were acquired. The analysis of MPAF intensity change accompanying the glycation process shows that collagen is more responsive to the formation of autofluorescent advanced glycation endproducts (AGE) than elastic fibers. Changes in spectral features were also used to estimate the rate of glycation in tissues with intrinsic AF. Our study shows that multiphton imaging may be used for the in vitro investigation of the effects of tissue glycation and that this approach may be used for monitoring AGE formation in the clinical setting. 相似文献
17.
Amara Khan Fernanda Ramos-Gomes Andrea Markus Matthias Mietsch Rabea Hinkel Frauke Alves 《Biomedical optics express》2021,12(11):7009
Heart failure is one of the most common causes of morbidity and mortality. Both maturational abnormalities and age-associated cardiac pathologies contribute to heart failure. Imaging-based assessment to discern detailed cardiac structure at various maturational stages is imperative for understanding mechanisms behind cardiac growth and aging. Using multiphoton nonlinear optical microscopy (NLOM) based label-free imaging, we investigated cardiac structural composition in a human-relevant aging model, the common marmoset monkey (Callithrix jacchus). Animals were divided into three different age groups including neonatal, young adult and old. By devising a unique strategy for segregating collagen and myosin emitted second harmonic generation (SHG) signals, we performed a volumetric assessment of collagen and total scattering tissue (collagen + myosin). Aged marmoset hearts exhibited an increase in collagen and total scattering tissue volume at the sites of severe tissue remodelling indicating age-related cardiac fibrosis. Significantly low scattering tissue volume in neonatal marmoset hearts was attributed to a lack of binding between the myofibrils in maturing cardiac tissue. Comprehensive quantitative assessment of structural composition during maturation and aging of marmoset hearts revealed significant differences in myofibril length, alignment, curvature and angular distribution. In conclusion, label-free high-resolution NLOM facilitates visualization and quantification of subcellular structural features for understanding vital age-related morphological alterations in the marmoset heart. 相似文献
18.
Jo-Ya Tseng Ara A. Ghazaryan Wen Lo Yang-Fang Chen Vladimir Hovhannisyan Shean-Jen Chen Hsin-Yuan Tan Chen-Yuan Dong 《Biomedical optics express》2011,2(2):218-230
Tissue glycation from diabetes and aging can result in complications such as renal failure, blindness, nerve damage and vascular diseases. In this work, we applied multiphoton microscopy for imaging and characterizing the extent of tissue glycation. The characteristic features of multiphoton autofluorescence (MPAF) and second harmonic generation (SHG) images as well as MPAF spectra of glycated bovine skin, cornea and aorta were acquired. The analysis of MPAF intensity change accompanying the glycation process shows that collagen is more responsive to the formation of autofluorescent advanced glycation endproducts (AGE) than elastic fibers. Changes in spectral features were also used to estimate the rate of glycation in tissues with intrinsic AF. Our study shows that multiphton imaging may be used for the in vitro investigation of the effects of tissue glycation and that this approach may be used for monitoring AGE formation in the clinical setting.OCIS codes: (120.3890) Medical optics instrumentation, (170.5810) Scanning microscopy, (170.6510) Spectroscopy, tissue diagnostics, (180.4315) Nonlinear microscopy 相似文献
19.
Sey-En Lin Dong-Yo Jheng Kuang-Yu Hsu Yun-Ru Liu Wei-Hsiang Huang Hsiang-Chieh Lee Chien-Chung Tsai 《Biomedical optics express》2021,12(8):5139
A technique using Linnik-based optical coherence microscopy (OCM), with built-in fluorescence microscopy (FM), is demonstrated here to describe cellular-level morphology for fresh porcine and biobank tissue specimens. The proposed method utilizes color-coding to generate digital pseudo-H&E (p-H&E) images. Using the same camera, colocalized FM images are merged with corresponding morphological OCM images using a 24-bit RGB composition process to generate position-matched p-H&E images. From receipt of dissected fresh tissue piece to generation of stitched images, the total processing time is <15 min for a 1-cm2 specimen, which is on average two times faster than frozen-section H&E process for fatty or water-rich fresh tissue specimens. This technique was successfully used to scan human and animal fresh tissue pieces, demonstrating its applicability for both biobank and veterinary purposes. We provide an in-depth comparison between p-H&E and human frozen-section H&E images acquired from the same metastatic sentinel lymph node slice (∼10 µm thick), and show the differences, like elastic fibers of a tiny blood vessel and cytoplasm of tumor cells. This optical sectioning technique provides histopathologists with a convenient assessment method that outputs large-field H&E-like images of fresh tissue pieces without requiring any physical embedment. 相似文献
20.
Latour G Gusachenko I Kowalczuk L Lamarre I Schanne-Klein MC 《Biomedical optics express》2012,3(1):1-15
The transparency and mechanical strength of the cornea are related to the highly organized three-dimensional distribution of collagen fibrils. It is of great interest to develop specific and contrasted in vivo imaging tools to probe these collagenous structures, which is not available yet. Second Harmonic Generation (SHG) microscopy is a unique tool to reveal fibrillar collagen within unstained tissues, but backward SHG images of cornea fail to reveal any spatial features due to the nanometric diameter of stromal collagen fibrils. To overcome this limitation, we performed polarization-resolved SHG imaging, which is highly sensitive to the sub-micrometer distribution of anisotropic structures. Using advanced data processing, we successfully retrieved the orientation of the collagenous fibrils at each depth of human corneas, even in backward SHG homogenous images. Quantitative information was also obtained about the submicrometer heterogeneities of the fibrillar collagen distribution by measuring the SHG anisotropy. All these results were consistent with numerical simulation of the polarization-resolved SHG response of cornea. Finally, we performed in vivo SHG imaging of rat corneas and achieved structural imaging of corneal stroma without any labeling. Epi-detected polarization-resolved SHG imaging should extend to other organs and become a new diagnosis tool for collagen remodeling. 相似文献