Figure 10.

Fabrication of concave microwells by milling. (A) Firstly, a metallic mold was fabricated by precise CNC micromachining, and its surface was coated with polytetrafluoroethylene (PTFE)-like plasma. After that, the metallic mold was used for PDMS soft lithography to obtain the concave microwells [78]. (B) At first, a POM mold was prepared by CNC micromachining, and then used for double replica moldings of PDMS and agarose, respectively [81]. Reprinted (adapted) from [81]. Copyright (2018) with permission from Royal Society of Chemistry. (C) Pictures of a cross-section of concave microwells fabricated by the method illustrated in (A) [78]. Scale bars: 200 µm. Reprinted (adapted) from [78]. Copyright (2014) with permission from American Chemical Society. (D) Pictures of concave microwells fabricated by a similar method as that described in (B) [82]. The scale bar in the left picture shows 1 mm, and scale bar in the right picture shows 500 µm. Reprinted (adapted) from [82] under the terms of the Creative Commons CC BY license.