Nanostructural and mechanical changes in the sclera following proteoglycan depletion

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Zhuola Z, Barrett S, Kharaz YA, Akhtar R. Nanostructural and mechanical changes in the sclera following proteoglycan depletion. MAIO [Internet]. 2018 Jun. 18 [cited 2024 May 22];2(2):14-7. Available from:

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collagen structure; proteoglycan depletion; scleral mechanical properties


The mechanical properties of ocular tissues, such as the sclera, have a major impact on healthy eye function, and are governed by the properties and composition of the microstructural components. For example, biomechanical degradation associated with myopia occurs alongside a reduction of proteoglycans (PGs). In this study, the role of PG degradation in the nanomechanical properties of the porcine sclera is explored. In-vitro enzymatic degradation of PGs was conducted with α-amylase and chondroitinase ABC enzymes. Collagen fibril morphology and nanomechanical stiffness were measured with atomic force microscopy (AFM). The elastic modulus of the tissue was reduced in all enzyme-treated samples relative to controls. In addition, collagen fibril organization was disrupted by PG depletion. Our data demonstrate that PGs play an important role in determining not only the mechanical properties at these length scales, but also collagen fibril arrangement.


Papi M, Paoletti P, Geraghty B, Akhtar R. Nanoscale characterization of the biomechanical properties of collagen fibrils in the sclera. Appl Phys Lett. 2014;104(10):103703.

Murienne BJ, Chen ML, Quigley HA, Nguyen TD. The contribution of glycosaminoglycans to the mechanical behaviour of the posterior human sclera. J R Soc Interface. 2016;13(119):20160367.

Trier K, Olsen EB, Ammitzbøll T. Regional glycosaminoglycans composition of the human sclera. Acta Ophthalmol. 1990;68(3):304-306.