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Florian Küng, Dirk W. Schubert, Piotr Stafiej, Friedrich E Kruse, Thomas Armin Fuchsluger; Influence of the molecular weight on the suture retention properties of polycaprolactone. Invest. Ophthalmol. Vis. Sci. 2017;58(8):151.
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© ARVO (1962-2015); The Authors (2016-present)
To optimize our existing biodegradable polycaprolactone (PCL) matrix towards suturability. Biopolymers like PCL are common materials for soft tissue engineering. The length of the chain molecule and its morphology can be measured by the molecular weight. Altering the molecular weight of a certain material results in modified material properties. In ocular surface surgery, attaching e.g. an amniotic membrane graft by sutures requires a certain strength and elasticity of the graft material. Here, PCLs of different molecular masses were studied in respect to the suture retention properties in order to enhance tensile strength.
PCL films have been cast in petri dishes, chloroform serving as a solvent. Samples were manufactured by using PCL batches with different molecular weights (Mn = 80 kDa, Mn = 45 kDa and Mn = 14 kDa). 21 round samples (diameter = 14 mm) were prepared from each PCL film. A vicryl 4-0 suture was sutured through each sample in a distance of 1.0 mm to the sample edge. The respective suture retention properties were determined for the different groups using the retention test established by our group (presented at ARVO 2016). A constant force was applied towards the suture with a pull rate of 10 mm/min, hereupon measuring the suture retention Fs strength of each sample.
The suture retention strength Fs showed a dependency of the molecular weight: PCL (Mn = 80 kDa) resulted in a higher performance than PCL (Mn = 45 kDa) (0.028 N/μm vs. 0.010 N/μm, medians). Pure PCL (Mn = 14 kDa) was not measurable due to its low mechanical properties. Blending the both PCLs (Mn = 80 kDa and Mn = 45 kDa) lead to an increase of the suture retention strength of 0.032 N/μm (median) at a composition of 60/40 (80 kDa / 45 kDa). Nearly all measurable blends (to a composition of 50/50) of Mn = 80 kDa and PCL (Mn = 14 kDa) provided a retention strength of 0.028 ± 0.002 N/μm (median).
We successfully modified our existing PCL biomatrix towards suturability by using PCL molecules of higher molecular masses. Blending different batches of sufficient big molecular weight leads to a maximum in the composition range of 60/40 to 40/60 in a binary blend. Further studies have to performed to achieve suturability with thinner material (e.g. nylon 10.0).
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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