High-Strength Fiber-Reinforced Composite Hydrogel Scaffolds as Biosynthetic Tendon Graft Material

Abstract

The development of suitable synthetic scaffolds for use as human tendon grafts to repair tendon ruptures remains a significant engineering challenge. Previous synthetic tendon grafts have demonstrated suboptimal tissue ingrowth and synovitis due to wear particles from fiber-to-fiber abrasion. In this study, we present a novel fiber-reinforced hydrogel (FRH) that mimics the hierarchical structure of the native human tendon for synthetic tendon graft material. Ultrahigh molecular weight polyethylene (UHMWPE) fibers were impregnated with either biosynthetic polyvinyl alcohol/gelatin hydrogel (FRH-PG) or with polyvinyl alcohol/gelatin + strontium-hardystonite (Sr-Ca2ZnSi2O7, Sr-HT) composite hydrogel (FRH-PGS). The scaffolds were fabricated and assessed to evaluate their suitability for tendon graft applications. The microstructure of both FRH-PG and FRH-PGS showed successful impregnation of the hydrogel component, and the tendon scaffolds exhibited equilibrium water content of ∼70 wt %, similar to the values reported for native human tendon, compared to ∼50 wt % water content retained in unmodified UHMWPE fibers. The tensile strength of FRH-PG and FRH-PGS (77.0–81.8 MPa) matched the range of human Achilles’ tendon tensile strengths reported in the literature. In vitro culture of rat tendon stem cells showed cell and tissue infiltration into both FRH-PG and FRH-PGS after 2 weeks, and the presence of Sr-HT ceramic particles influenced the expression of tenogenic markers. On the other hand, FRH-PG supported the proliferation of murine C2C12 myoblasts, whereas FRH-PGS seemingly did not support it under static culture conditions. In vivo implantation of FRH-PG and FRH-PGS scaffolds into full-thickness rat patellar tendon defects showed good collagenous tissue ingrowth into these scaffolds after 6 weeks. This study demonstrates the potential viability for our FRH-PG and FRH-PGS scaffolds to be used for off-the-shelf biosynthetic tendon graft material.

Porous Ultrahigh Molecular Weight Polyethylene/Functionalized Activated Nanocarbon Composites with Improved Biocompatibility

“…The latest technologies in the field of joint replacement include bone integration of artificial joints, improvements in bone replacement materials, implants, and rehabilitation devices, and joint replacement technology based on dynamic bone synthesis models [ 5 , 6 ]. New bone materials, such as PVA-H [ 7 , 8 , 9 ] and UHMWPE, with a high modulus of elasticity, biocompatibility, and mechanical properties, were studied systematically and in depth [ 10 , 11 , 12 ]. Ultra-high molecular weight polyethylene (UHMWPE) is the most common material used for the artificial joint bearing component, with the advantage of unique characteristics and favorable properties, such as biocompatibility, chemical stability, high wear resistance, and low friction [ 10 , 11 , 12 , 13 , 14 ].…”

Nano-calcium silicate mineralized fish scale scaffolds for enhancing tendon-bone healing

“…Tensile stress-strain curves (D) and Strain at failure (E) of O-FS and each CS-FS scaffold. (F) Ashby diagram of toughness and young's modulus for reported tendon tissue engineering scaffolds [ [63] , [64] , [65] , [66] , [67] , [68] , [69] , [70] , [71] , [72] , [73] , [74] ]. This indicates that the mechanical strength of CS-FS scaffolds with a certain amount of mineralization is completely suitable for tendon repair.…”

Mechanical reinforcement of granular hydrogels

“…For example, different chemicals can be infiltrated into microgels to control the local composition of granular hydrogels on a micrometer length scale. The requirements imposed on hydrogels used as tissue replacements are fundamentally different: these hydrogels should be tough and strong 14 yet resilient 28 to match the tissue mechanics of targeted natural tissues such as tendons 29,30 or cartilage. 31 Typically, tough and strong hydrogels are achieved by a double network architecture.…”