Ice-lithographic fabrication of concave microwells and a microfluidic network

We describe a novel method to produce concave microwells utilizing solid-liquid phase change. This method, named 'ice-lithography', does not require any lithographic processes and consists of a few simple steps that yield multiple concave microwells. We demonstrated that the shape and size of the microwells can be controlled by varying substrates and vapor-collection time. Patterned wells with sizes in the range of 10 mu m to several millimeters in diameter could be produced. Additionally, we fabricated a uniformly aligned concave microwell pattern and a microfluidic network. Ice-lithography has potential biological and biomedical applications in areas such as the fabrication of cell docking devices and microbioreactors as well as the formation of uniformly sized embryoid bodies.