Low-friction coatings on medical needles through atmospheric-pressure plasma-polymerization technology

The global needle market is growing due to an increase in the geriatric population, chronic diseases, and the high demand for vaccines. High insertion forces cause unpleasant effects on patients, needle deformation, and tissue displacement, affecting the accuracy of the methods. To reduce insertion forces, atmospheric-pressure plasma-polymerized coatings were deposited on spinal needles. The influence of liquid precursor, plasma power, precursor gas flow, and treatment time has been analyzed. To avoid plasma-polymerized coatings detached after the injection test, it is necessary to apply a precursor that not only has antifriction molecules (siloxane) but also has particles that promote the durability of the coatings (amines). N1-(3-trimethoxysilylpropyl)diethylenetriamine (TRIAP) was the most effective, reducing insertion-extraction forces regarding noncoated spinal needles, by 75% and 50%, respectively.