In vitro biodegradation of e-spun mesh based on supramolecular UPy chemistry

Abstract

Event Abstract Back to Event In vitro biodegradation of e-spun mesh based on supramolecular UPy chemistry Wiktoria Mozalewska1, Agnieszka Adamus1, Monica Ramos Gallego2, Jakob Vange2, Anton W. Bossman3, Tristan Mes3 and Radoslaw Wach1 1 Lodz University of Technology, Institute of Applied Radiation Chemistry, Poland 2 Coloplast A/S, Denmark 3 SupraPolix BV, Netherlands Introduction: The general goal of the research is to develop a medical implant, mesh for treatment of pelvic organ prolapse (POP) and stress urinary incontinence (SUI). Implant designed for this purpose should be easily fine-tuned in terms of bioactivity and should fulfill essential requirements such as mechanical and chemical stability in physiological environment during treatment and then gradually degrade when the natural tissue regenerate and replaces implant [1]. An innovative, polymer-based matrix that meets these criteria may be a supramolecular material comprising polyesters modified with ureido-pyrimidinone (UPy) moieties [2]. In the current study biodegradation of supramolecular polymer matrix of UPy-poly(ε-caprolactone) was evaluated, as well as mechanical and chemical stability towards sterilization with electron beam (EB) irradiation. Materials and Methods: The mesh of low molecular weight aliphatic polyesters based on modified with quadrupole hydrogen bonding UPy moieties PCL was manufactured by e-spinning technique, sterilized sterilization by electron beam irradiation (25 kGy) and subjected to biodegradation in vitro conducted in 3 media: PBS, lipase and hydrogen peroxide solutions. Tensile properties were examined and these results were complemented by measurements of mass loss, contact angle, morphology (SEM), molecular weight of polymer (GPC) and its thermal properties (DSC). Results and conclusions: There were no consequences of irradiation in terms of tensile performance and other physical-chemical properties. Sterile meshes were subjected to biodegradation. UPy-PCL mesh, similarly to regular PCL mesh degrades gradually in PBS solution. Through 18 months of hydrolytic degradation. despite no mass loss the UPy-PCL mesh stress and strain values decreased from 10 MPa to 3.5 MPa and from 360% to 25%, respectively. The Young modulus (YM) increased slightly throughout the 18 months of degradation, as same as the YM of PCL samples. The stress of regular PCL mesh decreased ca. 50% from 18 MPa and the strain reduced significantly from ca. 800 to 200 after 18 months degradation. Oxidative environment resulted in significant degradation of the PCL-UPy mesh. Young modulus was constant till 4 days but, similarly to stress and strain values which were reducing progressively, after 7 days material was too weak to be tested. Samples after 14 days of degradation were partially disintegrated – about 30% of mass loss and significant surface change were observed. PCL-mesh degraded much slower in H2O2 than UPy-PCL, 14 weeks. Enzymatic environment affects regular PCL more than UPy-PCL. Only minor reduction in values of tensile parameters of UPy-PCL mesh, ca. 10-15% were observed up to 6 weeks of enzymatic degradation. Afterwards the changes became more pronounced. Contrary, the PCL-mesh reduced tensile strength quickly, stress and strain decreased to about 25 and 10% of their initial values, respectively within 48 hours. PCL mesh reduced its mass in lipase solution c.a. 35% within 48h. The samples of UPy-PCL-mesh are quickly degrading in oxidative environment, much slower in lipase and they preserve their properties at acceptable level after incubation in PBS solution for 12 months. PCL-mesh is also stable in PBS solution but, unlike UPy-PCL, it degrades instantly in lipase and remains intact much longer in hydrogen peroxide solution. PCL is more susceptible to enzymatic degradation due to different microstructure of chain. UPy hard blocks in the UPy-PCL backbone has stabilizing effect, therefore the ester bonds are less accessible to lipase enzymatic activity. UPy-PCL materials are more prone to oxidative degradation than PCL because the urethane groups in ureido-pirimidinone and ether groups in PCL-diols, which are the part of UPy-PCL supramolecular materials, are susceptible to oxidative solution [3]. Ester groups of regular PCL seem to be less sensitive to oxidative degradation. Obtained results gave an overview on the degradation factors affecting supramolecular UPy-modified PCL, and will be further validated in vivo. This work has been partially financed by the European Commission within FP7 project ‘BIP-UPy’ NMP-2012-LARGE-6 310389