Soldering wounds with light and nano thermometers

Sometime more than 5,000 years ago, man came up with the idea of suturing a wound with a needle and thread. Since then, this surgical principle has not changed much: Depending on the fingertip feeling of the person performing the operation and the equipment, cuts or tears in the tissue can be joined together more or less perfectly. Once both sides of a wound are neatly fixed to each other, the body can begin to close the tissue gap permanently in a natural way.

However, the suture does not always achieve what it is supposed to: In very soft tissues, the thread can cut through the tissue and cause additional injury. And if the wound closure does not seal on internal organs, permeable sutures can pose a life-threatening problem. Researchers at Empa and ETH Zurich have now found a way to solder wounds using lasers.

Once the team had optimized the conditions for "iSoldering" (English for intelligent soldering) via mathematical modeling in silico, the researchers were able to investigate the performance of the composite material. Together with surgeons from the University Hospital Zurich, the Cleveland Clinic (USA) and the Czech Charles University, the team achieved fast, stable and biocompatible bonding of wounds on organs such as the pancreas or liver in laboratory tests with various tissue samples. Equally successful and gentle was the sealing of particularly challenging pieces of tissue, such as the urethra, fallopian tube or intestine, using iSoldering. A patent application has now been filed for the nanoparticle composite material.

But the researchers didn't stop there: They succeeded in replacing the laser light source with gentler infrared (IR) light. This brings the soldering technology another step closer to be used in hospitals: "If medically approved IR lamps were applied, the innovative soldering technology could be used in conventional operating rooms without additional laser protection measures," says Empa researcher Inge Herrmann.