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A Mitra, E Remsen, P Hamilton, N Ravi; Viscoelastic Properties Of The Porcine Beta-heavy Lens Crystallins Using Dynamic Light Scattering . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4653.
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Purpose: To better understand the pathophysiology of presbyopia and cataract formation, the viscoelastic properties of the components of the natural lens need to be evaluated. In this study, the viscoelastic properties of the porcine beta-heavy lens crystallins are determined using Dynamic Light Scattering (DLS). Methods: The relaxation time spectra of porcine beta-heavy lens crystallins was obtained using DLS (Temperature 27ºC, λ = 514.5nm, scattering angle 90º) by Laplace inversion of the time-averaged intensity autocorrelation function. The relaxation time peaks obtained using Exponential sampling, Non-Negative Least Squares (NNLS) method, regularization programs CONTIN and REPES were compared. Results: The overall relaxation time distribution obtained from comparison of the above methods was evaluated as a function of concentration. Using REPES, it was seen that as the beta-heavy lens crystallins concentration increases: (a) The number of slow diffusion modes increases and extends over longer range of delay times, (b) The relative amplitude of the fast mode decreases. The hydrodynamic radius was calculated using the Stokes-Einstein relation and solution viscosity. Conclusion: With increasing beta-heavy lens crystallins concentration, the ratio of the relative amplitude of the fast or transient network mode to the slow modes decreases, indicating that cluster formation dominates the distribution at high concentrations. Comparison of the decay time spectrum obtained with DLS and mechanical measurements as well as angular dependence measurements are being investigated. Overall Relaxation Time Distribution as a function of Concentration View OriginalDownload SlideView OriginalDownload Slide
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