Fabrication of silver microstructures via electrohydrodynamic inkjet printing as customizable X-ray marker in bio-structure for biomedical diagnostic imaging

X-ray markers have been applied for diagnostic purposes in the medical imaging field. However, they were not flexible enough to accommodate the fast evolution of biomedical applications leading to a considerable performance gap. EHD-inkjet printing technique as a high-resolution, low-cost, and flexible approach was used to fabricate a silver X-ray marker to fill the gap in the biomedical field. Even though X-ray characterization of bulk silver had been studied, silver nanoink has presented a different X-ray absorption response. To understand the X-ray characterization of silver microstructures, multiple samples were fabricated. The EHD-inkjet printing system was applied to fabricate silver microstructures under optimized printing parameters, including voltage amplitude, pulse width, frequency, and printing speed. To understand X-ray characteristic differences between bulk silver and nanoink silver, experiments were designed to print a single layer and multiple layers of silver nanoink lines. Microstructures, which were e-jet printed by silver nanoink, presented different X-ray absorption rate to the bulk silver under the same radiation condition and thickness. Sub-30 μm microstructures of silver nanoink were achieved by e-jet printing; part of them will serve as the X-ray marker in bio-scaffold. This research proposed a method to bridge the e-jet printing technique with a customizable X-ray marker in bio-scaffold, which could effectively resolve the problem of flexibility, improve the resolution, and reduce the cost of manufacturing. Moreover, it supported the development of biomedical products that were fabricated by silver nanoink material, such as in vivo embedded biosensors in computed tomography applications.