MIT researchers have developed a new double-sided adhesive tape that can be detached from the underlying biological tissue without causing any damage. The adhesive can be peeled away by applying a liquid solution.
“This is like a painless Band-Aid for internal organs,” said Xuanhe Zhao, professor of mechanical engineering and of civil and environmental engineering at MIT.
Reinforced Weak Hydrogen Bonds to form Unbreakable bonds
Researchers realized that thin layer of water lubricates and prevents most adhesives from taking hold. The team designed the adhesive out of biocompatible polymers including polyacrylic acid, that soaks up water and quickly forms weak hydrogen bonds with the tissue’s surface, to get around a tissue’s natural slipperiness.
To reinforce the weak hydrogen bonds, the researchers embedded the material with N-Hydroxysuccinimide (NHS) esters, to form strong and long-lasting bonds with proteins on a tissue’s surface.
The chemical bonds gave the adhesive its ultra-strong grip, they were also difficult to break, and the team found that detaching the tape from tissue was a messy and potentially harmful task.
Removable Adhesive Peels-away Without Causing Tissue Damage
To make the adhesive detachable, the team added disulfide linker molecule, which can be placed between covalent bonds with tissue’s surface proteins. Disulfide linker molecule bonds can be easily severed if exposed to a reducing agent.
The researchers the identified glutathione as suitable reducing agent that was both biocompatible and able to sever the necessary bonds within the adhesive. Glutathione is an antioxidant naturally found in most cells, was able to break long-lasting covalent bonds such as disulfide, while sodium bicarbonate, also known as baking soda, could deactivate the adhesive’s shorter-lasting hydrogen bonds.
The team mixed concentrations of glutathione and sodium bicarbonate together in a saline solution and sprayed the solution over samples of adhesive that they placed over various organ and tissue specimens. In all their tests, the researchers found that they were able to peel the tape away from the tissue within about five minutes, without causing tissue damage.
Bio-adhesive Technologies to Replace Sutures
The researchers also fabricated a version of the adhesive that they etched with tiny channels the solution can also diffuse through. The design is useful for attaching implants and other medical devices. In this case, peeling the adhesive tape would require a surgeon to apply the solution around the edges, where it could diffuse through the adhesive’s channels.
The team is working with Christoph Nabzdyk, the research paper co-author, and other surgeons to see whether the new adhesive can help repair other conditions, such as hemorrhages and leaky intestines.
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Our goal is to use bio-adhesive technologies to replace sutures, which is a thousand-of-years-old wound closure technology without too much innovation,” said Zhao.
Source: Massachusetts Institute of Technology