Southwest Jiaotong University

Nature has consistently inspired engineering applications. Recently, a group of researchers drew new inspirations from the vascular network and developed a new type of fluidic system named VasFluidics. The fluidic system can modulate fluid compositions via spatially-different reactions between fluids and channel walls, something that has not yet been realised in traditional fluidic systems. This work was conducted by the research team of Professor Anderson Ho Cheung Shum's Microfluidics and Soft Matter Team in the Department of Mechanical Engineering of the Faculty of Engineering. This discovery has been published in Nature Communications, titled "Vascular network-inspired fluidic system (VasFluidics) with spatially functionalisable membranous walls." "The brilliant control over blood compositions in vessels is remarkable and essential, inspiring us to think about how to design new fluidic systems," shared Yafeng Yu, the first author of the research project. The blood vascular network, a natural fluidic system, inspired the research. "Guided" by the vascular network, Professor Shum's team developed VasFluidics, a fluidic system with functionalisable membrane walls. Similar to blood vessel walls, the walls of VasFluidic channels are thin, soft, and capable of changing liquid compositions via physical or chemical means. This study demonstrates the power of VasFluidics in fluid processing. After separated channel regions are deposited with solutions or coated with enzymes, some regions of the VasFluidic channels physically allow specific molecules to pass through the channel walls, while some chemically change liquid compositions. The results are reminiscent of glucose adsorption and metabolism processes in the human body. "VasFluidics is quite different from the traditional fluidic systems. Channel walls of traditional devices are typically impermeable, and cannot work like real tissues to 'communicate' with fluids inside or outside the channel for fluid modulation." Yafeng Yu explained. The reported technique combines 3D printing and self-assembly of soft materials. The research group prints one liquid within another immiscible liquid, assembling soft membranes on the liquid-liquid interface. Besides microfluidics-related research, Professor Shum's group also focuses on soft material assembly on the liquid interface. The theoretical and experimental basis of soft materials in their previous research paves the way for fabricating VasFluidic devices. "VasFluidics has promising applications, especially for designing microtubule structures and bioinks. So it has great potential to be combined with cell engineering to develop artificial blood vessel models, which are expected to be used in biomedical applications, such as organ-on-chip and organoids," said Dr Yi Pan, a contributor to this research, previously a PhD student in Professor Shum's group, and currently an Associate Professor of the College of Medicine at the Southwest Jiaotong University. Dr Wei Guo, another contributor to this research and a Research Assistant Professor in Professor Shum's group, added: "Apart from the scientific merits and potential biomedical applications of this work, it also sparks our imagination. The vascular tissue of the human body, an efficient transport system, has been refined over millions of years of evolution. By demonstrating the potential of synthetic systems like VasFluidics to reconstruct vascular tissue, this research represents a substantial advancement in our efforts to mimic and harness the extraordinary capabilities of nature's most precise and efficient systems." Professor Shum's team has been focusing on cutting-edge microfluidic techniques to push the envelope in precise (bio)liquid control and efficient (bio)liquid sample analysis. Despite their progress in microfluidics-assisted biomedical applications, the research team refused to just settle on the traditional setups. By exploring and realising the potential of microfluidics for more efficient biofluid processing and analysis, the team realises that new paradigms in designing and fabricating fluidic devices are needed. "Our long-term goal is to utilise microfluidics to develop ultra-sensitive analysis of human body fluids, to assist precision medicine against diseases, and to benefit human health." Professor Shum said. Professor Shum foresees that the VasFluidics system will pioneer biomimetic platforms with complex fluid manipulation. "Potential biomedical applications are boundless. Examples are in-vitro modelling of biological fluid mechanics, biomolecule synthesis, drug screening, and disease modelling in organ-on-chips." He said.

Using smart technology to monitor the health, reproductivity, location, and environmental conditions of cattle can help with food safety and supply chain efficiency, but this monitoring adds energy cost to an already highly emissive industry. To combat this, researchers have designed a wearable smart device for cows that captures the kinetic energy created by even their smallest movements and uses it to power smart ranch technology. Using smart technology to monitor the health, reproductivity, location, and environmental conditions of cattle can help with food safety and supply chain efficiency, but this monitoring adds energy cost to an already highly emissive industry. To combat this, researchers publishing in the journal iScience on December 1 have designed a wearable smart device for cows that captures the kinetic energy created by even their smallest movements and uses it to power smart ranch technology. "On a ranch, monitoring environmental and health information of cattle can help prevent diseases and improve the efficiency of pasture breeding and management," says co-author Zutao Zhang, an energy researcher at Southwest Jiaotong University in China. "This information can include oxygen concentration, air temperature and humidity, amount of exercise, reproductive cycles, disease, and milk production." The team's smart ranch design involves cows wearing small sensory devices around their ankles and necks that are powered by everything cows do as they go about their regular ranch activities. "There is a tremendous amount of kinetic energy that can be harvested in cattle's daily movements, such as walking, running, and even neck movement," says co-author Yajia Pan, also an energy researcher at Southwest Jiaotong University.Once captured, the energy is stored in a lithium battery and used to power the device. "Our kinetic energy harvester specially harvests the kinetic energy of weak motion," says Zhang. The team's design is unique because it contains a motion enhancement mechanism that uses magnets and a pendulum to amplify small movements the cows make. Zhang hopes that implementing smart technology in ranches will be part of a larger effort to improve the world's food systems. "With the development of 5G technology and the Internet of Things, the operation of the entire industrial chain of the food system is more intelligent and transparent," he says. Zhang and his colleagues also tested the devices on humans and found that a light jog was enough to power temperature measurement in the device. The researchers see future applications in sports monitoring, healthcare, smart home, and the construction of human wireless sensor networks. "Kinetic energy is everywhere in the environment -- leaves swaying in the wind, the movement of people and animals, the undulation of waves, the rotation of the earth -- these phenomena all contain a lot of kinetic energy," says Zhang, "We shouldn't let this energy go to waste." This work was supported by the National Natural Foundation of China, Science and Technology Projects of Sichuan, and Science and Technology Projects of Chengdu.