Fabrication and characterization of gold microdisks for cancer treatment

Gold particles have been explored as radiosensitizers in cancer treatment due to their high-mass energy absorption coefficients and biocompatibility. However, the reticuloendothelial system recognizes and rapidly clears injected gold particles via phagocytosis from the blood circulation resulting in less than 1% of the gold particles reaching the tumor sites. Recent work has shown that disk-shaped particles are more resistant to phagocytosis in comparison to spherical particles resulting in prolonged circulation time. Here we report the fabrication and characterization of gold microdisks with varying geometries to investigate their ability to evade phagocytosis by macrophages. Gold disks of 2µm or 10µm in diameter and 20 nm or 100 nm in thickness were fabricated using photolithography, sputtering deposition, and the lift-off process and characterized by small-angle X-ray reflectivity and atomic force microscopy. The fabricated gold disks were incubated with macrophages, which enabled the study of the gold disk phagocytosis using confocal microscopy.