Innovative Tough Gel Sheathed Sutures

Sutures are among the simplest and most widely used devices in clinical medicine. However, their performance is limited by the mechanical mismatch with tissues and the lack of advanced functionality. In a recent study, scientists have developed innovative tough gel sheathed (TGS) sutures inspired by the human tendon. The research has been published in the journal Science Advances on April 07, 2021.

Sutures are a class of fiber-based devices primarily to mechanically approximate tissues or attach wearable/implantable devices to the human body. However, the performance of existing sutures has been limited by their poor biomechanical properties and lack of functionality, which are implicated in surgical and postsurgical complications. Therefore, researchers of the McGill University, Canada developed tendon endotenon sheath and reported a versatile strategy to functionalize fiber-based devices such as sutures.

The authors wrote, "This strategy seamlessly unites surgical sutures, tough gel sheath, and various functional materials." These next-generation sutures contain a slippery yet tough gel envelop, imitating the structure of soft connective tissues.

Highlights of the study were:

• The researchers demonstrated robust modification with strong interfacial adhesion (>2000 J m⁻²) of TGS.
• They noted that the surface stiffness, friction, and drag of the suture when interfacing with tissues can be markedly reduced, without compromising the tensile strength.
• Upon evaluation, the researchers found that TGS sutures provide nearly frictionless gel surface mitigated the damage typically caused by traditional sutures.
• Upon in vivo implantation studies of TGS sutures, the researchers observed minimal inflammation reactions, while pristine sutures elicit more severe foreign body response.
• They also noted that the hydrated surface of TGS is inherently antifouling, evidenced by lowering the bacteria adhesion for both Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacteria.
• They further demonstrated the drug delivery capacity of the TGS to improve the therapeutic function of surgical sutures for advanced wound management. They reported, "TGS can encapsulate and release small-molecule antimicrobial compounds and protein model drugs to the wound site for infection prevention and tissue repair."

TGS sutures are expected to be particularly beneficial for rejoining and reattaching mechanically active musculoskeletal tissues such as tendon. The researchers noted that compared with native tendon tissues, TGS sutures demonstrated much higher tensile strength yet lowered stretchability.

The authors concluded, "The facile generation of TGS suggested an extensive design flexibility for other fiber-based devices such as textiles and fabrics. This platform is an important step toward integration of hydrogel technologies, functional materials, and fiber-based devices to develop next-generation multifunctional materials. This work would open new avenues for the development of surgical tools, wearable and implantable devices, soft robotics, and fiber and textile materials."

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