Treating an open wound or surgical incision with stitches can potentially cause a variety of side effects: infection, scars, or dehiscence (the reopening of a wound). In a currently developing prototype, a new form of wound treatment externally and internally acts as a bandage, combining the knowledge of gecko adhesion, and a sugar-based glue. Created by Professor Robert Langer and Jeff Carp of the Massachusetts Institute of Technology, this gecko-inspired adhesive is biodegradable, biocompatible (does not cause inflammation), and flexible for the movement of tissues and muscles (Dougherty). As a result, nanoscale adhesive suggests a promising future for simplifying surgeries and implementing an easier recovery for patients through a chemically supported design.
A gecko’s ability to climb a vertical surface relies solely on the geometrical makeup of hairs on each toe. In a grid-like pattern, each toe contains microscopic hairs called setae. These setae, once again magnified, split into triangular shaped hairs called spatulae at the tips. Millions of spatulae come into close contact to the surface, as each hair fits into the “ridges” and “peaks” of the molecular landscape. In both the surface, and the hairs of the gecko, protons and electrons continually move within the molecules. However once in extremely close proximity, an induced dipole occurs, and the molecules become either partially negative or positive. These attractions, when magnified by the millions of other spatulae contacting the surface, create stability for the gecko to climb the wall. Moving its feet parallel to the surface, the gecko is able to easily adhere to the surface, and then quickly detach its feet by pulling away perpendicularly from the surface - or at an angle of at least 30 degrees (Autumn, Peattie). The strength of the van der Waal forces attraction depends on primarily the distance between the gecko and surface. Due to the surface tension caused by water, along with cohesion, van der Waal forces do not necessarily work as well after incorporating the thin layer of water which increases the distance between the spatula and surface (Autumn, Peattie).
The strength of the force adhering the gecko to the surface can be defined by the equation Force per area (N m^(-2) )= A/(6πD^3 ) where “A” represents the Hamaker constant which relates the volume and polarizability of the molecules. Here, the surface being compared is usually a solid or liquid, which has a Hamker constant typically between 4 x 10-20 and 4 x 10-19J. As stated, the distance between the surfaces is an important contributor to the van der Waals forces present. According to the equation, and the application of van der Waals forces, the smaller the separation distance, the stronger the force; the larger the separation distance, the weaker the force (Autumn, Peattie).
Although inspired by the spatulae and intermolecular forces of the gecko, the remaining challenge for a surgical bandage would be...