Sealing internal wounds in the body during surgery can be a challenge when dealing with sensitive or moving tissue in a wet environment. In these situations, it may be difficult to apply stitches without damaging the tissue or to use surgical glues without them being washed away. Gecko Biomedical has designed a synthetic bioinspired light-activated tissue adhesive that works as a surgical sealant. This adhesive has a thick consistency and is blood-resistant, making it easier to apply in challenging wet environments.
The surgical sealant is a hydrophobic light-activated adhesive (HLAA), which is a synthetic adhesive gel with polymer building blocks that link up when exposed to ultraviolet light. This elastic and transparent adhesive gel was inspired by sandcastle worm secretions. These marine worms secrete sticky protein-based glue granules that aggregate and set in 30 seconds in cold salt water. The worms use these glues to hold together building materials, such as sand, when making tube-like structures that encase their bodies and provide a home. Similarly, Gecko Biomedical has packaged the glue into injectable nanoparticles for delivery in minimally invasive surgeries. Once they are exposed to positively charged particles, the nanoparticles fuse into a functional glue. This glue then cures in five seconds when activated by UV light.
Existing surgical glues can sometimes have harmful side effects, may be easily washed out, and can take as long as 30 minutes to set. Gecko Biomedical’s adhesives are safe to use in the human body and harmlessly break down over time. The adhesive is also flexible, enabling it to conform to soft and moving tissues. This means they provide long-term support with no toxicity, friction, or inflammation. The technology platform may be customized for different applications in various target tissues (e.g. repairing wounds or attaching devices). Two applications of this platform are currently under research and development: GB02 Tissue Sealant for wounds (entering clinical trials in 2016) and GB04 Defect Closure, which is used to close tissue defects such as tears, for use with a patch on larger wounds. Future directions may look into using this platform for sustained and controlled release of active components such as drugs.
This inspired idea page was contributed by Leon Wang (Research Assistant, ASU Biomimicry Center).Edit Summary
“Delivery of tissue glues through small-bore needles or trocars is critical for sealing holes, affixing medical devices, or attaching tissues together during minimally invasive surgeries. Inspired by the granule-packaged glue delivery system of sandcastle worms, we have developed a nanoparticulate formulation of a viscous hydrophobic light-activated adhesive based on poly(glycerol sebacate)-acrylate… With the trigger of a positively charged polymer (e.g., protamine), the nanoparticulate glues can quickly assemble into a viscous glue that exhibits rheological, mechanical and adhesive properties resembling the native poly(glycerol sebacate)-acrylate based glues. This platform should be useful to enable the delivery of viscous glues to augment or replace sutures and staples during minimally invasive procedures.” (Lee 2015: 2587)
“Inspired by the granule-based controlled glue transportation/activation system of sandcastle worms, we demonstrate a strategy to formulate viscous glues into water-dispersible injectable glue nanoparticles that can be assembled into the native viscous glue state following injection and can be cured in response to on-demand external stimuli. As a model viscous water-insoluble glue, we used hydrophobic light-activating adhesive (HLAA). HLAA is a polymeric UV-activated adhesive based on water-insoluble poly(glycerol sebacate)-acrylate (PGSA) polymer. Previously we showed that the glue could be delivered on a patch to a challenging target site (e.g., inside a beating heart) without washout where blood generates significant shear stress. ” (Lee 2015: 2588-2589)