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Here we report the fabrication of an internal micropump based on magnetically actuated artificial cilia (MAAC) that functions like an artificial mini-heart. The micropump can provide versatile flows in a microfluidic channel network, when the MAAC are actuated to perform a tilted conical movement. Compared to other pumping methods, this in-situ micro-pump does not need tubing or electrical connections, which reduces the usage of reagents by minimizing “dead volumes”, allows the construction of a more compact system, avoids undesirable electrical effects and accommodates a wide range of fluids.

Biological cilia are versatile hair-like organelles that are very efficient in manipulating particles for, e.g., feeding, antifouling and cell transport. Inspired by the versatility of cilia, we experimentally demonstrate the anti-biofouling capabilities of active surfaces that are partially covered with magnetic artificial cilia (MAC) using real biofouling agents - microalgae Scenedesmus sp. Actuated by a rotating magnet in a circular microfluidic chip, the MAC can perform a tilted conical motion, which generates strong local flow and leads to the removal of the algae away from the central unciliated area, creating a clean area.

The effect of crack tip blunting on the initial stages of creep crack growth is investigated by means of a planar microstructural model in which grains are represented discretely. The actual linking-up process of discrete microcracks with the macroscopic crack is simulated, with full account of the underlying physical mechanisms such as the nucleation, growth and coalescence of grain boundary cavities accompanied by grain boundary sliding. Results are presented for C*-controlled mode I crack growth under small-scale damage conditions. Particular attention is focused on creep constrained vs. unconstrained growth. Also the effect of grain boundary shear stresses on linking-up is investigated through shear-modified nucleation and growth models. The computations show a general trend that while an initially sharp crack tends to propagate away from the original crack plane, crack tip blunting reduces the crack growth direction. Under unconstrained conditions this can be partly rationalized by the strain rate and facet stress distribution corresponding to steady-state creep.

This book gives an overview of the research field of artificial cilia, a novel technology for controlling and sensing fluid flow at microscopic scales. This field is inspired by nature, namely by naturally occurring cilia which are tiny hairs covering biological cells and that are used already for over a billion years by nature to generate and sense fluid flow. The research field started less than a decade ago and has grown fast in recent years, since it offers very interesting options for flow control in lab-on-a-chip devices.

Soft-bodied locomotion in fluid-filled confined spaces is critical for future wireless medical robots operating inside vessels, tubes, channels, and cavities of the human body, which are filled with stagnant or flowing biological fluids. However, the active soft-bodied locomotion is challenging to achieve when the robot size is comparable with the cross-sectional dimension of these confined spaces. Here, we propose various control and performance enhancement strategies to let the sheet-shaped soft millirobots achieve multimodal locomotion, including rolling, undulatory crawling, undulatory swimming, and helical surface crawling depending on different fluid-filled confined environments. With these locomotion modes, the sheet-shaped soft robot can navigate through straight or bent gaps with varying sizes, tortuous channels, and tubes with a flowing fluid inside. Such soft robot design along with its control and performance enhancement strategies are promising to be applied in future wireless soft medical robots inside various fluid-filled tight regions of the human body., Science Advances, 7 (27), ISSN:2375-2548