Han Wei-jing1, †, 
, Yuan Wei2, †, , Zhu Jiang-rui1, Fan Qihui1, Qu Junle2, Liu Li-yu1, ‡, , on behalf of the U.S.–China Physical Sciences-Oncology Alliance
, Yuan Wei2, †, , Zhu Jiang-rui1, Fan Qihui1, Qu Junle2, Liu Li-yu1, ‡, , on behalf of the U.S.–China Physical Sciences-Oncology Alliance (a) Diagram sketch of the PDMS chip. The horizontal cylinder channel between the two chambers is filled with matrigel (red). The left chamber is filled with the medium with 1.0% FBS, and the right chamber is filled with the medium with 10.0% FBS. (b) The picture shows the heterogeneous matrigel composed of matrigel I (red) and matrigel II (blue). The two sections form a funnel-like 3-D interface. (c) After the partial interface was filled with cells, the frontier cells escaped from interface confinement and produced finger-like invasions in the homogenous Matrigel, confirming the strong invasion of the MDA-MB-231 cells in heterogeneous gel space.[
