Starch-based materials have attracted significant interest for the development of innovative materials for biomedical applications due to its biocompatibility and bioresorbability. Moreover, biopolymers based devices are very well accepted by patients. Thanks to starch thermoplastic behaviour, 3D objects can be easily fabricated by use of process such as extrusion, thermomoulding or injection. In this study, starch-based materials were designed using a special extrusion die in order to concieve a tube-shaped device for an application in the endoscopic field of <i>saliendoscopy</i> devoted to the treatment of salivary ducts disease. For the site of application considered, starch is naturally degraded by the a-amylase enzyme present in saliva, guaranteeing the device disapearence and making it a potential interest in short-term sialendoscopic uses. In this work, the ageing of the starch material plasticized by glycerol has been assessed by the study of its structure, swelling and mechanical properties immersed in physiological medium. They present a high initial rigidity which facilitates the device insertion, with a Young’s modulus of 2 GPa and decreases to about 2 MPa during immersion. In order to predict the mechanical behaviour of the tube once implanted, a finite element study was performed using intrinsic mechanical properties determined for the immersed material. It simulates an external axial pressure, showing a symmetrical distribution of strain in the inner diameter as well as a longitudinal tube extension. It allows the determination of a maximum axial allowable pressure of 0.2 MPa before irreversible damage. The hydrolysis of the starch tube exposed under flow of a simulated salivary solution was studied as well as its glycerol kinetics release. After 2 days, about 55% hydrolysis of the initial material is achieved. Following physical characterization, an animal short-term implantation model for salivary ducts was proposed. Results showed that the tube-shaped devices is adapted to sialendoscopic guidewires and were able to be implanted in salivary ducts from pigs.

Design, fabrication and test of degradable starch based tube for a biomedical application

253rd National Meeting (2017)

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