S4E10

Abstract

Sutures pervade surgeries, but their performance is limited by the mechanical mismatch with tissues and the lack of advanced functionality. Existing modification strategies result in either deterioration of suture’s bulk properties or a weak coating susceptible to rupture or delamination. Inspired by tendon endotenon sheath, we report a versatile strategy to functionalize fiber-based devices such as sutures. This strategy seamlessly unites surgical sutures, tough gel sheath, and various functional materials. Robust modification is demonstrated with strong interfacial adhesion. The surface stiffness, friction, and drag of the suture when interfacing with tissues can be markedly reduced, without compromising the tensile strength. Versatile functionalization of the suture for infection prevention, wound monitoring, drug delivery, and near-infrared imaging is then presented. This platform technology is applicable to other fiber-based devices and foreseen to affect broad technological areas ranging from wound management to smart textiles.

Introduction of speaker

Zhenwei Ma is currently a Ph.D. candidate working with Prof. Jianyu Li in the Department of Mechanical Engineering at McGill University, Montréal, Canada. His research interests focus on engineering biomaterials adhesion for regenerative medicine, biomedical device functionalization, mechanobiology, and tissue engineering. He received his M.E. and B.E. degrees in Chemical Engineering from McGill University and Sichuan University (Chengdu, China), respectively.

Abstract

Hydrogels that provide mechanical support and sustainably release therapeutics have been used to treat tendon injuries. However, most hydrogels are insufficiently tough, release drugs in bursts, and require cell infiltration or suturing to integrate with surrounding tissue. Here we report that a hydrogel serving as a high-capacity drug depot and combining a dissipative tough matrix on one side and a chitosan adhesive surface on the other side supports tendon gliding and strong adhesion (larger than 1,000 J m-2) to tendon on opposite surfaces of the hydrogel, as we show with porcine and human tendon preparations during cyclic-friction loadings. The hydrogel is biocompatible, strongly adheres to patellar, supraspinatus and Achilles tendons of live rats, boosted healing and reduced scar formation in a rat model of Achilles-tendon rupture, and sustainably released the corticosteroid triamcinolone acetonide in a rat model of patellar tendon injury, reducing inflammation, modulating chemokine secretion, recruiting tendon stem and progenitor cells, and promoting macrophage polarization to the M2 phenotype. Hydrogels with 'Janus' surfaces and sustained-drug-release functionality could be designed for a range of biomedical applications.

Introduction of speaker

Benjamin Freedman, Ph.D. is a K99 postdoctoral fellow in the John A. Paulson School of Engineering and Applied Sciences and Wyss Institute for Biologically Inspired Engineering at Harvard University in Cambridge, Massachusetts. Dr. Freedman received his Ph.D. in Bioengineering at the University of Pennsylvania where he studied the effects of tendon injury and mechanical loading on multiscale tendon properties under the mentorship of Dr. Louis Soslowsky. Dr. Freedman continued research in the field of aging, orthopaedics, and biomaterials as an F32 and K99 Postdoctoral Fellow at Harvard University.

Dr. Freedman’s current research focuses on the design and synthesis of biomaterials to improve the repair of biological tissues, with a special focus in aging and orthopaedics. These tough adhesive biomaterials are designed to provide an adhesive interface to anchor directly to tissue surfaces and control release of therapeutics to improve tendon healing. Biomaterials are also tuned to create niche environments to control tendon stem/progenitor cell homeostasis and delivery to augment tendon healing during aging.