Researchers at the Terasaki Institute for Biomedical Innovation in Los Angeles have developed a gelatin-based surgical sealant. The sealant is thermoresponsive, meaning that it will rapidly form a semi-solid bolus when it reaches body temperature. It is also bioadhesive, adhering to slippery, wet surfaces in the body with relative ease. The researchers achieved this by incorporating caffeic acid, a substance that is naturally found in coffee and olive oil, into the gelatin gel, which helped to increase the adhesive strength of the formulation.
Sealing incisions within the body can be challenging. The slippery surfaces of our internal tissues are not amenable to ease of handling, and also repel many sealants that would work in more hospitable conditions. Moreover, many of our tissues move constantly, such as the lungs, making it difficult to seal incisions to accommodate this movement while also maintaining a seal. Traditional sutures and staples can take time to insert properly, and can cause tears or blood loss.
To overcome these issues, researchers have been developing new surgical sealants that can rapidly seal incisions within the body, even in challenging tissues such as the heart or lungs. As these substances must be biodegradable and biocompatible, many such technologies rely on naturally occurring materials, such as gelatin, which derives from animal collagen.
The problem with previous gelatin-based wound dressings and sealants was a lack of adhesion and strength because the material was brittle. One way to improve this is to add catechol, a naturally occurring molecule which binds to sites in the gelatin and improves its binding ability in the body. However, this was limited by the small number of binding sites for catechol in gelatin materials. Increasing the amount of catechol in the material could improve its adhesion.
To address this, the Terasaki Institute researchers turned to caffeic acid, which is more commonly found in coffee. This compound contains catechol, and when oxidized it forms caffeic acid oligomers which include repeating catechol units. The resulting gelatin/caffeic acid material demonstrates improved bioadhesion, gelation, injectability, and strength.
So far, the sealant has demonstrated impressive effectiveness, including being able to seal a hole in lungs that are actively being inflated. “Our team has utilized manipulative and strategic chemistry to significantly improve adhesive strength and versatility in biomaterials,” said Ali Khademhosseini, a researcher involved in the project. “This creates exciting possibilities for more effective surgical wound management in the clinic.”
Study in Cell Reports Physical Science: Injectable gelatin-oligo-catechol conjugates for tough thermosensitive bioadhesion
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