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Florian Küng, Piotr Stafiej, Dirk Wolfgang Schubert, Friedrich E Kruse, Thomas Armin Fuchsluger; Suture Retention Test as a novel Method for Scaffold Characterization in Ophthalmology. Invest. Ophthalmol. Vis. Sci. 2016;57(12):1262.
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© ARVO (1962-2015); The Authors (2016-present)
In order to attach a scaffold on a patient sutures are commonly used. The quantity describing the resistance of a scaffold against the pull-out of a suture is called ’suture retention strength’. This quantity is commonly tested for tubular cardial scaffolds. A novel approach to modify the testing procedure was performed in order to adjust the suture retention test for characterizing ophthalmological scaffolds.
Polycaprolactone (PCL) is dissolved in chloroform and cast into petri dishes in order to generate films by solution casting. The amount of PCL was varied in order to cast films of different thickness. The thickness of each film was measured in a circular pattern with a gauge. 21 round samples of a diameter of 14 mm were cut out of each film according to a circular pattern. The samples were sutured using a Vicryl Polyglactin 910 4-0 suture. The suture was tied to a loop. The loop was secured with a bolt and more than 50% of the sample was clamped in a tensile tester. Using a constant deformation rate, force was applied on the sample until the suture was pulled out. In order to generate benchmark data from a material currently applied in ophthalmology 20 samples of amniotic membrane were tested under the same conditions.
PCL films of 0.2 ± 0.02 g, 0.4 ± 0.02 g, 0.6 ± 0.02 g and 0.8 ± 0.02 g were cast. The thickness of the films was between 7 µm and 150 µm. Suture retention strength, elongation at the maximum force and the elongation at rapture were determined for each sample. The total mean of the PCL data of the suture retention strength is 1.85 ± 1.21 N while the mean of the elongation at maximum force is 4.09 ± 1.26 mm and the mean of the elongation rapture is 6.75 ± 1.54 mm. The amniotic membrane with a thickness of 51 ± 8 µm showed a suture retention strength of 0.20 ± 0.06 N at an elongation of 5.38 ± 1.51 mm and a total elongation of 6.95 ± 1.59 mm.
It is possible to measure samples on the scale of an ophthalmological scaffold in a suture retention test. The ’suture retention test’ is a reliable option to characterize the rigidity of scaffolds used in ophthalmology. By variation of input parameters first dependencies of the suture retention strength were revealed. Using the experimental data, a first comparison between the results of the amniotic membrane and PCL is accessible.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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