Group refractive index measurement of dry and hydrated type I collagen films using optical low-coherence reflectometry

Wang, Xiaojun

doi:10.1117/12.227699

Cited by 70 publications

(49 citation statements)

References 25 publications

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“…It has been reported that the group refractive index of the dry collagen is about 1.53 at 850 nm. 19 Our fitted refractive index of the main substrate matches well to this value and is consistent with the fact that collagen fibers are the major components in cornea. Overall, the corneal thickness, hydration, and refractive index changes during the storage were accurately monitored by OCT images with those changes strongly reflecting the effect of the storage media on the cornea structures as well as functions.…”

Section: Journal Of Biomedical Opticssupporting

confidence: 71%

Noninvasive optical coherence tomography monitoring of structure and hydration changes of human corneas in different preservation media

Clarke

Mathew

et al. 2011

J. Biomed. Opt.

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Abstract. The influence of different tissue preservation (a test solution under development and a standard storage solution) on human cornea morphology, refractive index and hydration was assessed noninvasively by ultrahighresolution optical coherence tomography (OCT) over time. For 28 days' or 15 days' storage in the preservation media, corneas in the two media exhibited different structural changes with different onset times including epithelial desquamation, edema-induced cornea thickening and change in tissue refractive index. It was found that the variation of the group refractive index over time was only about 2%, while 25% variation of hydration was observed in the storage and subsequent return to normothermic conditions in both preservation media. The results suggest the two media involved different but correlated preservation mechanisms. This study demonstrates that the noncontact, noninvasive, and high-resolution

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Section: Journal Of Biomedical Opticssupporting

confidence: 71%

Noninvasive optical coherence tomography monitoring of structure and hydration changes of human corneas in different preservation media

Clarke

Mathew

et al. 2011

J. Biomed. Opt.

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“…36 The RI of water content is close to 1.33, whereas the dry collagen fibrils have a higher RI of 1.53. 37 This special biochemical constitution of normal AC enables the increasing trend of RI along depth direction. The orientation of collagen contents has strong influence to the light propagation.…”

Section: Ri Distribution With Depthmentioning

confidence: 99%

Depth-dependent refractive index of normal and early degenerated articular cartilage

Wang¹,

Wu²,

Kirk³

2013

J. Biomed. Opt

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Abstract. The depth distributions of refractive index (RI) in normal and early degenerated articular cartilage (AC) were measured and correlated to the pathological statuses. Utilizing a confocal microscope, the depth distribution of RI was determined with an interval of 50 μm from the articular surface and approximated as a smooth curve. The fluctuation of RI was quantified with a specially defined coefficient and the proteoglycan (PG) loss was quantified with histological images. The overall RI of the AC collected from the femoral condyles of mature sheep was 1.4444. Significant differences existed in the refractive indices of different cartilage samples or even in the different depths of the same sample. The RI of normal cartilage distributed as a regular ramp or arch curve with depth and peaked in the middle-deep zone. The cartilage samples detected with high PG losses were coupled with severe fluctuations of RI. The fluctuating level was increased with pathological progress. The coefficient of RI fluctuation can distinguish the normal cartilage from the initially degenerated one, which potentially provides an indicator to detect the pathological development of AC. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…Anhydrous glycerol, such as was used in these studies, has a refractive index of 1.47 [21]. Collagen has a refractive index of 1.43 in the hydrated state and 1.53 in the dry state [22]. In the native state the extracellular¯uid has a refractive index of 1.35 [23]; however, the presence of glycerol or the loss of water due to glycerol will cause the extracellular¯uid refractive index to become larger, better index matching collagen and other tissue constituents.…”

Section: Microscopic Observationmentioning

confidence: 99%

Use of osmotically active agents to alter optical properties of tissue: Effects on the detected fluorescence signal measured through skin

et al. 2001

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Background and ObjectiveHyper‐osmotic chemical agents were used to study the effects of transient tissue scattering on the remitted fluorescence emission intensity from a target placed under a tissue sample.Study Design/Materials and MethodsA fluorescent film was placed underneath in vitro and in vivo samples of hamster skin, and the remitted fluorescent signal traveling to the tissue surface was monitored over time as the tissue was treated with an osmotically active agent.ResultsThe detected fluorescent signal increased as the scattering in tissue samples was substantially reduced. The increase was greater for dimethyl sulfoxide than glucose or glycerol. It was not statistically different between in vivo skin and in vitro skin.ConclusionsThe study shows how chemical agents can be used to improve the detected signal for a specific optical application. It could be useful in a number of optical therapeutic and diagnostic applications that can benefit from an increase in the penetration depth of light. Lasers Surg. Med. 29:213–220, 2001. © 2001 Wiley‐Liss, Inc.

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Group refractive index measurement of dry and hydrated type I collagen films using optical low-coherence reflectometry

Cited by 70 publications

References 25 publications

Noninvasive optical coherence tomography monitoring of structure and hydration changes of human corneas in different preservation media

Noninvasive optical coherence tomography monitoring of structure and hydration changes of human corneas in different preservation media

Depth-dependent refractive index of normal and early degenerated articular cartilage

Use of osmotically active agents to alter optical properties of tissue: Effects on the detected fluorescence signal measured through skin

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