US scientists created surgical sutures with temperature monitoring sensors and micro-heating nanowires. They make it possible to assess the postoperative wound temperature and facilitate its healing, according to Technology Review.
Postoperative infections and complications associated with them, despite the development of microbiology, are still a great threat in more serious surgical operations. In an attempt to remedy this, a team of scientists from the University of Illinois led by Prof. materials engineering by John Rogers, has developed a solution that enables constant control of wounds and places undergoing surgical intervention.
These are “intelligent” surgical sutures, i.e. cotton surgical sutures, covered with a polymer sheath in which ultra-thin microscopic sensors are embedded, enabling continuous monitoring of the temperature and condition of the sutured wound or the site after surgery.
The sensors work similarly to RFID tags – reading data from them can be done by bringing the reader connected with a USB cable to an ordinary laptop. In a special application written for the needs of the device, the wound thermomap will be displayed with the points of the highest temperature imagined. In the application, you can also track the rate of temperature increase and the places where it grows fastest.
The solution, developed by a team of scientists from the University of Illinois, is based on silicon films, gold microelectrodes and spiral wound nanowires several nanometers thick. The silicon membrane was obtained by chemically cutting a silicon wafer intended for the production of chips. It was surgically covered with cotton or polymer threads, and then gold electrodes were placed at even intervals, and they were wrapped in a spiral with wound nanowires.
The electrodes are the working parts of two types of sensors. The first is a silicon diode that changes the direction of the current flow as the temperature rises. The second is a platinum nanomembrane resistor that changes resistance with temperature.
The second layer of nanowires served other activities. The reader can emit a small magnetic field, which slightly warms the gold wire and allows the wound to be heated locally, which facilitates its healing. The entire thread with sensors is covered with neutral epoxy resin.
All materials used in the construction are safe for the body and the greatest challenge, according to prof. Rogers, it was not so much keeping them non-toxic as maintaining the flexibility inherent in surgical sutures. This was ensured by a silicon film placed on the surface of the thread itself, which was the basis for the sensors. Smart threads can be used in the same way as ordinary surgical threads are used.
Scientists conducted a series of tests on rats which showed that smart threads can reduce wound healing time by 20%. and prevent their contamination. Currently, work is underway to integrate a wireless micromodule into the thread, which enables data transmission up to 1-2 m without the need to bring the reader closer.
Rogers’ team has broader plans. Researchers would like to develop a solution that actively supports the treatment based on the wound temperature monitoring threads – the threads would contain microcapsules, under appropriate conditions, releasing drugs that cleanse the wound and destroying anaerobes, and electrodes acting on a specific wound site with pulses enabling quick healing. Scientists hope that in this way it will be possible to reduce the possibility of infection of severe, soiled post-accident wounds and significantly accelerate the healing of even extensive injuries.
The research process of the sutures facilitating the monitoring of wounds will probably last about 1-2 years until clinical trials and about 3-5 years until the first practical applications. (PAP)
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