Glowing particles help guide the process of soldering wounds closed
While sutures and staples suffice for closing most wounds, they can damage delicate tissue, plus they may allow fluids to leak out when applied to internal organs. Scientists have thus set about improving an alternative wound-closure method known as tissue soldering.
Putting it simply, tissue soldering is an experimental technique in which a gelatinous paste is applied to the pressed-together edges of a wound, then heated with a laser.
The heat causes the paste to polymerize and bond with the collagen in the underlying tissue, forming a flexible watertight seal which holds the wound closed until it heals. Not only is the process typically faster yet gentler than applying sutures or staples, it also produces less inflammation, less scarring, and provides better protection against infections.
That said, complications may occur if the paste isn't heated to just the right temperature. If it's too cold, it won't bond with the tissue properly, whereas if it's too hot, it will burn the tissue.
In an effort to address that problem, scientists from Switzerland's Empa and ETH Zurich research institutes have developed an albumin-based paste called iSolder (intelligent solder). It contains titanium nitride and bismuth vanadate nanoparticles – the former convert laser light into heat, whereas the latter fluoresce when heated to a precise temperature.
So, when a gelatinous sheet of the iSolder is applied to a wound and then exposed to laser light, it will visibly glow upon reaching the just-right temperature at which it bonds with the underlying tissue. This takes the guesswork out of tissue welding – surgeons just keep applying the laser light until the paste glows, then stop when it does.
Working with colleagues from the University Hospital Zurich, Cleveland Clinic (US) and Charles University (Czech Republic), the scientists have successfully used the technology to seal wounds in the small intestine, urethra, fallopian tube and renal vein of piglets. And as an added bonus, it was found that infrared light could be used as a safer alternative to potentially harmful laser beams.
A paper on the research – which was led Oscar Cipolato and Inge Herrmann – was recently published in the journal Small Methods.