A Novel Approach for the Utilization of Biocellulose Nanofibres in Polyurethane Nanocomposites for Potential Applications in Bone Tissue Implants

With the increasing number of surgical bone grafts per year, the application of biomaterials in tissue engineering has become a popular issue. In the present work, the potential of biocellulose-nanofibre-reinforced polyurethane nanocomposites to act as bone scaffold implants is established. Investigating properties of polyurethane shows that this widely applied biomaterial group cannot fulfil all properties required for bone implants in a stand-alone fashion. Bone implants require a high Young's modulus and tensile strength but low strain which makes it difficult to find a suitable polyurethane since higher hard segment content will reduce tensile strength and lower hard segment content will reduce the Young's modulus. Other factors such as biodegradation also become important. A literature review on carbon nanotube and nanofibre composites with polyurethanes shows that nanofibrous reinforcement leads to favourable implant properties. Young's modulus and tensile strength increase dramatically. Other properties such as thermal conductivity and viscosity are also affected. These types of nanofibrous materials, however, are the subject of an ongoing debate about toxicity and their use in bone implants is questionable. Biocellulose nanofibres formed from bacteria (also called bacterial cellulose (BC)) possess favourable mechanical properties and are highly biocompatible. A survey on works done on BC nanofibres and their composites show that nanostructured biocomposites that contains the nanofibres reinforced in polymer composites result in changes that are comparable to those of carbon nanotubes in regards to bone scaffold applications. Showing improvement on biocompatibility and mechanical properties, biocellulose nanofibre reinforcement on polyurethanes possesses strong potential for bone implants and other tissue-engineering applications. (C) Koninklijke Brill NV, Leiden, 2012