A Blood-Resistant Surgical Glue for Minimally Invasive Repair of Vessels and Heart Defects

A light-activated, biodegradable adhesive seals cardiovascular defects in the presence of blood flow and could be useful during minimally invasive surgery. Light-Activated Adhesive Seals Tissues An easy way to repair vessels or attach devices to tissues would be welcomed by surgeons. An adhesive, for instance, can reconnect tissue and interface prosthetics, but currently available materials have limitations such as low strength, high toxicity, and most do not function well in wet environments. In response, Lang and colleagues developed a new biomaterial glue that is biocompatible, biodegradable, and easily manipulated. This material, called poly(glycerol sebacate acrylate) (PGSA), when combined with a photoinitiator, creates a solution that the authors called HLAA: hydrophobic light-activated adhesive. The HLAA is a thick gel that can be slathered on a tissue and then cross-linked within seconds by ultraviolet light, which is a unique feature that avoids stitches. The resulting bond is water-tight yet flexible and stays intact in the face of high pressure and flowing blood. The authors first tested their material in rats, showing that the HLAA could be used to attach a polymer patch to the heart and that the HLAA alone could seal up defects in the heart wall, performing as well as sutures. Lang et al. then moved into pigs, whose hearts beat at similar rates to humans (by contrast, rats have much higher heart rates). Lang et al. showed that the light-activated adhesive could attach a patch to the interventricular septum of a pig’s beating heart and that this patch remained in place even under higher than normal heart rates (induced by adrenaline). Additionally, the HLAA alone was able to immediately close up defects in the pig carotid artery without any bleeding complications. The light-responsive adhesive performed well in several different in vivo scenarios, suggesting its broad applicability in the clinic, at least for cardiovascular surgeries and defects. As an added bonus, components of PGSA—namely, glycerol and sebacic acid—exist in the body and are readily metabolized. It is expected that this material could be translated soon to use in people. Currently, there are no clinically approved surgical glues that are nontoxic, bind strongly to tissue, and work well within wet and highly dynamic environments within the body. This is especially relevant to minimally invasive surgery that is increasingly performed to reduce postoperative complications, recovery times, and patient discomfort. We describe the engineering of a bioinspired elastic and biocompatible hydrophobic light-activated adhesive (HLAA) that achieves a strong level of adhesion to wet tissue and is not compromised by preexposure to blood. The HLAA provided an on-demand hemostatic seal, within seconds of light application, when applied to high-pressure large blood vessels and cardiac wall defects in pigs. HLAA-coated patches attached to the interventricular septum in a beating porcine heart and resisted supraphysiologic pressures by remaining attached for 24 hours, which is relevant to intracardiac interventions in humans. The HLAA could be used for many cardiovascular and surgical applications, with immediate application in repair of vascular defects and surgical hemostasis.