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Aimed at preventing wound healing disorders, the technique was developed by researchers at the Swiss Federal Laboratories for Materials Science and Technology (Empa) and ETH Zurich.
Suturing a wound with a needle and thread does not always achieve what it is supposed to, the researchers said – in very soft tissues, the thread can cut through the tissue and cause additional injury. If the wound closure does not seal on internal organs, permeable sutures can pose a life-threatening problem.
Soldering usually involves joining materials together using heat via a melting bonding agent. Narrow temperature limits for biological materials and difficulty measuring the temperature in non-invasive ways has held back use of soldering processes in medicine, however.
The researchers set out to change that by first developing a wound closure process in which laser soldering can be controlled gently and efficiently. For this purpose, they developed a bonding agent with metallic and ceramic nanoparticles and used nanothermometry to control the temperature.
The new soldering process is based on the interaction of the two types of nanoparticles in the bonding protein-gelatin paste. When the paste is irradiated by a laser, titanium nitride nanoparticles convert the light into heat.
The specially synthesized bismuth vanadate particles in the paste act as tiny fluorescent ‘nano-thermometers’, emitting light of a specific wavelength in a temperature-dependent manner, allowing extremely precise temperature regulation in real time.
“This makes the method particularly suitable for use in minimally invasive surgery, as it does not require stirring and determines temperature differences with extremely fine spatial resolution in superficial and deep wounds,” an Empa announcement said.
Working with surgeons from the University Hospital Zurich, the Cleveland Clinic in the US and Charles University in the Czech Republic, the team reportedly achieved fast, stable and biocompatible bonding of wounds on organs such as the pancreas or liver in laboratory tests with tissue samples. They also soldered challenging pieces of tissue, such as the urethra, fallopian tube or intestine.
The team also succeeded in replacing the laser light source with gentler infrared (IR) light. This could bring the soldering technology closer to being 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,” said Empa researcher Inge Herrmann.
The work was published in the journal Small Methods. The team has applied for a patent.
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