Due to its appeal in the merit of no external energy input, the passive surface is widely considered to be an ideal platform for liquid transportation. Despite the considerable progress attained, achieving long-range and high-speed liquid transport on a passive surface remains challenging due to several inherent difficulties, such as the insufficient driving force and undesired energy dissipation. Here, we overcome these limitations by proposing a cellular design of wettability pattern (CWP). This CWP is composed of cells with a wettability gradient and a cascaded super-hydrophilic divergent channel, where the cells are seamlessly interconnected with each other through the channel. Utilizing the enhanced driving force and reduced energy dissipation endowed by the special wetting and geometrical design, the proposed CWP can spontaneously transport a water droplet over a distance of 100 mm, the longest distance ever reported, with a high average velocity of ∼92 mm s⁻¹. We demonstrate experimentally and theoretically that the transport distance can be further enhanced by tailoring the wettability gradient. Using a predefined CWP, we also achieve on-demand liquid manipulation. We envision that our cellular design will find numerous applications in materials science, interfacial chemistry, and biomedical research.

Liver diseases are the primary reason for morbidity and mortality in the world. Owing to a shortage of organ donors and postoperative immune rejection, patients routinely suffer from liver failure. Unlike 2D cell models, animal models, and organoids, 3D bioprinting can be successfully employed to print living tissues and organs that contain blood vessels, bone, and kidney, heart, and liver tissues and so on. 3D bioprinting is mainly classified into four types: inkjet 3D bioprinting, extrusion-based 3D bioprinting, laser-assisted bioprinting (LAB), and vat photopolymerization. Bioinks for 3D bioprinting are composed of hydrogels and cells. For liver 3D bioprinting, hepatic parenchymal cells (hepatocytes) and liver nonparenchymal cells (hepatic stellate cells, hepatic sinusoidal endothelial cells, and Kupffer cells) are commonly used. Compared to conventional scaffold-based approaches, marked by limited functionality and complexity, 3D bioprinting can achieve accurate cell settlement, a high resolution, and more efficient usage of biomaterials, better mimicking the complex microstructures of native tissues. This method will make contributions to disease modeling, drug discovery, and even regenerative medicine. However, the limitations and challenges of this method cannot be ignored. Limitation include the requirement of diverse fabrication technologies, observation of drug dynamic response under perfusion culture, the resolution to reproduce complex hepatic microenvironment, and so on. Despite this, 3D bioprinting is still a promising and innovative biofabrication strategy for the creation of artificial multi-cellular tissues/organs.