Cells, like social teenagers, like to get together in groups. Some gatherings are harmless, but in medical settings the cells' get-togethers are less like carefree soda-fuelled game nights, and more like hanging out in dark alleys committing acts of violence - if the alleys were catheters and syringes. When cells stick to medical devices they can cause potentially lethal problems like bacterial infections, cancer metastases and blood clots. To prevent cells of all kinds from hanging out in medical equipment, researchers at the National Taiwan University of Science and Technology have recently developed a novel anti-adhesive coating that can be easily sputtered onto a variety of medical tools.
The coating is a zirconium-based thin film metallic glass (TFMG), said Jinn P. Chu, a professor at the National Taiwan University of Science and Technology. Metallic glasses are metals that have a disordered atomic structure. They conduct electricity like crystalline metals, but, like glass, they soften and flow easily with heating, which makes them easy to process.
"Our coatings are used as functional materials, such as diffusion barriers in electronic devices and hydrophobic coatings," Chu said. "The reason for using zirconium as the main component in TFMGs is mainly because of its good glass-forming ability and non-toxic properties." Chu and his colleagues will speak about their research during the AVS 62nd International Symposium and Exhibition, held Oct. 18-23 in San Jose, Calif.
The researchers prepared their thin-film metallic glass coatings with magnetron sputter deposition, a thin-film coating process widely used in industrial applications, such as creating LCD TV display panels. In the process, ions from a material are forcibly ejected by bombardment with a reactive gas, such as nitrogen or acetylene, and then deposited on a target substrate. For their coating process, the researchers sputtered TFMG onto stainless steel, for the syringes and dermatome blades, and fluorinated ethylene propylene, for the catheters.
When compared to syringes that were bare or similarly coated with titanium or titanium nitride, the TFMG-coated syringes demonstrated significant reductions in platelet and cancer cell aggregation, as well as insertion and retraction forces. The anti-aggregating properties were also present in the catheters - giving them the potential to prevent blood clots during extended insertion in blood vessels - and dermatome blades, which are used to take small skin samples. The TFMG-coated blades also exhibited enhanced durability and sharpness when compared to bare dermatome blades.
Chu chalks the devices' anti-adhesive properties up to the glass coating's amorphous structure and low surface energy, which make the surface smooth and give it a low coefficient of friction.
Future work for Chu and his colleagues involves applying the thin film metallic glass to industrial machinery and energy harvesting equipment like solar cells. The coating could act as an anti-corrosion barrier that keeps water and contaminate particles out, while its non-adhesive properties could help keep the equipment clean.