Structural characterization of silk-polyurethane composite material for biomaterials using solid-state NMR

In this paper, we performed solid-state nuclear magnetic resonance (NMR) measurements, including T1 H and T1q, of silk fibroin (SF)/polyurethane (PU) composites to examine their possible use as a material for artificial vascular grafts. In the development of new artificial vascular grafts made from SF/PU, it is important to examine the miscibility of the composites and their molecular dynamics, because these properties are intimately involved in the resulting physical properties of the resulting vascular graft. The T1 H measurements showed that the domain size of the SF/PU1⁄41:1 composite is smaller than the domain size of the 1:10 and 1:2 composites, indicating that the molecular miscibility between SF and PU are partially in close proximity, particularly in the SF/PU1⁄41:1 composite. Additionally, we observed that the molecular motion of the soft segment of PU in the SF/PU composites becomes slow, suggesting that the soft segment of PU interacts with SF to some extent. These analyses provided basic structural information for the development of silk-based artificial vascular grafts using PU. Polymer Journal (2012) 44, 802–807; doi:10.1038/pj.2012.119; published online 13 June 2012