Compared with monolithic materials, topologically interlocked materials (TIMs) exhibit higher toughness based on their enhanced crack deflection and deformation tolerance. Importantly, by reducing the block size of TIMs, their structural strength can also be improved due to the reduced flexural span. However, the assembly of microscale blocks remains a huge challenge due to the inadequacy of nanoscale self-assembly or macroscale pick-and-place operations. In this work, octahedral microblocks are fabricated and constructed into interlocked structures with different patterns through microfluidic channels with variable cross sections. The pattern of the interlocked panel is demonstrated to affect its strength and toughness. The failure strength and energy absorption of assembled panels significantly exceed that of their monolithic counterpart by ∼33% and ∼19.1 folds, respectively. Generally, the presented microfluidic method provides a unique technique for the assembly of interlocked architecture, which facilitates the design and fabrication of TIMs with highly improved strength and toughness.

Hemolysis usually happens instantly when red blood cells (RBCs) rupture under a high shear stress. However, it is also found to happen gradually in the extracorporeal membrane oxygenation (ECMO) under low but periodic squeezes. In particular, the gradual hemolysis is accompanied by a progressive change in morphology of RBCs. In this work, the gradual hemolysis is studied in a microfluidic device with arrays of narrow gaps the same as the constructions in ECMO. RBCs are seen to deform periodically when they flow through the narrow gaps, which causes the release of adenosine-triphosphate (ATP) from RBCs. The reduced ATP level in the cells leads to the fatigue of RBCs with the progressive changes in morphology and the gradual loss of deformability. An empirical model for the fatigue of RBCs is established under the periodic squeezes with controlled deformation, and it reveals a different way of the hemolysis that is dominated by the squeeze frequency. This finding brings a new insight into the mechanism of hemolysis, and it helps to improve the design of circulatory support devices.