With the current rapidly growing global population, the animal product industry faces challenges which not only demand drastically increased amounts of animal products but also have to limit the emission of greenhouse gases and animal waste. These issues can be solved by the combination of microfabrication and tissue engineering techniques, which utilize the microtissue as a building component for larger tissue assembly to fabricate animal products. Various methods for the assembly of microtissue have been proposed such as spinning, cell layering, and 3D bioprinting to mimic the intricate morphology and function of the in vivo animal tissues. Some of the demonstrations on cultured meat and leather-like materials present promising outlooks on the emerging field of in vitro production of animal products.

In recent years, microfluidic systems have been extensively utilized for biological analysis. The integration of pumps in microfluidic systems requires precise control of liquids and effort-intensive set-ups for multiplexed experiments. In this study, a 3D-printed centrifugal pump driven by magnetic force is presented for microfluidics and biological analysis. The permanent magnets implemented in the centrifugal pump synchronized the rotation of the driving and operating parts. Precise control of the flow rate and a wide range and variety of flow profiles are achieved by controlling the rotational speed of the motor in the driving part. The compact size and contactless driving part allow simple set-ups within commercially available culture dishes and tubes. It is demonstrated that the fabricated 3D-printed centrifugal pump can induce laminar flow in a microfluidic device, perfusion culture of in vitro tissues, and alignment of cells under shear stress. This device has a high potential for applications in microfluidic devices and perfusion culture of cells.

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The emerging interest in skeletal muscle tissue originates from its unique properties that control body movements. In particular, recent research advances in engineered skeletal muscle tissue have broadened the possibilities of applications in nonclinical models. However, due to the lack of adipose tissue, current engineered skeletal muscle tissue has the limitation of satisfying in vivo-like position and proportion of intermuscular fat. Adipose tissue within the skeletal muscle affects their functional properties. Here, a fabrication method for cocultured tissue composed of skeletal muscle and adipose tissues is proposed to reproduce the functional and morphological characteristics of muscle. By implementing prematured adipose microfibers in a myoblast-laden hydrogel sheet, both the accumulation of large lipid droplets and control of the position of adipose tissue within the skeletal muscle tissue becomes feasible. The findings of this study provide helpful information regarding engineered skeletal muscle, which has strong potential in drug screening models. K E Y W O R D S coculture, in vitro tissue, microfluidics, tissue engineering | INTRODUCTIONSkeletal muscles are major organs in mammals, accounting for 20%-50% of an animal's weight (Gunn, 1989