How New Thermosensitive Bioadhesives Improve Surgical Sealing Applications
A team of scientists from the Terasaki Institute for Biomedical Innovation (TIBI) in California has developed an injectable biomaterial with reportedly improved adhesive strength, stretchability and toughness.
According to researchers, the gelatin-based hydrogel demonstrated rapid gelation at room temperature and tunable levels of adhesion. Due to its controlled adhesion, injectability and adherence to assorted tissues and organ surfaces, the biomaterial is considered an ideal surgical wound sealant.
Making this sealing solution ideal is its reported ability to offer closure for surgical wounds, effectively sealing wounds on wet and slippery tissue surfaces of various shapes. Likewise, the adhesives work on sites that encounter tissue movement — for instance, on an expanding lung — or crumbly textures.
However, commercial gelatin-based wound dressings tend to lack adhesive strength due to brittleness. Earlier attempts to handle the issue of poor adhesion were made using functionalization with catechol, a naturally occurring compound that imparts adhesive properties when bound to gelatin. However, the few available binding sites on the gelatin results in minimal adhesion enabled by catechol functionalization.
To overcome commercial gelatin-based wound dressing shortcomings in the area of adhesion, the researchers employed caffeic acid (CA) — a catechol-containing compound in coffee and olive oil — to increase the tissue adhesion capabilities of gelatin. The team oxidized CA to produce CA oligomers (CAO), which feature repeating catechol units. By combining the CA derivatives to gelatin, the researchers determined that the chemical binding of catechol groups was amplified, and their adhesive function boosted.
In the lab, the engineered bioadhesive sealant demonstrated superior adhesive strength, stretchiness, toughness and injectability as well as rapid gelation. Additionally, the sealants can reportedly adhere to tissue in a selective manner.
Further, the team performed experiments in the lab, using the sealant on pig lung, heart and bladder wounds and demonstrated that the adhesive strength of the bioadhesive was an order of magnitude higher than commercial gelatin-based sealants, is biocompatible, possesses drug loading and drug release capabilities and promotes antioxidant effects that encourage wound healing.
The study, "Injectable gelatin-oligo-catechol conjugates for tough thermosensitive bioadhesion," appears in the journal Cell Reports Physical Science.