Chaotic vessels fabricated by fractal gelatin

A novel gelatin patterning technique applied to making capillary vessels with fractal dendrite configuration is presented. Such a chaotic tree-like pattern has been obtained by precipitating among the gelatin matrix that is spin coated on a glass substrate at room temperature. The weight percentage of the original gelatin solution is over saturated. As the temperature decreases, the gelatin crystallises and forms a natural fractal pattern extruding the film surface. The process conditions of spin coating and the gelatine concentration are varied so that the hydraulic diameters of the fractal branches are verified from 0.1 to 23 μm. The authors therefore fabricated hollow vessels by the polydimethylsiloxane (PDMS) de-moulding of the soft lithography. The water filling test of the PDMS vessel chip is done accordingly. The issue of the toxicity is also addressed.