A new study shows that a highly elastic and adhesive surgical sealant can effectively seal wounds in shape-shifting tissues without the need for common staples or sutures.

To repair ruptured or pierced organs and tissues, surgeons commonly use staples, sutures and wires to bring and hold the wound edges together so that they can heal. However, these procedures can be difficult to perform in hard-to-reach areas of the body and wounds are often not completely sealed immediately. They also come with the risk that tissues are further damaged and infected. A particular challenge is posed by wounds in fragile or elastic tissues that continuously expand or contract and relax, like the breathing lung, the beating heart and pulsing arteries.

To remedy some of these problems, biomedical engineers have developed a range of surgical sealants that can bond tissues to stop leakages. Yet, “currently available sealants are not suitable for most surgical applications and they do not work alone without the need for suturing or stapling because they lack an optimal combination of elasticity, tissue adhesion and strength. Using our expertise in creating materials for regenerative medicine, we aimed to create an actual fix for this problem in a multi-disciplinary effort with clinicians and bioengineers,” said Ali Khademhosseini, PhD, Associate Faculty member at Harvard’s Wyss Institute for Biologically Inspired Engineering.

Recently published in the journal Science Translational Medicine, a study performed by a team led by Khademhosseini at the Wyss Institute and Nasim Annabi, PhD, at Northeastern University presents a robust solution for the efficient repair of wounds in mechanically challenging body areas. The team also included researchers from Beth Israel Deaconess Medical Center (BIDMC) in Boston and the University of Sydney in Australia. The researchers demonstrated that a sealant, based on elastin—a human, resilience-imparting protein present in all elastic tissues such as the wall of arteries, skin, and lungs—can be photochemically tuned to effectively seal incisions in arteries and lungs of rats and to repair wounds in the lungs of pigs, all suture and staple-free. Khademhosseini is also a Professor at Harvard-MIT’s Division of Health Sciences and Technology and Brigham and Women’s Hospital and Annabi is Assistant Professor at the Department of Chemical Engineering at Northeastern University and Lecturer at the Harvard-MIT’s Division of Health Science and Technology.

In 2013, inspired by the natural abilities and synthesis of elastin fibers, Khademhosseini, Annabi, who at the time was a Postdoctoral Fellow at the Wyss Institute, and Anthony Weiss, PhD, Professor of Biochemistry and Molecular Biotechnology at the University of Sydney’s Charles Perkins Centre and Faculty of Science, started to explore the regenerative capabilities of tropoelastin, the precursor protein from which the body derives functional elastin. Essentially mimicking the body’s mechanisms, the researchers learned how to produce large amounts of recombinant human tropoelastin in E. coli bacteria and, using a so-called photocrosslinking reagent named methacrylate and a pulse of UV light, they crosslinked different tropoelastin proteins in a solution to create a versatile highly elastic hydrogel they named MeTro. This work showed that MeTro could be used to generate a micro-patterned matrix to which heart cells can adhere, and be grown as tissue constructs for the potential repair of cardiac damages.

For their most recent study, the researchers further teamed up with George Cheng, MD, a pulmonologist and Sidhu Gangadharan, MD, Chief of Thoracic Surgery and Interventional Pulmonology at BIDMC. “Discussing our earlier findings on MeTro with Sidhu and George, we became aware that lung injuries in particular pose a surgical problem for which there is no convincing solution yet, and started to investigate our materials appro