The 11th Global Conference on Polymer and Composite Materials (PCM 2024)

Abstract: Degradable biomaterials have emerged as a viable alternative to permanent materials for regenerative bone medicine. Although Polycaprolactone (PCL) exhibits remarkable extensibility and toughness, its low elastic modulus and strength, hydrophobicity, and excessively slow degradation rate limit its application in orthopedics. Natural silk fibers with macroscopic continuity and highly ordered morphology are selected to reinforce PCL to satisfy the mechanical and biological requirements for bone grafts. In this talk, we discuss the design, fabrication, and bone graft application of fiber silk-PCL biocomposites.
Silk-PCL composites with 20%/40%/60% silk were fabricated via layer-by-layer assembly and hot-pressing, allowing facile incorporation of drugs. The fiber silk composites exhibited compatible modulus (1GPa) to the majority of bone tissues, high compressive strength (150MPa), high toughness, hydrophilicity, and water adsorption behavior. The 6-month in vitro degradation experiment showed that passive surface erosion and bulk hydrolysis of the silk-PCL composite by the aqueous environment is negligible, and the fiber-matrix interfaces remained robust. In the in vivo rat subcutaneous model, the degradation of silk composites is significantly accelerated via inflammatory cells mediated PCL dissolution from the surface. Fiber silks are proposed to modulate the inflammatory responses toward synchronized material degradation and tissue reconstruction. A rabbit tibial defect model shows a strong tissue-composite implant bonding, suggesting sufficient mechanical function and the regeneration of new bone.
The silk-PCL composites bring forward exceptional comprehensive mechanical performance and desirable degradation behavior in vivo through the coupled inflammatory modulation effects of silk and PCL. This work may herald the advent of a novel biomaterial for load-bearing bone repair.

Biography: Dr Juan Guan is a polymer scientist by training. She obtained her bachelor’s degree in polymer science and engineering from Tianjin University (one of China’s oldest and prestigious universities), then obtained a Master’s degree in macromolecular chemistry and physics from Fudan University, and then studied at the University of Oxford for Doctor of Philosophy (PhD). After obtaining her degree in 2013, she returned to China and joined Prof. Robert Ritchie’s lab at Beihang University in Beijing. Since 2014, she has been an Associate Professor at the School of Materials Science and Engineering of Beihang University. Her research interest focuses on the glass transition behaviour of biopolymers using silk proteins as a model material, design and fabrication of natural silk fibre reinforced composites and the toughening mechanisms in natural polymer based composite materials. She has published over 60 peer-reviewed journal articles in Nature Communications, Advanced Materials, Matter, Advanced Healthcare Materials, ACS Applied Materials & Interfaces, Acta Biomaterialia, Composites Part A and etc.