Scientists have developed the first-ever hydrophobic (water-hating) fluid, which displaces body fluids surrounding an injury, allowing for near-instantaneous gelling, sealing and healing of injured tissue.
“Tissue adhesives that can perform in the presence of blood, water and other proteins in the body are the holy grail for instant wound closure and hemostasis, especially when time is critical in rescue operations and emergency responses,” said Mequanint, a Western chemical and biochemical engineering professor.
The new bio-glue, reported in Science Advances, and developed by University of Western Ontario biomaterials expert Kibret Mequanint, in partnership with Malcolm Xing from the University of Manitoba, has the capability to replace and revolutionise tissue adhesives (like fibrin glue) currently used in clinical settings, triage situations and mass casualty incidents.
“Fibrin glue, and the like, often fail to displace fluids around an injury,” said Mequanint. “This failure means (current tissue adhesives) never strongly adhere to the wound and often detach within the first hour or two.”
Tissue adhesive washout and detachment are major issues for medical practitioners and may prove fatal for patients, especially when the separation happens in vital organs like the lungs, liver and the heart. These organs – even when healthy – undergo frequent movement (contractions and relaxations) due to physiological needs, which cause additional strain on tissue adhesives.
Since the new bio-glue forms a strong bond with the adjacent tissue, it virtually eliminates detachment. In extensive preclinical studies, it was able to seal a punctured lung, heart, artery and even a fractured skull.
“This bio-glue is transformative in its deceptive simplicity,” said Mequanint. “There was no tissue reaction to it and the healing was fast.”
While its early days, this new discovery may mean an end to surgical sutures and staples made of plastic or stainless steel. The new bio-glue is designed using materials already approved by the US Food and Drug Administration (FDA) for other applications, which will potentially accelerate clinical translation and technology transfer opportunities.
“Underwater adhesion of materials is challenging since the boundary water cannot be displaced so that the adhesive can contact the underlying tissue. Many bio-adhesives actually absorb water instead of displacing it,” said Mequanint. “And that’s a problem with a lot of materials.”
For the new bio-glue, the primary material is silicone, which does not absorb the water from the tissue, so it sticks.
“Silicone forms a strong adhesion, so you don’t have to worry after the repair that it’s going to reopen and cause more problems beyond the initial injury,” said Mequanint.
Gelation of highly entangled hydrophobic macromolecular fluid for ultrastrong underwater in situ fast tissue adhesion
Yuqing Liu, Ge Guan, Yinghao, Li Ju Tan, Panke Cheng, Mingcan Yang, Bingyun Li, Quan Wang, Wen Zhong, Malcolm Xing, et al
Published in Science Advances on 20 May 2022
Although strong underwater bio-adhesion is important for many biomedical applications, designing adhesives to perform in the presence of body fluids proves to be a challenge. To address this, we propose an underwater and in situ applicable hydrophobic adhesive (UIHA) composed of polydimethylsiloxane, entangled macromolecular silicone fluid, and a reactive silane. The hydrophobic fluid displaced the boundary water, formed an in situ gel, bonded to tissues, and achieved exceptional underwater adhesion strength. Its underwater lap shear adhesion on porcine skin was significantly higher than that of cyanoacrylate and fibrin glues, demonstrating excellent water resistance. The burst pressure of UIHA on porcine skin was 10 times higher than that of fibrin glue. The cytocompatible UIHA successfully sealed ruptured arteries, skin, and lungs in rats, pigs, rabbits, and dogs. Together, the gelation of highly entangled hydrophobic macromolecular fluid provided a means to prepare underwater bioadhesives with strong bonding to tissues and excellent water resistance.