Hydrogel glue seals wet tissue in seconds, human trials next year

A tube of glue that holds a torn heart vessel together in seconds would change a surgeon's day. SanaHeal, a startup spun out of MIT, is building a hydrogel-based adhesive that does exactly that on wet tissue, and aims to replace the stitches and staples used in procedures ranging from heart bypasses to hernia repairs.

The problem it targets is old and familiar. Dozens of operations require joining two pieces of tissue, including triple heart bypasses, C-sections (caesarean deliveries) and hernia and tendon repairs. Most are done by hand or with robots that a surgeon controls. Small errors in suturing or stapling can cause leaks with devastating consequences. The thread and staples can also damage tissue, trigger immune responses and lead to scar tissue or infection. In microsurgery, Yuk said, needles can be thinner than a human hair.

A hydrogel is a soft gel made mostly of polymers and water. The company's material is designed to be biocompatible, so that it minimizes immune reactions and the build-up of scar tissue. Early versions behaved like double-sided tape: a polyacrylic acid, the same absorbent found in diapers, draws water out of wet tissue and holds within seconds. The current adhesive sticks to wet and uneven surfaces and forms seals that are tight to both air and fluid. Its inspiration came from sticky natural materials such as barnacles and spider webs.

The company says its technology has already received regulatory approval to stop trauma bleeding. Next year, according to SanaHeal, it will enter human trials to help control bleeding during surgery and repair various injured tissues. Those trials are the test that matters: the surgical uses have not yet been tried in patients. Yuk describes the approach as "more like a Post-it note" than suturing, which he says makes it less invasive and easier to use with surgical robots. Faster procedures, he added, could also help bring surgical costs down. That claim has not yet been measured.

For surgeons, hospitals and patients, the first beneficiaries would be the procedures where a suture is most fragile or most damaging, such as microsurgery, and the devices that already use sutureless implants, such as some hernia and nerve repairs. SanaHeal does not sell directly to surgeons: it supplies its material to larger medical device companies building products for open, laparoscopic (keyhole) and endoscopic surgeries. Whether a surgeon can reach for this glue in an operating room will depend on those human trials and on the partners who take it to market.