Mechanical properties of anterior lens capsule assessed with AFM and nanoindenter in relation to human aging, pseudoexfoliation syndrome, and trypan blue staining

Efremov, Yuri M.; Bakhchieva, N.A.; Shavkuta, Boris; Frolova, Anastasia; Kotova, Svetlana; Ia, Novikov; Акованцева, А. А.; Аветисов, К С; Аветисов, С Э; Timashev, Peter

doi:10.1016/j.jmbbm.2020.104081

Cited by 11 publications

(3 citation statements)

References 38 publications

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“…The silicone rubber for the artificial capsule was selected with a stiffness equivalent to a modulus (of 0.5 MPa), close to the lowest limit of human capsule under uniaxial tension. Different values beyond this range have been reported with higher values (of 2.0 to 8.0 MPa) and lower values (of 0.03 to 0.3 MPa) [2,40]. Although the liner-elastic model provided similar results to the hyperelastic model for the inflation test of capsule [37,38], there was a large disparity with the modelling of uniaxial tension [41].…”

Section: Discussionmentioning

confidence: 87%

Characterisation and Modelling of an Artificial Lens Capsule Mimicking Accommodation of Human Eyes

Wei

Wolffsohn

Oliveira³

et al. 2021

Polymers

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A synthetic material of silicone rubber was used to construct an artificial lens capsule (ALC) in order to replicate the biomechanical behaviour of human lens capsule. The silicone rubber was characterised by monotonic and cyclic mechanical tests to reveal its hyper-elastic behaviour under uniaxial tension and simple shear as well as the rate independence. A hyper-elastic constitutive model was calibrated by the testing data and incorporated into finite element analysis (FEA). An experimental setup to simulate eye focusing (accommodation) of ALC was performed to validate the FEA model by evaluating the shape change and reaction force. The characterisation and modelling approach provided an insight into the intrinsic behaviour of materials, addressing the inflating pressure and effective stretch of ALC under the focusing process. The proposed methodology offers a virtual testing environment mimicking human capsules for the variability of dimension and stiffness, which will facilitate the verification of new ophthalmic prototype such as accommodating intraocular lenses (AIOLs).

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Section: Discussionmentioning

confidence: 87%

Characterisation and Modelling of an Artificial Lens Capsule Mimicking Accommodation of Human Eyes

Wei

Wolffsohn

Oliveira³

et al. 2021

Polymers

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“…The mechanical properties of the samples' surface were studied in fluid (distilled water) at room temperature (25 • C), after 20 min of hydration, using an atomic force microscope (BioScope Resolve, Bruker, Billerica, MA, USA). The sample micromechanics was obtained in the regime of nanoindentation over a preset map of 50 × 50 µm with the 32 × 32 pixels resolution, as described in [84]. A ScanAsyst Fluid cantilever (Bruker, Billerica, MA, USA) with a nominal spring constant of 0.95 N/m and a nominal tip radius of 50 nm was precalibrated using a standard titanium sample.…”

Section: Micromechanics By Afmmentioning

confidence: 99%

A Collagen Basketweave from the Giant Squid Mantle as a Robust Scaffold for Tissue Engineering

et al. 2021

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The growing applications of tissue engineering technologies warrant the search and development of biocompatible materials with an appropriate strength and elastic moduli. Here, we have extensively studied a collagenous membrane (GSCM) separated from the mantle of the Giant squid Dosidicus Gigas in order to test its potential applicability in regenerative medicine. To establish the composition and structure of the studied material, we analyzed the GSCM by a variety of techniques, including amino acid analysis, SDS-PAGE, and FTIR. It has been shown that collagen is a main component of the GSCM. The morphology study by different microscopic techniques from nano- to microscale revealed a peculiar packing of collagen fibers forming laminae oriented at 60–90 degrees in respect to each other, which, in turn, formed layers with the thickness of several microns (a basketweave motif). The macro- and micromechanical studies showed high values of the Young’s modulus and tensile strength. No significant cytotoxicity of the studied material was found by the cytotoxicity assay. Thus, the GSCM consists of a reinforced collagen network, has high mechanical characteristics, and is non-toxic, which makes it a good candidate for the creation of a scaffold material for tissue engineering.

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“…1 – 3 Moreover, poor capsular visualization increases the risk of complications at this surgical step, including radial capsular tears, vitreous loss, or dislocation of the intraocular lens. 2 Therefore one of the most important innovations over the past years has been the use of vital dyes to enhance anterior capsule visualization. 4 …”

Section: Introductionmentioning

confidence: 99%

Ex-Vivo Method to Quantifiably Evaluate the Staining Effectiveness of Anterior Lens Capsule Dyes

Fernandez-Bueno

Pastor

Andrés-Iglesias

2021

Trans. Vis. Sci. Tech.

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Purpose High frequency of cataracts and the requirements of new European Union regulations for medical devices require the availability of preclinical models to adequately evaluate anterior lens capsule dyes before their use in patients. Herein, we describe an ex vivo method to quantifiably evaluate the macroscopic and microscopic staining effectiveness of anterior lens capsule dyes using porcine eyes. Methods Commercially available trypan blue–based products or physiological saline solution (negative control) was injected into porcine eyes. Anterior pole and lens (after extraction) were macroscopically photographed, and the images were quantitatively analyzed. Lenses were histologically processed, and the staining intensity microscopically was semiquantified. Results Macroscopic evaluation of the anterior pole revealed bluish staining of the anterior capsule; however, this coloring cannot be macroscopically discerned after lens extraction. Quantitative image analyses showed significant ( P < 0.01) staining of the lens capsule compared to the negative control, but not significant ( P > 0.05) between the products tested. Quantitative analysis of dying on lens images could not be performed. Microscopic semiquantification of the capsule staining intensity allows us to appreciate differences between products. Conclusions The described method is a quick and useful tool for macroscopic evaluation by surgeons to choose an anterior capsule staining for use during everyday surgeries, and a more specific microscopic evaluation also allows us to determine the effectiveness and usefulness of these products. Translational Relevance This method satisfies preclinical effectiveness evaluations required by European Union regulations and complements the safety and toxicity evaluations that new products must guarantee before they enter the market and are used in clinical practice.

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Mechanical properties of anterior lens capsule assessed with AFM and nanoindenter in relation to human aging, pseudoexfoliation syndrome, and trypan blue staining

Cited by 11 publications

References 38 publications

Characterisation and Modelling of an Artificial Lens Capsule Mimicking Accommodation of Human Eyes

Characterisation and Modelling of an Artificial Lens Capsule Mimicking Accommodation of Human Eyes

A Collagen Basketweave from the Giant Squid Mantle as a Robust Scaffold for Tissue Engineering

Ex-Vivo Method to Quantifiably Evaluate the Staining Effectiveness of Anterior Lens Capsule Dyes

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