Related Experiment Video
Updated: Jun 16, 2026
Preparation and Immunofluorescence Staining of Bundles and Single Fiber Cells from the Cortex and Nucleus of the Eye Lens
Published on: June 9, 2023
Small-angle X-ray scattering studies of the intact eye lens: effect of crystallin composition and concentration on
Amir Y Mirarefi1, Sébastien Boutet, Subramanian Ramakrishnan
1Center for Biophysics and Computational Biology in the Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Background:
The cortex and nucleus of eye lenses are differentiated by both crystallin protein concentration and relative distribution of three major crystallins (alpha, beta, and gamma). Here, we explore the effects of composition and concentration of crystallins on the microstructure of the intact bovine lens (37 degrees C) along with several lenses from Antarctic fish (-2 degrees C) and subtropical bigeye tuna (18 degrees C).
Methods:
Our studies are based on small-angle X-ray scattering (SAXS) investigations of the intact lens slices where we study the effect of crystallin composition and concentration on microstructure.
Results:
We are able to distinguish the nuclear and cortical regions by the development of a characteristic peak in the intensity of scattered X-rays. For both the bovine and fish lenses, the peak corresponds to that expected for dense suspensions of alpha-crystallins.
Conclusions:
The absence of the scattering peak in the nucleus indicates that there is no characteristic wavelength for density fluctuations in the nucleus although there is liquid-like order in the packing of the different crystallins. The loss in peak is due to increased polydispersity in the sizes of the crystallins and due to the packing of the smaller gamma-crystallins in the void space of alpha-crystallins.
General Significance:
Our results provide an understanding for the low turbidity of the eye lens that is a mixture of different proteins. This will inform design of optically transparent suspensions that can be used in a number of applications (e.g., artificial liquid lenses) or to better understand human diseases pathologies such as cataract.
Related Concept Videos
02:18X-ray Crystallography
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
01:29Determination of Crystal Structures
01:10X-ray Diffraction of Biological Samples
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...