Design of an electrospun tubular construct combining a mechanical and biological approach to improve tendon repair

Dipyridamole-grafted copolymer electrospun nanofiber membranes for suppression of peritendinous adhesions

Post-traumatic tendon adhesions significantly affect patient prognosis and quality of life, primarily stemming from the absence of effective preventive and curative measures in clinical practice. Current treatment modalities, including surgical excision and non-steroidal anti-inflammatory drugs, frequently exhibit limited efficacy or result in severe side effects. Consequently, the use of anti-adhesive barriers for drug delivery and implantation at the injury site to address peritendinous adhesion (PA) has attracted considerable attention. Electrospun nanofiber membranes (ENMs) have been extensively employed as drug-delivery platforms. In this study, we fabricated a polylactic acid (PLA)-dipyridamole (DP)-graft copolymer ENM called PLC-DP. This membrane exhibits enzyme-sensitive features, allowing more controlled and sustained drug release compared with conventional drug-loaded ENMs. In experiments, PLC-DP implantation reduced tissue adhesion by 47 % relative to the control group while not adversely affecting tendon healing. Mechanistically, PLC-DP effectively activates the FXYD domain containing ion-transport regulator 2 (FXYD2) protein, thereby downregulating the fibroblast-transforming growth factor beta (TGF-β)/Smad3 signaling pathway. PLC-DP leverages the anti-adhesive properties of DP and the enzyme-sensitive characteristics of graft copolymers, providing a promising approach for the future clinical treatment and prevention of PA. STATEMENT OF SIGNIFICANCE: Peritendinous adhesions (PA) are a common and disabling condition that seriously affects the prognosis and quality of life of post-trauma patients. Current treatments often have limited efficacy or severe side effects, leaving a serious gap in clinical practice. We developed a significant biomaterial, poly(lactic acid)-dipyridamole graft copolymer electrospun nanofibrous membrane (PLC-DP), specifically for PA inhibition. In addition, this study uniquely combines dipyridamole, an anti-adhesive agent, and enzyme-sensitive copolymers in electrospun nanofibrous membrane. Unlike conventional drug-loaded electrospun nanofibrous membranes, PLC-DPs have enzyme-sensitive drug properties that allow for sustained drug release on demand. Our experiments showed that implantation of PLC-DP was effective in reducing tissue adhesions by 47 % without affecting tendon healing. We elucidated the mechanism behind this phenomenon, suggesting that PCD activates FXYD2 to inhibit TGF-β-induced expression of Col III, which is a key factor in PA development.

Biodegradable Polymer Electrospinning for Tendon Repairment

With the degradation after aging and the destruction of high-intensity exercise, the frequency of tendon injury is also increasing, which will lead to serious pain and disability. Due to the structural specificity of the tendon tissue, the traditional treatment of tendon injury repair has certain limitations. Biodegradable polymer electrospinning technology with good biocompatibility and degradability can effectively repair tendons, and its mechanical properties can be achieved by adjusting the fiber diameter and fiber spacing. Here, this review first briefly introduces the structure and function of the tendon and the repair process after injury. Then, different kinds of biodegradable natural polymers for tendon repair are summarized. Then, the advantages and disadvantages of three-dimensional (3D) electrospun products in tendon repair and regeneration are summarized, as well as the optimization of electrospun fiber scaffolds with different bioactive materials and the latest application in tendon regeneration engineering. Bioactive molecules can optimize the structure of these products and improve their repair performance. Importantly, we discuss the application of the 3D electrospinning scaffold's superior structure in different stages of tendon repair. Meanwhile, the combination of other advanced technologies has greater potential in tendon repair. Finally, the relevant patents of biodegradable electrospun scaffolds for repairing damaged tendons, as well as their clinical applications, problems in current development, and future directions are summarized. In general, the use of biodegradable electrospun fibers for tendon repair is a promising and exciting research field, but further research is needed to fully understand its potential and optimize its application in tissue engineering.

Functional biomaterials for tendon/ligament repair and regeneration

With an increase in life expectancy and the popularity of high-intensity exercise, the frequency of tendon and ligament injuries has also increased. Owing to the specificity of its tissue, the rapid restoration of injured tendons and ligaments is challenging for treatment. This review summarizes the latest progress in cells, biomaterials, active molecules and construction technology in treating tendon/ligament injuries. The characteristics of supports made of different materials and the development and application of different manufacturing methods are discussed. The development of natural polymers, synthetic polymers and composite materials has boosted the use of scaffolds. In addition, the development of electrospinning and hydrogel technology has diversified the production and treatment of materials. First, this article briefly introduces the structure, function and biological characteristics of tendons/ligaments. Then, it summarizes the advantages and disadvantages of different materials, such as natural polymer scaffolds, synthetic polymer scaffolds, composite scaffolds and extracellular matrix (ECM)-derived biological scaffolds, in the application of tendon/ligament regeneration. We then discuss the latest applications of electrospun fiber scaffolds and hydrogels in regeneration engineering. Finally, we discuss the current problems and future directions in the development of biomaterials for restoring damaged tendons and ligaments.