CaproGlu bioadhesive is a non-toxic glue that can be applied with syringes to aid in suture closures. Light transforms the liquid glue into a sticky biorubber that bonds tissue and can dissolve drugs for long term release. The technology was designed to bond even in wet environments for repairing of arteries and internal organs.
CaproGlu bioadhesive is a non-toxic glue that can be applied with syringes to aid in suture closures. Light transforms the liquid glue into a sticky biorubber that bonds tissue and can dissolve drugs for long term release. The technology was designed to bond even in wet environments for repairing of arteries and internal organs.

Wounds or surgical incisions could be fixed back together with a new nontoxic glue that can be injected via a syringe and sets into a sticky biorubber when exposed to light. The bioadhesive, named ‘CaproGlu’ by its developers at Nanyang Technological University, Institute of Molecular and Cell Biology (IMCB), Singapore General Hospital, Universidad de Girona, University of Warwick, and PDPM-Indian Institute of Information Technology, works in wet environments, as well as dry, for repairing arteries and internal organs [Djordjevic et al., Biomaterials 260 (2020) 120215, https://doi.org/10.1016/j.biomaterials.2020.120215].

Wounds or surgical incisions are typically fixed back together with sutures or staples, which can cause nerve damage, necrosis, and tissue breakdown. As an alternative, bioglues made from animal-derived proteins and synthetic polymers are an attractive option to fix tissue back together but need to combine sometimes contradictory properties. Adhesives must bind to tissue but be nontoxic, flexible but hold tissue together firmly, and be activated instantly while having a long shelf-life. Current bioglues struggle to meet these requirements, especially on wet surfaces or inside the body.

Now Terry W. Steele and his colleagues have taken a fresh approach to the problem blending a biodegradable, food-grade liquid polymer, polycaprolactone, with light-activated chemical ‘hooks’ in the form of diazirine end groups. The novel VOC-free bioadhesive is injected into a wound with a syringe where it forms a biorubber, without a photoinitiator, in a matter of seconds when exposed to light. The biorubber does not damage tissue and can be resorbed into the body in a matter of weeks. As well as light, the bioglue can be triggered using low-voltage currents, ultrasound or heat. Because the components break down in the body, the glue never needs to be removed like metal staples and therapeutic agents can be loaded into the polymer.

“CaproGlu works on fundamentally different adhesion mechanism that does not require animal-derived products or acrylate components,” points out Steele. “[It] aims to address many unmet clinical needs that doctors are facing… [including] reconnection of arteries, local pain relief, and general repair not involving sutures or staples (which are painful to remove).”

The physical properties of the adhesive, moreover, can be tuned to the application by varying the amount of diazirine, UV dose, or concentration and type of organic filler, which can range from hygroscopic compounds such as citric acid for wet tissue surfaces, provide support for bone tissue in the form of hydroxyapatite, or prevent thrombogenesis.

CaproGlu could help the millions of patients undergoing surgery every year that require some sort of wound closure and solve tricky clinical problems such as repairing blood vessels.

“We hope to keep improving the technology so it’s easy to use and becomes a standard tool in every first aid box,” says Steele.