Many surgeries today are performed via minimally invasive procedures in which a small incision is made and miniature cameras and surgical tools are threaded through the body to remove tumors and repair damaged tissues and organs. While many procedures can be performed in this way, surgeons face challenges when sealing internal wounds and tears.
A new medical patch can be folded around minimally invasive surgical tools and delivered through airways, intestines, and other narrow spaces to patch up internal injuries. The patch resembles a foldable, paper-like film when dry. Once it makes contact with wet tissues or organs, it transforms into a stretchy gel — similar to a contact lens — and can stick to an injured site. The tape is designed to resist contamination when exposed to bacteria and bodily fluids. Over time, the patch can safely biodegrade away. The three-layer patch comprises a middle layer of bioadhesive made from a hydrogel material that is embedded with compounds called NHS esters. The bottom layer is made from a material coated with silicone oil, which acts to temporarily lubricate the adhesive, preventing it from sticking to other surfaces as it travels through the body. The top layer is an elastomer film embedded with zwitterionic polymers, or molecular chains made from both positive and negative ions that act to attract any surrounding water molecules to the elastomer’s surface. In this way, the adhesive’s outward-facing layer forms a water-based skin, or barrier, against bacteria and other contaminants. Origami-inspired techniques were used to fold the adhesive around instruments commonly used in minimally invasive surgeries such as a balloon catheter and a surgical stapler.
Massachusetts Institute of Technology, Cambridge
Bioadhesives currently used in minimally invasive surgeries are available mostly as biodegradable liquids and glues that can be spread over damaged tissues. When these glues solidify, they can stiffen over the softer underlying surface, creating an imperfect seal. Blood and other biological fluids can also contaminate glues, preventing successful adhesion to the injured site. Glues can also wash away before an injury has fully healed and after application, they can also cause inflammation and scar tissue formation.
The researchers are working with clinicians and surgeons to optimize the design for surgical use and they envision that the new bioadhesive could be delivered via minimally invasive surgical tools operated by a surgeon either directly or remotely via a medical robot. The bioadhesive could be manufactured in prefolded configurations that surgeons can easily fit around minimally invasive instruments as well as on tools that are currently being used in robotic surgery.