The Technology Behind Adhesys Medical
The Adhesys technology is entirely synthetic. It contains two main components: an entirely synthetically manufactured polyurethane prepolymer, which is functionalized with reactive isocyanate groups, and an amino-based curing agent. Both components are provided in a two-chambered syringe.
The polyaddition reaction begins as soon as the components are mixed in the syringe’s static mixing unit. Application of the product generates a transparent film that is easily applied to the injured tissue. The syringe’s spreader tip allows for a broad and targeted application over the wound site.
As soon as the pre-polymer mixes with the secondary amine acid based curing agent, a polyaddition reaction begins. Upon mixture, the components cure quickly, adhering to the tissue via mechanical and physical adhesion, forming a strong, yet flexible film. There is no reaction with the tissue itself. A strong polymer network is quickly formed and full polymerization is completed after a few minutes.
Based on this unique technology two product lines have been developed, one for use on the skin (CUTIS) and one for use inside the body (VIVO), which exhibit different properties.
CUTIS is an elastic, biocompatible, high-strength topical skin adhesive. Based on polyurethane, its chemical characteristics differ from commonly available cyanoacrylate-based adhesives, allowing for use in unprecedented settings.
VIVO, which is designed to stop bleeding, seal wounds and reinforce suture lines is additionally biodegradable and has a shorter setting time. This allows for quick sealing and use in bleeding situations.
Adhesys Medical holds 10 patents, allowing for fine-tuning of several properties of the technology for specific medical indications. These major tunable characteristics include viscosity, curing time and degradation time. In addition, the Adhesys sealants exhibit the following unique properties:
Biocompatibility and Biodegradability
Although entirely synthetic, the Adhesys technology is biocompatible. On the skin, the adhesive causes no relevant exothermic or inflammatory reaction, nor itching or redness. In comparison to existing topical glues based on cyanoacrylate, it forms an elastic film like a second skin, providing maximum patient comfort. The product normally peels off by itself after a few days after natural wound healing is completed.
Using VIVO inside the body, the risk of infection is virtually eliminated. Unlike sealants or hemostats based on human or animal components such as fibrin sealants, the product does not carry the risk of transmitting infectious diseases. Studies have shown the product’s safety and efficacy in a long-term setting (6 month preclinical study). Furthermore, contrary to currently available synthetic sealants, VIVO is biodegradable.
Given the chemical composition of the technology, the rate of degradation and the processing and curing time can be fine-tuned to meet the specific requirements of certain indications. Consequently, the technology allows for the development of a wide range of applications, tailored to each specific need.
Contrary to currently used surgical sealants, the Adhesys sealants can be used in wet spaces, opening up a wide variety of new application areas, such as venous or arterial bleeding. Not only can the Adhesys sealants be applied to wet surfaces, but the material’s reaction time is even accelerated. Due to its hydrophilic nature, bodily fluids accelerate the polymerization time and the wound is sealed even faster.
On the skin, the curing time is adjusted to allow for 30 seconds of wound edge adjustability after application in order to ensure maximum alignment of the wound edges.
Inside the body, the curing time is set to provide for quick sealing and hemostasis even in emergency situations. Notably, the fully synthetic adhesive does not react with the blood or the surrounding tissue, but forms a mechanical seal, independent of the body’s clotting cascade. This allows for use even on slightly bleeding wounds, where the current standard of care has significant shortcomings, but where having an effective adjunct to traditional methods of achieving hemostasis is most critical.
On the skin, the adhesive’s high viscosity allows it to be applied to uneven areas without running. A thick layer can easily be applied in one a single pass, creating safe and secure wound closure. Multiple applications are therefore not necessary. Furthermore, the honey-like viscosity prevents the glue from infiltrating into the wound and causing misaligned wound edges. The glue remains at the intended site and alignment of wound edges is possible in the first 30 seconds of application.
Inside the body, the sealant can be applied precisely to the intended area, even on hard to reach or uneven surfaces. Furthermore, the high viscosity ensures it stays in place, even in the presence of blood and the spreader tip allows for precise application to the wound site. Currently available medical fibrin-based sealants, are significantly less viscous and are therefore often washed away by high blood loss or are difficult to apply in a targeted manner.
In a tensile strength test (ASTM F2258) the adhesive reached 40-60 kPa, achieving a tensile strength comparable to that of cyanoacrylates. As a high-strength adhesive it is capable of providing safe and strong wound closure on a variety of different wounds, both on the skin and inside the body.
In ex vivo burst pressure studies in arteries and veins, the Adhesys sealants have shown to withstand pressures of up to 250mmHg. The physiological mean systolic pressure in arteries is 120 mmHg. Consequently, the adhesives are able to withstand more than the two-fold of normal pressure in arteries. As entirely synthetic adhesives, they form a strong mechanical bond with the tissue to which they are applied, forming a seal that is independent of the body’s clotting cascade.
The Adhesys sealants are highly flexible. Once polymerized, they form a flexible, transparent film. The high elasticity allows for use on a great variety of surgical wounds.
CUTIS forms a strong, yet flexible film as it polymerizes to re-approximate wound edges in areas of low tension. In particular, given the flexibility of the adhesive, risk of dehiscence, even in the event of movement is low.
On the skin, the adhesive forms a type of second skin, adapting perfectly to the underlying tissue. Unlike cyanoacrylate-based adhesives, the product is not rigid and brittle and therefore withstands movement of underlying tissue. Consequently, it has the potential to provide maximum patient comfort, while allowing for use even on moving body parts. This greatly enhances the use of topical tissue adhesives and provides for a far broader spectrum of use than is currently possible.
Inside the body, the adhesive easily withstands movements of organs and surrounding tissue. Due to its high flexibility, the risk of the wound reopening is considered minimal. Furthermore, the sealant remains soft over time, allowing for reoperation.
Ease of use
The sealants come ready-to-use in an off-the-shelf two-chamber-syringe. They require no preparation or mixing prior to use, making them suitable for instant use in case of emergencies. The syringe has an intuitive design and assembly can be completed in under 60 seconds.
In addition, the sealants can be stored at room temperature. Unlike fibrin-based sealants, they do not require refrigeration, or freezing, allowing for use on short notice. Consequently, the adhesives can be instantly applied to the wound site.
Furthermore, application of the adhesive is facilitated by the material’s high viscosity. This prevents it from running or landing on unintended areas. In addition, the intuitive device design and applicator tip make it easy to apply in a targeted manner.