*2.4. Micro/Nano-Structure of Al Template*

To generate a surface with micro/nano-structure, the micro-powder blasting method and an anodization process (voltage: 30 V, 0.5 M oxalic acid, room temperature, first anodized period time: 1 h, second anodized period time: 3 h) were utilized to form nano-holes in a micro-structured aluminum template. The novelty of this work is the use of an innovative method to fabricate an Al template with micro/nano-structure. This method is easy, fast, and cheap for the production of the micro/nano-structured Al template. The surface properties of the flat aluminum or aluminum templates with various structures (micro-structure, nano-structure, and micro/nano-structure) importantly affect the cell culture that is performed on these materials. Figure 1 displays the fabrication of Al template with various structures.

**Figure 1.** Fabrication process for different structures of aluminum (Al) templates.
