Super-strong Hydrogel Composites Reinforced with PBO Nanofibers for Cartilage Replacement.

Cartilage replacement materials exhibiting a set of demanding properties such as high water content, high mechanical stiffness, low friction, and excellent biocompatibility are quite difficult to achieve. Here, poly(p-phenylene-2,6-benzobisoxazole) (PBO) nanofibers were combined with polyvinyl alcohol (PVA) to form a super-strong structure with a performance that surpasses the vast majority of previously existing hydrogels. PVA-PBO composites with water contents in the 59-76% range exhibited tensile and compressive moduli reaching 20.3 and 4.5 MPa, respectively, and a coefficient of friction below 0.08. Further, they were biocompatible and supported the viability of chondrocytes for one week, with significant improvements in cell adhesion, proliferation and differentiation compared to PVA. The new composites could be safely sterilized by steam heat or gamma radiation without compromising their integrity and overall performance. In addition, they showed potential to be used as delivery platforms of anti-inflammatory drugs at the local level. These attractive features make PVA-PBO composites highly competitive engineered materials with remarkable potential for use in the design of load-bearing tissues. Complementary work has also revealed that these composites will be interesting alternatives in other industrial fields where high thermal and mechanical resistance are essential requirements, or which can take advantage of the pH responsiveness functionality. This article is protected by copyright. All rights reserved.