Scientists have developed an injectable gel that serves as a biodegradable adhesive for various kinds of soft tissue injury.
Soft tissue tears are a common injury, and it is difficult for surgeons to secure the tissue back together, since stitches often do more harm than good. According to Dominique Pioletti, the head of the Laboratory of Biomechanical Orthopedics at EPFL’s School of Engineering, such surgeries often don’t produce the best results because the tissue doesn’t properly heal.
Tears in tissue such as cartilage and the cornea, often fail to heal properly, and tissue repair strategies may be suboptimal. For example, loose pieces of cartilage are often excised for symptomatic relief, but the remaining cartilage in articulating joints is placed under greater burden and generates faster.
A long-standing goal for researchers around the world has been the development of an adhesive for soft tissue that can withstand the natural stresses and strains within the human body. Now, Pioletti’s group has come up with a novel family of injectable biomaterials that can adhere to various forms of soft tissue. Their gel-based bioadhesives, can be used in a variety of injury-treatment applications.
Like other hydrogels, this one has a high water content, 85%, and also has two key advantages: It is injectable anywhere in the human body, and it has high intrinsic adhesion without additional surface treatment. “What makes our hydrogel different is that it changes consistency while providing high adhesion to soft tissues,” said Peyman Karami, a postdoc at Pioletti’s lab who has developed the gel during his PhD. “It’s injected in a liquid form, but then sets when a light source is applied, enabling it to adhere to surrounding tissue.”
The hydrogel has an innovative design that allows its mechanical and adhesive properties to be tailored, making it an extremely versatile soft tissue glue that can be used throughout the human body.
To obtain these versatile properties in their hydrogel, the scientists took the base polymer and modified it with the compounds that play an important role in tissue adhesion. The first is known as Dopa and is derived from mussels. “Dopa is what lets mussels attach firmly to any kind of surface—organic or otherwise,” said Pioletti. The second is an amino acid that our bodies make naturally.
“The advantage of our hydrogel compounds is that, unlike some medical adhesives, they don’t interfere with the body’s chemical reactions, meaning our hydrogel is fully biocompatible,” said Karami.
The new hydrogel also possesses unique energy-dissipation characteristics that improve its adhesive capability. Karami added: “We had to achieve an adhesion mechanism for injectable hydrogels, through the resulting synergy between interfacial chemistry and hydrogel mechanical properties. The hydrogel is capable of dissipating the mechanical energy produced when the hydrogel deforms, so that it protects the interactions at the interface between the hydrogel and surrounding tissue.”
A further advantage of this hydrogel is that it can release drugs or cells to encourage tissue repair, which is especially beneficial for cartilage and other tissues that don’t regenerate on their own.
“Our in vitro tests showed that the hydrogel binds to many different kinds of tissue, including cartilage, meniscus, heart, liver, lung, kidney and cornea,” said Pioletti. “We’ve made a sort of universal hydrogel.”
The scientists have received a grant to research possible orthopedic applications of the gel, and hope to be able to release their innovation onto the market within the next five years.
Source: Medical Xpress
Journal information: An intrinsically‐adhesive family of injectable and photo‐curable hydrogels with functional physicochemical performance for regenerative medicine, Macromolecular Rapid Communications, DOI :10.100 2/marc.202000660
