New Bioadhesive Stops Bleeding in 60 Seconds

Image Taken From Google Images

Millions of car accidents occur every year. For a great many of the injured, it’s the holes and lacerations in internal organs that are the most worrisome, as many people perish due to massive blood loss. Stopping the bleeding as soon as possible is vital.

A surgical glue called MeTro is a phenomenal new tissue adhesive that can potentially save millions of lives: not only does it have the usual benefits of adhesives, it can seal a wound in less than a minute. Dr. Anthony Weiss states, ‘the potential applications are powerful — from treating serious internal wounds at emergency sites such as following car accidents and in war zones… [to] improving hospital surgeries.’ Dr. Weiss is one of the key collaborators involved in the development and study of MeTro. He, along with lead investigator Dr. Nasim Annabi and others, published the results of their investigation of MeTro in Science Translational Medicine earlier this month.

Surgical glues and/or tissue adhesives are alternatives to stitches and staples used to facilitate the healing of organ wounds. They are not new: tissue adhesives have been around for quite a while and there are a variety of them. But if they have been around, why is MeTro so important? And there is a prior question: why use tissue adhesives at all when doctors can already use stitches and staples?

The Process of Wound Healing

The Phases of Wound Healing (Image taken from

When an organ wound occurs, the human body naturally begins a wound healing process in the following order:

(a) Blood Clot Formation
(b) Inflammatory Response 
(c) Tissue Formation (Proliferation)
(d) Tissue Remodeling

Once a wound is made, and a blood vessel has been injured, blood clots will form around the wound to stop bleeding from occurring. Next, inflammatory cells will arrive at the area of injury to fight off any foreign substance and stimulate tissue regeneration. Then, new tissue will form over the course of weeks and/or months depending on the severity of the injury and the individual’s healing ability. Finally, once new tissue is formed, tissue remodeling enables the new tissue to regain contractile ability and tensile strength.

The Role of Sutures, Staples, and Bioadhesives in Wound Healing

Surgical sutures, staples, wound strips, and tissue adhesives facilitate the body’s healing process by joining the wound edges. The facilitation has a few significant advantages:

A. It reduces the time it takes for the wound to heal completely.
B. It reduces the amount of new tissue formed by limiting the space between the edges.
C. It minimizes scar formation by aligning the tissue surface together.

Although all four procedures support wound healing, tissue adhesives are preferable to sutures and staples, and research has enhanced their effectiveness.

Advantages of Tissue Adhesive

Advantages of Tissue Adhesive (Image Taken from Reference Article mentioned below)

Improving medical treatments and developing new and advanced medical tools have always been vital. Tissue adhesives present several advantages to sutures and staples, which include, but are not limited to: faster application, less pain, superior cost effectiveness, and more desirable results. Scientists have developed a variety of different tissue adhesives over the years. However, the new adhesive MeTro, may be the most potent yet.

Types of Tissue Adhesives

Most tissue adhesives currently used can be classified as either Natural Polymer-Based Adhesive or Synthetic or Semi-synthetic Adhesive.

Natural Polymer-Based Adhesives are derived from proteins or complex sugar molecules. Synthetic and semi-synthetic adhesives consist of polymers (complex chains of molecules). Each group has its set of advantages and disadvantages that have to be considered before their use (see reference article).

Determinging the Effectiveness of Bioadhesive

Several factors need to be considered prior to using tissue adhesives at all. Here are four of them:

1. Biocompatibility. Is the adhesive substance is biocompatible? While the term ‘biocompatible’ is ambiguous, it is important to know whether the adhesive substance is able to interact and bind with the tissue surface molecules to carry out the desired function without significant deleterious effects. If adhesives are biocompatible, it can better facilitate wound healing.

2. Biodegradability. Is the adhesive substance biodegradable or reabsorbable? In other words, can the body eliminate the adhesive substance on its own when the new tissues have been generated? Generally, one prefers to have the body itself eliminate or recycle the adhesive substance in wound healing.

3. Inflammation or Allergic Reaction. Does the adhesive substance trigger an inflammatory response or allergic reaction? It is important to know this because such responses and reactions can cause further tissue damage.

4. Adhesive Strength. Does the adhesive have high or low mechanical strength? The higher the mechanical and tensile strength of the adhesive, the more effective it is in facilitating wound healing.

Advantages and Disadvantages of the Various Tissue Adhesives

After it’s determined that adhesives are preferable to other techniques, several other factors should be gone over in determining which adhesives are best in a particular case. For instance, natural polymer-based adhesives are generally more biocompatible and biodegradable than synthetic or non-synthetic adhesives; however they have comparably weaker mechanical strength. The following chart highlights some of the advantages and disadvantages of the different types of adhesives.

The chart above lists the various common bioadhesive currently used, as well as their advantages and disadvantages.

Advantage of MeTro

Elastin’s characteristic elasticity enables it to stretch and contract tissues and organs ( Image taken from

MeTro is a tissue adhesive that is biocompatible, is biodegradable, expresses low toxicity, and possesses significant mechanical adhesive strength. Moreover, its high elasticity makes it a versatile sealant, enhancing its adhesive function. Its elasticity is due to its protein origin: MeTro is engineered from the human protein tropoelastin, which is a subunit of the larger protein Elastin. Elastin is found abundantly in tissues, and its name comes from its characteristic elasticity which gives tissues and organs the ability to stretch and contract.

Besides its elasticity, MeTro’s fast-acting response is an additional advantage. Using UV light, the adhesive sets in within 60 seconds of application. While other adhesives are also able to respond quickly, most are unstable in fluid-filled environments and do not demonstrate the same dynamic flexibility; hence, MeTro is able to overcome the limitations of those sealants. Eurekalert states, “The material also works on internal wounds that are often in hard-to-reach areas and have typically required staples or sutures due to surrounding body fluid hampering the effectiveness of other sealants.”

While most adhesives possess a few of the most desired features, MeTro possesses all the most important ones, making it more powerful than any of the other adhesives available. Because it can meet so many urgent surgical needs, such as those resulting from serious accidents, it is the therapeutic possibilities of MeTro that make it revolutionary.

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