The preparation of the ACC-encapsulated DOX-Fe2+ complex was achieved through a simple one-step gas diffusion method. Specifically, CaCl2 (150 mg), DOX (0.4 ml, 10 mg/ml), and anhydrous ferrous chloride (0.63 mg) were dissolved in 100 ml of absolute ethanol and extensively mixed. Subsequently, the mixture solution was transferred to a glass bottle and then wrapped with parafilm containing several small holes. The vial was placed in a desiccator together with another two bottles of ammonium bicarbonate and incubated at 30°C for 36 hours. The product was recovered via centrifugation at 8000 rpm, and the precipitate was washed twice with ethanol to remove residual reagents.