New research is deriving inspiration from nature to resolve some of the drawbacks of sutures and staples used for wound closures after surgeries. The latest surgical glue technology may prove to be a promising replacement for sutures.
Millions of surgeries and traumatic wound closures are performed worldwide each year. Most of these wounds are closed using mechanical methods such as sutures and staples. These methods have several disadvantages for patients such as discomfort, a risk of infection, and possible damage to the surrounding tissue. In recent years, surgical adhesives have been used for sealing wounds, but most of these adhesives do not work well in moist areas. Also, it is challenging to make medical adhesives that are nontoxic and biocompatible.
To design better surgical adhesive alternatives, researchers are looking at examples of adhesives that exist in nature. For instance, snails, slugs, sandcastle worms, and mussels can glue themselves to wet surfaces. The sticky goo that a Dusky Arion slug excretes from its skin when it feels threatened inspired a team of scientists to engineer a new adhesive material that combines the ingredients similar to those in slug slime with a flexible gel.
The clinical implications of this basic research recently published in The New England Journal of Medicine reported the work done by American researchers Li and colleagues. Â The scientists have been successful in creating a surgical glue that is stretchable, works on wet surfaces, and is nontoxic to humans. The synthetic glue they engineered achieves adhesion using electrostatic attraction, chemical bonding, and physical interpenetration. The researchers used animal models to show that this surgical glue strongly adheres to the skin, cartilage, and arteries. It also sealed holes in rat liver and pig heart.
The mechanism of action of the surgical glue is inspired by the slug slime. The researchers created surgical glue that consists of positively charged bridging polymers that react with the negative charge on cells and tissues on one side and a hydrogel with a net negative charge on the other side. The glue material can form a chemical bond with the tissue as well as physically attach to it by intertwining surface proteins. This forms a strong adhesion that works well on wet tissues and easily seals the wounds.
This surgical glue containing hydrogel, which is a network of gummy material mixed with water, and can dissipate energy through its matrix layer. This enables the surgical glue to deform before it breaks. Furthermore, other pressure sensitive tapes usually lose their adhesion in wet conditions, but the hydrogel patch is designed in a way that the matrix layer containing calcium ions is bound to the hydrogel with ionic bonds. This gives the surgical glue an unmatched level of adhesive strength in wet conditions.
This high-performance surgical glue has various potential applications in the medical field. There are other surgical adhesives with similar chemistry that are under development. The challenge that lies ahead for the researchers is to ensure the biodegradability of the surgical glue and work out ways for its large-scale manufacture. These types of materials need to undergo years of testing before surgeons could one day glue tissues together without sutures or even seal a hole in the human heart.
Written by Preeti Paul, MS Biochemistry
Reference: Jeffery M. Karp, A Slick and Stretchable Surgical Adhesive, Clinical implications of basic research, N ENGL J MED 377;21 Nov 2017.
