Iranian Researchers Locally Produce Silicone Stents for Lungs

In an inter-university project, researchers from Tehran University's Faculty of Mechanical Engineering, Tehran University of Medical Sciences and Shahid Beheshti University of Medical Sciences succeeded in designing, manufacturing and clicnically testing a silicone lung stent for the first time in the country.

Fabric stents, also called stent grafts, are used in larger arteries such as the aorta. Stents used in the airways of the lungs are often made of silicone.

“During the Covid-19 pandemic, in order to tackle the patients' problems, meetings were held with the doctors from University of Tehran's Medical Sciences and Shahid Beheshti University of Medical Sciences. Due to potential of the UT Mechanical Engineering Faculty, making silicone stents was prioritized in a research for our research group,” Mostafa Baghani, professor at UT Mechanical Engineering Faculty told Iranian media.

“Among the side effects of intubation in the acute stages of treatment of Covid-19 disease is damage to the patient’s respiratory tract. This injury can lead to clogging or obstruction of the airway and make it difficult for the patient to breathe. One of the ways to manage airway damage and inflammation is the use of silicone stents. These stents are in the form of flexible tubes that keep the patient's airway open and thus help patients breathe,” the professor said.

He added that due to the oppressive US sanctions, importing the product was very difficult and for that reason they prioritized locally producing it.

“Biocompatible silicone nanocomposite was used as the prime material of the stent, and the optimal percentage and manufacturing process of silicone-based nanocomposite was determined to obtain the required mechanical and surface properties,” Baghani added.

“To make the stent, the desired templates were prepared and the vacuum molding method was used,” the UT professor further explained.

“The fabricated stents were put under standard mechanical tests and after confirming the initial in vitro tests, they were used for pilot testing. Due to the similarity of human chip to sheep, sheep chip has been used for the animal pilot phase. Stenting was done using a completely new method in a special operating room," he added.

“Due to the fact that the stent is placed in the mucous membrane of the lung and the possibility of absorbing contamination is very high, the surface of the stent should be as free as possible from any protrusions or depressions to prevent the accumulation of bacteria. Also, in order to prevent the stent from moving and shifting after placement, a number of nail-like or flange-like protrusions are designed on the external surface of the stent. To make the lung stents visible in the X-ray during the procedure, gold sheets are placed inside the stent," Baghani elaborated more.

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