Fabrication of Organized Nanofibrous Scaffolds to Mimic the Macroscopic Curvature of the Meniscus: Structure and Mechanics

The menisci are crescent-shaped fibrocartilaginous tissues which function to transmit and distribute loads between the femur and tibia of the knee joint. As such, the meniscus experiences complex loads, including tension, compression, and shear. Meniscus function in tension arises from an organized microstructure — bundles of highly aligned collagen circumnavigate the tissue between insertion sites on the tibial plateau (1). These aligned collagen bundles endow the tissue with mechanical properties that are highly anisotropic, and highest in the primary collagen orientation (2). Commercial products to replace the meniscus lack this unique structure and organization (3,4). To address engineering the knee meniscus, we have developed aligned nanofibrous scaffolds that can recapitulate this mechanical anisotropy (5,6). However promising, fibers within these scaffolds are unidirectional, while the fibers within the native tissue have a pronounced c-shaped macroscopic organization. To mimic this macroscopic orientation, we developed a new electrospinning method to collect organized fibers on a planar spinning disc (7). The objective of this study was to quantify the structure and mechanics of nanofibrous scaffolds collected using this novel technique and compare the data to aligned scaffolds obtained from a traditional electrospinning approach. We hypothesized that these circumferentially aligned (CircAl) scaffolds would behave similarly to linearly aligned (LinAl) scaffolds on short length scales, but exhibit marked differences in mechanics as the length scale increased.